Has anyone replaced a stock muffler for a modified muffler, and actually noticed a substancial increase in power or performance?

Just want to see what you guys think or have experienced. :bounce

Not seen substancial improvement but definately some improvement. I went from the stock exhaust to a single quiet pack and was please with the difference!

Rob.

Exhaust is one of those areas where you can spend a lot of money on not much power improvement.

On a modern engine, back pressure is far more important than less restriction. On my engine for example, using a 3" drainpipe turbo-back will cause ECU to log fault codes and use the limp home mode. All modern engines use exhaust gases with intake/outtake overlap to improve fuel economy and reduce emissions. The TT with 165 kW has a 2.5" exhaust, and I have a 2.25" exhaust system, which is plenty big enough.

On an aircooled engine, I don't think you have any overlap between strokes, and as you have no O2 sensors (unless you've using modern EFI), I think the less restrictive the exhaust the better, within reason (noise is my concern). However, just like in the modern engine example, you'd be lucky to get even 5 kW out of it, max. But when you're engine is a pulsating 25-30 kW (1200 to 1300 engines), this can be worthwhile.

I prefer quieter exhausts myself. The Kombi style exhaust that was plonked on my Type 3 is just fine in this regard. Type 3 mufflers are not made any more as far as I can tell, so we have to make do with whatever is available.

Andrew

Considering the modest power output of most VW's, the factory I'm sure would have done its best to optimise power output. Also bear in mind that in these enviro. sensitive times, loud exhausts can be a turnoff & give the roadworthy test guys another reason to pull of the road for a spot test.

I've tried heaps of different mufflers over the years & the only real difference seems to be noise, the big difference was when I stepped up to a 1.5 inch merged header, there was a real noticable difference with the merged header, I would definantly reccomend one if u don't use heaters.
rgeards
Jak

Thanks everyone for your thoughts / experiences. The general message I'm getting is that modified mufflers don't necessarily make a drastic improvement - yet they're necessary for modified engines.

Modified, to what extent though? Would a progressive weber carby count?

I'll look into merged headers, Jakriz.

Thanks all! :party

Replaced the extractors and hot dog on the 57 with a standard exhaust and noticed a drop in performance. Mainly in engine reving out. Seemed like at the top end of the rev range some thing was holding it back with the standard pea shooter exhaust. Trade off was much reduced noise levels.

What size engine do you have, Grey?

A ground pounding 1600 single port.
Seriously tho it has had some stuff done to it Super 90 cam ect and it does go better than a 1600 SP has a right to.
Changing the exhaust system to stock did knock the performance back a bit. If could go the cost of a low restriction turbo muffler I'd put the extractors back on.

Vanderaj I have 3" stainless steel mandrel bent turbo back exhaust, made by Oettinger. Yes the TT has 2.5" and the cat is good for up to 200kw. but with the A3/Golf the exhaust system is much more restrictive, hence getting the 3" back. Another thing I also hate loud exhausts and although mine is 3" straight through its only 10% louder than stock when idling and cruising, but when u give it a hit thats when it roars :vader

Also I get no error codes either. The only reason i dont is because Oettinger set my ECU to run rich therefore cooling the exhaust system and getting maximum power out of it. If they kept it running like stock u would log error codes as it would be running too lean.:thumb

hey jak
whats the merged header exhaust system???is it the same as 4 into 1 extractors????
cheers
rhys

Yes Rhys, as opposed to 4-2-1 headers.

I don't think that VW necessarily tuned their exhausts for maximum power. I believe they tuned them to give maximum efficiency for the engine they were built for. I also believe that VW deliberately detuned and simplified their engines to prevent people flogging them to death.

I think exhaust choice matters quite a bit, but that gains aren't necessarily evident until induction is improved also.

My 1600DP seemed to lose power when I first fitted a Hotdog to the extractors that were already on it. It then improved dramatically when I rebuilt it with a 'warm' cam (I can't remember the specs). I'm quite certain that I could have gained more power with some better carbies and some mild head work too - power that wouldn't be available with a stock exhaust.

[Edited on 4-1-2003 by KruizinKombi]