city001

Anyone know what's the difference between
9:8, 10:0, 10:2,1, 10:5, 11:0??
is it higher or lower the better
like say 10:0 to 10:2;1 or 10:5?

G

Guest

The higher the compression ration, the more air/fuel mixture you can cram into the combustion chamber. The more air/fuel that you compress into the same area, the more heat(power)is released when the mixture is ignited. So, 10:1 is better than 9:1, etc.

Road Rage

It is a ratio that shows the amount of volumetric compression an air/fuel charge experiences between the bottom of the piston stroke and top dead center.

High or lower better? - that depends on what you are trying to obtain. Higher compressions result in more power and improved throttle response, at the expense of higher cylinder pressures and temperatures, and the need for higher (and more expensive) octane fuel which burns at a slower rate. It also requires more cranking power from the starter (if you have ever worked on a car and turned the motor over by hand, you will know that doing so with a hi-comp engine can be a bear - we used to remove the spark plugs to make it easier).

A turbo engine usually has lower compression to keep cylinder pressures and temps moderate, and to keep from frying the pistons.

All things being equal, a lower compression engine will last longer and have lower maintenance, but today's engines with superior boring, sealing, and piston crown designs have made that much less an issue.

Hi-comp engines also put more strain on the cylinder head gaskets.

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Rage On!
2002 TL-S w. Comptech header/exhaust, springs, airfilter
SSR Integral A2's
17x7 45mm offset
Pirelli P7000 (Summer) 215-50/17

city001

I was looking at NSX, Integra GSR and compare to TL type S compression ratio

NSX = 10.2:1
Integra GSR = 10.0:1
TL-S = 10.5:1

So which one is better?

i know 10:1 is better than 9:1
but i'm having a hard time distinguishing within the 10's.

G