I've not had my car long, but am already addicted to Subaru's. I got a 99 uk turbo, its gots prodrive ecu, scooby sport de cat centre pipe and rear box, k & n panel filter at the mo. I was thinking of getting de cat down pipes and a decat turbo up pipe. Does anyone know what sort of bhp i would likely to have with all this?

Thanks for all your help.

 

260bhpish?????????? depends on the car and or mods

 

Thanks mate and it should be ok with those mods and the prodrive ecu running it. I prob will get a re map sometime in the future, but i managed to pick up the prodrive ecu for £200 and its feels really good at the mo. I just wanna make sure that if i decat i the down and up pipe it wont ruin the running of it.

 

You don't need to "decat the up pipe" as the up-pipe on the classic shape cars doesn't have a cat in it to start with, so you can save some money there. A good open neck decat downpipe won't do any harm and will give you both a few horsepower and better throttle response, but you might have to watch for boost spiking.

That said, think the MY99-00 PPP ECU was supposed to be used with a smaller diameter restrictor pill than standard. If you've just bought a secondhand ECU and haven't changed the restrictor, that should give you a bit of insurance. Worth fitting a good quality boost gauge now if you haven't already done so.

 

When you say boost spiking, do you mean over boosting? How much do you think it cost to get a boost gauge and fitted?

Cheers

 

????? The up pipe is the same size on any impreza and an aftermarket one is always better than a standard one once chansing figures The headers and up pipe will always help with performance as they will improve air flow to the turbo

As for boost spiking ??? thats why the cars are mapped for better performance and safer running

 

wiseyd i no **** all about cars but i have just fitted a boost gauge to my sti trust me if i can do it then you can
go to the group buys on here and look for pro sport gauges there what ive got and thay are not bad of course im sure some one will say get defi's but at the price of one of them i got 3 prosports and thay do what thay say on the tin

 

did you get just a boast gauge and where about does it get fitted in the interior? Do you wires for it attach to the turbo?

Cheers

 

Yes and no. They're all "the same size" and general design, but the early newage WRXes have a very restrictive pre-turbo cat in the up pipe. Wisey, via his comments that he was going to fit a "decat up-pipe" seemed to imply that he thought he had a cat in his, which of course he doesn't.

Yes and no. You're right to say an aftermarket up-pipe replacement can, in general, help if you're looking for big power gains but at the level Wisey is at just at the moment, as he doesn't have the rubbish cat one in there, it'd be a waste of money replacing the OE item - which isn't that bad in a low power TD04 installation. In fact it's probably better than many of the aftermarket alternatives at this level of gasflow.

Yeah. It means that when you go from a "part throttle" to a WOT situation in the engine's powerband, the boost can shoot above (sometimes by a big margin) the target level and also possibly oscillate above and below for a while before the ECU can stabilise it. It isn't good for the engine as the overboost can cause transient det, and can be a right pain from the driver's point of view, especially if it takes you into fuel cut.

How long is this here piece of string? The best thing to have would be a gauge that records or datalogs to a file you can examine on your PC. That way you don't have to rely on looking at it while you're driving. They're obviously more expensive than a simple mechanical one so to a degree you get what you pay for. Fitting is, as Chris says, not that difficult at all.

To fit a mechanical one you need to run vacuum hose from the inlet manifold into the cabin. The electronic ones need a wiring bundle run in the same direction. Where you put it inside is up to you, there are plenty of places. Important thing is that it's in your eyeline.