| [ Total Views: 697 | Total Replies: 10 | Thread Id: 2776 ] |
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 Schmonno
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| posted on January 2nd, 2003 at 11:00 PM |
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Modified Mufflers and Increased Power!?
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
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London Bugger
A.k.a.: Robert Blackman (Prowagen)
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| posted on January 2nd, 2003 at 11:13 PM |
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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.
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 vanderaj
A.k.a.: Andrew van der Stock
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| posted on January 3rd, 2003 at 12:37 AM |
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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
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geodon
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| posted on January 3rd, 2003 at 04:36 AM |
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VW's R&D budget is bigger than yours!
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.
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jakriz
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| posted on January 3rd, 2003 at 10:17 AM |
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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 |
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Schmonno
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| posted on January 3rd, 2003 at 05:01 PM |
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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
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Grey 57
A.k.a.: Dean
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| posted on January 3rd, 2003 at 05:33 PM |
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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.
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Schmonno
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| posted on January 3rd, 2003 at 05:38 PM |
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What size engine do you have, Grey?
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Grey 57
A.k.a.: Dean
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| posted on January 3rd, 2003 at 05:58 PM |
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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.
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XXX-1.8T
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| posted on January 4th, 2003 at 10:18 AM |
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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
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XXX-1.8T
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| posted on January 4th, 2003 at 10:21 AM |
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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
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 kombi_kid
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| posted on January 4th, 2003 at 08:43 PM |
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hey jak
whats the merged header exhaust system???is it the same as 4 into 1 extractors????
cheers
rhys
it aint just cool its aircool'd
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KruizinKombi
A.k.a.: Col
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| posted on January 4th, 2003 at 09:36 PM |
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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]
Kruizin Kol
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