99ssleeper

iTrader: (98)

So can anyone answer....how would the GMPP LS6 heads compare?

With the GMPP LS6 heads' 61cc chamber, pistons out roughly .007, and a GM head gasket of .054"....static compression is 11.2:1.

With my intake valve closing angle of 40°, the effected compression is at 8.7:1....unless I've made an error somewhere along the way...

Is this too much?

PREDATOR-Z

Actualy you'll be at 10.7:1 SCR

JZ'sTA

iTrader: (23)

And no it isn't too much as long as you have good gas. 93 octane should work great.

99ssleeper

iTrader: (98)

How do you figure?

I've done it twice and get 11.2 with the .054 gaskets and 11.0 with the .060 gaskets.

98A4LS1

iTrader: (1)

As long as the cylinder heads are quality pieces, meets my goals, and priced right, I could care less what name is on them. my 0.02

PREDATOR-Z

http://www.c5frc.com/calculators/Com...Calculator.htm

99ssleeper

iTrader: (98)

Ahh...I was using a bore of 3.910, not 3.898

:thumbsup:

JZ'sTA

iTrader: (23)

Damn 3.910 bore.
Cant even get that big with a forged setup.

99ssleeper

iTrader: (98)

cometic head gaskets are 3.910 for whatever reason. i dont know if the GM ones are that way too...

:shrug:

Beast96Z

iTrader: (21)

FWIW, this calculator is the same as the one on ross pistons website. The piston height section will not read past zero deck. Notice it says, "enter .0001 for zero deck", it will not go past this for "out of the hole readings". When you enter .007" for your piston height, your actually telling it your piston is .007 in the hole. You have to enter a negative number if the piston sticks up past the deck, which this calculator will not read. When I figure it into this one: http://www.rbracing-rsr.com/compstaticcalc.html , I get 11.09 for his compression using the numbers he stated at the top of this page. I'd reccomend saving this calculator because it is LS1 friendly, whearas you have been getting false readings from the others.

Beast96Z

iTrader: (21)

Why not? my 383 was a 3.910 with 3.905 pistons. This leaves .005" ring clearence roughly. It a pretty common over bore on the stock block.

PREDATOR-Z

Ahhh soooooo.

No wonder I always under estimate. ****, I never paid attention to that.
One blind ****.

Thanks for pointing that out Beast.

Man, that means with my PRC's I'll be 10.97:1 (I like that)

99ssleeper

iTrader: (98)

Thanks...I knew I went through my Thermodynamics class for a reason. Looks like 60.9cc chambers with .060 MLS gaskets puts me at 11:1...quench is about .053...

Spellbound

I have had good results with both TEA and AFR

On my WS6...467, mods in sig...
My GF's car with TEA 5.3's, 430 locked, 410 unlocked with a 224/228 114 cam.
My ZO is a hybrid, AFR castings ported by TEA. 473/446< summer tune lol. Last winter it dynoed 488 Same dyno.

04Yukonxl

How do the AFR 225s compare? The port volume is not that much more than the 205 and is sure less than other Stage III ported heads.

JakeFusion

iTrader: (7)

Static Compression will be 10.71232231:1 with .054" gasket and 61cc chambers.

With .060" gasket it is 10.55853614:1 and 61cc chambers.

Actual formula is: Compression Ratio = Cylinder vol. + clearance vol. + piston Comp. vol. + gasket vol. + chamber vol. divided by Clearance vol. + piston vol. + gasket vol. + chamber vol.

PREDATOR-Z

Now I'm confused. That is what I got with the calculator I used.
http://www.c5frc.com/calculators/Com...Calculator.htm

But with this one it is different (putting a negative figure for out of hole)
http://www.rbracing-rsr.com/compstaticcalc.html

Which one is right???

99ssleeper

iTrader: (98)

Yup, just remember to subtract the clearence volume since the pistons come out fo the hole. And piston volume here is zero so that can just be omitted.

I'll be going with the 02+ GM MLS gaskets. Unless you guys see any reason to go with something else??? (PTV clearance and compression an issue)

99ssleeper

iTrader: (98)

I still get 11.07:1 with 60cc chambers and .060" gaskets....

Cyl vol= 43.2595 cid
Chamber vol= 3.661425 cid
Clearance vol (piston out)= -.0835356 cid
.060 Head Gasket Vol= .7160194 cid

So,
Swept vol= 43.2595 + 3.661425 - .0835356 + .7160194 = 47.553409 cid
Unswept vol= 3.661425 - .0835356 + .7160194 = 4.293909 cid

Swept/Unswept= 11.07..............11.07:1 SCR

Anyone back me up on this?

Beast96Z

iTrader: (21)

Like I said before, you have to factor in the piston coming out of the hole. The C5frc calculator does not allow you to go past zero deck. Even if you use the formula Jake posted, your piston height should be a negative number, it's never a positive unless the piston is in the hole.

As far as these numbers are concerned, aren't the heads supposed to be 61cc and the gaskets .064"? With the 3.898x3.622 with a -.008 piston height, .060" gaskets, and 60cc chambers, I get 11.09.