Megan Header Dyno Results

[ChinoCharles]

WEEEEEEEEE

2663

What a fun experience man... I got to shoot the shit with the guys from Twisted Innovations and talk about this car and other cars. I learned a lot.

As far as the results, their printer was down so they are e-mailing me the sheets tomorrow. The gain was 3 or so horsepower, but that doesn't tell the whole story of what the header does. There was also a steady 3 ft/lb gain in the torque curve that came on quick and stuck around for a few thousand RPM. There was no net torque gain though. We did both runs in third gear.

It was funny... we first ran the car in fourth gear and got a whopping 125 HP to the wheels! I was so confused! As the boys said, though, "the dyno doesn't lie." It was even calibrated a couple of weeks ago, so for a second we were stumped. Then one of the guys in the shop said that some of these fuel efficient pump gas cars have two overdrives to save some MPG's. Anyone know if that is the case with the Yaris?

The third gear runs had us in the 105 HP range. I'm sure if we had done the tests in first gear we would have been in that 70-80 WHP range that is documented. Either way, we got the gains.

The guys at TI seemed excited about the prospect of having the car in their shop, and hopefully I will be working with them to develop some more parts for the car. You'll see threads popping up in the appropriate forums meant to gague interest in certain parts. If you see something posted that you would like to be on the market, post in the thread, because they're watching.

I'll post the actual sheets tomorrow.

[vodkalush]

cant wait for the print outs! Like I said in the GB thread I wish i had the extra cash during the GB.... :frown:

[Nutzoids]

Congratulations man… I am beyond Jealous!

:evil:

[acrbill]

They are correct, 4th and 5th are overdrive gears. 105WHP is super strong considering the Scion guys are around 78whp.

[spkrman]

wow 105 to the wheels???

this is a swap from the stock header to the megan, while retaining your other mods...which your mods are all listed in your sig?

[Katana]

Great results!

[Notthy[Yaris/S]07]

105? awsome

[redglare45]

Sweet! Can't wait to see the dyno sheet

[ChinoCharles]

wow 105 to the wheels???

this is a swap from the stock header to the megan, while retaining your other mods...which your mods are all listed in your sig?

105 to the wheels in third gear. In fourth gear she puts 125 to the wheels! HAHA. I'l bet if she actually could get air in and out third and fourth gear would be really fun!

And yes, my mods are all listed in my sig.

[eco]

Only 3 ponys more,Im sorta let down,was hoping atleast 5.Well my car is in the shop today to get its ne custom 2.5" cat back,plus the header is being installed,I wish I could get my hands dirty on this one,but I curently have no welder,and I figured let them get the header while theyre at it.I have no dyno that I know of near me,I would love to actuall see some final numbers when Im done,I just might have to get them done at the NOPI car show next year.

[Fastnx]

It sounds like they were not using a pickup to read actual RPM.

A properly set up dyno reads the engine's RPM so gearing does not matter. whether you are in first, second, third, fourth or fifth gear, the dyno will know the RPM the engine is at, instead of just guessing.

Since going from 4th gear to 3rd gear yielded a lower power reading, this makes me think they are not using an RPM pickup. The hp numbers appear to be lower since the wheel speed is lower (hp=rpm*tq/5252).

The 105 at the wheels number is obviously not accurate, there is no way there is only a 3hp driveline loss. This means the 3hp gain that was noticed is also slightly overstated. Perhaps 3hp at the crank is a more accurate figure.

Either way, I am glad to see positive gains. Looking forward to seeing the dyno graph.

[ChinoCharles]

They were using a pickup to read RPM's. By the way, I had to giggle when I saw she idles at 600 RPM. Wow.

I'm still dying for someone to explain the differences in HP from gear to gear... or just confirm that the car has multiple overdrives.

[CASTREX]

Get those graph posted asap! I agree those numbers dosen't sound right. The HP's shouldn't go up and down when changing gears. Did this dyno concidered the atmosferic variables for correcting horsepower and torque to a known standard?

[riceboy]

Can't wait to see the data sheets...

[ChinoCharles]

Yeah, I just called and the shop is closed. They must have taken the night off... they were there until 11 PM last night, so I could understand. Looks like y'all sit in suspense for another day! HAR HAR!

[nevermorez]

Damnit, I just missed the Megan Header GB. Can I still get one though? Where should I buy it from?

[ChinoCharles]

Get the NST crank pulley instead. Better gains for the money.

Oh, and when you do get the header, get it from the generic seller on Ebay. Its a tad cheaper.

http://cgi.ebay.com/ebaymotors/Performance-Exhaust-Header-Toyota-Yaris-06-07-2006-2007_W0QQcmdZViewItemQQcategoryZ33633QQihZ012QQite mZ220066681746QQrdZ1QQsspagenameZWDVW

[nevermorez]

Get the NST crank pulley instead. Better gains for the money.

Oh, and when you do get the header, get it from the generic seller on Ebay. Its a tad cheaper.

http://cgi.ebay.com/ebaymotors/Performance-Exhaust-Header-Toyota-Yaris-06-07-2006-2007_W0QQcmdZViewItemQQcategoryZ33633QQihZ012QQite mZ220066681746QQrdZ1QQsspagenameZWDVW

Pardon my ignorance. Wut does crank pulley do actually. I thought header was a must upgrade for yaris.

[ChinoCharles]

With the Yaris, they're all a must upgrade... haha.

A lightened crank pulley will do two things for an engine.

[1] It will increase power (both HP and TQ) through the entire powerband
[2] It will increase throttle response, directly decreasing 0-60 times

Most mods increase HP or torque in one specific area of the powerband. That header specifically increased HP by 3 at the high end and torque by 3 at the low end. I will have the dyno results online very soon so you can see this. A crank pulley will increase HP and torque throughout. If you gain 8 HP at 1000 RPM, it will be there at 5500. Same with torque.

It is the same theory behind a lightweight rim. Since there is less mass to rotate, your car will be faster as you shave more pounds off of your wheel weight. Now, think about a pulley directly connected to your crankshaft that weighs 60% less. That 60% weight savings transfers into power gained, but in all reality the power was always there... you're just giving your engine the means to perform to its full potential.

You can view various dyno sheets in the group buy thread. The header is wonderful (trust me, I have it!) but I'm betting the pulley will be a better bang for the buck.

[nevermorez]

Alright, I'm SOLD! I'll sign up the GB. :D

[punch]

[QUOTE=ChinoCharles;45729]With the Yaris, they're all a must upgrade... haha.

A lightened crank pulley will do two things for an engine.

[1] It will increase power (both HP and TQ) through the entire powerband
[2] It will increase throttle response, directly decreasing 0-60 times

a lightened pulley will not increase hp!

[spkrman]

increase power to the wheels, yea :)

[Chris07LB]

Nice Charles! :clap:

[johnnyfive]

Oh, and how about that low end? 3 ft'lbs of torque straight through, and the HP curve just shifted upwards 2-3 HP. All in all, not a bad start to a full exhaust.

looks like it lost torque, and HP almost all of the way through....well, up until 5k'ish rmp...

[ChinoCharles]

OK! First of all, thanks to Mike from NST for talking me through how to interpret these sheets. I was way off.

Second of all, I will apologize beforehand for making some false claims about the header results for the past 24 hours or so. Like many of you, I'm learning ... now allow me to explain.

First, results.

STOCK THIRD GEAR PULL
2690

THIRD GEAR PULL W/ HEADER
2691

ALL RESULTS ON ONE GRAPH
2692

The first time I read the graphs, I immediately assumed the higher curves on the third graph had to be the header. I mean, we wouldn't spend money on this part to lose power, right? WRONG. We did lose power! Sure, by the numbers we didn't. Notice at the very end of the graphs at about 6000 RPM the header curves catch up and surpass the stock. For all intents and purposes, this piece can be advertised as providing an increase in HP and torque... about 2-3 HP and 2-3 ft/lbs respectively. However, that gain at the top end comes at a price, which can easily be seen through the first 5500 RPM.

This is typical of mods like this... specifically intake and exhaust mods. They do provide gains on the top end, but overall the price is often far greater than they payoff. I'm still not convinced this is the case with this header. The numbers seem to sway that way, but there is more to a car than horsepower and torque, and I'll be spending the next few days trying to understand every little nuance associated.

So again, sorry for not being as observant as I should. Like I said before, this has all been a huge learning experience, and it culminated with this information.

Allow me a day or two to contact TI and verify this information once again. I am also going to do some research and have Kevin help me explain why the numbers are a bit inflated.

Thanks one last time to Riceboy for hooking up the Group Buy, Twisted Innovations for doing the testing and letting me use their garage like I worked there, Mike at NST for your help in explaining the results, and Megan Racing for bringing us a header.

[eco]

Well I got my cat back and header insatlled,I have no dyno,but I do notice an improvment,Im guessing that header needs more room to breath.Now we need some serious effort in a full exhaust system,or a 1 stage or 3 stage high flow cat.

[ChinoCharles]

Now we need some serious effort in a full exhaust system,or a 1 stage or 3 stage high flow cat.

I'm working on it. :biggrin:

[Nutzoids]

ChinoCharles Thanks for the Dyno Lesson... Like you I am learning as much as possible and those will help me greatly!

As far as the apologies... No need man, I know what its like to get excited and to hear something but not understand, and instead of pushing just assume its on the positive end... Everyone here knows you love your car, and you just let the excitement carry you away... At least from my point of view... That is no reason to feel bad or apologize!


:evil:

[vodkalush]

thats it i can never trust another thread or post by ChinoCharles

:biggrin: :thumbup: :rolleyes:

[ChinoCharles]

ROFL! Fuckin' ball busters.

This makes 1337 posts. If you're a nerd, you understand why that is funny.

[acrbill]

That sucks man. I just looked at those pics of the stocker and the Megan side by side and I just can't understand how you lost power. Sometimes cars are strange like that.

You have to question the dyno itself though. Its obvious that the numbers are off since the same motor in the Scion makes ~78whp stock.

What is the rev limit on the Yaris? When peak HP comes at the end of the graph you have to wonder how much is hiding above the limiter.

[Russelt3hPirate]

new cars aren't as restricted exhaust wise.

congrats on your wise purchase.

gains will always be felt without a dyno, you wallet is positive of that.

[ChinoCharles]

acrbill, you'd be surprised how common findings like these are. It isn't hard to make a header that gains power at the top. It is, however, difficult to make a header that gains power at the top without sacrificing low- and mid-range power.

Don't question the dyno, because I've said it before and I'll say it again... the dyno doesn't lie. The reason for the inflated numbers can be explained, and will be shortly. For now, take the numbers as a ratio and apply it to our assumed 78 WHP. For all we know, though, that could also be wrong. I just saw an xB sheet today that had the car closer to 90 HP, which would be more on par with the expected 15% drivetrain loss from the stated 106 HP. If anyone has undisputed numbers proving one way or the other, now would be a wonderful time to share.

Here are a couple good reads on intake/exhaust related parts. The first has to do with a Mustang intake, and the second is all about a P&P job on a stock Celica GTS header that left the owner losing on the low end to gain up top.

http://www.musclemustangfastfords.com/projectcars/mmfp_0609_1996_ford_mustang_gt/

http://www.newcelica.org/forums/showthread.php?s=&threadid=60156

[spkrman]

the yaris doesnt have power steering, take that into account with the power output :)

[spkrman]

What is the rev limit on the Yaris? When peak HP comes at the end of the graph you have to wonder how much is hiding above the limiter.

yea, i saw the graph and wonder the same thing.

I can take it to the limiter and it doesnt feel like its losing anything up there.

[acrbill]

I have seen graphs where trq. suffers a little down low but HP gains up high are decent. I have never seen a header take power away across the board.

Is there a splitter in the stock collector? I have seen that on stock headers before. It keeps the gases on each bank separate until it gets into the mid pipe. I guess the larger primaries don't help since they are merging into the same size collector.

With a mid length header and a larger mid pipe I bet there would be significant gains.

[spkrman]

i think we'll have to wait for some of hte scion products to come on over... there are gains shown with headers over there, not sure whats up here.

[RossP]

TBH I think you might have a bit of a dodgy dyno. What make was the dyno?

[gr8yaris]

From what I have learned so far from my other car projects (http://usantonio.com/Titan4x4link.htm), the exhaust mod works best in conjunction with an intake mod. Although individually, each can individually improve performance, one is inter-dependent on the other for maximum combined performance outcome.

There's really not much sense in making the exhaust diameter (e.g.: header) exit much larger if there is no current increase in the a/f volume to start with or vice-versa. Using the Bernoulli's principle (http://home.earthlink.net/~mmc1919/venturi.html), the increase in the pipe diameter does not neccessarily improve flow. However, if there is an increase in the a/f volume (because of e.g.: CAI or Forced Induction) then improving the corresponding exit (exhaust) is of proportionate benefit.

[largeorangefont]

If the individual runners are larger than stock, you will lose power until very high RPMS. On a low powered engine like this, you wont have any noticeable gains until you do other mods such as intake and full exhaust. A 4-2-1 header might be better for this application.

The design of the Megan and the OEM manifold look very similar. It looks like the Megan has slightly larger diameter runners, which would explain the results.

That being said, the OEM manifold looks pretty well designed for what it is.

[CASTREX]

Any one knows anything about the Weapon R header? That's a 4-2-1 desing. It was supposed to be out early this year.

[ChinoCharles]

Nope.

Oh, and it is official... the Dyno was OFF. Confirmed by Mustang Dyno themselves, and they will be out yet again to look at it soon.

Fourth gear in the Yaris is 0.969:1, so fourth being closest to a 1:1 gear ratio, that is the gear you should use to dyno test Yarii. Well, our fourth gear pull read at 125 HP, so that means this dyno is screwed up... off by about 40 HP. Easy to miss when tuning a 400 WHP car, but it became extremely apparent when they threw the little-Yaris-that-couldn't on there. MD's peeps are coming to look at it soon, and then I will be going back yet again to retest the car. Hopefully by then I will have the pulley in my posession so I can do before, w/ header, and w/ header and pulley runs. It would be interesting to see if the pulley can negate the low-end losses from the header.

I'm dreadfully fucking sorry for all of this.

[Fastnx]

Fourth gear in the Yaris is 0.969:1, so fourth being closest to a 1:1 gear ratio, that is the gear you should use to dyno test Yarii

Gearing does not matter.

Did you know that after the power leaves the output shaft, it goes through the final drive where it is reduced again by approximately 4:1?

[largeorangefont]

Gearing does not matter.

Did you know that after the power leaves the output shaft, it goes through the final drive where it is reduced again by approximately 4:1?

On certain types of dynos it does matter. It depends on how the dyno calculates load. They assume that the transmission ratio is 1:1

If you did the test back to back on the same day, I would consider the results valid. Even though the dyno read high, it is better than comparing before and after numbers on 2 differend dynos or different days.

[Galavoxx]

Any one knows anything about the Weapon R header? That's a 4-2-1 desing. It was supposed to be out early this year.

I was the test subject for the first header and they told me about three months. That was in November some time. They are supposed to call me when it's done. Who knows if they will. I'm just waiting...

[ChinoCharles]

On certain types of dynos it does matter. It depends on how the dyno calculates load. They assume that the transmission ratio is 1:1

If you did the test back to back on the same day, I would consider the results valid. Even though the dyno read high, it is better than comparing before and after numbers on 2 differend dynos or different days.


The first statement is correct. On Mustang Dynos, you need to know your gear ratio. I didn't know this until I got there of course, hence why we ended up doing the pulls in third. Now I know, so next time we will use fourth.

I second what you said also about the results being valid. Viewing the original results as a ratio rather than cold hard numbers, you can apply those to the expected 80 or so WHP. Having said that, we are still going to start the whole process over. I want a real baseline so I can document what each mod does to this car throughout. She wont be stock much longer.

[Fastnx]

You guys do not know what you are talking about. You are dyno newbies, I have about 30 hours of experience on a 4 different kinds of dynos.

Do you even know what a final drive is? Do you really think the wheel speed is almost the same as the crankshaft speed?


If there is an RPM pickup, you do not need to know the gear ratio.

[ChinoCharles]

First of all, settle down.

Second of all, I hardly believe 30 hours designates you as an expert there princess.

Third, I am a dyno noobie, and I don't profess to be anything else... unlike yourself, who apparently believes 30 whole hours makes you an expert. There are people that spend more time on a dyno in a week than you have in your life, my trusted tech included. Apparently he doesn't know as much as you, though.

Everyone thinks they're a fucking expert. Give me a break. Didn't your mother ever tell you no matter how much you THINK you know, there is always someone out there who knows more... or in your case, a whole lot of people.

[vodkalush]

Listen I've touched a computer and use it atleast 4hrs a week and since I've been working with them for 2yrs I am a computer expert!!!


but really, simmer. All around I think if anyones followed this thread then you would know that this is chino's first dyno experiance (unless I missed something; in which case go suck an egg) so there are bond to be some issues, and 30hrs experience does not make you an expert in anything... unless your talking about 30 straight hours of making some grilled cheese goodness.... ummm grilled cheese :drools:

either way lets try and keep it friendly boys, we're all here to learn so some mistakes are bond to happen. Well it's been fun and all but its time to go watch "Children of Men" and passout on my couch.

[largeorangefont]

You guys do not know what you are talking about. You are dyno newbies, I have about 30 hours of experience on a 4 different kinds of dynos.

Do you even know what a final drive is? Do you really think the wheel speed is almost the same as the crankshaft speed?


If there is an RPM pickup, you do not need to know the gear ratio.

I've had 130 hours across 5 dynos brands and about 10 facilities, and I'm no expert. Shut up, you don't know what you are talking about. Not every dyno in the world is a Dynojet. If that was the case you would be correct.

[Fastnx]

way to back up your opionions with facts.

Again, find out what a 'final drive' is and then see what you think.

[Russelt3hPirate]

Chino,

would you be willing to do the following?

Go back to stock, Dyno
Header, Dyno
Pulley and Header, Dyno
stock headers and pulley, Dyno

and how is the pulley making power on the yaris and not on every other car in the world? would a lightweight flywheel make more power too?

[largeorangefont]

way to back up your opionions with facts.

Again, find out what a 'final drive' is and then see what you think.

Way to back up your opinions with misinformation and crying.

GENERALLY, changing the final drive on your car shouldn't affect peak horsepower, only the curve. There are some dynos with calibrations that will change HP output if you put on a shorter final drive. This is obviously incorrect as changing the final drive does not change HP. The general consensus is to dyno the car in the gear that is closest to 1:1 to keep results similar across all types of cars. Dynoing a car in 2nd and another in 4th gear would give two completely different curves, and be an invalid comparison of the 2 cars.

[ChinoCharles]

Again, this isn't my opinion, this is the opinion of the man that owns the dyno I run at. He tells me that his particular dyno relies on the fact that the car is run in a gear that is as close to a 1:1 ratio as possible.

In 8 posts on these forums, you haven't posted one bit of usable information, so you have no room to talk about facts.

If it makes you feel any better, I had no idea what a final drive was until you mentioned it and I looked it up. Now I have yet another thing I can learn from my trusted dyno EXPERT when I see him next. Hooray.

For anyone that doesn't know and would like to...

http://auto.howstuffworks.com/differential.htm

[Fastnx]

Right, but it is important to know what final drive is and how a transmission works.

According to chinocharles, the engine's power goes through 4th gear, the speed is multiplied by 0.9xx and that's it. This is not correct.

The power goes through the clutch to the input shaft, then through a gearset to the output shaft. This gearset is different for every gear. The output shaft then travels through the differential, which reduces the engine's speed once again. Most final drives are in the 4:1 range.

So if your first gear ratio is 3:1 and the final drive ratio is 4:1, the wheels are actually travelling 1/12 the speed of the engine.

If your fourth gear is 0.9:1 and the final drive is 4:1, the engine is still travelling 3.6 times faster than the wheels.

The assumption that you have to dyno in the gear closest to 1:1 is false, since the power is going through a final drive, the wheel speed will never be close to the engine speed. If your dyno guy is telling you this, he is wrong. Just because you own and operate a dyno does not mean you know the science behind how a dyno works.

At a dyno I went to, the operator did not even know the fundamental relationship between horsepower, torque and RPM which is HP=(Tq*RPM)/5252.

[ChinoCharles]

I will definitely be going back to the dyno to retest the header. Right now my car is stock, as I have the header off to save me some work when I do go back. If the pulley is delivered before the dyno is fixed, I will be testing that too.

Since the dyno was just reading heavy, I am looking at the graphs now and thinking that if you reduce the numbers by about 25% it should be somewhat accurate. Knowing that, the header does so little on its own that I don't see much of a point in testing the car with the stock header and pulley. Whatever the pulley does with the Megan header on is going to be on par with what it does with the stock header, and that saves me having to put the car on the lift twice.

[Fastnx]

In 8 posts on these forums, you haven't posted one bit of usable information, so you have no room to talk about facts

So the only thing i know about cars is from the time I have spent at yarisworld?

I am not the typical Yaris owner. I have been involved with cars for more than two decades. I race Nissan NX2000s, I build our motors which make 270hp from 2160cc. Before that I was a race mechanic on a Formula BMW that my brother raced.

I just happen to be an environmentally responsible consumer, and consequently have an interest in Yarii. I'm on this site to find out about what is available for this car and what others have done.

Heres a pic of my racecar

http://f5.putfile.com/6/15818544834.jpg


http://f5.putfile.com/6/15818553373.jpg

[Russelt3hPirate]

Whatever the pulley does with the Megan header on is going to be on par with what it does with the stock header, and that saves me having to put the car on the lift twice.

so, you really think that pulley is going to make power to help negate the loss else where in the power band from the improperly design'd header?

wouldn't it make more sense to just buy a header that makes real power instead of trying to cover an open wound with a bandaid?

you're claiming 10hp from a pulley right?

[acrbill]

A quick google search.

http://www.awe-tuning.com/pages/faq/awefaq_main.cfm?FAQ=22
Gearing: a chassis dyno is susceptible to gearing bias. Recorded power can be affected on a dyno graph by simply running the test car in too low or too high a gear. Dyno operators should pick the trans gear that is closest to a 1:1 ratio to avoid gearing bias. This ratio is 4th gear in most cars. In a 1:1 ratio, the two gears that make up a gear set are the same size. When one is larger than the other, either in a lower gear than 1:1 or a higher gear than 1:1, there are frictional losses that translates to less power put to the wheels. Also, too high of a gear that causes the test car to go to a top speed far greater than the available fan cooling capacity will produce invalid results.

http://www.bristoldyno.com/info/procedure.htm
Many dynamometer operators go right for the gear that is the closest to a 1:1 ratio as it has the lowest drag in the gearbox and therefore the highest horsepower reading (usually) on a vehicle that is properly sized to be tested on this dyno.


There is dozens more hits that back up that being close to 1:1 is important.

[ChinoCharles]

According to chinocharles, the engine's power goes through 4th gear, the speed is multiplied by 0.9xx and that's it. This is not correct.

DEE DEE DEE!

When did I say that? Let me make the font bigger so you can read it.

My dyno tech told me that we need to test the car in a gear with a ratio as close to 1:1 as possible.

I don't even know enough about engines to say what you quoted me as saying, so please, don't put words in my mouth.

I edited the rest out because acrbill was nice enough to quote those pages for me. I knew I had read articles online backing up my tech's statements, but I couldn't find them again, so thank you Bill.

[acrbill]

So the only thing i know about cars is from the time I have spent at yarisworld?

I am not the typical Yaris owner. I have been involved with cars for more than two decades. I race Nissan NX2000s, I build our motors which make 270hp from 2160cc. Before that I was a race mechanic on a Formula BMW that my brother raced.

I just happen to be an environmentally responsible consumer, and consequently have an interest in Yarii. I'm on this site to find out about what is available for this car and what others have done.

Heres a pic of my racecar

http://f5.putfile.com/6/15818544834.jpg


http://f5.putfile.com/6/15818553373.jpg

Oh man! If you would have mentioned this earlier it would have saved some misunderstanding. Instead of thinking you where a moron we would have had proof of it.

Your obviously full of shit, and you thought you could come onto a site and pull the wool over our eyes with your supreme knowledge of all things automotive.
What you failed to realize is that we are not little kids enamored with pictures of "race cars".

Do everyone a favor and buy a Honda Fit.

[Fastnx]

A quick google search.

http://www.awe-tuning.com/pages/faq/...ain.cfm?FAQ=22

Quote:
Gearing: a chassis dyno is susceptible to gearing bias. Recorded power can be affected on a dyno graph by simply running the test car in too low or too high a gear. Dyno operators should pick the trans gear that is closest to a 1:1 ratio to avoid gearing bias. This ratio is 4th gear in most cars. In a 1:1 ratio, the two gears that make up a gear set are the same size. When one is larger than the other, either in a lower gear than 1:1 or a higher gear than 1:1, there are frictional losses that translates to less power put to the wheels. Also, too high of a gear that causes the test car to go to a top speed far greater than the available fan cooling capacity will produce invalid results.

http://www.bristoldyno.com/info/procedure.htm

Quote:
Many dynamometer operators go right for the gear that is the closest to a 1:1 ratio as it has the lowest drag in the gearbox and therefore the highest horsepower reading (usually) on a vehicle that is properly sized to be tested on this dyno.


There is dozens more hits that back up that being close to 1:1 is important

Hey, anyone can post anything on the internet, that doesnt mean it is correct.

Here, check out the flat earth society's webpage:

http://www.alaska.net/~clund/e_djublonskopf/Flatearthsociety.htm

[Fastnx]

Oh man! If you would have mentioned this earlier it would have saved some misunderstanding. Instead of thinking you where a moron we would have had proof of it.

Your obviously full of shit, and you thought you could come onto a site and pull the wool over our eyes with your supreme knowledge of all things automotive.
What you failed to realize is that we are not little kids enamored with pictures of "race cars".

Do everyone a favor and buy a Honda Fit

What, are you calling me a liar?

[largeorangefont]

What, are you calling me a liar?

Hes calling you dumb. So am I.

[ChinoCharles]

so, you really think that pulley is going to make power to help negate the loss else where in the power band from the improperly design'd header?

wouldn't it make more sense to just buy a header that makes real power instead of trying to cover an open wound with a bandaid?

you're claiming 10hp from a pulley right?

With numbers that were inflated about 25%, the graphs only showed 2 HP and 3 ft/lb losses. Assuming peak HP numbers will drop from 105 HP to around 80 HP after the dyno is fixed, the losses will be minimal... a little more than 1 HP and about 2 ft/lbs.

I don't see that as a huge tradeoff considering...

1) This is still an N/A car, and the 2.5" diameter piping on the Megan header will probably do more for the car with forced induction.
3) After 5600 RPM I'm gaining more than what I'm losing in the rest of the powerband.

Sure, my lofty hopes got shot down a tad. Lesson learned... when dealing with low displacement econoengines, don't expect much from simple bolt-ons.

10 HP from the pulley... I'm not that dumb, haha. Judging from what I've seen from the dyno results from other cars, I think 2-3 HP is a good estimate. Considering the piece is a tad over a hundred bucks and you see that 2-3 HP from 0 to 6500 RPM, I'm happy NST decided to make it.

[ChinoCharles]

+8 to the first person that finds out the final drive ratio for the NCP91.

[largeorangefont]

Here are the transmission ratios for the 5MT

Manual five-speed transmission with shift lever on floor,
3.545:1 first gear ratio,
1.904:1 second gear ratio,
1.31:1 third gear ratio,
0.969:1 fourth gear ratio,
0.815:1 fifth gear ratio
3.25:1 reverse gear ratio manual

Final drive ratio, 3.941:1

[acrbill]

tree'd

1st-3.545:1
2nd-1.904:1
3rd-1.31:1
4th-0.969:1
5th-0.815:1
final drive-3.722:1
reverse-3.25:1

[largeorangefont]

With numbers that were inflated about 25%, the graphs only showed 2 HP and 3 ft/lb losses. Assuming peak HP numbers will drop from 105 HP to around 80 HP after the dyno is fixed, the losses will be minimal... a little more than 1 HP and about 2 ft/lbs.

I don't see that as a huge tradeoff considering...

1) This is still an N/A car, and the 2.5" diameter piping on the Megan header will probably do more for the car with forced induction.
3) After 5600 RPM I'm gaining more than what I'm losing in the rest of the powerband.

Sure, my lofty hopes got shot down a tad. Lesson learned... when dealing with low displacement econoengines, don't expect much from simple bolt-ons.

10 HP from the pulley... I'm not that dumb, haha. Judging from what I've seen from the dyno results from other cars, I think 2-3 HP is a good estimate. Considering the piece is a tad over a hundred bucks and you see that 2-3 HP from 0 to 6500 RPM, I'm happy NST decided to make it.

2.25 piping is going to be the best for this car unless you are going for all out HP or forced induction.

[largeorangefont]

tree'd
final drive-3.722:1


Not saying you are wrong, but we found different final drive #s. I got mine off some canadian site. Where did you get yours? Just want to clear it up so we aren't posting misinformation.

We could figure it out mathamatically I guess but I'm too lazy, and don't have a car to veryify it yet :)

[ChinoCharles]

largeorangefont, +8. I don't know what the points means either... you'll have to ask Bigsky2. I got it from him. :wink:

To get an idea of how widely these ratios vary, a Cadillac STS-V's final drive ratio is 2.56:1. I wanted to assume most cars had a final drive ratio near 4, but that would obviously be wrong.

Now that we know this, fastnx... what the hell was your original arguement? It seemed like you were trying to say that the idea behind a dyno is to get the engine speed to match wheel speed, but there is no gear on a Yaris that comes even close to this. The closest you will come is in fifth when your ratio is 3.212:1. I'm trying to understand where you were coming from.

[largeorangefont]

largeorangefont, +8. I don't know what the points means either... you'll have to ask Bigsky2. I got it from him. :wink:

To get an idea of how widely these ratios vary, a Cadillac STS-V's final drive ratio is 2.56:1. I wanted to assume most cars had a final drive ratio near 4, but that would obviously be wrong.

Now that we know this, fastnx... what the hell was your original arguement? It seemed like you were trying to say that the idea behind a dyno is to get the engine speed to match wheel speed, but there is no gear on a Yaris that comes even close to this. The closest you will come is in fifth when your ratio is 3.212:1. I'm trying to understand where you were coming from.

It depends on the torque of the engine. Smaller displacement cars have gear ratios near 4:1 to get them up to speed better. Consequently, they run at a higher RPM on the highway.

My mustang has a 3.55 final drive, and a 6 speed transmission and at 80 MPH it is doing 2200 RPM. A Xa I test drove was doing well over 3000 RPM approaching 80 MPH.

I will explain more about how a dyno works and how gearing can affect the results after I get some lunch.

[ChinoCharles]

Thank you largeorangefont, I'm looking forward to it.

[acrbill]

largeorangefont,
when I google the transmission ratios I get hit for 3.722:1 and 3.941:1.
Perhaps

[largeorangefont]

largeorangefont,
when I google the transmission ratios I get hit for 3.722:1 and 3.941:1.
Perhaps

If you have access to a tach, get a RPM reading at 80 mph in 5th and we can figure it out. My guess is 3.9.. but I could be wrong.

[Russelt3hPirate]

If you have access to a tach, get a RPM reading at 80 mph in 5th and we can figure it out. My guess is 3.9.. but I could be wrong.


I has access to a tach :)

Defi Concept HUD in my yaris FTW! :headbang:

[largeorangefont]

Ok here is a quick and dirty version of how the dyno figures out horsepower. A dynojet is the simplest, because there is no load. The dyno takes the known weight of the roller(s) and derives hp based on how long it takes the car to get the roller up to speed. So if you have the car in 2nd for example, the roller is going to spin up faster, relative to a 4th gear pull. It is just like doing 30 on the street in 2nd gear vs 4th gear.

In real terms you *should* have the same horsepower either pull, but the curve will be very different looking. Think how the car pulls from 30 mph in 2nd vs. 4th gear, and how that will translate to a HP curve.

Some dynos will measure more horsepower just from switching a lower final drive and some don't. You arent gaing HP, but you are spinning up the roller(s) quicker. You can see how the dyno could then traslate that difference into more HP. I have personally seen this happen, and it is obviously incorrect. Alot of newer dynos are calibrated not to do this, but just be aware that is can happen.

The reason you want to use 3rd or 4th gear on a dyno pull is to put more of a load on the car. For tuning, you want to see what happens with the air fuel ratio and timing high in the load range. Tuning in 1st and 2nd does not give you an accurate picture of how the car will run in higher gears with more load.

Depending on the dyno operator and the car, sometimes shops do their tests in 3rd gear because speeds are too high in 4th on some cars. For seeing gains of a particular part, as long as you can eliminate every variable possible, you should get an accurate picture. Dynos, their calibrations, and HP numbers can vary greatly so it is not valid to compare numbers from dyno to dyno. Just think of the dyno as a tool to check gains. I would always try to go to the same dyno facility, and make sure that all calibrations are as close as possible each time you dyno for the best result.

Hope all this helps.

Ashley

[ChinoCharles]

Thank you Ashley, everything makes a bit more sense.

Mustang Dynos apply a small amount of resistance and use that load and not the mass of the roller to determine horsepower. Got it.

Russel, how do you like that HUD? It has to take some getting used to...

[largeorangefont]

Thank you Ashley, everything makes a bit more sense.

Mustang Dynos apply a small amount of resistance and use that load and not the mass of the roller to determine horsepower. Got it.

Russel, how do you like that HUD? It has to take some getting used to...

You got it. A mustang dyno is much better for tuning because you can simulate driving conditions with more realistic loads on the car, and do steady state tuning, That is more effective and accurate than using a Dynojet and doing WOT tuning.

[Russelt3hPirate]

Russel, how do you like that HUD? It has to take some getting used to...

I love it. it doesn't take anytime to get used to.

the shift light and audible beep is awesome :)

[Yaris TTE JWRC]

WEEEEEEEEE

2663

What a fun experience man... I got to shoot the shit with the guys from Twisted Innovations and talk about this car and other cars. I learned a lot.

As far as the results, their printer was down so they are e-mailing me the sheets tomorrow. The gain was 3 or so horsepower, but that doesn't tell the whole story of what the header does. There was also a steady 3 ft/lb gain in the torque curve that came on quick and stuck around for a few thousand RPM. There was no net torque gain though. We did both runs in third gear.

It was funny... we first ran the car in fourth gear and got a whopping 125 HP to the wheels! I was so confused! As the boys said, though, "the dyno doesn't lie." It was even calibrated a couple of weeks ago, so for a second we were stumped. Then one of the guys in the shop said that some of these fuel efficient pump gas cars have two overdrives to save some MPG's. Anyone know if that is the case with the Yaris?

The third gear runs had us in the 105 HP range. I'm sure if we had done the tests in first gear we would have been in that 70-80 WHP range that is documented. Either way, we got the gains.

The guys at TI seemed excited about the prospect of having the car in their shop, and hopefully I will be working with them to develop some more parts for the car. You'll see threads popping up in the appropriate forums meant to gague interest in certain parts. If you see something posted that you would like to be on the market, post in the thread, because they're watching.

I'll post the actual sheets tomorrow.

Where's the pic of your header that's installed on your car?? Can you take some pics of it installed on your car??? i really want to see it, cause im thinking to get a header too:middlefinger: :moon: .:bs: :laughabove: :bow: :bellyroll: :needpics:

[Chris07LB]

Here's some for you... Search for my How_To if you need more info.

[Doc Zaius]

Alright... I started doing a bit of poking around and reading online as to the relationship between "backpressure" and torque, and why free-flowing headers and exhaust systems can decrease the amount of low/mid torque. People assume that since a more restrictive muffler/header/whatever has higher low-end torque, then it must be because of increased backpressure. Right? Wrong! Its b/c with a smaller diameter exhaust system, the exhaust gasses move faster. These faster moving gasses produce a slight vacuum behind them, which actually helps to pull the remaining exhaust out of the cylinder. This process is known as "scavenging". Otherwise, these gasses would be left in the cylinder, displacing new, fresh air/fuel, and thereby producing less power. As the engine speeds up (higher RPM), the scavenging effect is less pronounced, and the exhaust system's ability to flow gasses makes more of a difference, which is why the megan header works very well at very high rpm.

For some better information on this, please check out the following two very good quick-reads: Exhaust: The straight scoop on backpressure (http://www.dsmtuners.com/forums/showthread.php?t=168578) and Exhaust system backpressure (http://www.mustangforums.com/archive/threads/exhaust-system-backpressure-9765-1.html). :thumbsup:

Any thoughts/comments? :biggrin:

[Moose]

Alright... I started doing a bit of poking around and reading online as to the relationship between "backpressure" and torque, and why free-flowing headers and exhaust systems can decrease the amount of low/mid torque. People assume that since a more restrictive muffler/header/whatever has higher low-end torque, then it must be because of increased backpressure. Right? Wrong! Its b/c with a smaller diameter exhaust system, the exhaust gasses move faster. These faster moving gasses produce a slight vacuum behind them, which actually helps to pull the remaining exhaust out of the cylinder. This process is known as "scavenging". Otherwise, these gasses would be left in the cylinder, displacing new, fresh air/fuel, and thereby producing less power. As the engine speeds up (higher RPM), the scavenging effect is less pronounced, and the exhaust system's ability to flow gasses makes more of a difference, which is why the megan header works very well at very high rpm.

For some better information on this, please check out the following two very good quick-reads: Exhaust: The straight scoop on backpressure (http://www.dsmtuners.com/forums/showthread.php?t=168578) and Exhaust system backpressure (http://www.mustangforums.com/archive/threads/exhaust-system-backpressure-9765-1.html). :thumbsup:

Any thoughts/comments? :biggrin:

You beat me to it.