mart h

I have an STI8PPP and want it to sound how it should do (better)
and have found an after burner downpipe for sale that i would like to fit.

The problem is the buyer says that I will need a "small brass restrictor/bung" thing to prevent overboost. This item is apparently £3-£4 pound from scoobysport but they are not open until monday, by which time the downpipe will probobly be sold!

Can anyone confirm that with this "Brass thing" the downpipe will be ok. I don't really fancy a re-map as I've already paid £1800 for my PPP.

THANKYOU
Martin

Absolute Shower

I would of thought you've already got a restrictor, but changing the size changes the control of boost from ECU. Smaller means more low boost and less control. Bigger means more control, but less low boost.

PPP for STi8 is Tek3 remap anyway I think.

greasemonkey

Your car already has an actuator restrictor fitted. What he's saying is that you'll need a different one (with a larger bore) to cure any overboost. You may also need a CEL fix if the downpipe doesn't have a catalyst fitted.

You'll probably need to buy two or three restrictors and experiment to get the best combination of boost build without spiking, but to do this you will also really need a good quality "needle" boost gauge to check the effects. Do you have one fitted ATM?

As mentioned above, it should be okay provided you take time to get the restrictor size right. I'm sure Pete will have a good idea what bore to use, but a bit of experimentation may still be necessary. Just bear in mind that there can be consequences to this sort of thing. If you get it wrong, a blown engine can be the result, and thanks to the changed downpipe invalidating your warranty, you may be left with a very meaty repair bill...

If all you're really interested in is changing the exhaust note, swapping the PPP backbox for something else is probably the most logical option.


[Edited by greasemonkey - 12/31/2003 10:36:35 AM]

Gidney&Knowlesy

Brass Restrictors I have got loads of, open today until noon, open again Friday...8-5

The TunnelMeister

Agree with GreaseMonkey,

swapping b/box for big tailpipe is preferable to big bang!

If it's already ppp'd I would'nt have thought that on it's own a decat d/p would make all that much difference anyway? At least not in my experience.

IMHO of course,

Steve.

Sti_Lad

I have decatted my Sti8 PPP and I dont get a check engine light, I am guessing that the prodrive map has a lower tolerance, or higher maybe... Sorry its new years and am feeling stupid.

I unplugged the MAF once and forgot about it and got a CEL, I have found if you start the car raise revs to 4 K and repeat this 4 times it clears a CEL!! So you dont have to do a full ECU reset and have the car running like a dog for a few hundred miles.

I get the occasional boost spike but its only to about 1.4 bar nothing too high... but I am going to sort that with a restrictor change courtesy of extreme. ( havent forgotten knowlesey )
I didnt feel a massive change in power but it is more tourquey thats for sure... Just dont expect a huge gain from changing the pro drive cat! Think a remap from pat is probably best thing to do now

mart h

thank you all!!!