what is my 96 wrx bottom end/piston able to handle?
 

can anyone tell me what my 96 wrx bottom end can handle power wise? (i.e pistons con rods and crankshaft)

depends on application, and the way you drive, andy forrest recons around 400bhp on standard engine. but i dont know for how long!

Thats a great help thanks! can't belive they can handle thats power standard!!

engines are amazing things as long as they are warmed up corectly, kept in good oil and water, ran on quality fuel and are not asked to make too much power for a sustained time.

Be aware that the gearbox will no doubt be on borrowed time over 360bhp though! See the note at the bottom of the level 3 tune:-

http://www.andyforrestperformance.co.uk/58637.html

Personally, I would be happier running the early TY752 5-sp at <340bhp!...

Obviously, driving style/how you treat the 'box accounts for a lot though. Plus there is the element of 'luck' too...

good luck at 400 is all i'll say, that's extremly optimistic.

circa 350 is more about the level

i would have said 350 ish is safe any more is on driving style & luck & general health of the engine for more power

Don't forget that the WRX doesn't have 'forged' pistons (even then, the MY94-96 STi's "dogbone" forged ones aren't exactly that 'great' either). Plus, the bearings won't exactly be fresh as daisies on an original MY96 bottom end.

I agree with Tidgy and timmy.

They cant, your looking at around 330-350 and even then it can be fatal, it all depends on how good the engine is to start with, it will reduce the life expectency of a classic engine if you dont do the supporting modifications also, 330 would make for a fast road car tbh, 350 would really be the tops your looking at unless you had 3k or so spare to replace it when (not if) it goes bang.

Tony:)

this always amazes me. Fuji Heavy Industries invested tens of million of dollars designing and engine that was capable of 260 horsepower. tolerance allowances for say 10 - 15 % would make that about 300 horsepower. yet people reckon they can get 400 horsepower (an increase of nearly 54%) out of and enfine designed for 260.

They then wonder why the engine fails and gearboxes are spat out?

but there is no fun in being "safe" is there

Bit off topic as mines a uk turbo. I ran mine at 385bhp for two years before mine started knocking on big ends. Engine was totally standard. Gearbox lasted 2 wks, so ended up having 6 SPd fitted. There is a certain amount of luck involved I'm sure. I would say you ate better arroubd the 300 mark. Gearbox and engine will be under less stress, and it will still be a very respectable road car none the less.

the most i want out of the engine is 350, i will be more than happy with 320bhp. i know the engine wont last forever as its already 15years old!! currently running around 290bhp but would like a little more

If yours is a JDM saloon, then it will have the TD05H 16g turbo, so 320-340 is achievable for sure.

Really need a FMIC, and at least 440cc injectors, for 320+ (I'd fit 550s though, if it was me).

Also, a Walbro 255; cone filter (if fitting a FMIC); NGK PFR7 plugs; and possibly a later MY99/00 MAP sensor. Finally a remap (I assume you're already currently running a mappable ECU if you're already at c.290...?)

I ran my WRX Wagon MY95 at 385 bhp for a long period and with methanol we had a few runs over 400 bhp but when quoting these figures a lot depends on what rolling road(s) you are using. The engine ran like this no problem. I then fitted STi pistons and forged rods and ran at 420 bhp for a long time with no difficulty.
As already pointed out, your gearbox will give up the ghost before a well looked after engine running 380 bhp.