compared with the likes of P1, EVO, M3...
thank you.

 

I haven't had a head to head yet with any of the above, but STI7 performance before & after de-cat is like driving 2 completely different cars. Noticebly much quicker.

I had an Audi S3 up my **** that I was only just managing to shake off when my STI had its OEM exhaust, saw the same guy again once the de-cat system was on a few weeks later and now wiped the floor with him. Speaks for itself really.

 

From what Dave-TS has found with the Decat the boost is spiking - in fact Im sure hes now put the original exhaust back in.

 

What is "spiking"? ( I don't use my english on daily basis)

 

Elondan

Told you before, your English is just fine

If you do a full decat on an STi7 including turbo up pipe it will spike (peak momentarily) to 1.7 bar boost (25psi). This is *NOT* good.....

Either replacement up pipe with decat from downpipe backwards (i.e. original downpipe); or original up pipe with decat from turbo back will result in 1.5 bar peak boost. This is still too high.

It is the combination of replacement up pipe plus downpipe that together cause the 1.7 bar boost spikes.

There are some people that say you can fix the spikes by changing the restrictor in the compressor to boost solenoid to a larger one, equally there are other people on here that state that this does NOT fix it. Some have apparently cured it with a combination of restrictors, Unichip and Dawes Device.

Basically the problem is that the issue is relatively new and has happened to a relatively small number of STi7's as not that many have been decatted, so there has not been enough research or testing done yet to find out the ultimate cure for this.

As said, one of our STi's was spiking to 1.7 bar, this has now had the exhaust replaced with the original one as 1) we do not want the engine to go bang, and 2) do not want to be part of the development process for a cure.

It will be fixed, when more cars are worked on.....

 

Hi Elondan

STi was *very* fast when decatted - but power delivery all wrong. Once the turbo hit 1.7 bar boost (around 3500 to 4000 rpm) it took off like a rocket, and torque steered all over the road. Not actually very nice to drive.

The UK STi7 is actually 261.5 bhp (265ps). Main engine changes over JDM version are reprogrammed ECU, multi hole injectors, bigger catalyst and modified air-fuel ratio sensor to meet Euro3 emission controls.

The best indication I can get is that it will be at least 4-6 weeks before the PPP will be available in the UK.

 

What will the PPP be? i.e. BHP, torque and cost????

 

Prodrive are not saying at this point what power and torque the PP develops, and are notoriously conservative on boost levels, but bar talk on here says somewhere between 300 and 315 bhp.

Final spec not signed off yet anyway, and according to some sources it *may* include a new downpipe with sports cat which will put the price up.

Spec is similar to the WRX one which is £1600, and I would expect a small premium as it is for the STi, and of course if it does have a new downpipe this will be on top of this figure.

Full decat/Unichip will work out similar, but of course you have no warranty issues with the PPP

 

Thank you,
and how where you impressed with the performance while decated?
is the 265hp (compared with the Jap's 276) due to the cats, or is it also a different ECU?
one last question, do you know of any PPP due to hit the market anytime soon for the STI?
and again thanks.

[Edited by elondan - 4/7/2002 12:41:21 PM]