2,5l cast crank

[MAKO]

I wonder, how much power can 2,5l cast crank take,does anyone had problem with it?

[moparfreak3]

Relentless ran 10's with a cast 2.5 crank. From what I have read and been told they will hold 300+

[ZoskalonMPI]

Quote:

Originally Posted by moparfreak3 Relentless ran 10's with a cast 2.5 crank. From what I have read and been told they will hold 300+

It ran 10s all right, but not because of massive power (although it was massively powerful), the car weighed almost nothing, hence the crank wasn't under as much load as it would be in a heavy car. I never seen what his crank HP actually is.

People argue over that crank, some said it handles a little over 400HP. Yeah, you may be able to hold a 200lb barbell over your chest for a while, but how long will you last? A few min? But at 100lbs or even 150lbs, you would hold it for much much longer. When people tell me what pistons or cranks are good to, I always interpret it as the breaking point. So if TI pistons are good to 300HP, for example, I would not go a pony over 250HP.

[moparfreak3]

Yeah, but still with the setup that he had it still had to put down some impressive numbers. But how long it will last depends on how bad you abuse it.

[Reaper1]

If I'm not mistaken there is a minivan running 11's, and a LOT of other TD's in the 12's running the 2.5 crank.

I think the block needs to be addressed before you really HAVE to worry about the crank....

[KClarryb]

Last dyno with my 2.5 was 473hp and 485ft lbs at the wheels on a dynojet dyno. Clevite bearings, ARP main studs. The car weighs approx 3400lbs. with driver.
Now somebody please jump in and say the 2.5 cranks are good for over 500whp not that I'm worried about it ..................much

[ZoskalonMPI]

Quote:

Originally Posted by KClarryb Last dyno with my 2.5 was 473hp and 485ft lbs at the wheels on a dynojet dyno. Clevite bearings, ARP main studs. The car weighs approx 3400lbs. with driver. Now somebody please jump in and say the 2.5 cranks are good for over 500whp not that I'm worried about it ..................much

WOW.

[Reaper1]

Like I said..I'd be more worried about block flex than the actual crank strength.

Larry, waht rpm are you spinning that engine to?

[ZoskalonMPI]

I thought the common block was good to 600HP?

[1983Rampage]

LOL, and there is Larry, LOL. I guess the new number is at ~475 HP. I have seen Larry's car in person, and the thing is built like there is no tomorrow.

[KClarryb]

Quote:

Originally Posted by Reaper1 Like I said..I'd be more worried about block flex than the actual crank strength. Larry, what rpm are you spinning that engine to?

At the track I try to shift between 6500 and 7000rpm. Although it has bounced off the 7500rpm rev limit a few times when the clutch slipped. And since I lift to shift it survives all my missed gears ok.

[Reaper1]

Yeah...seeing that I'd start thinking about block flex. That crank is seeing some pretty large forces not only because of the power, but also because of the rpm's. I'm not 100% how you have the engine mounted in the car, but that *could* be helping.

I know if it were me I'd be possibly looking in to going with some 4-bolt mains just for peice of mind. Of course this would require some block work as I don't know of any *bolt-in* 4-bolt mains, they all require line-honing of the main journals(which isn't all that bad in the grand scheme of things). I suppose you could just take a look at #3 main bearing and see if it exibits any strange wear characteristics(the thrust surface is just as important as the journal surface in this case).