how much boost can a stock lt1 handle?

how much boost can a stock lt1 handle?

0 psi... this question gets asked a lot but the answer is the same every time. People always look for some kind of assurance from some board members that they have a chance to safely run boost. However, there is no safe boost... with 4-6# and good conservative tune AND safe driving (most important), people have gotten upwards of 30k out of the stock motor. Do not expect that much though.

well is there any way to get a t-trim down to around 6 or 7 pounds?

Originally posted by Frans96SS
well is there any way to get a t-trim down to around 6 or 7 pounds?

Sure, just pulley it down to produce the desired boost. But don't assume it's "safe". The motor is just not very tolerant of boost in stock form. The CR is too high and the hypereutectic pistons, while fine for NA use, even with some modding, are just not appropriate for boost.

Rich Krause

If you purchase a T-trim and use it with the factory pulley set-up (6 / 3.33), it will only make 6 - 7 psi on the stock engine. The T isn't very much bigger than the S trim.

Your question about the boost a stock LT-1 can handle: do a search. This question pops up weekly.

Mike

oh i thought the t-trim cam with around 10 stockso if i have enought fuel and a good tune will it be ok for a while

Originally posted by Frans96SS
oh i thought the t-trim cam with around 10 stockso if i have enought fuel and a good tune will it be ok for a while

That's not what anyone said from my reading. No boost is "safe". The stock T-trim kit comes with the same pulleys as an S-trim, last kit I looked at. I would expect ~7psi on a stock motor, like Mike said. But if you concerned about the cost and bother of swapping a pulley, you better think about this a bit before you go ahead. A word to the wise..........

Rich Krause

Originally posted by rskrause
That's not what anyone said from my reading. No boost is "safe". The stock T-trim kit comes with the same pulleys as an S-trim, last kit I looked at. I would expect ~7psi on a stock motor, like Mike said. But if you concerned about the cost and bother of swapping a pulley, you better think about this a bit before you go ahead. A word to the wise..........

Rich Krause


no im not concered about the cost at all i was just curious

Originally posted by Frans96SS
no im not concered about the cost at all i was just curious


Then put it on blow your motor and build a real blower setup. No psi is safe on a LT-1.

My setup lasted about 95,000 s/c miles, but the FMU went south and I am sure that is when I cracked #1&7 ringlands. In any case did a easy rebuild and put forged slugs,etc, freshed up the motor & new seals in the blower and now back in the fight.

Originally posted by ATMINF
My setup lasted about 95,000 s/c miles, but the FMU went south and I am sure that is when I cracked #1&7 ringlands. In any case did a easy rebuild and put forged slugs,etc, freshed up the motor & new seals in the blower and now back in the fight.


how much boost were u runnin

I ran my stock engine with about 6 psi for 8,000 miles or so and just rebuilt it over this past winter. I found a broken top compression ring in my #1 cylinder. Not sure how badly it was effecting performance, but I never noticed it while driving......obviously not good for the engine though.

Don't know when it happened either. But I was running basically stock timing advance tables with just mixing in race gas to avoid detonation, no BTM was being used. With reduction of the timing, I sure that broken ring could have been avoided.

You can run 6 psi and be "OK" as long as you're running GOOD gas (higher than 93 octane) and reducing the timing. But beware that a rebuild will more than likely be necessary soon. You just never know when it's going to let go, these engines weren't designed for boost.

It runs about 7-10 psi, depending on the outside temp and elevation. I ordered it as a 7 psi sytem but it has always run a little higher that that.

You people make me sick. A stock bottom can hold boost but just not much. My friend went 140,000 miles with a supercharger a 6psi( He is not the only member in my car club to go over 100,000 with a blower) but you just can't throw a charger on there. He took steps like a larger fuel pump(fmu suck), A intercooler is a must and retard his timing I think 8 degrees. And you want to get good plugs, and bigger fuel injectors. :eek: I think thats all. I will have to ask. But yea compression ratio is on the high side you just have to work around it and hope that you don't get predetation. Because that how motors go boom. And another thing is be beefed up his cooling system.

Leaving aside the dispute about "is 6psi "safe?" there's something else to consider. 6psi on a stock motor doesn't add all that much performance. Maybe 75rwhp, certainly not more than 100rwhp. Headers will help a lot, but even with headers, the performance increase may not be what you are expecting.

If there's a theme here, it's that most of the people who have "been there and done that" don't recommend a blower on a stock motor.

Rich Krause

I picked up 130rwhp, and 119tq on the dyno seeing 6-7lbs to the gauge during the dyno run. It may be a freak. Just comparing to what Mr. Krause said.

Originally posted by DJ:BOTA
I picked up 130rwhp, and 119tq on the dyno seeing 6-7lbs to the gauge during the dyno run. It may be a freak. Just comparing to what Mr. Krause said.

I'm surprised. Was that on a stock LT1 with a stock exhaust? Even Vortech's optomistic literature doesn't claim that. Headers make a huge difference on a blower car. I have seen numbers like your with headers, but not without.

Rich Krause

Stock internals, BBK shorties, and a cat-back flowmaster less the cat. I have the 2 core intercooler on my Procharger.