Foxmod

Can someone give me a straight answer?

When I de-cat my STI 8, apart from losing my warrenty, what are the other downsides?

what damage could I do my engine?
do I need to remove any sensors?

Any advice is greatfully recieved

Dave

[Edited by Foxmod - 8/26/2003 9:29:25 PM]

Brewstaa

I don't know much about 'em technically but I would say any modification needs a re-map to ensure things are running properly. I fitted a BOV which made the car back fire, stutter, stall on occasions etc.

I think the EMS's on these beasties are pretty trick, and any tickering needs to be done properly which I assume means £££££££'s

Only my opinion and it could be bo!!ox

ALi-B

iTrader: (1)

Damage to engine will only occur if you start running lean and detting

I can't confirm that a decat would make the engine run lean, but its a possibilty. A check on a RR would confirm any problems with mixture.

The only sensor that would be affected is the Oxygen sensor, Presuming your having a decatted downpipe the sensor would be swapped from your old down pipe to the new one.

Foxmod

Thanks guys -
so a re-map (£££??) and a sensor swap, anything else?

nellie

On a STI7/8 de-cat all that needs to be done is a restrictor fitted to the turbo(i think),if you contact scoobysport they will know all the details and supply you with all the right parts.

GREEN SCOOBY

can i just ask why would you want to de cat and loose a 3 year warranty in the progress? or are you just curious?

BretMan

Decat is fine provided you keep an eye out for boost spikes. These can be avoided by increasing the restrictor size slightly or using a flow control valve. In either case, a boost guage and knock link are good insurance.

As mentioned, Scoobysport can do this.

A ECUTEK remap will add more power but is not "required", unless you don't want to mess with restrictors.

drb5

iTrader: (4)

i read, from a guy on here that works for prodrive, that fitting a de-cat down pipe, actually LOOSES power. the engine therefore needs some sort of pressure to keep the boost up. he said prodrive had tried a few different ways of increasing power and a de-cat dp was by far the worst thing to do to the sti7/8.

i think that's what he said anyway. can't remember his name though.

dba

why not have a remap without the decat?

Foxmod

thanks all for the input

I think I can conclude that unless you want to spend the £££'s it may be better to stick to standard.

I Would consider just a backbox change (Afterburner or firestorm) but would this cause any problems with the engine?

Paul N P

Foxmod,

I went through your thoughts a year & a half ago when I got my STi7.

If you fit just backbox, you are unlikely to do any damage to the engine. This will naturally invalidate your warranty generally. One point to note though, is the Firestorm (TSL) is made by the same place that currently makes all the Prodrive exhaust systems for PPP, however with thicker material. Technically if you had a problem you would have a good case to argue the point. Speak to Paul @ TSL he will be able to elaborate on this, I believe they've got experience of this principle in practice.

In terms of full decat (which I did, but used sports cat in centre section), nellie is correct, restrictor change does control the boost spikes. This is definitely not messing about, moreso a quick & easy job by those in the know! You will see 300-310bhp easily with decat/restrictor change, and more bhp without the restrictor although with sh*te overboost control.

Be a bit careful with just decat/restrictor option though, overboost is controlled, but boost control is not brilliant via standard ECU settings. Although the car ran well I eventually went down the EcuTeK route, which is absolutely superb. Prior to that there was a tadge of neg knock correction, causing slight timing retardation which was basically due to poor boost control of standard ECU, although not engine threatening

All in all though, OK-ish with just de-cat, but much safer with EcuTek plus you see 330-350bhp depending on mapper, exhaust system and boost levels. The main benefit is the flatness of the torque curve though, mine is absolutely flat from about 3300rpm through to just over 6500rpm and drives like a dream.

Mail me offline if you want anymore info, I picked up quite a bit last year on this subject.

By the way, fitted Power Engineering T75 system and car was mapped by Mervyn @ Power Engineering/EcuTeK. Top bloke!

Paul