Fiero, are you talking about boosting an import or something?

I'd for a stock LSx longblock, with stock head bolts, I'd go 10-12 psi and then I would use better head studs. Might do 15 psi but beyond that it's just a matter of time.

 

No, boosting an import is fundamentally the same as boosting an LSX.

I'd say the boost pressure means absolutely nothing, considering a stock LSX longblock can be safe at 100psi yet blow up the second it sees 5psi. Boost pressure means nothing, and has no affect on the engine's reliability/durability.

 

I think that you're totally confused Fiero... Where as you CAN flow the same cfm with 5psi on a good flowing engine as 8psi on a not so good flowing engine there's going to be more to it... Even though it's a representation of "restriction" it can still affect the longevity of the engine because the more boost the more it heats up the air velocity going into the cylinders... Why do you think it's much more beneficial to have a intercooled 8psi vs a non intercooled 8psi... Because the more boost there is the hotter it's going to get...

Just a side note this IS an information forum board... I.E. not all people start out at the same skill level and come here for assistance... I'm sure at one time you didn't know all there was to the godly fiero engine and you needed some assistance... I can understand you giving him a hard time about newby stuff but this isn't an isolated incident... Condescending is not a quality revered by many as a good trait to look for when asking for information... There are plenty of other people that have been there and done that before and have seen these questions a million times BUT they don't choose to act as if it's below them to even help... If it's too much for you to help someone along then why post??

for everyone else I'm sorry for posting this but I'm just sick of seeing these type of people only coming into a thread just to show their extensive wiseness... This is an LSX forum but I respect all enthusiast equally except when they try to prove that someone is lesser simply because they look for a little help..

 

ALL boost pressure is is a measure of restriction. It isn't a representation of "restriction," it is restriction. Also, boost and air temps are not directly related. In fact, on my turbocharger on my engine, it is more efficient at 10psi than it is at 5psi, meaning less heat is added tot he intake charge. So while in some parts of the map they are related, it is not all. Furthermore, the flow through decides a compressor's efficiency just as much as the pressure it builds. And while the temperature does matter, that A) isn't why the poster is worries, and B) isn't a thought of the repliers who blindly said 10spi or whatever. The IATs aren't what we are worried about here, because those are easily lowered and taken care of to the point of ambiance in a variety of different ways.

So you'd rather see 50 ignorant people with absolutely no idea his setup, his compressor, or anything else about his car blindly suggest a number that means nothing? You actually want this guy to average out the pressures suggested, and run that because he assumes it's safe? That's NOT spreading factually correct, helpful knowledge, that's spreading ignorant opinions that can have a very expensive affect.

 

I think you are generalizing too much. You can boost some small cube imports to 45psi, but it would be hard to boost a stock LSx to 45psi and it would probably not survive more than one or two dyno pulls. Remember that a 45 psi Supra TT also has aftermarket head studs and other work.

My built 348ci has seen 26psi, and for it to take 45psi would require more work.

 

I'm not going to get in a pissing match with you bro.. I'm just saying it's not THAT you're delivering your message but HOW... That's it..

to the thread starter, good luck and be careful...

 

I guarantee you a stock LSX can handle 45 psi. If you provide the compressor, I'll donate my 17,000mi SS Camaro to the cause, and I'll let it peg 45psi. Hell, if your compressor can handle it, I'll go up to 100psi. At the same time, I guarantee you cannot find me an import enigne, that I get to build using parts we agree on, that can take 45psi. Hell, I helped a friend build one (A built motor), that snapped a forged H beam connecting rod at 14psi.

I can make your LS1 handle 45psi in about 10 minutes, at a cost of about $10.

PSI means absolutely nothing. The only reason to have a boost gauge is to detect a failure of a part.

 

I would LOVE to see this... Would there be video??

 

I think the original poster wants to focus on what can be done, not the blow it up to prove a point approach.

I'm just saying that there is a lot of evidence out there that would say that 10-15psi is possible with a stock longblock, and I think the first thing that would be problematic would be the head bolts. Then the ringlands.

 

wow, I'd pay to see that myself. Then again I have boost over 250psi on my bicycle

 

If he wants to bring the pressurizing device, I'll do it.

CFM > PSI.

PSI means absolutely nothing. It is a measure of how poorly designed your engine is, and a notifier of failure in a pressure producing/controlling component. What blows up engines, what creates HP/TQ, is CFM. 10psi is a f*ck load of horsepower if done at 10,000cfm, and it is sure to make spaghetti with meatballs out of your stock short block. But 10psi at 10cfm isn't enough to move a Geo Metro, and isn't enough to even idle an LSX.

 

i got a question. lets say he has a turbo that flows alot of cfm. and runs around 10 psi. isnt there a point where the amount of boost isnt the question but the amount of power your making? from my lurking on here i thought about 600 rwhp was about all a stock long would make and still be reliable?

 

That is basically my point. The boost pressure has no affect whatsoever on how long the shot block will last. It is the power it makes, the maintenance, and the tune. Assuming proper tune and maintenance, the power a block makes is one of the only things that will cause it to blow (Disregarding oiling/cooling failures). And the power an engine makes is in direct relationship to how much air is brought in, which is the CFM. So if his engine flows very high amounts of air (CFM), it will probably make a lot of power, and probably blow up a lot sooner than if he made less power (Lower CFM).

Notice boost pressure has no affect on this. That is because my LS1 might make 500rwhp at 15psi, while some other guy's will make 500rwhp at 10psi, while John Doe's won't make 500rwhp until 20psi.

So the much more correct answer would be a power figure, say around 500rwhp (Assuming that's right, as I haven't blown up an LSX).

Edit 600rwhp to 500rwhp, I stand corrected.

 

500rwhp is the max you want to put on a stock engine and consider it in the reliable realm. And that will most likely occur with 8psi from a P1 or D1 procharger. There, that is the 'generalized' answer.

 

Boost pressure does have a direct impact on the life of a longblock, especially a stock one. Why wouldn't it? Lots of things can kill a stock motor, like heat, head bolt stretch, oiling issues, hypereutectic pistons breaking...

500-600 rwhp, stock longblock, 12-15 psi would be the max IMHO.

 

12-15psi? It would take that much psi to make 500-600rwhp? Not to call you out, or anyone else...but remember he did upgrade to a T67 turbo, which that turbo alone is good for about 600-700hp, for one..not two of them. Furthermore, I could slap two GT30R's on my bone stock LS1 w/ the same STS plumbing and hardware and run it to the dyno shop to tune. I bet anything that 500whp could be seen out of my kit with less than 7psi. Most kits I've heard of are normally putting down 500-550whp @ 6-7psi with the kit alone and some solid tuning. I couldn't imagine anything like 12psi on a stock block.

I would stud the block, upgrade the fuel pump, make sure injectors are going to run at a good duty cycle for my hp goals, and take that sucker to a dyno shop to get tuned. I've always understood that 550whp is pushing the envelope on a bone stock motor.

 

I dont think anyone asked whatthe most power you could make, the question was how much boost can you safely run.
The voices keep re-aranging the question. I think i'll try running 45psi tonight when I get home.

 

We're very sorry for offending your sensibilities, oh wise one. We are not worthy.

To the O.P., again, I would run 7-8psi, or maybe 10-12psi with meth on your turbo setup.

I am personally am running 7psi with my blower setup and 98 octane t be a little on the conservative side.

I wish I could use the vast wisdom of FieroZ34 in my setup, but alas those unworthy fools at ProCharger and/or ECS can only recommend me pulley sizes based on about what psi I will see with each size on my LS1.

 

Did you read my posts? Please do. Boost pressure has no affect on any pat of your engine. None. It means nothing. All it is is a measure of how poorly designed (aka how much restriction), is in your induction side, and if there is a failure of a pressure producing/controlling component (Wastegate, BOV, turbo, etc).

Did you take DA into account with your know all 12-15psi? Because 15psi at 7,000ft altitude in Colorado isn't the same as 15psi in Death Valley California. One will leave you with a decently quick LS1, the other will leave you with a rod out the side of your block. So don't tell him 15psi when 15psi can easily blow a stock short block to pieces.

Did you read my posts? The boost doesn't matter. A LS1 can be just as safely run at 5psi as it is at 100psi, so long as the IATs are the same and the CFM is the same. Boost doesn't blow motors, CFM and hp do. He wants to know what is safe, and you all answered with a pressure number that has no affect on the power output, longevity, durability, or reliability of his setup.

Don't just turn your **** to 45psi, that isn't what I said. You need to restrict flow, that way you don't have 45psi of air making it into your cylinder, because that will blow it up very quickly. So put a 2" restrictor plate in front of your throttle body, then run 45psi read from in front of this plate. You won't make anymore power (Probably less), but fact is, you'll be seeing 45psi. This is essentially what a cylinder head is and does, it restricts flow. So you may see 10psi before your head, but into the cylinder, at most 8psi.

How can ProCharger know how much PSI their pullies will make? In order to do that, they need to know the VE of EVERY engine combination their blower is put on. It isn't possible. It is mearly an educated guess. Because I guarantee you a pulley for 10psi on my stock LS1 will have trouble making 4psi on a built 427. Pulleys don't change pressure directly, they change flow levels. Since the engine is inherently poorly designed (aka a restriction to flow), the FLOW produced by the blower overcomes that of the engine and creates pressure. But the pressure it creates depends on the efficiency (Read volumetric efficiency), of your engine. They can't/don't know these VE numbers, so they guess.

 

I would push a bone stock motor, head bolts and all, to ~600rwhp. I was also saying that I would push it to a max of 12-15psi. Now in a blower car, a stock LS1 would make 350rwhp with headers, and so 10 psi might bring the car to 600rwhp. H/C LS1's with blowers make 575-650rwhp all the time.

I would expect a bonestock LS1 to make 700rwhp with 15 psi and M6, but it wouldn't last long.

This thread is all about generalizations, and your turbo example is cool again how many old Incon TT guys made over 600rwhp with a bone stock longblock... Not many.

Though most of the time it's because guys are spending money left and right and don't leave engines stock very long.