sturu

thanks for that so if i want run the 450-500 reliable what do you thinkis my best routecos i don't mind the money aspect but need the relible side of things and the ablity to have serious fun with out the worry of failure

john banks

On a 2.5 I simply wouldn't bother going beyond low 400s if you want it reliable based on present evidence, choose another engine size - personally I think 175 BHP/litre is more than enough to ask out of any engine and expect it to be long term reliable, as well as driveable with a nice fat powerband, but opinions vary widely. You may have issues with any or all of piston slap, costly builds, seemingly random failures, delays and expense, as well as a narrow power band if you choose wrongly though.

Low 400s is still plenty for a road car though IMHO, I'm no longer dreaming at night how to make it faster, as it has felt fast enough for some time, on a challenging road it is often left on the low boost setting as the extra power and torque unsettles the car and makes it too frantic. Let some other people prove it first if you don't want to risk reliability.

buzzard

i agree with just about everything john has just said in his post. while electronics is my trade i have a huge interest and love for machinery , particularly cars. i have just built my own 2.5 engine which i am very pleased with. however i did not build it for more power,but for better reliability. having owned some very hi power/hi torque cars such as a rebuilt and modified 300zx 3L twin turbo that no subaru or porsche was able to keep up with, it was always in the back of my mind.."when is this going to let go" which i have to say took an awful lot of the pleasure from driving it. i have had 4 EJ20's die on me and very nearly said fek these subarus, they are a pile of ****e and do nothing but break my heart and my wallet. just recently i had to sell my R33skyline for extra cash to give subaru another go BUT with an engine thats more likely to last a half decent length of time. the 2.5 was the obvious choice. i intend a 300/300 set-up which isnt much above the 2Lspec. i think i would be a little more conservative in my expectations of reliable power from these subaru engines. personally i think 120bhp/litre is "relatively" safe with standard internals so 300 on the 2.5 should still be more reliable than the factory 2L wrx. time will tell.

GRIFF007

I have to say that I have had my first full exploratory days driving an Impreza yesterday - 03 UK STi Prodrive on Optimax with 5 deg ambient - what an awesome machine it is ...... now I have always been a power freak (had a Griff for nearly a decade, and semi designed a Porsche 944 Silver Rose engine replacement conversion to an approx 6.5 chevi alloy V8 with nitrous - target 450-600 bhp.....) - well, I guess I am getting older - having nailed the Scoob wherever it was safe to do so, and without throwing it around - ie mainly acceleration sprints at full throttle for the best part of the day - I came to a conclusion -- if this is 300bhp and less torque - I dont need 450!!!! - In fact I was contemplating just how useable a T25 would be -- I would consider that a realistic max for the road - never thought i would say that - but the roads are just toooo crowded and restricted now - I will also throw in for controversial good measure that a top spedd of 125 ish would also be fine...

Would like power to be available above present 2700 and not to trail off so much approaching 7000 - The ECU definitely allowed more and more power throughout the day, to the point where I actually suspect whether or not this is still a Prodrive basemap - frequently pinks slightly and brieifly through the sprints - now stays hard on boost through 6000 - stammered and flattened above 4500 when I collected it from Dealer - he had been running it on 95 - se separate thread..

Anybody know who owned C8 LEP ? - Certainly the strongest pulling Prodrive STi I have tried.

vulnax999

iTrader: (7)

That'll be the ECU learning once it gets proper fuel ... the newer models adjust advance etc. in near real time, unlike our older ones that take hundreds of miles ( or a reset )