Mustang Novice

If you supercharge an engine to the "max HP" for a stock engine, would the HP gains from adding underdrive pulleys and modifying the exhaust increase or decrease the chance of breaking a rod? Part of me says decrease because you're decreasing the forces the engine is having to work against, but the other part says increase because you're "allowing" the engine to work harder.
If it did decrease would the cast crank then become the problem?
TIA

Acer2428

wtf?

U/D pulleys would WAY DECREASE the rosk b/c it would make the s/c spin slower, making less boost and less hp. Exhaust will decrease also b/c you'll make more hp from a lesser amount of boost.

Mustang Novice

But couldn't you change the pulley size on the supercharger to get back the loss from the underdrive pulley? Wouldn't it be just like changing a gear ratio? Make the pulley on the SC charger smaller and it would increase its spin, right?

vfast

why would you even use underdriven pulleys iether use a stock crank pulley or a race one..

Mustang Novice

Thanks. You're right, I didn't think it all the way through. But that's why I need these forums to slap me back to reality.

roundman

When you push a stock engine to the "MAX" horsepower level, whatever the weakest link is will be what causes a failure. it could be a rod bolt, rod, valve, pushrod, piston, hairline crack in the block, or just about anything internal in the engine that will fail under the load. since no two engines are really identical, then the failure could come from just about anywhere in the engine.