Steve Holmes

I am considering a de-cat centre pipe on my UK STi with PPP. I am assuming that as I have the Prodrive fast flow downpipe and back box that they should remain.

Has anybody ever added a de-cat to the PPP set up and have any experiences, good or bad?

Ta

Steve

JIM THEO

Centre section on STI PPP is already catless so adding a decated pipe is useless.
Your PPP modification includes free flowing downpipe, decated centre section (after the downpipe), back box, fuel pump and ECU remap. The "rear" centre section has only resonator/silencer no cat on it.
JIM

Steve Holmes

Cheers Jim,

Does this mean that PPP only has one cat!!

Is the Centre section a straight through one?

Ta

Steve

MTR

Yes,
The STi7 PPP has one cat in the downpipe.
The rest of the silencers/resonators are of the straight through perforated tube design.

Cheers
MTR

p1doc

the centre section has a resonator in it ,igot mine changed at TSL during the triple 3 and got told changing it would release 6 bhp
martin

partyondude

Can you tell me how many cats the STi8 with and without the PPP has?

G00ner

2 standard, 1 with PPP.

MARK MORRIS

ive put a straight through centre section on mine, makes it slightly louder, just about right for me
mark

Steve Holmes

Mark,

have you noticed any change in performance at all?

I'm getting the ScoobySport centre sections fitted next week.

R.B

Im going to de-cat mine soon so we will soon see

loscooby

I am running a STi8 (MY03) with Magnex decat + Magnex backbox and std downpipe, It resulted in 280HP on the rollers before ECUTEK!

/L-O

Steve Holmes

Hi

I am hoping for plus 304 BHP as this is what I have at the moment with PPP and induction kit.

MikeWood

Steve

If you have a PPP, you already have a decat centre pipe. If you change the centre pipes all you will have is more noise, less money and no warranty! But I guess you've already done that with the induction kit.....

Sti_Lad

I have just taken part in the G force rollin road day on saturday...

got a ppp MY 03 Sti with ITG Decat down pipe and rear center section changed too, got 317 BHP which I am pretty happy with, needs a remap now to smooth out the boost..

MARK MORRIS

cant say i noticed any change in performance, just a little bit louder, just about right now
mark

Steve Holmes

Hi Mike,

I took the induction kit off after the rolling road as I felt it wasn't adding anything to the experience. Also, the K&N was recommended by my local Subaru dealer as they advised that it would not affect the MAF sensor as do the ITG oil based panels.

I get my centre section done soon but on the basis that the PPP centre is just a silencer rather than CAT and as such will not affect the warranty.

Excuse me if I'm dumb here Mike but what difference does it make if I change the silencer as this should only effect the cosmetics/esthetics of the car i.e gives the sound of the car more purpose. I can see what impact changing a CAT would have but not this??

[Edited by Steve Holmes - 1/27/2004 5:04:33 PM]

MikeWood

Steve

ANY filter can affect the afm sensor, it's not just about oil contamination. If the filter doesn't take out small enough particles (and we're talking really small here) then they can contaminate the sensor.

Changing any exhaust component may have an effect on how the whole system works. If you've gained anything in performance terms, then it must have made some difference to the engine. How do you know it's safe? And why should someone else potentially pick up the bill if it goes wrong?

As I said, all you will have is less money, more noise and a potential warranty problem........

Mike

Steve Holmes

Mike

I accept most of your comment BUT let's be quite clear here. If as a result of fitting the CAT things do go wrong then I undersatnd and accept your point.

I however am keen to just understand what the possible risk could be by doing so when the performance isn't changed by the replacement of the silencer. I am hoping for a more purposeful exhaust tone but not any gains in power...??

Please persevere with me on this Mike? What threat/risk am I creating here?

Ta

MikeWood

Let's say it allows the boost to build at a different rate to what it's mapped for. You may get boost overshoots that aren't in the control of the ECU, and potentially experience det.

If the flow characteristics are different (and they will be) then other elements of the boost control may need to be changed.

Mike

Steve Holmes

Thanks Mike,

I think this helps.

Ta

timbow

Mike, would this be the case if just the prodrive backbox was replaced for say a Blitz backbox just to give the car a little more noise after all the prodrive box is stainless and straight through also isn`t it ?????????????????

MikeWood

Is the Blitz silencer E marked and does it give the same characteristics as our silencer?

I doubt it as it's noisier and probably a larger bore through the silencer. We also haven't tested it so we can't be sure either way.

Mike

timbow

Thanks for your input Mike.
I had the Blitz backbox fitted on my car when it was standard and run it for six months with no problems so does the pack really change the car that much???????
Whats the worst that could happen???
Regards Tim.