Anyone thought about raising the compression?

pehN · Post by **pehN** » Sun Jul 17, 2005 11:32 pm

Anyone thought about raising the compression by carrying off from cylinder head?

MMamdouh · Post by **MMamdouh** » Sun Jul 17, 2005 11:35 pm

it will be irreversable mod. so if you got it wrong you got to get a new head. also you will have more tendancy to detonation, piston/valve clearance issues and i think you will have to use hight octane fuel from now on.

MMamdouh

Audacity Racing · Post by **Audacity Racing** » Sun Jul 17, 2005 11:48 pm

it would be great if you had extra heads and high octane fuel... but man you'd get hella good fun out of it

i thought about it for my woo, but i'm going turbo and dont' want to raise the cr

pehN · Post by **pehN** » Sun Jul 17, 2005 11:50 pm

I wasn't thinking about more than 11:1 of compression. In Germany that is/was a very common way to power up your car. So I don't think that it would be so critical!

Brian5475E · Post by **Brian5475E** » Sun Jul 17, 2005 11:51 pm

I'm probably gonna get the 11.5:1 compression pistons made from JE pistons. $650. not too bad for custom pistons. Of course rasing that much in compression I guess I my need new rods? Maybe 360 Dynamics can come up with something. if the Lanos cams don'r work on the Aveo, then I'm going forced induction, not sure if turbo or S/C. not much room for a turbo on the Aveo, my have to squeeze a centerfugal S/C in there

BosnianLanos · Post by **BosnianLanos** » Mon Jul 18, 2005 12:13 am

Not to mention you would need to run racing fuel with such high compression to stave off detonation. With gas prices so high, it really isn't practical to have super high compression in a street vehicle. I still think best bang for the buck would be either Turbo/NOS or an N/A engine with ported heads tuned cams, etc.

tango · Post by **tango** » Mon Jul 18, 2005 12:34 am

Have to be carefull when raising compression ratio...you may have a valve clearance problem (exhaust valve). RESEARCH is key...Oh...and a bit of trial and SERIOUS error too!

pehN · Post by **pehN** » Mon Jul 18, 2005 12:52 am

BosnianLanos wrote:Not to mention you would need to run racing fuel with such high compression to stave off detonation. With gas prices so high, it really isn't practical to have super high compression in a street vehicle. I still think best bang for the buck would be either Turbo/NOS or an N/A engine with ported heads tuned cams, etc.

High gas princes? In America? I don't think. What's the gas price in america? In germany it's 1,25?/litre

lanos2001 · Post by **lanos2001** » Mon Jul 18, 2005 12:56 am

in the US its not as high as other places but considering that it used to be like an average of like $1.25 a gallon to $2.15 a gallon thats almost twice as much. when my folks came back from korea they said it was almost $4 a liter over there.

nick

woo · Post by **woo** » Mon Jul 18, 2005 1:56 am

shaving your cylinder head is a common thing to do. The people at the machining shops will know how much to take off. While you head is off the car you might aswell kill 2 birds with the one stone and get the ports polished.

KnightWalace · Post by **KnightWalace** » Mon Jul 18, 2005 4:44 am

Brian5475E wrote:I'm probably gonna get the 11.5:1 compression pistons made from JE pistons. $650. not too bad for custom pistons. Of course rasing that much in compression I guess I my need new rods? Maybe 360 Dynamics can come up with something. if the Lanos cams don'r work on the Aveo, then I'm going forced induction, not sure if turbo or S/C. not much room for a turbo on the Aveo, my have to squeeze a centerfugal S/C in there

If you get new pistons get springs and rods atleast, if not valves.

check with Pauter, Crower, Je and theres another good company i'm forgettin.

tango · Post by **tango** » Mon Jul 18, 2005 2:09 pm

woo wrote:shaving your cylinder head is a common thing to do. The people at the machining shops will know how much to take off. While you head is off the car you might aswell kill 2 birds with the one stone and get the ports polished.

You forget that on this side of the planet machine shops hardly see Daewoos for that sort of modification. We'll probably have to be standing over their heads to make sure they get it right.

daewooluvr · Post by **daewooluvr** » Mon Jul 18, 2005 2:11 pm

tango wrote:
woo wrote:shaving your cylinder head is a common thing to do. The people at the machining shops will know how much to take off. While you head is off the car you might aswell kill 2 birds with the one stone and get the ports polished.
You forget that on this side of the planet machine shops hardly see Daewoos for that sort of modification. We'll probably have to be standing over their heads to make sure they get it right.

Well a Daewoo head isn't much different than any other DOHC head for any other vehicle. It should be a fairly straight forward thing for any reputable machine shop to do.

Audacity Racing · Post by **Audacity Racing** » Mon Jul 18, 2005 4:21 pm

using the engine building formulas sheet found on http://www.racingdownloads.com, i found that to raise the compression to 11.1 from the stock 9.5, you need to mill .058 inches (or 1.4732 mm) to get the desired result. it should be a stright forward job, easy for any good machine shop to do...

pehN · Post by **pehN** » Mon Jul 18, 2005 9:16 pm

Audacityracing wrote:using the engine building formulas sheet found on http://www.racingdownloads.com, i found that to raise the compression to 11.1 from the stock 9.5, you need to mill .058 inches (or 1.4732 mm) to get the desired result. it should be a stright forward job, easy for any good machine shop to do...

That's really damn a lot. I know about cutting Cylinder Heads by 0.3-0.5 mm but thats really a lot. I could believe you can get real problems with the valves breaking into to pistons!