single pipe exhaust system

[foxie389]

ive got to replace the exhaust on my track car and was thinking of saveing some weight at the same time.i was thinking of replaceing the twin system with a 3" single pipe system.possibly with only a single box .has anbody tried this and did it give any improvements?

[UweM3]

Pro:
it's chepaer
might be lighter as well
less fabrication work

Con's:
less ground clearance
single endpipe looks a bit naff (but that's only personal opinion)

doubt that there is a power gain (if two equally systems are compared)

[Trise30rally]

I have been thinking about doing this to my rally car, it will save a fair bit of weight.......

[agreen]

[quote="UweM3"]Pro:


Con's:
less ground clearance
single endpipe looks a bit naff (but that's only personal opinion)

quote]

Need also to consider noise limits at uk track days.[/b]

[e30_Turbo]

I've done it, full 3 inch system, made it on the car, looks and sounds the NUTS!! if I do say so myself

Then again I have a few more CFM's coming out than most M20B25's

It made a HUGE difference to mine but not sure if that would be the same for N/A.

It's a single box system too, bloody backbox is tiny....... I'll see if I can find a picture.

[e30_Turbo]

There you go, I've still got the welding scars from that day, will never lean on a fresh weld again!

[agreen]

Nice.

[DRIFTBOY]

Depending what engine / spec you've got, I'd say 3" pipe could well be a little OTT! ?

[Jhonno]

3" is waaaaaay ott for a m20b25

2.25 is good to flow over 200bhp easy

[UweM3]

There you go, I've still got the welding scars from that day, will never lean on a fresh weld again!

nice system. But you can't compare this to a NA engine. With a turbo your pipes can't be big enough and the noise level is different as well. The turbo acts like a silencer and therefore you get away with a much smaller silencer.

[UweM3]

Pro:


Con's:
less ground clearance
single endpipe looks a bit naff (but that's only personal opinion)

quote]

Need also to consider noise limits at uk track days.[/b]

Noise has nothing to do with single or twin pipe. Your silencer(s) needs to be large enough in either system to get the noise down.

[zaust]

Done mine 4-5 years ago. Custom 2x3 into 1 and then 2 into 1 and straight through. never had a problem and sounds the nut's.

[fuzzy]

although my application is abviously different i have a single 3" straight through system from the turbo with one large rear silencer to keep the noise to a reasonable level. the problem mentioned about ground clearance is an issue but not overly so and handles most speedbumps without a problem but i have hit excessively high bumps causing damage in the past. i still have twin tailpipes sticking out the back of the box

[ed325i]

[foxie389]

was looking at an exhaust catalogue in my local motor factors and noticed a 318is exhaustis quite a large diameter and single pipe with a small back box.my question is,
i was thinking if i replace the centre box with a 2 into 1 y piece and run with a perfomance back box.what diameter is the standard 318 exhaust and will removing the centre box affect the cylinder scaveging.cheers

[ed325i]

I have gone for 2.5" single pipe.

[JungleGus]

3" is way way too big for an n/a m20 - go 2.25 - otherwise you lose flow. even 2.5 is quite big and IMHO you lose torque

[djs325]

2.5" Single on my E30 325i with BTB Extractors.

[michealewk]

i have just taken off a single pipe exhaust didnt like the sound but i think the car was slightly sharper with the single pipe than the twin
pipe

[TVRTASMIN]

The twin system on a straight 6 cylinder will give you better torque and mid range. Turbo needs one big pipe.
I'd use two twin silencers of the straight through variety with 2 x 1 3/4" pipes from the primaries.