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Author Subject: Tell me about Exhaust Designs?!
honestly3k

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Post #1
I just wondered if anyone could tell me a little more about the GTI-6 standard exhaust setup...

I am thinking of getting a stainless steel system custom built but im only really interested in doing it IF it will give me a noticeable increase in performance or responsiveness....dont get me wrong im not expecting miracles and stupid power gains but can anyone tell me.....

1.) How restricive is the 6 standard exhaust?

Currently i have a standard system but with scorpion back box....

2.) What sort of design should i be asking for when they are measuring up a system for the car?

(ive read about pipe sizes and inwards or outwardly rolled lips on tail pipes - what does this all mean?)

3.) What settings will give the best results?

Im planning on keeping my cat, or maybe even getting a sports cat but im not sure on that front at the moment, all i really know is i dont want the hassle of having a decat come MOT time....

Any info greatfully received Big grin Roll eyes

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''Oh, it does handle like a golf!'' Why drive a Golf....when you can drive a GTi-6?
Posted 8th Aug 2011 at 02:12
welshpug!

Capt Pedantic

Location: Bigend, Wales.

Registered: 27 Mar 2007

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Post #2
1) not particularly, I've helped put a V6 306 together that ran over std power through that exhaust with a cobbled together cat/downpipe which wasn't ideal.

2)something like the original but lighter LOL

the next is precisely what they say on the tin... think about it!

3) settings?!

3)

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Posted 8th Aug 2011 at 02:25
cwspellowe

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Post #3
Unless you want pops and bangs, keep the cat. Removing loses some of the midrange and provides very slight top end power. Given the fact you'll hardly ever use top end power and use more mid range torque under normal or spirited driving the cat makes sense.

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Posted 8th Aug 2011 at 02:30
honestly3k

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Post #4
With settings i meant ive read about having certain sized pipes and mid-boxes etc...just a little bit of a dumbass when it comes to exhausts!

So really its not worth getting one or what?

Surely there are less restrictive systems out there that improve performance?

________________________________________

''Oh, it does handle like a golf!'' Why drive a Golf....when you can drive a GTi-6?
Posted 8th Aug 2011 at 02:34
bigbadbowen

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Post #5
In my experience and I have had a few years Whistle a decat does very little accept destroy the mid silencer

Most of the S/S systems are pretty much the same. Scorpion used to have terrible mid boxes, Magnex used to have cracking problems, powerflow just used to be crap !

Mongoose and Piper may be worth a shout as not had much experience with them ???

I can say that maniflow make good systems but usually make them to order and you generally take your car to them ?
Posted 8th Aug 2011 at 02:48
bigbadbowen

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Post #6
Sports cats are a waste of time as well

Posted 8th Aug 2011 at 02:48
welshpug!

Capt Pedantic

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Post #7
Miles does good systems Smile

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need a part number? get on here - http://public.servicebox.peugeot.com

Bring on the Trumpets.

Posted 8th Aug 2011 at 02:50
honestly3k

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Post #8
I would be getting a custom built system and taking my car to them....ive heard good things about 'Top Gear' in Aylesbury for exhausts....

Just wondered if theres any kind of design that is known to produce good results with regard to what pipe sizes should be used and how many mid-boxes etc....? I also heard something about the need to maintain back pressure? Whats that all about? Unsure

________________________________________

''Oh, it does handle like a golf!'' Why drive a Golf....when you can drive a GTi-6?
Posted 8th Aug 2011 at 02:59
swiftyboi006

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Post #9
If anything keep it all standard apart from the centre box have a straight through, keep the standard back box as IMO 1 silencer is enough. Realy on a standard engine you want the standard exhaust as peugeot in the 1st place would have spent alot of time and money making it as good as they can to suit the engine. Unless you want noise or have other engine mods such as cams and tb's then its not worth the money or effort.

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Posted 8th Aug 2011 at 03:00
honestly3k

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Post #10
So basically ya'll know about as much as me about exhaust systems! LOL Shut up

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''Oh, it does handle like a golf!'' Why drive a Golf....when you can drive a GTi-6?
Posted 8th Aug 2011 at 03:39
bigbadbowen

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Post #11
2 ¼ inch is std size

But yes we are not exhaust specialists

I was lead to believe that getting the hot gases out the engine as fast as possible was always best but back pressure had to be considered as well ???

Posted 8th Aug 2011 at 03:45
honestly3k

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Post #12
So does anyone know the effects of decreasing or increasing pipe size at any given point? And why back pressure is important?

That seems right bowen re the gases exiting the system....

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''Oh, it does handle like a golf!'' Why drive a Golf....when you can drive a GTi-6?
Posted 8th Aug 2011 at 04:13
allanallen

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Post #13
The way I understand it is that as the exhaust gases cool you can reduce the diameter of pipe to keep the flow consistent. I believe that's why the standard exhaust starts at 2.5" and reduces down to 2.0" ID.
I built a stainless exhaust for my 309 gti6, it's a 2.5" downpipe which reduces down to a 2.25 middle box then onto a 2" rear silencer and tail pipe. I've not r/r'd it but it certainly isn't restrictive and it's a much nicer sound than all the boomey 2.5" systems I've experienced.
I also used this principle on my supercharged 205s exhaust; 2.5 downpipe-2" middle box and rear silencer. It MAY be restrictive but it makes 250 bhp through it and it doesn't deafen you.

You also need to be aware that stainless steel doesn't dampen the sound like mild steel does, Stainless systems from my experience always sound harsher/louder.

The type of wadding/packing used in straight through silencers is also quite important. I think the perforated tubes In the more expensive silencers are wrapped in wire wool aswell as the silencer being stuffed full.

Just my 2 pence

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Posted 8th Aug 2011 at 05:05
eliotrw

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Post #14
I'm just going to stuff all this worry and whack a jetex on come exhaust time

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Posted 8th Aug 2011 at 05:31
mik

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Post #15
Good idea - I think keep it close to standard or get a decent quality aftermarket one.

Back pressure is important for the torque characteristics of the engine, and is worked out to deliver a good compromise of characteristics that work in the circumstances where the vehicle is going to be used. What you need on track might be different from what will keep you sane on the road.

Some years ago I was getting an exhaust for a Golf VR6 and in discussions about which exhaust to go for, I was told about a Golf Mk2 GTI 16V in the shop with a replacement exhaust that the owner got made up by a shop, and it lost all its torque, so to get up hills he had to rev the nuts off it. It might have made better peak power figures and sounded good etc, but in the real world it was a pain in the backside. He went back to a factory exhaust.

Another example is a Audi Coupe quattro (non-turbo) I had; the centre section went and a generic part was put in to replace it as I was too cheap to pay the outrageous price for a factory part. It made a really annoying resonance just at motorway speeds.

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Posted 8th Aug 2011 at 17:50
anth

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Post #16
Jetex are good, the tailpipe looks like UTTER shit though. Only thing i dislike about mine.
Posted 10th Aug 2011 at 23:27
smegal

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Post #17
anth wrote:
Jetex are good, the tailpipe looks like UTTER shit though. Only thing i dislike about mine.


It soon grows on you when you have it though.

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Ex SC-6

Now in a Megane R26
Posted 11th Aug 2011 at 00:33
adam b

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Post #18
If you don't mind the extra noise i'd go Magnex Group N original on a standard cat. Mostly because they weigh about half as much as the original. Just got to find one now...

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Posted 1st Nov 2011 at 16:21
honestly3k

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Post #19
Im still in debate as to what to do about my exhaust at the moment. Mid section has a blow. Scorpion backbox has no o-ring to link the mid section with the backbox where the clamp is.

So im in mixed ideas as to what i want to do.
At present im probably losing a bit of performance.

I want the new exhaust to be:

-quiet/slight rumble on idle.
-quiet in normal driving.
-quiet on the motorway at 70.
-have a nice raspy induction roar when i boot it. Dont want it boomy.
-preferably increase performance by increasing gas flow.
-keeping the cat.

So the way i see it i can either.....

a.) Source a stainless steel full system from someone on the forum which takes into respect all the characteristics i want (a big ask i know?)

b.) Custom exhaust made by powerflow or the like (at around £300 way more than what i wanted to spend)

I could go standard exhaust again but i would quite like a stainless system where i dont really have to worry about in future Hmm

________________________________________

''Oh, it does handle like a golf!'' Why drive a Golf....when you can drive a GTi-6?
Posted 1st Nov 2011 at 16:31
braymond

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Post #20
For info - I have a stainless Powerflow exhuast from the cat back, and it is boomy around 3k

EDIT: I am in fact in a similar position to you, and been mulling over exhausts for some months now, and am coming down on the side of one of Miles' (Pug Racing) sytems. I've had a couple of chats with him and it sounds like a good system, and he quotes some good db values.

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Posted 1st Nov 2011 at 16:35
honestly3k

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Post #21
braymond wrote:
For info - I have a stainless Powerflow exhuast from the cat back, and it is boomy around 3k

EDIT: I am in fact in a similar position to you, and been mulling over exhausts for some months now, and am coming down on the side of one of Miles' (Pug Racing) sytems. I've had a couple of chats with him and it sounds like a good system, and he quotes some good db values.


Yeah ive heard he does good systems, but arent they all made of mild steel and are more prone to rust? (hence will i be in the same situ in a couple of years?! - if i have the 6 for that long!)

Would be good if he has any expert advice on this subject.

I really cant handle the idea of spending £300 on an exhaust though LOL

Thats my only problem with buying a brand new system

________________________________________

''Oh, it does handle like a golf!'' Why drive a Golf....when you can drive a GTi-6?
Posted 1st Nov 2011 at 16:46
anth

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Post #22
smegal wrote:
anth wrote:
Jetex are good, the tailpipe looks like UTTER shit though. Only thing i dislike about mine.


It soon grows on you when you have it though.


I've had one for ages LOL Just too big for my liking I guess.
Posted 1st Nov 2011 at 17:26
braymond

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Post #23
honestly3k wrote:

Yeah ive heard he does good systems, but arent they all made of mild steel and are more prone to rust? (hence will i be in the same situ in a couple of years?! - if i have the 6 for that long!)



He does mild and stainless

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Rallye-R

Nurburgring article
Posted 1st Nov 2011 at 21:21
matt evans

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Post #24
Going back many years, REVS magazine (remember them?) did some back to back RR tests on a pg gti (think it was a 306??) and they concluded that all the aftermarket ones did was increase noise and the OE pug system flows very very well on a standard engine.

Partly the reason i've kept mine OE and binned the Magnex off sharpish as it made my ears cry lumpy tears.

________________________________________

1999 Astor Grey GTi-6 OEM+ (now gone...)
2004 Aegean Blue 206 GTi 180 (also gone...)
2006 Skoda Fabia vRS in Sprint Yellow

honestly3k wrote:
Do you wrestle for a living matt? You sound like a monster LOL


owain wrote:
Nothing involving a 306 can be considered worthwhile.

Posted 2nd Nov 2011 at 08:24
rallyeash

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Post #25
My brother matty_rallye will be selling a 2 1/4" piper full system with a 3 1/2 outward rolled tailpipe if your interested?

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Posted 2nd Nov 2011 at 08:34

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