I have been told by a professional engine builder that my compression, after adding up the figures, is about 12.4:1. I did a compression test on the 3 day old built motor and it spit out 305 psi at WOT on all four cylinders!! Now that seems quite high for 12.4:1 if you ask me, so I need everyones help in finding my TRUE compression. Here are the details:

Skunk2 stage 2 tuner cams
Race ported GSR head with chambers opened to 85mm
Supertech STD race valves (stock size)
I was told the head was milled mildly to about 0.0007"
Block was decked about the same
Endyne roller wave 85.5mm pistons (raised wristpins)
92mm Crower crank
5.531" Crower rods
4.3cc dome
0.993" compression height
0.0030" GE 86mm headgasket

 

we need to know the combustion chamber size (cc's) to accurately calculate the comp ratio.

 

I would not worry about that number. I like to see less than 2 or 3 psi difference between any two cylinders. Also, I would think a high compression 2.2L motor would peg a good gauge.

Did you do a leak down check?

 

I don't know the combustion cc's, all I know is that they were opened to 85mms.

 

about 12.4:1 is not accurate enough the only way to measure anything is before final blueprinted assembly...the motor has to come apart and you'll need to measure the chambers cc's with a glass burret kit and measure the piston cc's also find out the actual volume/cyl., head gasket volume(theoretical)

he did not even give you a complete spec sheet consisting of clearances and measurements??
that's not too professional in my books...

as mar said previously look at cyl. variations more so then the number...every gauge will vary as well and having the rest of the spark plugs still in the cyl.'s also affects your numbers so watch out...

Lubo

 

That doesnt mean anything. CC is all that matters. Who cares what the comp tester says. All gauges read differently. Is it knocking?

I doubt the head was resurfaced less than .001"

 

To tell the honest truth, I have never recognized knock and don't know what it should sound like over the other vibrations of the engine (solid mounts).

 

I know hondata has a knock sensor volt feature. Is there a specific volt that identifies knock?

 

That's the truth. I've compression tested a couple of "high compression" 2L with my autocrap tester and the most I've seen is 280 psi.

Just look for consistent numbers.

 

I also noticed that my water temp is a bit on the high side today. It hovered around 212* with a high of 217* on my digital cobalt gauge. I am using a Mishimoto half rad for the 00' civic with a Mishimoto slim fan. The outside temp was around 80*F and I was averaging 4000rpm cruising speeds. Under those conditions, do you think the water temp is high? should i get a bigger fan?

 

Mine usually stay's around 190-195ish (daytime) while crusing around 4000K (part-throttle)stock DC radiator, but it probably varies slighly in each persons setup.

 

Compression test numbers cannot tell you your static compression ratio...Drop in some stock cams and redo the compression test, youll see what i mean...

To acurately calculate your compression, you NEED to know the bore,stroke,piston compression height,piston to deck height,piston dome volume,headgasket thickness,and combustion chamber volume.
If you play around with those compression calculators, you should be able to get a fairly good idea where your at...
http://www.c-speedracing.com/howto/c...c/compcalc.php

BTW, hows the engine run? Im doing a similar build, but with an 85mm 2cc dome piston.

 

The engine runs great otherwise from the water temp being a tad bit on the high side. I have not taken it over 4000rpms and the speedo is bouncing all over and just quit this afternoon. I cleaned the VSS switch and connections but it still doesn't work. It should be dyno tuned shortly so i will keep you guys updated.

 

Is it at least street-tuned?Too little of ignition advance can cause higher exhaust temperatures which may be contributing to the overall coolant temperatures.

 

It is at 18* on idle in Hondata low cam ignition maps with 14.3-14.9 A/F ratio.

 

If you are using a ODB-1 distributor then it has gone bad. If you are using a crank postion sensor then it has gone bad.

 

I don't use either.

 

Would it make sense to put a 10" slim fan on the from of the rad as a pusher in conjunction with the Mishimoto puller on the other side?

 

No. . .

212 isnt all that bad . .

Is it consuming water/coolant?

 

the overflow bottle level dropped a tad because I had an oring leak on my water neck, but that is fixed now.

 

Yeah..I have to second this sentiment. You're going to have to get accurate combustion chamber volume for anyone to be able to figure your static CR.

 

If your car runs better with less than 25 than it does with 32 degrees timing at WOT then you are most likely running too much compression for the gas you got. If not, why worry?

 

cspeed.com

 

Off topic a bit: Why did you choose Stage 2's?

 

Yeah...for all practical purposes, Rocket's right. Who cares what your exact CR is. If you can run the fuel you can get with full timing, what does it matter?