[stacey]

Originally Posted by SpdFreak

Hears a few Shiv,

1 - Stainless steal
2 - Tig welded
3 - Try to make a turbo back system
4 - Choice of tips (I think Miltech did this)
5 - And oh yeh... Keep the price as low as possible
6 - Make systems for both the 335i coupe and sedan available at the same time

why not just say, make the best exhuast for the lowest price?

[DrH]

I personally am NOT A FAN OF QUAD exhaust. Other than that I say form over function, as long as there is no drone.

I have to say it sounds to me like you know what your doing Shiv, so stick with what you've already got and are working with

I like the fact that you've got 2 separate exhaust lines going back all the way. My only concerns: sound, aesthetically pleasing and quality appearance, good price/performance ratio.

[BayerischeMW]

with fear of making this thread take another direction, how much power do you (shiv) expect from an exhaust on the 335i?

[Jeeves915]

<sarcasm>
I want a giant 4" tip, with a muffler large enough for a family of squirrels to live in! I want it to be made of superduperultraunobtanium weighing .5 oz! I want to be heard from a mile off at idle! I want...
*deep breath*
</sarcasm>

Yea...sorry, someone had to.
Anyways, I'm all for a mandrel bent (not sure if the stock is mandrel or crimp bent) 2.5" system. Nice tips are a definite plus (duals only please, no trying to mimic an M3 with the quads). Stainless steel is a requirement of course.
And yea, most of that has been said before, I know.
-Adam

[TheAcAvenger]

Stainless steel is played out. Ti it is!

[jbake]

don't forget the flames out the tailpipe option


sound and performance, keep it classy sounding!

[purplewidow]

turbo back!!turbo back!!!turbo back!!!turbo back!!!
________
Fucking Tubes

[andyc]

Originally Posted by andyc

I'm not too sure whether I'm too late to add my two cents, but I think the exhaust pipes should be as straight as possible from the downpipe to the tip, with minimal bends.

As little back pressure as possible would be ideal for better spooling of the turbos.

Exhuast note: low rpms should be bassy and high rpms should be a roar

Lightweight assembly at a 'reasonable' price.

I would like to add.. if possible, maybe you could design an exhaust and downpipe all in one. Straight from the turbo outlet pipe, a downpipe and cat back with complete catdelete and minimals bends, complete divorced exhaust system.. some people might say that sounds really crap with the cats removed.. but if designed with the back box... I believe you can get a great sounding exhaust with the maximum potential possible only loosing out to a straight pipe. Obviously this wouldnt be cheap, but ill pay for quality!

Back pressure sucks!

[bnj]

Thinking of the exhaust design. I wonder if there are some positive effects of having the catalysators close to the turbos? I have been thinking that the later the cats, the better, since the later the restrictions, the less they harm due to the lower temp and smaller volume of exhaust gas.

However, they could be there as pressure wave termination boxes to set the secondary length. Turbo exhaust systems usually do not need to consider scavening, but small turbos could benefit of it. This is more of a speculation, as the header design is just to minimize the needed space and the loss of thermal energy, rather than optimizing the wave lengths.

It would be interesting to compare what a turboback exhaust can do. Someone trying it out could dyno 1. stock exhaust, 2. no exhaust and 3. turbo-back exhaust (in that order, naturally ). The small percentual gains so far are probably attributed to the high backpressure of the tiny turbos. Therefore, no exhaust cannot seem to be able to decrease the total backpressure very much.

Does anybody know what is the turbo outlet diameter? Or the specs of the turbine wheels? The turbos could create less backpressure by slight modification.

[Lost Cosmonaut]

Originally Posted by shiv@vishnu

It's one of the things I haven't had the time to test thoroughly yet in the 335i since our own car doesn't need it. But its certainly something useful for those guys who choose to go catless down the road (boo hisss!).

-shiv

I remember from the Subaru forums you were anti-Catless.

For me, I'd pretty much just want a race-catted turbo-back that had a nice rumble at idle and a decent roar at WOT. I loved the sound of my exhaust on my STi (HKS DP to a HKS Carbon-Ti) but it got old fast, especially at highway speeds. I'd actually like to be able to talk to my passengers instead of having to scream over the roar of my exhaust!

An electronic switcher would be a plus as well if it's possible to be able to switch from catted to non-catted when you want.

Stainless steel is just fine. No need for super expensive exotic materials.

- LC

[andrew20195]

Originally Posted by bnj

Thinking of the exhaust design. I wonder if there are some positive effects of having the catalysators close to the turbos? I have been thinking that the later the cats, the better, since the later the restrictions, the less they harm due to the lower temp and smaller volume of exhaust gas.

However, they could be there as pressure wave termination boxes to set the secondary length. Turbo exhaust systems usually do not need to consider scavening, but small turbos could benefit of it. This is more of a speculation, as the header design is just to minimize the needed space and the loss of thermal energy, rather than optimizing the wave lengths.

I would think that the spinning turbo, regardless of size, would destroy any pressure waves that are created prior to that point... though that is merely speculation on my part.