easist way to bump compression

neon angel · Post by **neon angel** » Mon Apr 06, 2009 7:40 pm

what is the easist way to bump comp from 9.3 to 9.8?

ragek23 · Post by **ragek23** » Mon Apr 06, 2009 8:02 pm

no easy way really. U can deck the head, that is probable your best option.

ZeroChad · Post by **ZeroChad** » Mon Apr 06, 2009 8:41 pm

Removing the middle layer of the head gasket gains you a few tenths right?

OB · Post by OB » Mon Apr 06, 2009 8:49 pm

Mill the head, thinner head gasket, 9.8 pistons, etc. No easy way.

INVUJerry · Post by **INVUJerry** » Mon Apr 06, 2009 9:50 pm

Mill .030" brings it to 9.8, if you take out the middle layer along with a .030" mill, you'll be close to 10.2:1. Your cam will be retarded close to 4 degrees though, if not more.

RoysNeon · Post by **RoysNeon** » Thu Apr 09, 2009 11:13 am

If you're looking for cheap, pistons from a 2.0 DOHC will bump compression up a decent ammount.

Post by **occasional demons** » Thu Apr 09, 2009 12:29 pm

RoysNeon wrote:If you're looking for cheap, pistons from a 2.0 DOHC will bump compression up a decent ammount.

Not really cheap, once you figure in all the costs/other parts needed to replace pistons.
Not "easy" either.

Easiest would be milling the head, but then there is the expense of an adjustable cam gear to get the cam back into time.

excon · Post by **excon** » Thu Apr 09, 2009 3:14 pm

if you bumped the compression up on a NGC neon, what would happen besides pulled timing?

Post by **occasional demons** » Thu Apr 09, 2009 3:33 pm

The only reason it would pull timing is if it was detonating, like non NGC.

And I don't have any detonation troubles with 9.8:1/87 octane.
If the 2.0 had a cast iron head, then yeah, possible issue.

I really don't see how it is going to change much in relation to fuel/timing maps.

I think this is one area that they really can't do much about in the programming. There is no sensor to monitor cylinder pressure.
It may raise the exhaust NoX levels slightly, but the o2 sensor can't detect that, only the smog sniffer test does.

But having said that, I don't see a huge gain on just raising the C.R. alone.
You have to push the envelope on what can be gotten away with the supporting mods.
You would still have issues with a larger TB, the PCM keeping the A/F ratio at stoich, etc...