SquatchMachining

Over the past couple weeks a few threads have popped up about spun crank pulleys and broken crank pulleys. Because of this I did some digging an contacted the manufacturer for some information about the issues.

I contacted Innovators West after seeing "Unreal's" thread about his failed crank pulley. Since there are many forum members running this pulley and making similar horsepower it is just a matter of time before this failure happens to someone else.

In talking with Innovators West, I learned a couple things and Im going to share that with everyone here so that there is no confusion regarding what is going on.

When they designed the 10 rib pulley setup they never imagined what horsepower levels would come with it, so they never expected a failure. With the growing number of people pushing well past the 1000whp mark a few started to fail so they changed the design a bit.

They now offer two options, both of which can be added/upgraded to your current pulley if you ship it back to them.

First, they added 6 additional 3/8" bolts to the shell to ensure it was not going to come loose or shear the other bolts do to rotating load.

Second, they made a thicker, more heavy duty inner hub for the unit. This hub ships with a new front cover seal as well because the OD of the hub is slightly larger for increased thickness.

Now I spoke in length with them about these upgrades and they said that the 3/8" bolts are highly recommended for anyone really pushing the car but the inner hub was more designed for the Truck/F-body applications initially because of how much further they stick out. I don't believe anyone has had the inner hub fail to this point on the corvette application, just the outer shell. But it is available if you want it.

Also, for those of you looking to convert your 4 rib A/C drive to the 6 rib A/C drive instead of going to a COG setup when using a direct drive, they offer that as a service for pulleys that are sent in as well.

Here is the pricing I received from Innovators West for the upgrades: (obviously subject to change)

Machining and Installation of the 6 3/8" Bolts - $40
Installation of the new heavy duty hub - $84
Machine 6 Rib A/C Drive - $75 - 2 Week Lead Time
New Cover with 6 Rib Drive - $175 Available Immediately

SquatchMachining

Below is a comparison of the standard hub vs the HD hub.
(Wont load the picture for some reason, working on it)

algZO6

Have they had any issues with the 8 rib or is isolated to the 10?

SquatchMachining

I did not ask. But one would think that because it shares the same design as the 10 it would still be effected and the inner hub is likely exactly the same in the 8 rib as it is in the 10 rib. Like they stated to me though, the inner hub was more of a concern with the F-Body/Truck units as they stick out further unlike the corvette units that are tucked in very close. I would contact them for further information if you need it though.

Arctic Vette

8 rib has flat outer surface and 10 has a lip from what i have now those are the differences..

SquatchMachining

That was the only difference between them that I could see as well when I had both of them in front of me a few months ago. The 10 rib just has the lip for the additional ribs. They appear to offer the same "upgrades" for the 8 rib unit as well per their website. I never thought to ask about the 8 rib stuff as I saw no point. There is no reason not to just go directly to 10 Rib if upgrading.

Xtremespeed

I haven't seen any 8 rib failures like Unreal's but I would guess most of the people in that Hp range have a 10 rib anyways. I can confirm the upgrades are available for the 8 rib though as my 8 rib was shipped with the upgrades already done.

Unreal

I doubt you could make enough power on an 8 rib to have an issue.

Balancer should be on way back soon. They never said anything about inner hub part but I've never heard of that failing. Then again until my balancer came apart never seen that before either. I wish they offered the cog just so it doesn't have to go to two places, as it works SOOOOOO much better than a 6 rib IMO.

Looking forward to a new way to break the vette after this.

Blackonblacksls

People have made 1200rwhp+ with 8ribs

Unreal

Just messed with a car yesterday that did 1100rwhp on a stock crank pulley. Amazing things can happen.