How should I feel about these compression numbers?

[R32GT-R]

I have a newly rebuild, highly modified rb26 at a local shop, they have done a compression and leakdown test on it, below are the results.

What do you think, are they not they really low?

Its got major head work, thicker HG etc....

Leakdown and Compression results
Cyl #1 112psi 6% leak
Cyl #2 111psi 7% leak
Cyl #3 114psi 10% leak
Cyl #4 114psi 7% leak
Cyl #5 110psi 7% leak
Cyl #6 115psi 6% leak

[hp44incgtr]

normal number for an fresh built how much k you put on it so far??

[Coombsy]

I wouldn't be TOO worried given those leakage numbers. What's the compression ratio?

[R32GT-R]

its got like 100 kilometers on it.

i dont know the CR its got a thick HG, Carillo rods and CP Pistons.

[nimblestix]

Cold or hot numbers?

sent from a galaxy far, far away

[Dragon Humper]

Seeing as how they are all within 5% of each other I wouldnt worry about it. Seems odd though that the cyl with the most leakage had close to the most compression.

It's also the cam timing that plays into the dynamic compression (that being the # you get when you do a compression test). You can vary the psi you get by 10+% by just altering the intake closing point. One thing you can do is verify the settings and make sure they are close to spec. (and not the stock spec either, the one listed on the cam card).



Jon.

[Skym]

Seeing as how they are all within 5% of each other I wouldnt worry about it.

I agree.

[Bruizer]

Could it be that the break in isn't done yet? Depending on type of ring, hone and break-in procedure, it might not be done yet.

[R32GT-R]

yes, it probably isn't broken in yet. VEX is gonna do the Cosworth break-in procedure on their dyno.

[Skym]

Sometimes new valve springs with cut factory valve seats dont create enough seat pressure, thus valve might not be properly closed.

Tomei sell optional sheets (look like shims) for their valve springs to restore factory like spring seat pressure -

http://www.tomeiusa.com/_2003web-catalogue/e095_valve_seet.html

[R32GT-R]

ive got tomei spec c double springs, should be enough seat pressure. plus leakdown is good.