ricochang

Hello everyone, Just finished accumulating all my mods. Currently, I will be running an Evo 9 turbo, open o2 dump, 750cc injectors and a 3" exhaust. I am not sure where I should call it quits on boost. My car still has the stock bottom end but only 59k km on it. Ive read that evo 4 pistons are weaker than later models so what power level should i call it quits at?
Was planning to run around 320 WHP. Im guessing detention would cause engine failure if the pistons are thinner than later models but whats a safe number you guys would call it quits at?

RS200

iTrader: (1)

The Evo IV is notorious for having a lot of weaknesses in the engine - crankwalk, weak pistons, cooling, oiling. The pistons have weak ring lands, so the slightest hint of detonation will take a chunk out of them, and they just don't deal well with power. Even with a rock-solid tune, I wouldn't run it much past your goal unless you want to be picking up pieces.

ricochang

Yeah not planning to go much higher. Crankwalk wont be a issue tho, adding power doesnt necessarily cause it more of a clutch thing? I think ill stick to 320 wheel or so.

barneyb

I think the reason these engines crank walked is still an untold story. Make sure the oil squirters are clean and not stuck open.