Josh-'04 GTO

Exactly. If you offered those Indy teams more displacement they would be all over it.

No one is saying a 302 can't make power. But it's cheaper, easier, and more powerful to do it with a larger cubed motor.

cndctrdj

ok so is thier a safe way to make our engines spin faster?

bad96firechikin

Air Flow Research makes a rev-kit. A lot of people don't believe in them, I've got one, I think its great. My car pulls until 6800 RPM, and never goes into valve float. The rev-kit basically utilizes another spring, wedged between the cylinder head, and the lifter body itself, to allow the lifter to remain riding the camshaft, even at higher RPMs. Otherwise, an engine goes into valve float, which basically means that the lifter is being thrown off of the camshaft lobe, and momentarily "floating" and keeping the valve open. This is the main reason why high RPMs are so hard on a valve train. The AFR Hydra-rev kit solves this prob.

cndctrdj

so how much are these kits? do they work on engines with high milage? how hard are they to put in? are they worth the trouble? would i need a new cam to take advantage of the engines new found spin? do they work with after market parts?

Larnach

Its about $250-$300 for the late model rev kit.

HM Murdock

One thing to remember is HP in a car is a product of Torque. Period.

The formula for getting horsepower is torque in ft./lbs. times rpm, divided by 5,252, which is also why all dynographs HP and Torque WILL meet at 5252RPM's.

So what you want is a motor capable of making torque at all RPM's, not just a peaky motor, whether low end or high end...

Those who say that HP is what you want and torque is secondary are either dyno queens(those that want peak numbers for sigs and bragging) or are not concerned with the lowest ET. This is why a car with 335rwhp at 5000-6k but only makes 200lbs-ftat 2000K rpm can lose to a car that makes only 300rwhp from 5000 to 6000 but makes 315lbs-ft at 2000rpm.

Peak HP is 35 less, but line em up, run em in the 1/8th, and all other factors being equal, the lower HP car will win every time, take it to the 1/4 and the 335rwhp car will start to overtake...

This is why LT1's are not that much slower than LS1's in the 1/8th, but the gap widens in the 1/4.

Basically, you need volumetric efficiency at all RPM's, not just high up or low down. Get it across the board.

A real world example is the equally rated HP wise S2000 and a 1992 L98 A4 F-body. Run them in the 1/8th or 1/4, and guess who wins.

I have seen stock bottom ends go 7200RPM's before. Larger engines can turn just as high as smaller ones, it just takes more power to turn them, and higher volumetric efficiency. If you can get enough air and fuel in there, you can get a 502 to go 8K+

And yes, you can rev one of these cars higher than stock, but a mostly stock car won't really benefit because torque seriously starts dropping after about 4800RPM's. The stock cam does not have enough lift to support high RPM turning.



BTW, my rev limit is set lower for break in, but will be at 7000 fuel cutoff when all is said and done.

cndctrdj

i like to do things differently. i was just thinking if i did the math right i could raise the rev of my car enough so i could go with lower gears and not lose speed. like if i go up 500rpm's and go up a little in my gears, i could gain acceleration and still do 70 in second.

instead of doing everything the same way as everyone else, get the same result from a different standpoint. and if i don't get to do it maybee someone will stumble upon all the info you guys have put here and be able to do it instead