Could one of the SC gurus educate me a little here. What is the difference between having a high compression engine and having a roots type supercharger as far as making power is concerned. Can you make more power out of the supercharger? I guess it would be easier to change pulleys than to change CR. Any thoughts?
thanks
Jes

 

Wow what a question. I will try and keep it simple.

With a high compression motor you are putting wear on the motor at all rpm ranges and at all times. However you will make power at all times. To make the same amount of power out of a na motor you will have to spend some jack.

With a blower you only put strain on the motor when you put your foot into it. At steady cruise you are at a vacuum and are not creating boost. When you hammer it the blow off closes and you have boost.

With a blower your truck will act as a normal setup during daily driving and act like a demon when you gas it.

hope this helped

 

To take Skid's answer one step further, a SC raises the effective CR of the engine when under boost. When you are not under boost the effective CR = static CR.

Engines that run high boost often have lowered CR to allow more boost and more power but they are doggy off boost. What you want to avoid is high CR and high boost (unless you have a supply of high octane gas).

Ian

 

Thanks guys thats what I was looking for. The more I thought about it the more it sounded like a supercharger is like a variable CR device.
Jes

 

HIGH COMPRESSION DOES JUST THAT.

 

High compression does just that, it compresses the air - gas mixture more so that the ignition is more powerful. a supercharger for lack of a better word "crams" air into the engine.
look at the differnce between the new cobra and a corvette. the cobra has a low compression engine with a supercharger - the zo6 corvette has a high compresion, high flow intake and cylinder heads. horse power is comparible but the vette need alot more cubic inches.
they each have there place but for a heavy truck the s/c is the way to go.