Engine Exaust Q's

Exaust Q's

ok this is a bunch of questions in one post but they all have to do with prity much the same thing...

1 does any body have the HKS chrome 90mm outlet 60mm inlet the one on the bottom "link"

know how it sounds, performence ganes with a full system headers back etc.

2 does anybody know where I can get some headers for my 04 rolla.

3 this ones for the colorado guys, a shop where I can get piping bent and installed 2.25 inch to fit the muffler inlet flange...

4 what magnaflow highflow cat will work for me.

I'm sick of waiting for somebody to bring out an exaust so I'm just making my own

1: ...No.

2: ...Keep in mind...they just put out headers for my truck, and it's an '03. Be patient.

3: ...Any metal working shop will bend piping for you...but specifically pick an exhaust shop. There's one right over by your dad's house...they were going to do the Ravin' exhaust on the Firebird...I'm sure they could do it.

4. ...A high-flow cat will actually decrease your performance unless you install a complete exhaust system, from start to finish.

Just remember with exhaust...backpressure is your friend.

I'd rather not get into a heated argument on the basis of backpressure.

Backpressure is a 50/50 based on opinion of either friend of foe.

I happen to believe that backpressure is important. If it wasn't, everybody and their mother would run around blowing their exhaust straight out the heads.

Yeah, backpressure isn't really good or bad. The question is "how much is right for me?"
If you have too large of a diameter piping, say 3.25" on your corolla, the exhaust will become too turbulent. Exhaust exits the engine in pulses. The pulses surge through the exhaust pipe and create a "seal" against the inside of the pipe and travel out.

When there is a good "seal" the exhaust will pulse through smoothly, and create a negative pressure as it is leaving, drawing out the next exhaust pulse. If the "seal" is bad, the pulses will be too small for the diameter of pipe, and turbulence or tumbling will occur and exit will be less free flowing.

The trick is to balance a larger pipe size while keeping exhaust velocity up. So bigger pipe doesn't always mean better performance. You will actually lose low end torque with too large of pipe. A larger v8 engine would be able to put out enough exhaust pressure to use a 3.25" pipe, where a 1zzfe would lose efficiency.

So it's not all one way...

lololol so what the fuck does all this mean?

^^^ I go with a 2.25 inch pipe and i should be good

Check out this article, very helpful:

http://www.nissanperformancemag.com/august02/revenge_nerds/

I went with a 2.5 catback with a trd muffler but I lost some throttle responce. The good thing is Im ready for a turbo now but I am not sure if I lost hp or tq.

The biggest thing I'd advise you to do...
is research, research, research.

I happen to believe that backpressure is important. If it wasn't, everybody and their mother would run around blowing their exhaust straight out the heads.[/QUOTE]

Wrong. Everyone can't drive around with straight pipes because it's too loud and there's a thing called emissions. You have to have a tuned exhaust that works with the "backpressure" to create pulses that help push and pull the exhaust out. It's called scavenging, and there's a whole lot of physics involved because your getting into fluid motion.

Precisely. But it seems as if everyone I meet is "angry" at backpressure...and they blame backpressure for their exhaust problems.

My continued view on backpressure stands just at that.

A lot of people (% is far less on this forum than on the street) believe that bigger their exhaust, the less backpressure you have. From how I understand it, there is a line that you shouldn't cross on either side. You want a "negative" backpressure, where you are creating a vacuum and sucking the exhaust out (scavenging) instead of letting it sit. But like I said, how I understand, if your exhaust piping is too large, you are going to get an increase in backpressure due to the fact the piping is too large, and rather than flowing freely out to the end, it builds up in the massive exhaust pipe until finally there is enough built up to push the exhaust through the rest of the system.

...I wasn't trying to create a big "thing" with this, just trying to throw in my two cents on this particular question.

Obviously everyone has their own opinions on backpressure, and it's a touchy subject...so can we all simply agree on doing research on an exhaust before buying one?

And can I at least get people to agree with me that the following is not the way to build an exhaust? Because it seems too many people don't learn enough about the particular system and their car before throwing one together.

(A former friend "built" his exhaust this way.)

1988 Audi Coupe, 5 cylinder.
1. Remove main muffler.
2. Remove second muffler. (Yes, he really did have two.)
3. Remove catalytic converter.
4. Purchase 6 inch resonated exhaust tip from Pep Boys.

Finished.


:dot:

I just sit inside my car myself and go "weeeeeeeeeeee" and "pshhh."

but seriously, if the exhause is too loud/high pitched, just get a couple of resonators. I managed to get away without a resonator because I went with a semi chambered oval muffler.

My turbo and 3" and exhaust works great.......lol.

been ther done that and yes its true you also burn the cv joint boot

Wrong. Everyone can't drive around with straight pipes because it's too loud and there's a thing called emissions. You have to have a tuned exhaust that works with the "backpressure" to create pulses that help push and pull the exhaust out. It's called scavenging, and there's a whole lot of physics involved because your getting into fluid motion.[/QUOTE]
I thank texas for lean laws and pretty much no restrictions, but also depends you you take your car to.

My car has no catalytic converter, no resonator and just two small Borla universal mufflers and two borla 3.5 inch tips and the noise level is purrrrrrrrfect and is not loud at all and after testing creates a correct amout of backpressure. It has 2.5 all the way to the back. starts from a 3inch at flange then decreases to a 2.5 then a 3.6 at tips.
The honda had
1 three mufflers
2 two resonators
3 removed all mufflers and one resonator
4 left the cat and added a really long glasspack with a 2 3/4 all the way to the back and then added to four inch borla tips (replacing stock dual exhaust). after doing all engine work vehicle actualy gained a 22.34 hp at the wheels and 13.68 of tq. so everyone needs to do thier homework.
A ver si todo se va bien y no se descomponen sus motores. (lets hope everything goes good and nobody's motors screws up).