Need2gofaster

Please dont yell at me JRP...i did a search and couldnt come up with a direct answer... stock ls1 heads milled .030 with stock gasket whats the compression? and stock compression is 10.5 to 1 on a 98 right?

gojo

iTrader: (12)

It's about 11:1

cut .005 = 1cc

9.1:1 = 77.27
9.2:1 = 76.21
9.3:1 = 75.16
9.4:1 = 74.15
9.5:1 = 73.16
9.6:1 = 72.19
9.7:1 = 71.24 (Approximate Combustion chamber of 6.0L heads +/-)
9.8:1 = 70.32
9.9:1 = 69.41
10.0:1 = 68.53
10.1:1 = 67.66
10.2:1 = 66.67 (Stock LS1 Head)
10.3:1 = 65.96
10.4:1 = 65.18
10.5:1 = 64.45 (Stock LS6 Head)
10.6:1 = 63.61
10.7:1 = 62.85
10.8:1 = 62.10
10.9:1 = 61.37 (Approximate Combustion chamber of 5.3L heads +/-)
11.0:1 = 60.66
11.1:1 = 59.96
11.2:1 = 59.27
11.3:1 = 58.60
11.4:1 = 57.93
11.5:1 = 57.28
11.6:1 = 56.65
11.7:1 = 56.02
11.8:1 = 55.41
11.9:1 = 54.81
12.0:1 = 54.20
15.4:1 = 38.00 (Stock C5R Head)

Need2gofaster

I found that in a tread i just didnt know how to translate it! thanks man!

Need2gofaster

ok next question....will i have and clearance issues with a tr 224 cam with the heads milled?

felton316

You should have plenty of clearance, but always check to be sure. I'm running the TR227 with 98 heads milled .030, and 2.02 valves. Your results may vary though.

jrp

iTrader: (16)

https://ls1tech.com/forums/showpost....2&postcount=41

gojo is wrong, your @ around 10.6 SCR milled .030. i agree with felton, only way to know for sure is to check your clearance, dont take anything for granted.

Need2gofaster

what is the best way to check the clearance?

BOTTLE ROCKET

iTrader: (4)

Need to go

What gasket thickness did you go with? The graphite and MLS are a little different thickness, and will affect your compression just slightly.

Need2gofaster

i dont want it to be much more than 10.6 to 1 because of the cam and i will be spraying a 150 shot so which on is close to a stock gasket? anyone have a link to the specs of the stocker and how much it compresses?

gojo

iTrader: (12)

JRP, help me out here. It requires 6cc removed from an LS1 head to get to 11:1 CR. At .005 that is .030 and at .007, .030 gets 10.7-10.8 CR.
My Z06 heads needed .018 to get to 11:1CR (The heads were CC'd), that's using .005. Is this related to the CC of Z06 heads vs LS1 heads?

PREDATOR-Z

10.6 with a .054 gasket I believe.

jrp

iTrader: (16)

stock SCR is 10.1. why dont you want it to be highere then 10.6? i was under the impression n2o liked higher compression.

i've yet to get a definative answer but Richard from WCCH said the perimeter bolt heads (97-98) use a thiner gasket .040-.042 to compensate for the bigger chamber, 69 cc. 99+ heads have a 66.67 chamber and use a gasket .052-.054.

Need2gofaster

Well since i have a 98 i would need to get the 2000 gasket to keep my compression at 10.6 to 1. I just worry about my stock internals with heads cam, 10.6 to 1 and 150 shot. I really dont use my n20 that often, but it still worries me! I'm sure it will be fine if i dont abuse it. I think 410 hp is obtainabe with this setu NA. JRP if you get anymoe info on that please post it. Any more thoughts are welcome!

jrp

iTrader: (16)

ls6 heads have a 64 cc chamber, ls1 heads are 66cc. the reason you need to mill less is because of the smaller chamber to begin with. what gasket thickness are you using and have you measured your deck height or are you just going by what it should be?

jrp

iTrader: (16)

i calculated your 10.6 w/ with the thinner 98 gasket, if you use the 99+ gaskets compression will be lower. off hand i dont remember if you can swap gaskets of different years, i know either the 98 or the 99+ have a little notch in the head were you have to use the specific made gasket. i havent done gasket research in a while. as far as 10.6 CR and n20 and problems, its all in the tune. 10.6 CR isnt that high, can still be run on pump gas no problem.

gojo

iTrader: (12)

Thanks for the info. That is what I suspected.
In that case Need2gofaster should be around 10.6:1.
I "just" went by what it should be with measured CC volume. It's close enough for my purposes.
I'm using the 2003 stock metal gasket #12498544. .054?
.

Need2gofaster

I remember something about a gasket problem between years also...hopefully someone can chime in here before i do my install. I think i will go with the 98 gasket....i think you are right JRP...thats not that high. I wasnt planning on doing a n20 tune just a NA tune for the heads and cam since i dont spray that often. I would just like to see a 11 flat on this setup which i think is a obtainable goal.

BOTTLE ROCKET

iTrader: (4)

Need to go

There IS a difference between the 97-98 and 99+ gaskets. There is an indention on the early heads that will cause a water leak (according to my machine shop) if assembled with the later gasket.
10.6 will be great for power and the occasional tank of bad gas.
If you are only using the spray occasionaly, you definitly need to run a "Timing Tuner" with the 10.6. to allow you to tune it for optimum everyday performance, but prevent detonation when you spray