Expert: Dan Liddy - 4/1/2004

Question
what causes a powerband in an enigne?
what can you do to change the powerband/make it bigger?
when people design engines to they "build" the powerband into the engine or is just a guess?

thanks a bunch

Answer
I don't have your name - - -sorry, looks like you put my name in the space.

Powerbands are changed by altering the pattern of fuel induction. This is accomoplished in two ways, first with the use of a modified camshaft, and second by modifying the induction itself, by the addition of carburetors, or changes in the fuel injection system.  Some subtle changes can also be netted by alterations in the exhaust system.

Normally, the focus in a race engine is really to narrow the powerband, between say 6000 RPM, and 9000 RPM.  However, by narrowing it, the engine produces more horsepower and torque, which is the focus of the race mechanic.

Most amateur racers try to approximate a power band of sorts, by using specific components in an engine. Depenpding upon which car one races, there is a wealth of information about modifications.

The upper level professional teams either build their own engines or have them built by a pro engine shop.  These people have engine dynomometers, which will tell whether a modification is working for them or not.   They machines are expensive, and running time is very costly too.  However if you are making a couple of million dollars a year, a $10,000.00 dyno bill isn't all that much in the grander scheme of things. They can design and build nearly whatever power band they want...

Hope this clears it up for you a little bit

Dan Liddy
Sarasota, Florida