De-cat trouble
 

i'm fairly new to the scooby scene. I picked up my 1996 STi RA about a month ago and have loved every second. But like every one does..... i got hungry for more power and stuck the car in for a de-cat downpipe. its the type with the the open neck at the turbo, which i thought would be the best.

However, i picked it up tonight - de-cat intact - and am not impressed with it at all. Its lacking power, it backfires, it splutters if i really plant the foot. it has less power than before.

When i bought the car i was told it was chipped, looking at all the paperwork that came with the car, i've found a little booklet that says "booster chips". so i'm assuming thats the type of chip.

It feels like if i had enough road, it would be faster than ever, but the power is just not there, it doesnt throw me into my seat like it used to.

Any help would be very much appreciated.
cheers

Kyle

I think you need a remap, to get the ECU to work properly with the engine and mods, no idea on the chip / ecu mods you have, maybe some one on here will!
Sounds like it's over fuelling so fuel is "pop" ing at the exhaust .
Too much fuel may mean less power .. think of the bunsen burner in school chemistry .. open the air it gets blue-r and hotter! Close the air off and it gets yellow and weaker flame.

is/was the lambda in the downpipe?

Early cars had Lambda sensor in the up headers by the joint with the up-pipe. Later cars ( certainly UK 1996 cars ) had the lambda in the downpipe post turbo

well i bit the bullet today and got a Dastek unichip fitted to sort my problems. As the guys were rolling roading it, they tried to map it to 1.5 bar but it turns out the spark is blowing out.either plugs or more likely....coil packs. they mapped it back to 1 bar, still backfiring now and again but at least i know the problem. 305bhp at 1 bar. Coil packs R us here i come......

is uprating the plugs an option?

Harper, I'm more of a newbie than you are and, with our slight misifre, I'd be interested if you find a supplier of coil packs, unless you plan to go to a dealer of course?

Cheers

Grim

supposedly this is a common fault with scoobys. I'm thinking on buying new but they're quite expensive. As far as i'm concerned ifi buy second hand, they could be as bad as the ones i'm taking out. So i reckon i'll just go to Subaru for them.

Try ASPerformance or APi Engines for prices of coil packs. Somewhere around the £60 - £65 mark IIRC.

I have a used set that work up to 21 psi ( spark blows out before 24 psi ) which can go cheap tho' ... ;)


Plug upgraded usually to NGK PFR7B ( colder type by 1 grade ) when going to 300 plus levels.

Thanks Vulnax :thumb:

New genuine Subaru coil packs at APi £48.00 each plus postage and VAT.
Always in stock.

Call me if I can help.

David APi lmpreza / APi Engines
www.apiengines.com

I've got a set that of Subaru ones that have only done a couple of hundred miles PM if interested.