I was wondering if when i put my high comp. cool head on for more low end punch do i lose some top end power or speed. If i do lose top end am i better off with the stock head for more top end speed? please tell me i need more speed , too much is never enough.[img]i/expressions/face-icon-small-happy.gif[/img]

 

Hmm.... Good question. More compression does equal more low end power. I can't say for sure if that also means less top end but I would say that you definately get more low end from high compression than top end. It may even be accurate to say that high compression will hurt top end performance - it is my guess that it does.

I think what you want is a good balance but I don't know what that balance is.

 

You should not lose top end with a higher compression head. You should gain more low and mid range punch as well as retain top end power, or possibly a modest improvement. What you lose with increased compression is reliability. The more you increase compression, the more reliability you sacrifice. More power being transferred thru the bearings and rod/crank will tend to wear them faster not to mention you will decrease the safety margin for detonation, etc. if you happen to get fuel of poor quality. Don't get me wrong, a head can be a good mod, just has to be done right by a good shop.

 

There is kind of a happy medium when it comes to compression. If you have too high of compression, then it will cause topend speed problems, but I'm not exactly sure how high is too high.....Depends on the machine as well. Put it this way, my cousin was racing against a raptor with A LOT of work done to it but he still beat him because the raptor had so high of compression it wouldn't rev like it was supposed to. It couldn't build enough RPM.

 

high compression is the most inexpensive upgrade for your buck, itll add more hp throughout the powerband. higher compression doesnt really lower maximum rpms it actually makes it rev quicker because of the added hp. IM not too sure about the bad effects of high compression, but it seems logical that it would be less reliable and more likely to have some problems, because of the added power/ stresses that are put on all the parts of the motor , but that is true about any upgrade that adds power to a motor designed to have less.

 

i keep blowing gaskets with my cool head and then burn up a piston. if you increase the cooling capacity then they say it increases reliability,then why the !@#$ is it blowing up the way it does . my buddy has a stock head and he dont blow gaskets then fry a piston. think i should get a stock head?i want more top speed. please give me all the thoughts you can think of.

 

There is absoutly no downside to higher compression in terms of power, there is no positive/negative tradeoff,higher compression makes more power throughout the entire powerband. As long as your engine can sustain the added compression and power output, and you have the fuel to back it up.

 

What about regearing? Put 1 tooth bigger front sprocket on. If you have a 500 it should pull it.

 

the problem wasn't how to get top speed it was that my cool head was blowing gaskets and pistons. and i was wondering if the stock head was better off with reliability than the high compression cool head. i reall y need good solid knowledge of the problem like it happen to you and you know how to fix it. i really need help because i am ready to rebuild it and i want the most reliable head to put on it so it dont blow it out in a matter of weeks. i need everybody's comments ,advice and most of all their knowledge.

 

huedog: This may not be what you want to hear, but the best way to figure out a problem with a modded engine is to put it back to stock and start over. Your best bet would be to put it back to stock and ride it. If you insist on modding it up, change only one thing at a time, otherwise you never know how 2 (or more) aftermarket parts are interacting. IMO, you're better off buying fast with displacement straight from the factory rather than squeezing more out of a smaller engine with hop-ups. Been there/done that. Keep in mind this is a general rule of thumb, there are exceptions, and it's only my stinking opinion. Best of luck,

Gary