My Long Tube header build

[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.

[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.

[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]

Originally Posted by xnamerxx

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.

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...


...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.

[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

[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.