Has anyone seen any crankshaft failures from too much power? I'm wanting to make my built motor work for me. I am going to max out my turbo and then put on a shot of nitrous that will make my differential cry. So, should i worry about the crank?

 

never heard of a crank failure on a miata...actually any car. it's worth trying

 

never seen a crank fail either, at least not on a street machine.

 

'80's EFE's will twist their crank if driven hard. They're generally welded and turned to fix this issue. I think FM had some issues with some of the prototype stoker motors, but I think that was all block's blowing up. I also have never heard of a miata crank failing. You can scrap it by destroying the key way, seal surface, or bearing surface, but that's another story and often repairable.

 

The crank is forged steel, so I doubt you'll have an issue.

 

As markp put it at 500 whp he considered oringing the heads but other than that the **** will hold together.