My Long Tube header build

[xnamerxx]

Well I figured I would start here just to let everyone know that I've started step one on my long tube header build and got the parts needed to make it. Hopefully I can get this finished in the next couple of weeks as I need a few parts cut.

[tooter]

I'll be following your exhaust project with great interest. Be sure to post lots of pics. :thumbsup:

[xnamerxx]

Thanks, I've had this design on paper for a while so its finally time to move forward.

I should have the flange cut some time next week...kind of surprised how close my design was from working from some random dimensions I found on the internet and looking at pictures. The only problem I'm running into now is that 1.375" mandrel U-Bends are ridiculously difficult to find but otherwise everything else is pretty much ready to move forward.

The only thing left I really need to get a hold of is a stock manifold so I can jig everything up and get the basic shape tacked in place then test fitting and fixing everything in place and finish machining the flange so its surface can take a gasket.

[tooter]

If I was going to build a header, I'd get one of these cheapies off Ebay for $59 and free shipping... :smile:

http://i.ebayimg.com/t/4-1-STAINLESS-RACING-MANIFOLD-HEADER-EXHAUST-06-10-TOYOTA-YARIS-VITZ-DOHC-1-5L-/00/s/NzAwWDcwMA==/$(KGrHqV,!pcE9eMM4r4ZBPZ7mnkClg~~60_58.JPG

...chop off the tubes and use the factory machined ready-to-bolt-on flange, 4 to1 collector, O2 sensor bung, and two bolt gasketed fitting for your own long tube header. It's worth more than that just as separate parts. :thumbsup:

[xnamerxx]

Most of the cheapies use 1.5" tubing which is way way to large for this engine so you'll end up with a huge loss of torque and a powerband that's to high up. I initially thought of that but the material cost of the header isn't all that expensive and buying SS to modify that thing isn't worth it.

I'm building it out of regular carbon steel even making the flange myself and all in it should be less than 300 dollars for metal plus the 3-4 hours its going to take me to weld everything up.

I'm actually working on a 4-2-1 header, so I can make it small enough to fit before the second cat.

[tooter]

Most of the cheapies use 1.5" tubing which is way way to large for this engine so you'll end up with a huge loss of torque and a powerband that's to high up. I initially thought of that but the material cost of the header isn't all that expensive and buying SS to modify that thing isn't worth it.

I'm building it out of regular carbon steel even making the flange myself and all in it should be less than 300 dollars for metal plus the 3-4 hours its going to take me to weld everything up.

I'm actually working on a 4-2-1 header, so I can make it small enough to fit before the second cat.

Oh, I see. Very well thought out. :thumbsup:
Steel should be easier to work with. I'll enjoy seeing what you come up with.

[Viperoni]

When I finally build mine, it's going to be a 1.5" to 1.75" to 2.0" 4-2-1 header. From the numbers, it's a bit big, but it will be 30-36" long, so the power band should peak in the 4-5k area.

Can't wait to see your build! :)

[xnamerxx]

All i'm going to say is 1.5" is really really big for initial primaries if you're dead set on that I'd set it from 1.375 to 1.5. Going to big on the primaries is bad but going to small isn't necessarily.

Overall I think the length is close to 30" but my peak torque spot shouldn't change only get a few % higher.

[tooter]

I notice that you're SoCal, namer. How will you deal with smog tests?

[xnamerxx]

Since my setup still has a cat it should pass but I'll likely just swap back the stock parts for the smog test.

[cali yaris]

pics pics pics

[subscribed]

[1.5]

There was a race header in works pre-hack so glad someone's finally going through it!

[xnamerxx]

I'll try to get as many pics as possible :wink:

I think that was richard holdener's header. I looked at his design for initial inspiration but there was a few things here and there I felt that could be improved. The 4-1 design works and it works really well but I can accomplish the same performance if not better in a lighter/smaller 4-2-1 package, the only downside being that a 4-2-1 is more expensive to make due to all the collectors required to make it work.

[1.5]

It was his.

Well I'm sribin

[07stlYaris]

I'm not a metalurgist but the ebay one is about as stainless as a hookers underwear. I bought one and am currently using it with no failure. Upon slight modification, I learned that I could weld on it with mild wire and it held up very well to a grinder. Penetration was good and rainbowing was non-existent. I would almost guess that they use the minimum possible chromium and nickel to be able to call it stainless. As soon as this header craps out, I'm using the flange to make a long tube header myself.

[Viperoni]

You can get flanges on eBay for about $30 + shipping, that's where I got my OBX flange from.

[xnamerxx]

That was originally my plan but I didn't like the sloppiness of the OBX flange from the pictures, plus being 1/2" thick would be a bitch to weld on. So I decided to draw and make my own. It's in a format the machinist likes and I should have it cut some time this week.

http://i52.photobucket.com/albums/g21/xnamerxx/1nz-feflange.jpg

[Viperoni]

That was originally my plan but I didn't like the sloppiness of the OBX flange from the pictures, plus being 1/2" thick would be a bitch to weld on. So I decided to draw and make my own. It's in a format the machinist likes and I should have it cut some time this week.

http://i52.photobucket.com/albums/g21/xnamerxx/1nz-feflange.jpg

I can definitely confirm that, the OBX flange is not cleanly cut. It will take some finessing with a die grinder to get it smooth.

[Viperoni]

Are you mating 1-4 and 2-3 for your collector pairs?

[xnamerxx]

Yes

[xnamerxx]

Looky what I have here ;)

https://sphotos-b.xx.fbcdn.net/hphotos-frc1/665607_409931399077809_1916513125_o.jpg

[tooter]

Oooh... nice. :smile:

What kind of welder are you going to use?

[Jason@SportsCar]

Great effort. Cant wait to see the results. :thumbup:

Are you going to compare it to the stock manifold, or one of the existing headers that are on the market? I have a spare DC if you want to use it for a dyno comparison.

[xnamerxx]

I'm not a strong welder, but my exhaust guy will probably tig weld everything except maybe the collectors(not sure if they can be tig welded or not).

[1.5]

ooo shiny pipes lol

[xnamerxx]

There will be a comparison to either the stock or your DC if you don't mind me borrowing it :thumbup: its gonna have to come off after a few weeks of driving around so it can be coated. Hopefully if everything goes well the machinist will have everything cut today and I can start with upper portion today.

The results should be interesting, I know what the simulation numbers say so lets see if I end up beating them ;)

[Jason@SportsCar]

There will be a comparison to either the stock or your DC if you don't mind me borrowing it :thumbup: its gonna have to come off after a few weeks of driving around so it can be coated. Hopefully if everything goes well the machinist will have everything cut today and I can start with upper portion today.

The results should be interesting, I know what the simulation numbers say so lets see if I end up beating them ;)

It is just sitting on the shelf, so happy to let you use it for the test. Being that you are going long tube, are you going to do a clamp together patch section of some type so you could get from the DC/stock collector location to your mid-pipe?

[xnamerxx]

It is just sitting on the shelf, so happy to let you use it for the test. Being that you are going long tube, are you going to do a clamp together patch section of some type so you could get from the DC/stock collector location to your mid-pipe?

I'm going to have 3-4 3 bolt flanges cut so everything can be relatively compatible with the stock mid pipe and my race mid pipe. The piece that's being cut out will be flanged along with the cut midpipe so I can swap them back and forth.
My header will retain to stock rear cat so I can drive around on the street and get all the stress out of the metal before it goes to be coated. I will be able to move back to the stock mid pipe and header with relative ease for maintenance/repairs or emissions testing.

[justjesus]

Freaking guy is thinking of everything on this!
Good job Namer!

[Viperoni]

Have you ever seen any v-band flanges that are 1-3/4"? I've never been able to find any, retail anyhow.

Are you going to do just a single flex pipe after the 2-1 transition?
Part of my 2 pipe section is going to be a pair of flex pipes - they'll be just after the tubing turns parallel to the ground, so I figure it's a good place to put them... needs tubing and help save the header at the same :)
It's the inner braided style too, so relatively low flow restriction compared to an open bellows style flex pipe.

[xnamerxx]

http://www.reidwashbon.com/racing_parts_racing_products/v-band.aspx

They aren't all that difficult to find but they are usually pricey. I wasn't going to be using a flex pipe due to packaging issues, so I'm getting around the flex problem by using a beatrush dogbone. I have just enough space to fit a ball and cone socket while still utilizing the stock rear catalyst.
I'd caution against using flex pipes in the header pipes due to the fact you can't have them coated without damaging the coating. Also you might find yourself being unable to fit 2 flex joints on the secondary pipes remember they are about an inch wider than the pipe their based off of.


I wish I could post an update but my machinist has been swamped with work, so I haven't been able to get the flange cut and the exhaust started :( I've been told I should have the part by Monday but I'm not holding my breath.

[Viperoni]

http://www.reidwashbon.com/racing_parts_racing_products/v-band.aspx

They aren't all that difficult to find but they are usually pricey. I wasn't going to be using a flex pipe due to packaging issues, so I'm getting around the flex problem by using a beatrush dogbone. I have just enough space to fit a ball and cone socket while still utilizing the stock rear catalyst.
I'd caution against using flex pipes in the header pipes due to the fact you can't have them coated without damaging the coating. Also you might find yourself being unable to fit 2 flex joints on the secondary pipes remember they are about an inch wider than the pipe their based off of.



Thanks a bunch for the link - I think Burns Stainless has them, but they are around $80 a piece. Hope these guys have them for cheaper.

I've already got the flex pipes welded onto the 2-1 merge collector :)
Off the top of my head, the total width is around 4.5", but if that ends up being a problem, I can always clock it at a 45* angle to make the package a little skinnier.

At this point, I'm not too worried about coating the header, worst case scenario I'll coat the top part and wrap the bottom.

Echo's only have one cat, so I'm lucky there, but I have other issues to contend with...

[xnamerxx]

Ahh I thought you had a Yaris...can't comment on the echo engine bay I know I'm limited width wise but have enough space for my pipes. Burns and Coastfab both have them but V bands are expensive, even the cheap vibrant ones are still 75 for the package. Burns is overprices for most everything, you can get SS and associated parts for less money elsewhere.

[Bluevitz-rs]

Any progress?

[1.5]

This + the mi intake Mani is gonna make my yaris breathe so well.

[xnamerxx]

I hope to have the flange finished today, but so far no progess :(

Once I have the flange I can start with the build and it should be a fairly quick process from there on out.

[Bluevitz-rs]

cool

[xnamerxx]

Just picked this up from the shop :thumbup:

I need to do some finish work on it but overall everything came out better than I hoped.

https://sphotos-b.xx.fbcdn.net/hphotos-ash3/543030_411878338883115_1814733367_n.jpg

[tooter]

Looks really neatol! :thumbsup:

Will you put the runners inside the flange holes?

[xnamerxx]

sorta I'm either going to flare the tube or cut and wedge the pipe in the flange. I matched the flange port diameter to that of the gasket so I don't induce any extra sharp edges that will mess up the initial shockwave from the exhaust.

I'm going to speak with the welder and see if I can get this started tonight.

[tooter]

I had a similar issue building the manifold, and had little "shelves" machined into edges of the ports to hold the runners in alignment while they were being welded up. It worked great because the weld filled in the shelf and covered it up smoothly... :smile:

http://i17.photobucket.com/albums/b90/compost_bin/car/IMG_6399_zps38f5008b.jpg

...leaving the inside relatively clean.
http://i17.photobucket.com/albums/b90/compost_bin/car/IMG_6406_zps75fd30af.jpg

[xnamerxx]

All cleaned up and ready to be welded on :)

https://sphotos-b.xx.fbcdn.net/hphotos-prn1/54698_411958745541741_2099924286_o.jpg

[xnamerxx]

Well its time for me to post a real update :smoking:
I now understand why Richard Holdener went with a 4-1 design its so much easier to package and get the correct length out of. I'm about 1/3 to about a 1/2 of the way finished with the primaries. Thank god the welder who is helping me out had experience building motorcycle race exhausts because I made some bone headed mistakes. All in all my primaries are longer than the stock primaries and my secondaries will be cake on top of that. So to keep you guys tided over here is a picture of the first tube being tacked in place.

https://sphotos-b.xx.fbcdn.net/hphotos-prn1/558866_412375418833407_625774430_n.jpg

[tooter]

It's so exciting to see your project begin to take shape. :smile:
It's like creating a work of functional art! :thumbsup:
What are you using to cut the tubing so cleanly?

[xnamerxx]

I'm a bit fortunate to have access to shop equipment but I've been cutting everything with a band saw, grinder, or belt sander.

So in order to get the clean cuts after I make the initial cut I deburr the edge of the tube both inside and out and it makes that nice clean lines, makes it way easier to weld as well apparently too. I can't take all the credit though, I'm getting lots of help from the welder on how to properly work with tubing.

I'm amazing on how much work it is to make these pipes, its been quite fun, but quite a bit of work. I wish I took some more pictures after I got the collector on but it was getting late and I needed to home. Hopefully I'll get the other 2 pipes welded up tomorrow and a initial test fit to see if everything's kosher.

Something I thought was a bit funny but my primaries right now on my tri-y header are longer than the primaries on the stock header and I still have about 2 feet of secondaries to add.

[Bluevitz-rs]

are you going to dyno the results before and after?

[tooter]

I'm a bit fortunate to have access to shop equipment but I've been cutting everything with a band saw, grinder, or belt sander.

So in order to get the clean cuts after I make the initial cut I deburr the edge of the tube both inside and out and it makes that nice clean lines, makes it way easier to weld as well apparently too. I can't take all the credit though, I'm getting lots of help from the welder on how to properly work with tubing.

I'm amazing on how much work it is to make these pipes, its been quite fun, but quite a bit of work. I wish I took some more pictures after I got the collector on but it was getting late and I needed to home. Hopefully I'll get the other 2 pipes welded up tomorrow and a initial test fit to see if everything's kosher.

Something I thought was a bit funny but my primaries right now on my tri-y header are longer than the primaries on the stock header and I still have about 2 feet of secondaries to add.

If yours going to be this long?

http://i277.photobucket.com/albums/kk54/joshua92677/K24headerTRI-Y001.jpg

(just joking :wink: )

[xnamerxx]

I have dyno results from when I was stock, but I'm going to dyno it against a DC header after its been vetted.

LOL its going to be close but thats all I'm going to say :rolleyes:

Another taste ;)

https://sphotos-a.xx.fbcdn.net/hphotos-ash3/558866_412536142150668_28904524_n.jpg

[tooter]

Is your header going to have an 02 sensor bung? I was thinking of chopping my WR header in half and adding a couple of straight tubes to lengthen it. :wink:

[MBSPE]

nice work

[xnamerxx]

It will but I'm a ways from being able to weld the bung in place. It might be difficult to extend the primary length for the WR header which is what you would want to do.

Thanks :)

[tooter]

I only was thinking about lengthening the secondaries as its easier. :bonk:
The logical place to cut would be at the first welded joint up from the bung where everything is pointing straight at each other.
http://i17.photobucket.com/albums/b90/compost_bin/car/IMG_5897.jpg

[Jason@SportsCar]

I have dyno results from when I was stock, but I'm going to dyno it against a DC header after its been vetted.

LOL its going to be close but thats all I'm going to say :rolleyes:

Another taste ;)



Good stuff, cant wait to see dyno numbers. :thumbup:

[xnamerxx]

I don't think you'll see any benefits to doing so just because the primaries are far more important than the secondaries for base scavenging.

What I would do is cut the point before the primaries join get a u bend SS in the right diameter cut and bend it so the pipes sit on top of each other like a 4-1 and pull them out about 18-30"s and use the existing merges as a way to terminate the pipes.

[Jason@SportsCar]

I only was thinking about lengthening the secondaries as its easier. :bonk:
The logical place to cut would be at the first welded joint up from the bung where everything is pointing straight at each other.
http://i17.photobucket.com/albums/b90/compost_bin/car/IMG_5897.jpg

Cut the tubes off at the flange and start over, it would be less work. :laugh: A lot of fab guys hate coming in and trying to piece stuff together from an existing part - they seem to look at it as fixing the previous guys screw up. In the end the labor to piece together cost more than building from scratch.

[tooter]

Cut the tubes off at the flange and start over, it would be less work. :laugh: A lot of fab guys hate coming in and trying to piece stuff together from an existing part - they seem to look at it as fixing the previous guys screw up. In the end the labor to piece together cost more than building from scratch.

But I'm the fab guy. :wink:

[Jason@SportsCar]

But I'm the fab guy. :wink:

You are making it to easy. :laugh: But hey, if you want to build another part with no appreciable gains for the hell of it. :evil:

The only way to know is to try, worst case you cut up a relatively inexpensive header and waste a few hours.

[tooter]

That's what life is all about... finding out. :smile:

[xnamerxx]

Well last update for a bit...I won't be able to start up on this project until next week as well as I need to get a few flanged cut to mate the 2 sections of pipe to allow installation. Again I wish I would have chosen a 4-1 design soo much easier to work with. I say this because the header path has a kink to the left and a quite narrow path that it needs to fit in.


https://sphotos-b.xx.fbcdn.net/hphotos-ash3/546934_412821935455422_478795570_n.jpg

[tooter]

Wow...:eek:
Man, that's absolutely beautiful work. :thumbsup:
Are you using a jig, or the car itself for test fitting?

[xnamerxx]

No actually, its been mostly done by eye but i needed to make a few changes last night when i was test fitting it.

[Autocross72]

Subscribe

[vten]

https://sphotos-b.xx.fbcdn.net/hphotos-ash3/546934_412821935455422_478795570_n.jpg[/IMG]



wow me likey ...any chance you'd make an extra copy for me :P ?

this and a custom midpipe, 200 cells race cat, and custom central muffler with a dual twin outlet would be noiceee!!

awesome build sir :thumbsup::thumbsup:

[xnamerxx]

wow me likey ...any chance you'd make an extra copy for me :P ?

this and a custom midpipe, 200 cells race cat, and custom central muffler with a dual twin outlet would be noiceee!!

awesome build sir :thumbsup::thumbsup:

Still working on that ;) Gotta make sure it actually makes power before I even start to think about making more.

[1.5]

oooo already a prototype. Good work Namer.

[4/20 NEVER FORGET]

Looks strangely similar to a dc header in that pic. :)

Awesome project, can't wait to see the finished product!

[xnamerxx]

Yeah i guess it kinda does...although i still need to add secondary pipes top it ;)

[xnamerxx]

Yeah i guess it kinda does...although i still need to add secondary pipes top it ;)

[tooter]

Looks strangely similar to a dc header in that pic. :)

It's a smart move to use a similar profile to the DC as it fits into the available space. :thumbsup:

[xnamerxx]

I didn't borrow from any existing designs, but with the given lengths I need to work with it just happened to follow their design.

[Jason@SportsCar]

If you find yourself needing to test fit for clearance, my car is up in the air while I wait for the struts to be serviced.

[xnamerxx]

I might just take you up on that offer. Any idea how long the car is going to be down for service?

[Jason@SportsCar]

I might just take you up on that offer. Any idea how long the car is going to be down for service?

I would guess at least another week. But it is not getting raced again until Jan, so it would not be a big deal even after I get the suspension back in.

[tooter]

I didn't borrow from any existing designs, but with the given lengths I need to work with it just happened to follow their design.

I know. It's the available space that defines the shape, so all the headers are constrained to follow the same basic conforming profile.

When you get it done, post a video of how the engine sounds with the open header. I bet it'll sound awesome! :thumbsup:

[xnamerxx]

I've got an ideal length to work with so in order to hit that ideal length while staying within the constrains of the chassis. My bends aren't quite as smooth as the DC since I've got to hit certain lengths so my bends snake a little bit which you don't quite see in the pictures.
I just decided to have the primaries terminate in about the same location as the stock header. The secondary is going to have some of that snaking as well just so I can get a few extra inches of tube length.

I'll make sure to give you a video after everything is said and done :)

[Jason@SportsCar]

Test fit. Looks good so far.

https://lh4.googleusercontent.com/--J19da11tYM/ULGAhYFt8FI/AAAAAAAABFM/TMNA-cGTD2U/s1024/2012-11-24_13-42-52_91.jpg
https://lh4.googleusercontent.com/-WOv2sARdMFA/ULGAr46PtsI/AAAAAAAABFU/V1c9d8KrCww/s1024/2012-11-24_13-43-27_140.jpg

[4/20 NEVER FORGET]

That looks awesome! Primary length looks fantastic.

Hey, quick question. How many wires does the secondary o2 sensor have? (the sensor after the 1st cat) Thanks!

[xnamerxx]

4

[tooter]

It looks like the tubing is oriented very nicely... :smile:

By the way, what mm inside diameter tubing are you using? And had you considered using twin runner bolt on connector plates similar to this one to make your header two-piece?

http://www.z1auto.com/images/tomiokatwinscrollwrxsti.jpg

[xnamerxx]

The 2 halves will be flanged so it can be installed.
The tubing diameter is 1 3/8 for the primaries.

[malibuguy]

looks good. where are you going to locate the flex joints?

ive still havent decided if i want to build one as well, or go turblose. if the motor seems to respond very well to your header, i may stay n/a

[tooter]

The 2 halves will be flanged so it can be installed.
The tubing diameter is 1 3/8 for the primaries.

That's just about the same as the 36mm Weapon R tubing. I'm really curious how much you'll gain by the longer runners. You definitely have the principles of performance working in your favor. :smile:

[xnamerxx]

Its going to terminate at the flexjoint. There is only so much power that the exhaust, but with that being said there is a serious restriction with the exhaust. This mod will really pair well ecu tuning so I may not see a whole lot of power over existing ots headers, I should see a ton more torque over any of the existing pieces which is one of the reasons I decided to build this.

[Bluevitz-rs]

I'm quite certain you're going to snap the header if you move the flex joint that far down the line. The reason the joint is where it is, is because of the engine movement. If you try and move it that far down, it'll either break away at the head or break the joint where the stock flex joint should be located.

[cali yaris]

http://4.bp.blogspot.com/-SRnNgNfHXNA/TxXkWWeDypI/AAAAAAAAETM/23Z_dY3a1jA/s1600/orville-redenbacher-logo.jpg

[xnamerxx]

The stock motor doesn't have a flex joint, it uses a ball and socket joint. The reason the joint is located where it is stock is because that's the easiest and cheapest place to put it. There does have to be some flex in the exhaust and ideally it should be as close to the motor as possible but you work with the space you're given.
The exhaust itself is hung which allows some movement there so the only reason you even need flex in the exhaust itself is to reduce the wagging motion of the main pipe and reduce load from the header. If you look at the header there is a support beam the bolts to the block and the header and that's what's carrying most of the fore and aft load from the header which is another reason why the ball and socket is located where it is. I've done some analysis on this I have an idea of where the load is sitting. If the side bracket isn't in place all of the load will sit on the flange and the failure will be located on the flange, if the side bracket is in place the pipes are thick enough to handle most of the load but the secondary flange will still be taking some load under movement but its substantially less with the flex joint in place. So to get some flex I chose a flex joint over a ball and socket because its easier for me to incorporate it the multiple center section exhausts that I have.

[1.5]

:biggrin:

[xnamerxx]

Well the primaries are all welded up so I'm stuck waiting for my new flange to be made but once I get that piece it'll be finished quickly.

[xnamerxx]

https://sphotos-a.xx.fbcdn.net/hphotos-ash4/302778_415444348526514_503160693_n.jpg

So nice and purdy :smile:

[tooter]

:drool::drool::drool:

When you weld stainless steel, does the electric welder need to use any gas?

[xnamerxx]

I can't directly comment since I'm a pretty terrible welder but SS requires a different kind of gas and filler material.

I guess it depends on if you're using a Flux weld material or MIG/TIG welding. If its MIG or TIG you need gas otherwise it'll splatter and sugar really bad plus just weld like crap.

I think this might be helpful (http://www.brazing.com/techguide/procedures/stainless.asp)

[Viperoni]

https://sphotos-a.xx.fbcdn.net/hphotos-ash4/302778_415444348526514_503160693_n.jpg

So nice and purdy :smile:

Lookin good!

[xnamerxx]

Here are my baseline numbers. The car is stock aside from a DC header, MI pulley, and a K&N air filter.

I'm guessing Toyota breathed a little extra magic on my car when it was made.

Also an acceleration run in 2nd gear from 12-62 mph. Just to get an idea of vehicle acceleration, another thing to add aside from dyno numbers.
http://www.youtube.com/watch?v=dquJkQfjUYM&feature=g-upl

https://sphotos-b.xx.fbcdn.net/hphotos-ash3/73250_416426188428330_741163314_n.jpg

[Bluevitz-rs]

Looks like they did a 2nd gear pull. Makes the numbers inflated, but it's only for comparison. As long as you use the same dyno.

[xnamerxx]

Yeah, Church's is known to dyno high as well, I think he uses a gear correction for torque to negate which gear the pull was made. The numbers just seemed high to me even if I took 15% off.

I got a kick out of it because I was making the same amount of power as Jason up until his cams started doing their thing.

BTW my motor has 100k on the clock so it shows how impressive these engines are even after a long life of use.

[Jason@SportsCar]

Yeah, Church's is known to dyno high as well, I think he uses a gear correction for torque to negate which gear the pull was made. The numbers just seemed high to me even if I took 15% off.

I got a kick out of it because I was making the same amount of power as Jason up until his cams started doing their thing.

BTW my motor has 100k on the clock so it shows how impressive these engines are even after a long life of use.
I was 132hp on that dyno with a stock motor, just had an ECU on you. My pulls were in 3rd gear.

[xnamerxx]

Hmm, he showed me a side by side and there was a big boost at 5k or so, and he said it was because of the aftermarket cam.

[Jason@SportsCar]

Hmm, he showed me a side by side and there was a big boost at 5k or so, and he said it was because of the aftermarket cam.
Not sure what he showed you, but it had to be old if the number was that low. Likely from when we first got the car and had the camcon. And none of the cams have made low end, they all lost tq, they dont start to make power till way up high.

[xnamerxx]

No the number was way higher than mine but the curves were really similar up until 5k or so than yours sort of shot up by 15 or so and kept climbing.

[Jason@SportsCar]

No the number was way higher than mine but the curves were really similar up until 5k or so than yours sort of shot up by 15 or so and kept climbing.

I misunderstood. Yeah most of the stuff we did to the engine would not help for autocross, we just could not find tq. Maybe your header will change that.

[xnamerxx]

Well if everything goes according to plan I should have the new header finished and running next week.

[malibuguy]

The stock motor doesn't have a flex joint, it uses a ball and socket joint. The reason the joint is located where it is stock is because that's the easiest and cheapest place to put it. There does have to be some flex in the exhaust and ideally it should be as close to the motor as possible but you work with the space you're given.
The exhaust itself is hung which allows some movement there so the only reason you even need flex in the exhaust itself is to reduce the wagging motion of the main pipe and reduce load from the header. If you look at the header there is a support beam the bolts to the block and the header and that's what's carrying most of the fore and aft load from the header which is another reason why the ball and socket is located where it is. I've done some analysis on this I have an idea of where the load is sitting. If the side bracket isn't in place all of the load will sit on the flange and the failure will be located on the flange, if the side bracket is in place the pipes are thick enough to handle most of the load but the secondary flange will still be taking some load under movement but its substantially less with the flex joint in place. So to get some flex I chose a flex joint over a ball and socket because its easier for me to incorporate it the multiple center section exhausts that I have.

the motor mounts in our cars are incredibly soft & these motors go all over the place. a flex joint at the end of a 3-4foot long 'lever' would not be adequate.

to get an idea of how much front scratchers (FWDs) boucne about. go to your local test-n-tune with all the kids beating the fuck out their cars...its quite alarming.

the flex joint NEEDS to be located as close as possible to the motor to reduce the leverage on the rest of the exhaust, period. the further away it is, the less its able to absorb.

[xnamerxx]

the motor mounts in our cars are incredibly soft & these motors go all over the place. a flex joint at the end of a 3-4foot long 'lever' would not be adequate.

to get an idea of how much front scratchers (FWDs) boucne about. go to your local test-n-tune with all the kids beating the fuck out their cars...its quite alarming.

the flex joint NEEDS to be located as close as possible to the motor to reduce the leverage on the rest of the exhaust, period. the further away it is, the less its able to absorb.

I've measured a touch over 2.5",on the rev limiter, of movement. With that being said it doesn't matter in my case since my roll mount will have been taken care of.

Yep, but you can't package a a flex joint in the location it needs to be in with joints that are a proper diameter.

[tooter]

the motor mounts in our cars are incredibly soft & these motors go all over the place. a flex joint at the end of a 3-4foot long 'lever' would not be adequate.

to get an idea of how much front scratchers (FWDs) boucne about. go to your local test-n-tune with all the kids beating the fuck out their cars...its quite alarming.

the flex joint NEEDS to be located as close as possible to the motor to reduce the leverage on the rest of the exhaust, period. the further away it is, the less its able to absorb.

It took me a while to catch onto what you're getting at, malibu. It's like a lever. The farther away you are from the axis of rotation, the more movement there is. I'd never even considered this as a factor.

[tooter]

I can't directly comment since I'm a pretty terrible welder but SS requires a different kind of gas and filler material.

I guess it depends on if you're using a Flux weld material or MIG/TIG welding. If its MIG or TIG you need gas otherwise it'll splatter and sugar really bad plus just weld like crap.

I think this might be helpful (http://www.brazing.com/techguide/procedures/stainless.asp)

Thanks for the useful info, namer. :smile:
I only have a flux core welder with no gas, so that won't cut it. If I need anything done, I'll just go to the pro welder who does the manifolds.

[xnamerxx]

Flux core welds look like crap but you should be able to weld SS with it as long as you have the correct filler.

There's also quite a bit more that needs to be considered with header design, just welding longer tubes can actually result in power loss if it calls into a dead range where the reverse shockwave happens too quickly or too slowly. There are other things to consider in regards to load and heat and such but that would quite a bit of time to type out.

[Viperoni]

I've measured a touch over 2.5",on the rev limiter, of movement. With that being said it doesn't matter in my case since my roll mount will have been taken care of.

Yep, but you can't package a a flex joint in the location it needs to be in with joints that are a proper diameter.

I've already got the 2-1 section of my header welded up, and it's mostly made up of a pair of 10" long, 1.75" ID flex pipes. Should allow for tons of flexibility, right where it's needed.

[xnamerxx]

I'm tired of arguing this point. There is lots of math and formulas to determine the best length and diameter for a header. The formula I use specifies something different than what you chose to use. With the dimensions I chose I cannot package a flex pipe on the secondaries and wouldn't do so because laminar flow is substantially worse through a flex pipe than a tube. If you look inside a flex pipe there is a series of baffles which make it behave similar to that of a crush bent tube.

[Bluevitz-rs]

What we're all trying to get at is that we hope it works, but would hate to see it crack because of how you designed it without any flex in it.

On that note have you considered the use of spring clamped slip joints? Laminar flow but will allow the pipes to move should they need to.

[xnamerxx]

it doesn't matter in my case since my roll mount will have been taken care of.

I'm not using the stock dog bone spring bolts flex joints are all irrelevant. The only reason I'm even considering a flex joint is to reduce exhaust noise slightly and help remove thermal growth caused by the catalyst.

My comment about the flex joint is that the bellows cause friction in fluid flow which causes turbulence which reduces flow. For that alone I wouldn't want to run them in my primaries where any slowing of gas flow can have drastic consequences.

I've done the math, run the simulations and calculated the load and stress points. I'm very confident in my design that I don't feel its going to suffer a fatigue failure.

[tooter]

Flux core welds look like crap but you should be able to weld SS with it as long as you have the correct filler.

There's also quite a bit more that needs to be considered with header design, just welding longer tubes can actually result in power loss if it calls into a dead range where the reverse shockwave happens too quickly or too slowly. There are other things to consider in regards to load and heat and such but that would quite a bit of time to type out.

That's ok. I think at this stage of the game I'll just leave everything be.

[Bluevitz-rs]

I'm not using the stock dog bone spring bolts flex joints are all irrelevant. The only reason I'm even considering a flex joint is to reduce exhaust noise slightly and help remove thermal growth caused by the catalyst.

My comment about the flex joint is that the bellows cause friction in fluid flow which causes turbulence which reduces flow. For that alone I wouldn't want to run them in my primaries where any slowing of gas flow can have drastic consequences.

I've done the math, run the simulations and calculated the load and stress points. I'm very confident in my design that I don't feel its going to suffer a fatigue failure.

Dude, you're so worked up you can't even read what I typed. I said SLIP JOINT. Not FLEX JOINT.

This is a Slip Joint.

[xnamerxx]

I skipped over that point as I assumed you thought slip joints are a way to control exhaust flex.
Yes I did consider a slip joint originally as a way to join the 2 sections of pipe but chose against it for various reasons. The biggest reason I chose against it was that slip joints are weak. In my situation there is still load traveling through the second set of pipe even though there is minimal engine movement in the exhaust its still carrying the load from the 30 lbs of exhaust and that load is effectively being distributed through only one of the pipes which doesn't have a ton of bearing area. If I was mounting the second section of pipe lower down I would probably go to a slip joint, it wasn't appropriate in my situation.

[tooter]

Would one of these help?

http://t2.gstatic.com/images?q=tbn:ANd9GcRBu7Eegy1K8XgduR4F4SneXANvqEyG_ DzYuBr6hiJDkDKXDAdsiFe9mhqqkA

[xnamerxx]

I don't know maybe. I prefer to stiffen the dogbone rather than add weight somewhere else.

[Jason@SportsCar]

I think some of you guys are loosing focus on the big picture... Build a prototype, get it on the car and see if it makes power. If needed issues like a flex joint, ball joint or the engine support can be addressed when a production piece is made.

[cali yaris]

^ +1.

The TRD Trans mount is stiffer and does more to control engine movement than the NITTO torque damper (which does work, just to a lesser degree).

[BEEF]

is this going to delete the cat and O2 sensor or just relocate it farther down the path? sorry, I am a latecomer.

I do like the idea of the longtube header. can't wait to see the finished product and dyno sheet.

[xnamerxx]

+2^ Jason

Cali do you know the durometer of the rubber used in the TRD mount?

The rules require I run a catalyst so I will have to keep that. I will be modifying my existing race mid-pipe for this exhaust system so it will accept the new collector location, but I will likely have to redesign that as there is an issue with length. The mid pipe is actually one of the bigger issues I'm still battling, there's a problem unique to this engine design that create a really bad off throttle drone.

The rear o2 will be kept since there isn't a reason to remove it, I may just weld a new bung onto the rear of the cat or use an CEL eliminator I'll probably try both and see which one is easier to keep in the long run.

[cali yaris]

Cali do you know the durometer of the rubber used in the TRD mount?

I've not been able to find that information. So the answer so far is "Stiffer."

I have the TRD engine mounts + trans mount and my motor doesn't move much at all any more. Nice and loud in the cabin too. :smile:

[Viperoni]

I have the TRD engine mounts + trans mount and my motor doesn't move much at all any more. Nice and loud in the cabin too. :smile:

I can definitely vouch for the Energy poly motor+tranny mounts doing exactly the same thing lol
The car is loud and whole car vibrates

[xnamerxx]

well no pictures but everything has been tacked together...the secondaries were way more difficult than I was expecting. All that's left is to burn everything together and my header will be done.

[xnamerxx]

Well its finally finished. I'll post a video our something later tonight.

[xnamerxx]

All I'm going to say is I'm glad i did this the seat of the pants feeling is intense

[Bluevitz-rs]

Can't wait to see it in action!!! First one!

[tooter]

All I'm going to say is I'm glad i did this the seat of the pants feeling is intense

You took an idea and made it real... that's a respectable accomplishment.:thumbsup:

Now how about some pics and videos? :wink:

[xnamerxx]

unfortunately there's not much to show right now :( I have a bit of an interference issue with my mid pipe right now and its causing the car to extra loud and annoying, but with the headers the car did get quite audibly louder even with a big 15x5" muffler its almost unbearable.

I decided against showing pictures of the completed project as its a prototype and doesn't really look all that good. in its completed form.

Driving the car around is a bit of a strange experience because in most situations the power isn't really noticed due to how the cams behave, but I can light the tires up with ease without a clutch dump, and hold it well into 2nd gear, but this has created a bit of a problem for me as I now am having trouble getting traction coming out of corners, the tires blow away at part throttle pretty easily.

I don't think I gained much top end if any, and I'm pretty sure I lost some at the bottom but in the middle it feels really really strong much stronger than a little 1.5 should feel. Again I don't want to post a video of this just yet until I figure out this interference issue.

[tooter]

I understand the process you're experiencing. There's always at least a few backward steps whenever you engage in research and development. But how the creative process itself unfolds is totally fascinating. Maybe you'll discover a new out of the box idea while you're working on overcoming obstacles. :thumbsup:

[xnamerxx]

Yeah this piece of exhaust has been a bit of a pita from the get go. The big issue is that I don't really understand acoustics, or how to control them, plus this motor is a bit extra complicated to make it that much worse. Going to a giant muffler doesn't really fix the issue and I'm not sure a resonator will either but I've got a lot more reading to do so I can fix this problem.

My car is actually louder under light throttle acceleration that it is at WOT isn't that a bitch.

I was testing the header in the private lot behind my office. This picture isn't from a clutch dump. I could have held it longer but didn't have enough space. That line is probably about 50-70ft long.
https://sphotos-a.xx.fbcdn.net/hphotos-snc7/312819_419523608118588_1893384146_n.jpg

[tooter]

Is the resonance being transmitted through actual direct contact between the header runners and the body of your car? What are you running behind your header? Is it all just pipe to the muffler? And what diameter? When you say that the car is louder under partial throttle than under full throttle, that tells me that the muffler is too large. Not in outside dimensions but the inside tubing diameter.

[xnamerxx]

Nope no contact aside from the muffler hitting the heatshield at idle making a slight rattle noise. The noise in and of itself isn't from contact but mostly due to the location of the muffler. Behind the header is a cat, muffler, and turndown or side exhaust depending on how I want to run it. The muffler is tubing diameter is 2.25" and the tubing is perforated its a magnaflow. I've had the same behavior with all the mufflers I've used the small and large ones so Idk.

The exhaust is much louder at lower rpms and high load because its a low frequency and when the motor is screaming its a higher frequency. I think its partially due to how the cam timing behaves are high load low engine speed since there is a ton of overlap.

[NJ Drive]

There's really nothing you can do to avoid low rpm drone short of adding a second muffler/resonator and having the exhaust exit at the back of the car. It's just how it is, especially on naturally-aspirated 4 cylinders.

[tooter]

Nope no contact aside from the muffler hitting the heatshield at idle making a slight rattle noise.

That's great because direct physical contact is the hardest to correct. :smile:


The noise in and of itself isn't from contact but mostly due to the location of the muffler. Behind the header is a cat, muffler, and turndown or side exhaust depending on how I want to run it.

If the end of your exhaust is terminating under the car, you'll gets lots of low frequencies. If the muffler is farther away from the termination point and closer to the header, you'll also get low frequencies. that's one reason the Yaris muffler is all the way in the back.

I have a long tube header on my truck...
http://i17.photobucket.com/albums/b90/compost_bin/toyotamotor1.jpg?t=1241891724

...and with the rest of the exhaust exactly the same, it does not make the exhaust any louder. I don't think yours is either. My guess is that noise issue lies in the rest of the exhaust.


The muffler is tubing diameter is 2.25" and the tubing is perforated its a magnaflow. I've had the same behavior with all the mufflers I've used the small and large ones so Idk.

Straight through Magnaflow, or offset? Mine is a little tiny 11 inch long 2 1/4 inch tubing Magnaflow but it's offset and very mellow.

The exhaust is much louder at lower rpms and high load because its a low frequency and when the motor is screaming its a higher frequency. I think its partially due to how the cam timing behaves are high load low engine speed since there is a ton of overlap.

In my opinion, you don't have a serious problem. The exhaust just needs a little more tinkering. You'll get it dialed in. :thumbsup:

[xnamerxx]

Well got the rattle figured out...the bolts on the collector were loose, whoops that was an easy fix.

Yeah the header is actually quieter at idle than the stock exhaust not by much but its definitely quieter. The header is currently bolted up to my race exhaust so I figured it was going to be loud and it is but the low frequencies are much worse than I was expecting. Its a straight through muffler so its not really muffling much. I'll get the exhaust figured out but I just wanted it to be mostly finished :) its been a long project.

[Golddeenoh]

with the straight through design and the fact that it end under the car instead of out the back it is no wonder that it is loud. when it exit under the car it will echo and on top of the louder exhaust design.

as for traction, I am lead from other post that our cars love exhaust and gain a lot of power. has there been any thing else done to the car? A limited slip would resolve some issues as well as handling mods (i.e. sway bars and such). what tires are you using, they might not be gripping well enough. cold tires, cold street, lower grip conditions.

[Bluevitz-rs]

The resonator makes a HUGE difference in the sound. Just an FYI.

[Flipper_1938]

Does the "race exhaust" dump under the car? or exit out the back?

[1.5]

When is dyno day?

[xnamerxx]

A couple of weeks.
Just finished an autox and a few people were convinced i had cams because if how hard this car was accelerating.

[1.5]

dang so butt dyno says big gains? I see youre leaving rubber behind lol

[xnamerxx]

Yeah I was just going over my data...the car is definitively faster than before. I actually had problems getting power down.

[BEEF]

c'mon man, just one little pic???

(please)

[xnamerxx]

I'm a bit embarrassed to d say this but i never took a picture if the final piece, only the tracked together piece. There are some changes thatwere made from this

https://photos-a.xx.fbcdn.net/hphotos-ash3/s720x720/532445_420067541397528_1944280069_n.jpg

[BEEF]

I'll take it all the same.

I like seeing projects like this come together. Reminds me a lot of tooter's intake manifold experiment. Cant wait to see the dyno sheet.

[1.5]

Soooo long!!!



^ that's what she said hehe

[Viperoni]

unfortunately there's not much to show right now :( I have a bit of an interference issue with my mid pipe right now and its causing the car to extra loud and annoying, but with the headers the car did get quite audibly louder even with a big 15x5" muffler its almost unbearable.

I decided against showing pictures of the completed project as its a prototype and doesn't really look all that good. in its completed form.

Driving the car around is a bit of a strange experience because in most situations the power isn't really noticed due to how the cams behave, but I can light the tires up with ease without a clutch dump, and hold it well into 2nd gear, but this has created a bit of a problem for me as I now am having trouble getting traction coming out of corners, the tires blow away at part throttle pretty easily.

I don't think I gained much top end if any, and I'm pretty sure I lost some at the bottom but in the middle it feels really really strong much stronger than a little 1.5 should feel. Again I don't want to post a video of this just yet until I figure out this interference issue.

Glad it's putting out some power :)

[justjesus]

glad to see this is completed.

[xnamerxx]

Yeah :) I just can't wait to get it on the dyno. All in all this project has at least forced me to learn far more about engine dynamics than I ever expected to know.

[justjesus]

"and knowing, is half the battle."

[BEEF]

G.I. JOOOOOOOOOOEEEEEEEEE.....

[justjesus]

LOL
I knew someone would get that!

[Autocross72]

Any Dyno results yet?

[xnamerxx]

Not yet, I've been out of town. I should have it done some time in the next 2 weeks depending on my schedule.

[xnamerxx]

Well the car is going in for a dyno tomorrow, anyone want to guess how much power it'll make?

Stock was 120/121.

[tooter]

Take a video of the dyno run so we can hear how it sounds. :smile:

[xnamerxx]

Will do :)

[Bluevitz-rs]

I'm going to go with 130/122.

[malibuguy]

my comment about the flex joint is that the bellows cause friction in fluid flow which causes turbulence which reduces flow. For that alone I wouldn't want to run them in my primaries where any slowing of gas flow can have drastic consequences.


that is true if your using a low quality flex-joint. Ones like the premium Vibrant units feature a very smooth liner that is not restrictive at all.

Im glad you got it all done & i cannot wait to see the results!

[xnamerxx]

To everyone that said I needed a resonator to fix my issue, you're dead on the money. I got bored today and decided to kludge the stock muffler than the stock mid pipe onto my short/light exhaust just to see what would happen. First I stuck the stock muffler on and the exhaust sound didn't really reduce pretty much none at all it was quite loud, than I stuck the mid pipe on there and while at idle was quieter it still wasn't all that quiet but during revving the it lost that annoying low pitched drone and sounded pretty nice. Looks like I need to add a resonator to this exhaust to fix the low pitched drone.

[malibuguy]

^ look into the Hushpower shorty. they work extremely well, and they tuck up well under our cars.

[xnamerxx]

Well the numbers are in, It gained 6.5 hp and 4.5tq over a DC Sport header. Not overly impressive but there was some decent gains in midrange torque.

A video of the dyno run.

http://www.youtube.com/watch?v=fpkgkDjwHVg A

[JustDidIt]

Well the numbers are in, It gained 6.5 hp and 4.5tq over a DC Sport header. Not overly impressive but there was some decent gains in midrange torque.

A video of the dyno run.

http://www.youtube.com/watch?v=fpkgkDjwHVg A

Still pretty awesome! Did u ever get it Dyno'd b4 u put the DC header on and again with the DC header installed?

[JustDidIt]

Sounds good also, any chance of seeing the print out of both dyno runs?

[tooter]

Nice gains!!! :respekt:
In which gear did you do the runs?

[Absolutely Red 12]

Well the numbers are in, It gained 6.5 hp and 4.5tq over a DC Sport header. Not overly impressive but there was some decent gains in midrange torque.

A video of the dyno run.

http://www.youtube.com/watch?v=fpkgkDjwHVg A

Not bad, how's the AFR?
LTHs are prone to lean.

[xnamerxx]

I have a dyno from before but its not comparible. All runs were done in 3rd gear that was actually an issue today. There was a slight lean spot but it was still very safe. Illl post the sheet later tonight.

[Autocross72]

Where is the chart?

[xnamerxx]

Spaced On That Sorry.
http://i52.photobucket.com/albums/g21/xnamerxx/IMG_20121228_113727_576_zps0f8a908f.jpg

[xnamerxx]

Remember these gains are over a dc header and the car doesn't have a cai or tune. I'd expect some healthy gains with a tune on top of this and another 2-5 with a cai. These numbers also represent fwhp not whp. I'm also mostly shocked that I didn't have any noticeable powerloss anywhere in the powerband.

Dynapack dynos need to be calibrated for a gearing so it doesn't matter which gear it was run in. The numbers appear high because they are typical of what you would be seeing at the crank not at the wheels, so typically you'll need to take about 9% off to get typical dynojet numbers and 15% off for a Mustang dyno.

[Viperoni]

SICK!!!!

Are the different lines the runs from the previous (DC header) run?

[discomark10]

Good work, looking forward to see the finished item!

[vten]

This is awesome !! I have my car supercharged and dynoed on a 4wheels dynojet and made 125whp and 128lbft.......not that much different from this but a lot more Moolah spent !!

Any chance to make a copy of the header?

[xnamerxx]

The lower lines were from the DC header run the upper lines are from my header.

You can see the VVTI freakouts on the runs with the green line between 5k-5.7k but overall it performed about as I expected. Now I just need some tuning and a CAI and I'll probably get another 7-15 hp from it :)

[xnamerxx]

I am looking at making additional header but have some issues I haven't quite figured out yet. My welder is down for making additional ones and I have all the models for the flanges and tubes, but the big issue I have is that most CNC bending shops require I buy at minimum of a certain amount of tube bends which would make it extremely expensive to reproduce so that's the big thing that I've been trying to figure out.

[thebarber]

This is awesome !! I have my car supercharged and dynoed on a 4wheels dynojet and made 125whp and 128lbft.......not that much different from this but a lot more Moolah spent !!

Any chance to make a copy of the header?

You can't compare your #'s to his. I ran intake, header, res-back exhaust and supercharger to 135whp and 130wtq....ran 106whp/107wtq same dyno, different year with just intake and exhaust

[vten]

Wait ... I'm confused .

Xnamerxx, those number you posted , are those on the wheel # or on the crank #?
What mods did u do beside that long tube header ?

@barber : if the number he posted is on the wheel hp # , then I guess I have a really weak engine .... I have the AEM CAI, weapon r header, blitz supercharger, nitto mid and exhaust .

[malibuguy]

very solid gains, congrats! I guess i'll be making my own header now to replace my Weapon-R...

[Viperoni]

The lower lines were from the DC header run the upper lines are from my header.

You can see the VVTI freakouts on the runs with the green line between 5k-5.7k but overall it performed about as I expected. Now I just need some tuning and a CAI and I'll probably get another 7-15 hp from it :)

It'd be sweet if you could gain more power from it for sure.

The best part is that you're up 5lbft at ~2700rpm and still up by that much near redline... SOLID gains!

[thebarber]

@barber : if the number he posted is on the wheel hp # , then I guess I have a really weak engine .... I have the AEM CAI, weapon r header, blitz supercharger, nitto mid and exhaust .
Every dyno is different

[xnamerxx]

This dyno is a reflection of engine hp not wheel hp so the numbers appear kinda high. A dynojet is roughly 9% lower than this and a mustang is roughly 15% lower. Every dyno is different but I chose a dynapack because its far more consistent since there are less variables that will affect it.

Aside from exhaust changes I have a drop in air filter and a lightweight pulley. There is no other changes to the motor. With a supercharger you'll likely see minimal gains from a header since forced induction cars don't really scavenge, its far better to just go with the biggest tubes available and have them be large enough to take the total cylinder volume with total psi added that would be far more beneficial.

Yeah when I speced the header with the software I was running, I chose a powerband between 2500-5800 which is exactly what I ended up with, I was actually a bit surprised on how accurate that number ended up being but it was supposed to be.

A word of warning I would advise against this unless you feel comfortable running a solid/semisolid torque strut mount. Even with flex joints in place there is nothing that allows them to move for and aft so the exhaust will end up moving in 3 dimensions up down forward and backward and flex joints will only help in the up and down and you'll still end up with interference issues. Its not so much an issue with acceleration movement but deceleration movement as the motor moves a ton when you downshift or brake hard, far more than when you bang it off the rev limiter and it shifts everything up into the tunnel which you have less clearance to the floor. If you want to get an idea of how much movement you actually have get a camera pointed at the dogbone get in the car and slowly load the motor up until it stalls, you'll see the rubber twist a considerable amount. In essence you'll end up with the mid pipe hitting the chassis with the stock torque strut mount on deceleration.

This project has kinda shown me why no company has produced one of these before, its not that gains can't be had because its clear they can, there are just quite a few drawbacks to doing this.