Is that just a straight pipe from the exhaust manifold?

Surely you will loose a lot of power with that and crate a lot of noise.

________________________________________

1997 Black GTi6
smithers205 at hotmail.com

Back pressure didn't get a look in.

Those Arcan jacks are good.

________________________________________

Senior Test Automation Engineer for the 306GTi6 Owners Club Forum

---

depends what the noise limit is....

No power or eardrums ftw!

Seriously, just buy a proper one

________________________________________

Membership expiring soon, get in contact on our new little forum project.

Get a vid up of the sound hehe.

First rule of removing silencers and cats is to reduce the bore to make up for the loss in back pressure.

I run a full stainless manifold back on my 6 with no cat 1 mid silencer which is pretty big and a rear silencer which is also pretty big. I had my bore reduced from the standard 2.5 inch bore to a 2.25 inch bore to compensate.

You have to remember straight through boxes and or no boxes in your case allow the exhaust gases to escape alot quicker but without back pressure your losing soooo much power.

Increasing bore sizes to gain power only works on engines with forced induction.

________________________________________

Team Nile 6
Team: 40.2 MPG
5 x a 306 owner!
currently abusing type r's in a town near you ™
I truely live for the 306 ®
Build date: 29th October 1997 Wednesday's car
midweek madness

Shame cos it looks
Like You went to
Some effort.

________________________________________

andrew315rawson@live.co.uk
Moonstone phase 7 gti6
My Project thread: http://www.306gti6.com/forum/showthread.php?id=119992&page=1

Scaffold
Pole
Exhaust
Nice
Touch

________________________________________

Ph2.5 Nile - Slowly trying to de-East London it and restore to former glory...
Built on the 9 Febuary 1999 - Tuesday's car..is full of pace?

Currently looking slightly molested due to some c*nt trying to get into it..

According to the forum Social Worker, because I work in IT, I am socially retarted..

^^What he said.

I'd stick a resonator on though.

________________________________________

- Bespoke rollcages/additions/adjustments. Half cages right up to complete custom spaceframes - MSA/FIA spec, CDS, ROPT, T45, etc - PM me
Email me!
Custom-made polybushes available - need an odd size or fitment? - anything from batch work to one-off pieces.

he's just doing it to fit in with the other Belgians

________________________________________

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

Bring on the Trumpets.

So by adding a silencer its going to make huge gains is it? I think if i can aim somewhere in the region of 0.2psi or below of back pressure, then that will be sufficient! Anything over that is likely to produce a minimal loss of power, depending on just how much of it there is.

It is exhaust gas velocity that is the difference between making power or not, if i used a 5 inch bore system, id end up with the gas just hanging round! Im pretty sure its going to be moving along at a fair rate of flow as it is.

As for the time taken, that took me less than an hour putting that together, was only 3 cuts to make, then slot it all together.

Yes, to a certain degree, but as with most things to with the complexities of IC engines - there's more to it than can realistically be explained in a forum post, and there will always be those you believe you need backpressure for torque and other such things such as overheating ex' valves. (And to a certain extent they're right, it can affect drivability)

Speaking in general, the exhaust manifold ("banana bunch" ) geometry affects your scavenging effect the most, whereas your exhaust's main tube geometry has most effect on the backpressure produced by the system as a whole.

One of the important things to remember about backpressure is that really, there's no constant pressure - just pulses blasting around the manifold from the other cylinders, it's a load of spikes. The idea is to tune your exhaust so that these pressure spikes (and corresponding pressure dips ) help to a) suck the dead-volume exhaust out of the next exhausting cylinder, and b ) help draw in the fresh charge. Also if you've got a turbo, you can funnel these pulses in pairs to the turbine wheel, which gives better performance. Google 'twin scroll turbo' images to see manifolds which pair cylinder pulses and feed them to the turbo.

Once you start looking for maximum power, you want your banana bunch you give you a nice scavenge effect at your target power band (when you're "on-cam" ), and then you want as little back pressure as possible after that so you have as little tube length as you can get away with.

The engine releases a certain amount of energy from the fuel. The less of this energy you use trying to push gas down tubes, the more makes it to the road.

Take a look at an F1 exhaust. Banana bunch to atmosphere, cos all they care about is maximum power, drivability comes a close second.

Been designing engines for Cummins for the past year btw

Edit: To get rid of accidental smileys!

________________________________________

Feelin so fly like a Gti6
Team >160,000mi