What kind of boost will a cast crank and stock type rods handle? When would a forged crank and forged H beam rods become a necessity?

 

I think the first thing boost would take its toll on is the pistons, they take the most abuse. Now I am not positive about boost, but I have seen plenty of 500+HP cast/ cast steel/ nodular iron cranked cars in the past. I think more important than boost, is the amount of power the engine is actually producing...I know this varies with the amount of boost. When it comes to bottom ends, I also don't believe you can say "thats after xxx amount of power you need h beam rods, and if you add xx more HP you will need a forged crank", a bottom end is only as strong as its weakest part. Therefore, there are many more variables that can determine whether your engine would hold more boost. For example, why put a cast/ cast steel crank, with H beams, and a forged piston, and a 2 bolt block....There is no purpose in that. Your weakest part is your crank, and 2 bolt mains...so its really no stronger then it was b4. Basically, I would build a boost engine the same way I build an N/A engine....determine the HP levels I will be trying to obtain...b4 deciding on parts.

 

Boost does not kill an engine. Detonation and too much RPM does.

You can make a lot more hp on stock bottom end with boost than you can with an N/A engine. The engine with boost require al lot less RPM to make the same power and that saves the engine.

 

I ran 8-9 lbs of boost on my stock bottom end L98 with no problems. I snapped the nose of the crankshaft by trying to eliminate belt slippage and over tightening the belt. So assuming you dont do that you can run at least that much boost with an intercooler.

Just get forged and dont look back.