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View Full Version : no more e-testing - headers or what?


kamus
09-12-2007, 04:03 PM
Folks - my 87 E30 is now exempt from the Drive Clean program. The whole exhaust system is stock (manifolds, cat and muffler). I have a set of headers from the previous owner. I can put these back on the car at the same time as my new engine is installed this week.

Question is... should i? I prefer the feel of lots of low end torque. I do not want to sacrifice that for more power - if that power is only available at hi revs. (Please counter this from your experience - does adding headers have anything at all to do with torque?)

Give that, does it make sense for me to fit the headers now, while keeping the stock cat and muffler.. or should I change the whole chain?

SamE30e
09-12-2007, 04:40 PM
The power gains would depend on the size of the headers. Put the headers on and punch the cat. I have a fully stock exhaust with a punched cat and it made a little bit of a noticeable difference at the higher rpms.

kamus
09-12-2007, 04:45 PM
punched cat

What is 'punching the cat' ?

Boots R
09-12-2007, 04:53 PM
What is 'punching the cat' ?

A Hollowed out Catylitic converter. Used for free flow exhaust, but still have the look of a cat.

But you wouldn't need that, because you don't need emissions anymore. You could just weld up a straight pipe.

BMW325BMW
09-12-2007, 06:57 PM
A Hollowed out Catylitic converter. Used for free flow exhaust, but still have the look of a cat.

But you wouldn't need that, because you don't need emissions anymore. You could just weld up a straight pipe.

just because he doesn't need a cat doesn't mean he can legally hollow out the cat. It still has to be kept to factory specs. Meaning if the police book him, he can get in a heap load o crap. But does it ever sound good straight pipe.

Axxe
09-12-2007, 07:53 PM
just because he doesn't need a cat doesn't mean he can legally hollow out the cat. It still has to be kept to factory specs. Meaning if the police book him, he can get in a heap load o crap. But does it ever sound good straight pipe.

Yes and no. Most cops don't give a shit about exempt cars, especially older BMW's. If it doesn't make too much noise and isn't running pig rich, you won't have any problems.

Mystikal
09-12-2007, 07:56 PM
Question is... should i? I prefer the feel of lots of low end torque. I do not want to sacrifice that for more power - if that power is only available at hi revs. (Please counter this from your experience - does adding headers have anything at all to do with torque?)

Give that, does it make sense for me to fit the headers now, while keeping the stock cat and muffler.. or should I change the whole chain?

Yes, the headers can drastically affect low-end torque. We'd have to know which headers you're referring to before we can tell you what should happen.

The stock exhaust really isn't restrictive on a stock displacement motor. I wouldn't change it. Then again, the headers aren't that restrictive either; aftermarket ones with gains will really only move the power upwards.

Jay

e30_kid89
09-12-2007, 07:56 PM
Damned 88's, stuck in the farking system.

e30_kid89
09-12-2007, 07:57 PM
Wtf Jay, we posted @ the same time - In the same thread:D

Mystikal
09-12-2007, 07:57 PM
Damned 88's, stuck in the farking system.

Not only does BMW take a dump on the 88's with their ugly bumpers and tails, but the province of Ontario too!

Jay

Mystikal
09-12-2007, 07:58 PM
Wtf Jay, we posted @ the same time - In the same thread:D

**** we did it again. 3 times and you're banned due to my homophobia.

Jay

Chris de la Cruz
09-12-2007, 08:44 PM
Not only does BMW take a dump on the 88's with their ugly bumpers and tails, but the province of Ontario too!

Jay


shat up about the bumper already.

replace the cats with that cherry bomb shit... do it.

bmdoubleya
09-12-2007, 10:43 PM
I've got Shorty headers straight back to the muffler No cat..It doesn't sound super hot but has nice performance gains. Just make sure you get a nice sounding high flow muffler..

craz azn
09-12-2007, 10:50 PM
Kamus, sell me the headers :P

kamus
09-13-2007, 06:16 AM
Kamus, sell me the headers :P
You're welcome to take a look at them. From what I'm hearing, they're not for me. I love the low-end torque way too much!

Someone mentioned stock displacement with a stock muffler. That's no longer me: My new engine is 3.2litre. What kind of muffler should I get? The engine maker recommends the stock muffler from an E46 323i

SamE30e
09-13-2007, 11:33 AM
Hollow out the cat, don't put a straight pipe, because the cat still has to be there because it is part of the original emission equipment from the factory. If a MTO officer looks under the car and see's no cat, then you're in shit. But if it looks like there is a cat they can't really do much about it because they don't have x-ray vision.

craz azn
09-13-2007, 11:45 AM
Hey Kamus, please PM me your number. Thx!

Mystikal
09-13-2007, 04:48 PM
Someone mentioned stock displacement with a stock muffler. That's no longer me: My new engine is 3.2litre. What kind of muffler should I get? The engine maker recommends the stock muffler from an E46 323i

3.2L, M50 based? With the volume of air that motor is pushing (even if it's an M20) is far too much for a stock anything in the exhaust. Think full length headers and nice large piping.

Who recommended a 323i muffler? That is a single inlet unit with less cross area than a stock E30 325i exhaust, they're way way way off.

Jay

BmW1819
09-13-2007, 06:04 PM
you adding more air and adding more fuel sooo what does that leave??? that more air has to go somewhere

kamus
09-15-2007, 03:40 PM
3.2L, M50 based? With the volume of air that motor is pushing (even if it's an M20) is far too much for a stock anything in the exhaust. Think full length headers and nice large piping.

Who recommended a 323i muffler? That is a single inlet unit with less cross area than a stock E30 325i exhaust, they're way way way off.

Jay

Ha! I sure need to do some more searching for the right muffler. It's an M20 but I'm not sure the current muffler is stock after all (the twin tubes look kinda big). And the E46 323i recommendation came from the man who built the engine - at Metric Mechanic. I may have misled you all - I was asking him about how to keep it quiet at the time.

No worries - I can swap the muffler anytime. I'll show you all at the next meet and I'll take copious notes!*drink*

Mystikal
09-15-2007, 06:38 PM
He has the right concept with the muffler idea, but is off on the details; a 325 or 330 exhaust would be the good choice, they're dual inlet. That said, I don't even know if that huge thing will fit properly under an E30.

Jay

Slowered318
09-16-2007, 10:00 AM
Legally you still need to have ALL your emissions components in tact on the car. A "punched out cat" means you took it off the car and that’s not going to be legal. Also its going to be pretty tough to modify the original cat without making the air flow more turbulent and defeating the propose.

Cops have a thing called a nose, some are big, some are small but they will be able to tell when following you that you have no cat. Noise aside, it's going to be a dead giveaway.

If you want to free up a few ponies you’re going to need a full exhaust setup built with performance in mind... Supersprint is a great example! Pipes are not too big or too small, mufflers are a little bit heavy but do their job well. Something thrown together half assed by some muffler shop isn’t going to give any performance gains unless you drive an 80’s Camaro IROC-Z.

kamus
09-16-2007, 10:14 AM
He has the right concept with the muffler idea, but is off on the details; a 325 or 330 exhaust would be the good choice, they're dual inlet. That said, I don't even know if that huge thing will fit properly under an E30.

Jay

Right -and his key comments about the 323 was that it was quiet and it fits very well under the E30.

kamus
09-16-2007, 10:25 AM
Legally you still need to have ALL your emissions components in tact on the car. [...] Supersprint is a great example! Pipes are not too big or too small, mufflers are a little bit heavy but do their job well. [...]

Ya the last thing i want is my baby getting crushed. Supersprint lists one muffler for the 87 325is. Easy enough. Does anyone have experience of alternate manufacturers for the sake of comparisson?