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Discussion Starter · #1 ·
I have a '98 Indy Ultra, and in school we have this class that I take called applied tech math, it's where you study every aspect of an oval track car. Right now we're studying engines, and I started relating some of the processes for more power to my sled. The one that seems the most cost efficient is shaving the heads. There is a mathematical formula to figure out how much to take off. But since my teacher seems to be putsing around, and stalling when it comes to teaching us that fomula, I figured I'd ask here. About how much should I have taken off? and about how much would it cost? Thanks a lot guys. Oh yeah, I was reading the other post of the guy with the yamaha, when I get the formula I'll post it here, so everyone can benefit.
 

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Before you can raise the compression you need to know three things. The installed head volume, the exhaust port height, and what type of fuel you plan to use.
The formula to find effective compression ratio is((.000785*bore*bore*exhaust port height)/installed head volume +1).
You can run premium fuel if you don,t go above 9 to 1 effective compression. When you get above 9 to 1 you may need to run race fuel.
You can use the same above formula to calculate how much to remove from the head to get the desired head volume(example (.000785*bore*bore*amount removed from head=amount that installed head volume is reduced).
Remember to watch the squish clearance on the edge of the piston, if it gets to be less than 40th. of an inch it may begin to detonate on the edge of the piston.
There is no magic number that works for every engine. You must know how to measure your parts and adjust your machining to get the desired results. I have seen a lot of engines that have burn't down because the owner didn't understand what they were doing when they began working on thier engine.
Remember double check your measurments!
Good Luck
 

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Rider828X you would be better off buying aftermarket heads. Just remember the Ultra has a cover over the head that that uses O-rings to keep the antifreez from leaking. If you cut the heads you would also need to cut the head cover which would be very tough because there is a groove in the bottom of the head cover for the O-ring. Aftermarket heads are the only way to go with the Ultra. Remember one other thing if bump up your compression you need to run good gas and the first time you fuel up out in the middle of nowhere you may not get the good gas you need. Can you say squeeeeek. Riley
 

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Good point Riely, never though about the head cover..
 

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Discussion Starter · #5 ·
I talked to my tech teacher about the haed covers, and he said that the amount that I would be taking off wouldn't really make that much of a difference on ehte O-rings. He said probably at the most I would be taking off about 20 thousands of an inch. I think the o-ring would still seal.
 
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