Mike96z

Alright, I have a 388 stroked 96 Z28. I am wanting to know what my engine is most likely going to be rated @ HP wise, like how much power can I put on my bottom end. For instance, thinking about spraying the motor so dont wanna surpass the limits.

Internals:

GM Powdermetal Rods 5.7 (Floated)
Eagle Nodular Iron Crank 3.75
Kieth Black 4.060 Pistons (Floated) 2 valve reliefs (Hyper)

OTHER:

Clevitte 77 Bearings
Hastings Race Rings
HV Oil Pump

I have more mods but these are probably the only ones that matter for stress. I am thinking the engine will only take max 500hp. In other words, if I make 450 on the dyno, then I could only use a 50 or smaller shot. I am expecting atleast that, but if I am making that much power, should I risk spraying it? I will eventually go forged (build a separate shortblock) but it will be awhile. Any thoughts? Thanks

Mortify

rwHP and crank HP... if you think that 450rwHP = 450crankHP then you are in for a suprise!

Mike96z

Im talking in terms of rear wheel horsepower from a dyno, but im talking about how much crank HP the engine can handle. For isntance if the car pushes out 450 to the wheels then im very near my 500hp mark (i think its 500HP max, this is why I made the thread to find out what my max is) then I cant spray on it.

Injuneer

You're already claiming 480HP.... can we assume that's at the flywheel? Since you have a "shifter" listed in the mods, I'm guessing that you have an M6???? 480 at the flywheel would be about 417 at the wheels. 450 at the wheels would be about 517 at the flywheel. Adding any nitrous would be risky at that point, with the PM rods and hyper pistons.

I've seen two cases documented of the PM rods failing at about the 600HP level.

Mike96z

Thank you for that and what is the % loss you using for the RWHP over Flywheel HP? Im sure ill have atleast 450 @ the wheels so that would mean NO NITROUS for me. Thanks man.

But am I right about my limit being @ 500 with that crank? I know the PM rods are def good to 500 + they are floated so thats less friction.

Injuneer

There's no absolute HP value for when a component will fail. People have sprayed 200HP on a stock bottom end without failure... others manage to break stuff at lower HP. The more HP, the shorter the life expectancy of any component. Using low $$$ cranks, PM rods and hyper pistons with nitrous is going to increase the chances of failure as you approach 600HP.

I measured the actual drivetrain losses when my car was still an M6, and at 500 flywheel HP it was 12.6%. That was through a steel flywheel Street Twin, stock T56, 3" chrome moly DS, 3.73 Strange 12-bolt and 17x9.5 wheels with 275 street tires. At 762 flywheel HP, the losses dropped to 12.2%.

96LT1TX

all I will say is that if you expect to have 450rwhp just because you have a 383 w/ heads and cam be prepared to be surprised
That is 100% dependent on your heads/cam. Do you have the flow # of your heads? What are the specs on the cam? Even knowing this would not guarantee a horsepower number, but it would make it easier to guesstimate.

Mike96z

Already had it estimated int he past on this site, listing my mods.

Mike96z

Ive decided not to spray, I knew I couldnt, just wanted to confirm that I was correct, going to build a fully forged long block for nitrous use.

96LT1TX

let me clarify, just cause this site says you have 450 rwhp, doesnt mean you have 450 rwhp.

Mike96z

already made my decision + you dont even know my specs on my engine, my mod list isnt even descriptive of what I have, I know the power range im going to make on the dyno + ive seen similar setups, and if it will make you happy ill pm you the link to the dyno sheet when its done.

Mike96z

and this tread is not about how much power im making but about how much power my internals can take, and Injuneer has already clarified that. Thank you.