how much boost can a tbi350s bottom end handle?
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Car: Chevy truck
Engine: supercharged 355 tbi
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Axle/Gears: 14 bolt w/4.56 and detroit locker
how much boost can a tbi350s bottom end handle?
i have a basicaly stock 350 tbi motor, its the truck motor so it does not have have a roller cam but other than that its the same motor you guys have. heres what im running, a whipple supercharger, bored throttle body, 80# injectors, methanol injection, and im tuning with a moates ostrich 2.0. the motor is a 2 bolt main, and i am peeking about 12 pounds of boost wide open at 5000 rpms, but for the most part, the truck doesnt see much more than 8 unless im either tuning or plain out drag racing it, which shouldnt be often once im done tuning.
so what do you guys think, its never crossed my mind before, but it is pretty obvious that this is alot of boost for a stock motor.
im building a 383 for it next summer with forged internals and it will be built for the blower, but for now, any one think its a big deal to run 12 pounds through this poor abused 200k mile motor for another 10 months till i build a new motor?
would it be wise to run the truck all the way down the drag strip pushing 12 pounds at a stock motor?
so what do you guys think, its never crossed my mind before, but it is pretty obvious that this is alot of boost for a stock motor.
im building a 383 for it next summer with forged internals and it will be built for the blower, but for now, any one think its a big deal to run 12 pounds through this poor abused 200k mile motor for another 10 months till i build a new motor?
would it be wise to run the truck all the way down the drag strip pushing 12 pounds at a stock motor?
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Re: how much boost can a tbi350s bottom end handle?
its all in the tune..12 lbs is fine with a good tune. No detonation = no breaking ****.
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Car: Chevy truck
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Re: how much boost can a tbi350s bottom end handle?
do you really think? its still a 2 bolt main bottom end. everything is pretty sound mechanically on this motor, it is very tough, and i have never ran it lean at 12 pounds of boost, the worse that happens is it will go to rich, maybe 10.5:1 worse case. but once again, its still a 2 bolt main bottom end. i read this reply no more than a minute after a read some one assuring me that my motor will go boom on another forum lol in my mind, i just couldnt see this motor going boom, i mean, it is just a really tough motor and has no real mechanical problems, the compression checks out at about 150-160, doesn't burn oil, its just a good motor, cant beet a good ole small block chevy....
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Re: how much boost can a tbi350s bottom end handle?
There is that one guy running around with a bone stock truck 350 (two bolt main) in his trans am running a big turbo setup..were talking like 700+ hp. He said he believes the key to his success is the fact that detonation is monitored extensively and he makes sure it never happens. Sure i mean parts do play a big part in the strength of a bottom end. But most failures stem from improper tuning and lean conditions. They say rich is safe and it's for the most part true. Plus 12 lbs isnt really THAT much, i mean for a stock bottem end i would say your still on the safe side. Everyone will give you different opinions though. I have 2 friends with mustangs..one has a 5.0 makeing over 400whp on the stock short block with 12psi unintercooled vortech. The other runs 15psi on a 3.8l mustang making over 400whp as well. It's all in the good tuning they both recieved.
But like i said, other people will say no no and that I'm wrong.
It's just like the arguement of nitrous..some say 100 is the limit on cast internals...holley says 20hp per cly so 150 is the limit. I run 125 right now and plan on going to 150 soon enough. Hell i run 8 degrees more timing then stock on 100 shot with stock plugs...even ran it on 87 once on accident. It's all in the tune...at least thats what i say haha.
But like i said, other people will say no no and that I'm wrong.
It's just like the arguement of nitrous..some say 100 is the limit on cast internals...holley says 20hp per cly so 150 is the limit. I run 125 right now and plan on going to 150 soon enough. Hell i run 8 degrees more timing then stock on 100 shot with stock plugs...even ran it on 87 once on accident. It's all in the tune...at least thats what i say haha.
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Car: Chevy truck
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Axle/Gears: 14 bolt w/4.56 and detroit locker
Re: how much boost can a tbi350s bottom end handle?
There is that one guy running around with a bone stock truck 350 (two bolt main) in his trans am running a big turbo setup..were talking like 700+ hp. He said he believes the key to his success is the fact that detonation is monitored extensively and he makes sure it never happens. Sure i mean parts do play a big part in the strength of a bottom end. But most failures stem from improper tuning and lean conditions. They say rich is safe and it's for the most part true. Plus 12 lbs isnt really THAT much, i mean for a stock bottem end i would say your still on the safe side. Everyone will give you different opinions though. I have 2 friends with mustangs..one has a 5.0 makeing over 400whp on the stock short block with 12psi unintercooled vortech. The other runs 15psi on a 3.8l mustang making over 400whp as well. It's all in the good tuning they both recieved.
But like i said, other people will say no no and that I'm wrong.
It's just like the arguement of nitrous..some say 100 is the limit on cast internals...holley says 20hp per cly so 150 is the limit. I run 125 right now and plan on going to 150 soon enough. Hell i run 8 degrees more timing then stock on 100 shot with stock plugs...even ran it on 87 once on accident. It's all in the tune...at least thats what i say haha.
But like i said, other people will say no no and that I'm wrong.
It's just like the arguement of nitrous..some say 100 is the limit on cast internals...holley says 20hp per cly so 150 is the limit. I run 125 right now and plan on going to 150 soon enough. Hell i run 8 degrees more timing then stock on 100 shot with stock plugs...even ran it on 87 once on accident. It's all in the tune...at least thats what i say haha.
Last edited by chevy1500z71; 10-24-2008 at 06:09 PM.
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