scooby_will

Hey all i will be going down the route of the 2.5 bottom end soon as my classic's engine will soon be popped with it having 144k on same engine and starting to make some nasty noises.

I am aiming to build a car which is capable of 650hp but not run it, i will be running it at 450hp but want all my parts to be safe to run up to 650hp, i am doing this simply to have yes a fast car but also one that isnt running at full capacity.

What i need to know is what sort of heads will i need to be running as my uk turbo ones simply wont do it so will sti ones with work or am i looking at different to that?? also will the sti heads work on my intake manifold, thanks

scooby_will

bumpty

FB Tuning

iTrader: (30)

If you are planning on fitting ALL the supporting mods for a 650hp capable car, then be prepared to be tipping in LOTS of money

scooby_will

well i think i may have worded this incorrectly, basically i want a 450hp road car with simalar if not more torque, basically what i meant by car capable of running 650hp is that it isnt running at full potential at 450hp as this would be fast for a while but not last long.

I just need to know if my heads with modifcation will be able to produce 450hp+ or am i best of gettin a set of v3-4 heads and having a smaller amount of work done on them

My other question then if the sti heads are the case will my intake manifold fit onto these as i dont want to have to change all the wiring loom bits to suit.

Things like my turbo and injectors will need to be ones that max out at around 500hp, just mainly the main engine parts such as short block and heads that need to cope with more as this will make it a far more reliable car.

Syph

Cosworth!!!!!!!!!!!!

finchyboy

An engine that will run 450 bhp safely can be build reletively cheaply. To build something that will handle 650 bhp it gets very very expensive !!!

dazdavies

iTrader: (22)

You'll have to do a some strengthening work.

The stock 2.5 block will NOT cope with 650bhp. You'll split the bore where it's recessed for the block bolts.

I like a few others have used 2.0L closed deck blocks and then bored them out and sleeved them.

If you've not considered this do a search for Chy Wright from Penine Subaru.
His 2.5 forged closed deck 2.5 short engines can be had on ebay from roughy the £4k mark and are reputed to be good for 800bhp.

But 650 on an untouched EJ257 casing just isn't going to happen.

Heads wise you'd be far better of with some STI items as the cams will allow for more flow.