335 exhaust system

[charlE30]

Hi guys, I'm after some advice as to what size tubing I should use to build a suitable exhaust for my 335i? The engine is stock bar a K&N panel filter and megasquirt (soon). I'm thinking of a single pipe system with a twin exit rear box.

I know bugger all about exhaust theory and want to build something that isn't going to loose me power/torque... if possible and to be reasonably cheap and cheerful (mild steel as budget can't stretch to stainless)

Jetex exhaust's are just down the road from me and this will be where I source my parts unless someone else knows of a better place.

Any advice, opinions etc all welcome

Charlie

P.S having internet issues so willcheck back when I can.

[Simon13]

50mm bore twin pipes right through.

Some peeps fit modified E30 M3 systems as they are 50mm. Scorpions a fav cause they loose power on S14's but not on an M30!

[tomtomiS]

my new flatmate works for a very special exhaust company, i shall ask him over the weekend for you!

[Theo]

2.5" single pipe is good, but will need to be fabricated. I have a scorpian M3 system for sale if you fancy that. Just get a matching flange made up and welded to your downpipes.

[Ritchie]

I have a chopped, standard e34 frontpipe with a flange welded on to mate to a M3 middle section with a welded on stainless Mongoose backbox.
It sounds good, not too loud but beefy enough.

[zaust]

Mine is the m30 manifolds with custom down pipes into a collector, then single 2.5" straight through to a powerflow single pipe exit.

[pegase747]

It depends on what YOU want !

Personnaly in the same situation, i would love to have a sleeper 335i, so the exhaust would have to be quiet in town, and bit more agressive when pressing the right pedal, but not too much !

If going with Jetex, I would use :
- Standard E34 manifold and downpipes as they aren't too restrictive.

- Then make a flanged Y-pipe from the 2 downpipes, exit in single 2.5" pipe ( mount O2 sensor there if cat ) I believe you can use Jetex part#U906351R and reverse it.

- if using a Cat, put Jetex Part #UFILOK635MM flexi-joint to absorb vibes and heat.

- Install a Cat, 2.5" In/Out ( if you want one, I would use magnaflow as they are cheaper than Jetex ),

- For a more quiet ride, put a first silencer right after the cat ( smallest of the cylindrical 2.5" In & out Jetex part # U456300R).

- Then again single 2.5" pipe to an aft silencer with 2.5" single in, and straight 2x2" exits for the 325i look, Jetex part #U346351R.

- For the tailpipes I would just weld some 2' pipes and make a nice angle cut and polish, to look like a OEM replacement part.


For more sound, delete the first silencer !
All stainless of course !

I believe single pipe 2.5" is ideal for an M30, so that is what I would do if my M30 projects comes true !

Also try to get all components flanged up, then you will be able to replace any single part if failed, but you can weld the pipes and elbows.

All please tell me what you think of that setup ! thanks.

Cheers / Pierre

[charlE30]

Cheers for the input guys, sent Theo a PM regarding his M3 Scorpion system. I do like the idea/simplicity of a single pipe system and if a 2.5inch single pipe is good enough for the Miltek E30 M3 system then I'm sure it would be fine on mine. I was just concerned that a single 2.5 would still be restrictive in comparison to the standard 535 exhaust.

Pierre what you have written is very much along the lines of what I was thinking (minus the cat)

Ideally I'd like to end up with a system that sounds standard and not boy racer, is this even possible using aftermarket parts?
I'm not in the position to drive my car into a custom shop and hand over a load of cash as I know this would be the perfect solution.

Would a single pipe alter the exhaust note at all over a twin pipe setup?

Cheers guys

Charlie

[Theo]

I think the only way you're going to get a standard sounding exhaust which performs ok is if you use a mild steel M3 system.

[Andy335Touring]

Yep OEM M3 exhaust is supposed to be good, if you can weld, buy your self an E36 328 back box, this sounded really nice and wasn't too loud on Toby's car back when it was still N/A.

My old Scorpion M3 exhaust sound nice but was too loud, the X-pipe made it a bit less noisey. If i'd have kept the car i was going to get some one to repack the back box for me.

[charlE30]

Standard M3 systems seem harder to get than anything, stupidly I had a complete system of a 320is but sold it when I was going to give up on the project way back.

I've currently got a full 325 scorpion system on the car and the noise outside is lovely, it just gets a bit tiresome on long journeys inside.

Andy I was under the impression that the E36 328 back box was the wrong shape & size to fit under the E30?? Would I be right in guessing he didn't have a centre box, just straight through pipes? I've just had to cut and weld my downpipes to clear my new rack so could most probably do a complete system, not pretty but functional

AAhhh so many options my head is hurting.

[Andy335Touring]

Yeah, just the back box, drop Toby a PM about it ?