[rbahr]

I asked this question of a well known BMW race shop and parts supplier, who told me that they had 2 cases of spun crank hubs on their cars.

That said, the jigs for drilling straight holes in a crank had better be pretty good.

I will be planning this as well as upgrading the wheel hubs in my track-toy M2.

Ray

[F87source]

Originally Posted by rbahr

I asked this question of a well known BMW race shop and parts supplier, who told me that they had 2 cases of spun crank hubs on their cars.

That said, the jigs for drilling straight holes in a crank had better be pretty good.

I will be planning this as well as upgrading the wheel hubs in my track-toy M2.

Ray

In conjunction to the jig, I think you should have the radiator, bumper support bar, and full front bumper removed for the drilling, so the mechanic can actually sit down in front of the crank hub and hold the drill in a comfortable angle. This way you can ensure it is drilled straight vs. looking down from the top of the engine bay and trying to drill straight (which more so relies on the jig holding the drill bit straight).

[MR RIZK]

Originally Posted by rbahr

That said, the jigs for drilling straight holes in a crank had better be pretty good.

That is why I personally prefer the gintani design.

[M3R1]

Originally Posted by MR RIZK

That is why I personally prefer the gintani design.

This is correct, you drill 90 deg from the pinned versions.

[chris719]

Originally Posted by MR RIZK

That is why I personally prefer the gintani design.

I don't like VTT... but I do think the VTT is the most sensible design. Gintani is definitely better in theory than multi-pin though.

[M3R1]

After many (many) hours contemplating all of the CH designs, Gintani and Precision Dynamics were the ones I was most confident in. Both of these employ the same philosophy, however the drilling approach is different. As I said the Gintani is drilled 90 degrees from the crank. Both of these have all of the geometry machined and would need a very large piece if steel to fail in order to spin.

I am happy I did it, it alleviated that slight anxiety I felt. Very similar to how I felt about my E92 M3 rod bearings.

[Navy Davy]

How much hp is an upgraded one piece crankhub like the gintani one good for? When would a fullly built engine be needed? If venturing past 700? 800?

Crankhub cost - About $4-5k?

Built motor cost - Does anyone know? $8-12k?

[M3R1]

Originally Posted by Navy Davy

How much hp is an upgraded one piece crankhub like the gintani one good for? When would a fullly built engine be needed? If venturing past 700? 800?

Crankhub cost - About $4-5k?

Built motor cost - Does anyone know? $8-12k?

My crank hub was just under $4k. As a street car, 500-600whp is arguably too much, which should be no problem for all of the CH solutions. Once you are near 800hp, anything can happen...

A built motor would likely be much more.