sti.dean

at what bhp do standard v7 uk sti heads become a restriction? also whats the max rpm theese will cope with
thanks dean.

Jolly Green Monster

iTrader: (4)

not much point going beyond 8k rpm due to other issues (pistons speed, VE dropping off etc)... few sets running around the 500 and a bit mark.. would be worth looking at replacing valves at that point and beyond really.. and therefore port etc.. not necessarily the heads causing a restriction.. more a risk of reliability.

Simon

sti.dean

thanks Simon, that was a quick response.i,m wanting to build a 500 bhp engine and was trying to work out what was useable from my motor to get some idea of costs involved. i,m running a 321h + all supporting mods at the minute but i,ve got used to it and i want more. not sure wether to go 2.1 or 2.5
any suggestions?

Jolly Green Monster

iTrader: (4)

the sti 2.5 block won't like 500 for long.. or rather the liners are very thin... some last, some don't..

so imho your choice is a 2.5 relinered CDB.. a 2.35 with either a relinered 2litre CDB to 97mm, 2.5 crank and 2.35 stroker rods and pistons or if you can find one a 2.2 CDB.. or a 2.1 using a CDB and 2.1 stroker etc..

I would go 2.35 or 2.5 CDB route.

Simon

sti.dean

in your opinion whats the most reliable power you can have from a forged 2.5
without relinering it
thanks dean.

Jolly Green Monster

iTrader: (4)

450 seem fine..

other ones are running about with more.. you just don't know if/when it might fail.

Simon

sti.dean

thanks for the info simon, gives me something to think about.

StuS

iTrader: (5)

What mods/power are you currently running Dean? I'm still trying to decide whether I should keep tweaking my current set up, or just to start saving for something a little more serious

sti.dean

321h,650 injectors,ss headers a upipe,k a n induction,3" full system with sportscat in second cat position instead of top of downpipe,simtec ecu,standard tmic. don,t know what power its running (not enough )
i,m going to scooby clinic for a power run in a few weeks time, i,ll let you know the results.

StuS

iTrader: (5)

I'd be very interested in your results since my v7 has been modded + mapped by SC. See my profile for mods + figures (recorded on SC's RR)