how much boost?

[gipper72488]

ok guys this question has nothing to do with a 3s platform. a buddy of mine is looking to boost his 3rd gen formula, with a 305 motor, freshly rebuilt. i believe that it runs a 9.5:1 compression. everyone on his board are to busy arguing to give him an answer, and seeing as how you guys have more experience with boosted motors, i figured id ask. what boost could he safetly run? i was thinking 8 psi. any help would be greatly appreciated

[Hammer]

Originally Posted by gipper72488

ok guys this question has nothing to do with a 3s platform. a buddy of mine is looking to boost his 3rd gen formula, with a 305 motor, freshly rebuilt. i believe that it runs a 9.5:1 compression. everyone on his board are to busy arguing to give him an answer, and seeing as how you guys have more experience with boosted motors, i figured id ask. what boost could he safetly run? i was thinking 8 psi. any help would be greatly appreciated

You of course already know the answer. You log engine knock and turn up boost until you log knock then back off.

If someone tells you he can run 10 psi safely would you tell him set it for 10 psi and run the car like that? Of course not.

Next question is how much does your friend value his new engine? Enough to log knock perhaps?

You also know that he should run the highest octane fuel he can get if he wants to boost that engine right?

For the test you probably want to start at 6 psi and increase 1 psi at a time
while logging for knock.

Something else to consider if he wants to convert to E85 fuel then he could
run a few psi higher before he counts knock and produce more power but then
he would always have to run E85.

[gipper72488]

thanks for the help, im still learnin the FI ropes, and im lookin to boost my stealth soon. ill show him your post. thanks

[jandoaudio]

Theres way more to it than when does it knock. Whats on it for heads, rods, pistons, and crank all dictate the boost limit not knock. The injector size will determine the amount of fuel available which will determine the amount of air that can be run through the motor before experiencing knock. Don't forget timing either

Why did he stick with the 305 instead of a 350? What tranny and can it even handle a boosted motor?