We've all heard it: No Big boost without forged internals...but I'm curious exactly what those "internals" are. I mean, duh, I know how an engine works, and the crank, rods, and such...But - what parts, while under boost are stressed in an engine?

Thanks!

 

Are we talking a stock car? Usually the first thing to go is the hyper cast pistons. High compression + no way to "sense" boost means its easy to detonate, and a little rattle will trash them.

Keeping headgaskets in is a chore - Usually want studs.

Other than that you run into the normal strains of any powerful motor - Not really much different about being boosted.

 

however hyper pistons and low boost can be done...

 

Aye didn't mean to mislead, thats just the first thing to cause problems for most people.

 

Depends on the type of boost.

Boost pressure does not kill engines most times, detonation and heat do. Properly tuned, I have taken cars well past what stock internals were supposed to hold. My Mitu 6G73 engine went 14lbs of boost on pump gas for a year before I got tired of replacing transmissions and parked it all.

Forged parts are just built for that kind of abuse and give you a cushion when hiccups happen........ and they do. It is always smart to go forged on the internals no matter what.

I have no experience with anything but turbochargers, but from what I understand belt driven blowers also put stress on the crank snout and alot of failures for them happen there.

 

this would be why they make the big snout cranks made especially for belt driven blower..