What power shall I expect?

[Christophski]

Hey guys I have an aby s2 avant homefried so 280bhp at last dyno. I am fitting a stainless system from the downpipe back, not including downpipe. It's standard diameter, with cat bypass section and a tiny centre box and is from powerflow. What power should I expect? I'm guessing close to 300bhp??? Accurate guess?

Cheers
chris

[Rusty]

If it's all running right then 290+ sounds about right, will need to have all the boost hoses airtight, some decent spark plugs and Tesco 99

[Christophski]

It's all boost leak tight n samcod up and fairly fresh in most ways. I would have thought 295+? Don't really know hence my questionning.... Cheers rusty dude

[Rusty]

There's having the boost leak section airtight and then there's having the whole thing airtight, all the little vacuum hoses including those around the ECU, everything that's under pressure There's so many places that can leak just a little bit and throw it off the power you want!

Also, it depends on the make of the dyno and the day (correction factor should make things the same...ish) and how much the operator fiddles it to make you happy

[terrybullwon]

I would have said 280 still

[Christophski]

Oh well, lots of the hoses have been checked and tested with new clips and ties so it should all be leak free, I hope. Fair enough with the power gain. I would have thought there would be some gain from cat bypasses still. I would expect the boost to appear slightly more aggressive with the bypasses too? Guess I will find out on sunday afternoon. I dont know what the make of the dyno day was but I have a print out from the previous owner who had done it a matter of months before I brought the car.

[Jamo]

Even if it made 280-290 I'd be highly concerned with backpressure and EGT's with a stock downpipe

[dest]

My guess is that it would make a bit more torque

[nip]

Chris I replaced a standard exhaust with a stainless steel one removing the cats no back box and made 289 bhp before it was 277 bhp so I would have thought you should make a tad more power

[Rusty]

Even if it made 280-290 I'd be highly concerned with backpressure and EGT's with a stock downpipe

My 297bhp on homefries N stream was on stock DP and cats poor alpinweiss Torque was 320-330ftlbs.

The hotside is rather small on the stock turbo so gains with freer flowing exhausts are limited a little.

On a stock car running properly it's worth about 10-15 ponies but that's with the turbo being pushed less.

Only way to find out is to get it tested I should get mine done again at some point really...

[Christophski]

Egt? Sorry I don't know highteccar talk. If I was to fit a stainless downpipe in the same diameter would that help free more ponies and sort out back pressure and egt?

[driftin jo]

Egt? Sorry I don't know highteccar talk. If I was to fit a stainless downpipe in the same diameter would that help free more ponies and sort out back pressure and egt?

In a word , no !

Why would you bother fitting a downpipe of the same size ? Why would it being made from stainless steel help ?

[Christophski]

I thought stainless was smoother so more free flowing? I guess not. If I got a larger downpipe with a join to standard size on cat bypass to the rest would that improve things or not really by dropping back down to original size.

[HMS-S6]

I may be wrong - after all i can't fix my own S6 despite being a mechanic But i think what the guys are getting at is the only way to gain anything by means of an exhaust is to go 3" turbo back!?!?!?

[terrybullwon]

I may be wrong - after all i can't fix my own S6 despite being a mechanic But i think what the guys are getting at is the only way to gain anything by means of an exhaust is to go 3" turbo back!?!?!?

Yes pretty much so.

And Cat less of course.