setzep

On a 13b-re what is "good" compression? (think it has 9.0:1 rotors??) I just ran a test on mine and came up with 120 front and rear. I've been told thats pretty good but I'd like to see what others think. What would you consider low? What is new?

thanks

setzep

not a person knows? Thats strange...

fastrotaries

i think that anything under 75 psi isn't too good. it'll operate but rough. Try a search

Nathan Kwok

Don't get compression ratio mixed up with compression "pressure", they are two different things although they are related. Stock factory spec compression is 120psi or 8.5kg/cm^2. , so your numbers are perfect, just like a brand new engine. Original factory manuals specified 7.0kg/cm^2 (100psi) as a minimum, and this was later changed to 6.0kg/cm^2 (85psi). Both versions specify 1.5kg/cm^2 (21psi) maximum difference between the 6 chambers. I think the newer number is more accurate because I've heard of engines in the 6's that ran just fine and made excellent power, but higher is still better. I'm more concerned with even numbers across the chamgers than absolute values, fwiw.

*edit* whoops, I thought you were referring to a 13BREW, not 13BRE, these numbers are for the 13BREW.

HWO

the larger the ports the less compression your guage will read

setzep

Any one know what rotors I have in my 13b-re? I would guess they are the same as the 13b-rew's 9:1??

cool, so 120 is pretty damn good then. I don't know if it is 120 on all rotor faces but I did hold the check valve open open once on the compressoin gauge and it did bounce evenly so I'm guessing the compression is about the same on all rotor faces.

Blake_AE

rotor #1: 6.5-6.6-6.6 kg/cm^2

rotor #2: 6.5-6.5-6.6 kg/cm^2

this is supposedly a rebuilt with about 30,000kms on it.

from what I've read, I'm middle of the range, good even compression for a series 4 T2