Maximum HP @ RB26DETT stock crank?

[Careless]

You meant crank right?

 

both.... the cam is phased out during manufacturing in relation to how much the cam and crank twist during testing.

[Booztd 3]

What PSI were you running there Andy??

 

 

24psi

[RIPSNZ]

Here's a GTR running 8.1 @ 172 with a stock crank, manual box and good 60fts:

 

http://www.godzillamotorsport.com/content.php?c=6

 

Rob

[cheftrd]

I've been thinking about this some more.

 

The cranks described above didn't actually fail from the high rpm, or the power they were making at the time, ie, if they were on a dyno or in a different situation they wouldn't have failed.

 

They failed due to a very sudden shock loading applied to them in a way that is not always the case for alot of high output RB engines.

 

If they were in a 'locked' 4wd situation, with a very strong clutch and alot of traction, when they launched there would be tremendous loads on the rear of the crank, hence they broke there.

 

Obviously a good billet crank will cope with this situation better, no dought about that, but it still doesn't actually mean that under different circumstances, ie a launch without 50/50 lock up, a high speed road car, an auto drag car or other applications that the stock crank would have failed.

 

I agree, in the sitautaion described above a billet crank would be better, but I still maintain that a stock crank in other applications is still fine with 1000hp+ and 9,000rpm+ and is still reliable as we have it in our own car doing just that.

 

Rob

 

You're correct in that none of the cranks in question failed from RPM or "power". They failed from the repeated shock of dropping the hammer at 9,000-10,000 rpm with the drive train locked out, good traction, manual trans behind a tripple or four late clutch. The RB26 crank in incredibly strong and I don't see you failing it in front of an auto. At least not for a very long time. I'm actually a big proponent of stock parts in the Japanese engines (with the exception of pistons). Cranks and engine blocks are waaay under rated. Aren't you guys going to be making an attempt for sevens pretty quick here? That'll be cool to see.

[cheftrd]

both.... the cam is phased out during manufacturing in relation to how much the cam and crank twist during testing.

 

That's interesting. I knew they ground the cam to compensate for crank twist, but not the crank itself. I wouldn't think the cam would really have that much torsion in it, but I guess when they go to around 9,000 rpm from idle in tenths of a second... who knows.

[Careless]

That's interesting. I knew they ground the cam to compensate for crank twist, but not the crank itself. I wouldn't think the cam would really have that much torsion in it, but I guess when they go to around 9,000 rpm from idle in tenths of a second... who knows.

 

and with roughly 7000 hp (ala bud king) making a 6 second debut and demise, it's probably a science project with crank pin offsets.

[RIPSNZ]

Aren't you guys going to be making an attempt for sevens pretty quick here? That'll be cool to see.

 

We are working towards 7s for sure.

There's a big jump from an 8.7 to a 7 so its not going to be easy but we have alot more power and few other things in place that should at least get us a little closer before too long

 

Rob