Texas_WS6

iTrader: (9)

I know that if you make a sh*t load of internal mods, a LS1 can handle alot of BMEP. But what I am after is does anyone know exactly what is the max BMEP a stock 02 LS1 can handle?

I am running an NX 150 wet shot and I think I am pulling 325 BMEP from 2000 down to 300 BMEP at around 3500 with the juice. I am getting the ATI D1-SC Procharger kit and I am trying to calcutate how much BMEP my engine will see if I use the NX system with the D1-SC but lowerring the juice to 50 or 75 shot and utilizing a window switch of 4000 to 6500.

Does anyone have the cam specs for the stock 02 LS1 cam? I am talking all the specs, IVO IVC EVO EVC ICL ECL etc. ?

Texas_WS6

iTrader: (9)

TTT

99 Black Bird T/A

iTrader: (4)

For us dummies out there, what is BMEP?

Nickn20

Brake Mean Effective Pressure you are pushing it with stock internals anything past 450 rwhp, you can calculate BMEP from that..... lol

Texas_WS6

iTrader: (9)

Actually, 450 rwhp is not exactly acurate. BMEP is figured off of rpm, torque, and Cubic inches of an engine. So as inches goes up you can make more power before you reach a specific BMEP. Also the higher the rpm the more power you can make before you reach that max BMEP. So if you go with the Stock 346 inch that the standard 5.7 LS1 is, and you say 300 BMEP is the max the engine can handle without prematuraly failling. Then the max Torque at any RPM you can make without dammaging the engine is 688 LBS. So if 688 lbs= 300BMEP at any RPM then the fallowing HP chart would be the max safe HP you can make:
RPM HP TQ BMEP
2000 262 688 300
2500 327 688 300
3000 393 688 300
3500 458 688 300
4000 524 688 300
4500 589 688 300
5000 655 688 300
5500 720 688 300
6000 786 688 300
6500 852 688 300
7000 917 688 300

So as you see, the max hp goes up to make the same torque and BMEP. Now these numbers would be what the max Safe HP would be at any given RPM if you decided or knew for a fact that 300 BMEP is the max the engine can handle. Also, if you incress the cubic inches, and keep the same max 300 BMEP then the engine can make more torque and HP before reaching the 300 BMEP limit.

Here are the formulas for each.
BMEP=(HP*13000)/(L*RPM)
L= Liters
1 cubic inch= 16.39 cc
80 cc= .08 Liters
346 cubic inches= 5.67 Liters

HP=(TQ*RPM)/5252
TQ=(HP/RPM)*5252

So I ask again, does anyone know what the max BMEP raiting on a stock 2002 LS1 is?

Texas_WS6

iTrader: (9)

BTW 450 rwhp would work out to close to 175 BMEP at 6000 to 6500 RPM. That may be the true number I am looking for. Do you think 175 BMEP would be the max?

Texas_WS6

iTrader: (9)

Any thoughts any body?

Nickn20

I think nobody really cares too much about what you are looking for 450 rwhp is about where I would not be suprised if the motor let go for any specific reason period for stock internals, I said 450 rwhp, becuase that is a specific amount of TQ at a given rpm. BTW spraying below 3000 rpm is a bad idea, IMO

CAT3

iTrader: (9)

Not educated on this, but it is interesting. Seems a GM Engineer should be able to answer the question, hmm might have to call Dad (retired GM R&D).

Sprayin below 3k cause the torque spike I take it? If not that and because of puddling due to the charge stalling in the intake then go DP.

Would like to know this info more for S&G than anything else.

Joe Kizzire

This guy is asking a question that he already knows the answer to with a chance that someone will ask him what he's talking about. Then he will get to impress us with his knowledge.

Remember the old saying... If you can't dazzle them with your brillance just baffle them with your bullshit.

99 Black Bird T/A

iTrader: (4)

Ok let's see if I get this...BMEP basically means at what point does the extra power your making start to shorten the engines life?

Cal

iTrader: (1)

Most hop-up mods done to any engine work by increasing cylinder presure, with the exception of things like pulleys that reduce parasitic losses. And anything you do to increase cylinder presure will result in fewer hours between rebuilds, it's a fact of life. But if you run an LS1 at 7000+ rpm the oil film thickness gets very small and you will see very accelerated cylinder wear.

Freak

you know, this is EXACTLY what I was thinking when I saw this post earlier.

Nickn20

yep that about sums it up, also spraying below 3k rpms create a lot of cylinder pressure, and the timing tables are more than likely not used to that as well, so you will either detonate, pop a head gasket, or both, maybe even snap a rod? hehe

Texas_WS6

iTrader: (9)

No, I am not trying to impress anyone. I do know what BMEP is and does but that is not the point. I am just trying to figure out what is considered max BMEP for a stock LS1. Some engines can handle more BMEP then others. If a person knows what the max BMEP a specific engine can handle then he can figure the max torque and HP the engine can handle at any given RPM. With this knowledge we can Accuratly figure when the spray should not come on and what we need to do to the engine to handle the expected power output we are trying to reach. I see alot of guys asking what is the most power the LS1 can handle and so far the only way to answer them is with guesses. If you figure the BMEP of a specific engine then you can give them an Accurate answer.

I am not trying to start some flaming thing. I think some people have mistaken my intent. I do know what BMEP is and I do know how to calculate it. I do know what it will tell us and what it's out come is. I just don't know what the MAX limit is for the LS1 and was hopeing some one here might know the answer. So please do not FLAME me or anything. I am just tring to help and learn at the same time.

Cat3, please ask him or ask him to ask someone he knows still there. I have asked GM this question via e-mail but they will not give me the answer do to their fear of being sued and warrenty issiues. They just don't like to give up that kind of info to just anyone.

I know most people consider 300 BMEP the max for stock engines. If you take that as the max mark then for a 346" engine you should never exceed 688lbs of torque at any rpm. Thats Flywheel torque. But remember when you incress the Cubic Inches of an engine, then it will develope less BMEP with the same torque.

Anyhow, Does anyone know what the max BMEP raiting is for the LS1?

99 Black Bird T/A

iTrader: (4)

I know some of the guys with forced induction blow stuff up a lot. Might get able to get a lot of data points and the rwhp made when the engine blew up and calculate an estimated BMEP. Probably can get in the ball park. I don't blame GM for not letting that out, at least offically anyway.

Texas_WS6

iTrader: (9)

Thats a good idea! I will make a post and see what answers I get. Once I get several failure points I will do the calculations and then post the results. Thanks!!

383LQ4SS

iTrader: (33)

What your talking about is exactly why i set my nitrous up in several stages and always RPM based.

Now as far as your answer...tough call. I have seen plenty of stock bottom LS1s hit 550-600 rwtq on a regular basis and survive for long periods of time. Of course that is assuming there is no detonation which of course raises peak pressures sharply.

There is a local stock bottom, H&C LS1 that we copied my rpm based dual stage setup for...he is making over 600 rwhp right now. And has been making over 560 rwhp for several months now...no problems. I think it could go higher safely.

Texas_WS6

iTrader: (9)

What is the cubic inches of that and your engine?

VINCE

iTrader: (1)

346 and 383ci..