You all are the go to guys for this...
I'm having a heck of a time calculating my DCR. I found & used the excel spread sheet based on Comp grind cams.

Here is what I have for my setup:
Heads are 241's milled down to ~58cc (~11.5 CR)
Stock GM MLS gaskets
Cam is F13 (230/232 .595/.585 114*)

Punched in the #'s I knew into the spread sheet & got an error on the DCR tab (orange) but got it to work on the DCR Manual Calc (Blue Tab). I calculated out the following:

Static Compression Ratio 11.58
Dynamic Compression Ratio 9.00

Static looks right but got a DCR of 9.?.?.? That has to be not good b/c I thought mid to upper 8's we about the max for 93 octane pump gas.

If I did it correctly & my DCR is 9 I am worried it will be too high.
If so how do I fix it? Thicker gasket? Could I remove some of the material in red to increase the CC size? Would that mess up the swirl & flow of the heads? HELP

 

I would need the .006 advertised durations of that cam.

If you are indeed over 9.0 DCR, you can retard the cam a bit like 2* or 4* to lower DCR.
Also you can un TR6 plugs (colder than stock) to help with detonnation and through tuning (reduced timing)

 

I think they are 279/281 (XER lobes)....
Good idea to use the TR6 plug.

 

I got

SCR = 11.56
DCR = 8.67

assuming the cam is advanced 2* for 112 ICL

 

Cam is F13 (230/232 .595/.585 114*)

That is a Futral cam. They use Cam Motion to grind their cams. XER is Comp Cams.

F13

.050" 230\232
.200" 151\150
.006" 280\284

Assuming -.007 deck height, .0053 compressed head gasket and 114+4 (a guess) I came up with 11.58 and 8.81.

 

in that case...


114 LSA / 112 ICL

SCR = 11.56
DCR = 8.63

114 LSA / 110 ICL

SCR = 11.56
DCR = 8.79

 

What are the numbers for the following setup:

226/228 581/585 114 + 4
Stock height head gasket
60.9cc LS6 Heads

 

need adverised duration (.006)...who's cam ?

 

do you have any chamber work done?

 

DrkPhx, THANKS for the #'s!!!
OK, so it is looking like 8.6 to 8.8 DCR. Is this too high?
No chamber work done, just milling the heads. If I need to do something what can be done? Can I open them up in the red area in the pic? Will that effect the flow?
Thanks for all the help guys

 

Nope, not a good idea IMO, that is the quench pad area and you'll create turbulence into the valves.
Are the heads allready milled?

 

Yes, they have been milled already.
So no cnc work to the quench pad area b/c of created turbulence?

 

Any ideas?

 

was using -.008 for deck height, if yours is lower that will help some, if not using a .060 gasket will bring the numbers down to 8.5 DCR, 11.3 SCR

 

Is the stock LS1 deck height .-006" or -.008"?
The cheaper GM gaskets are how thick, .052"?
Where can I get some cheap .06" gaskets?
Thanks

 

I guess it's hard for me to understand why you mod a car and then de-tune it and loss the optimal performance level of the set up. The 93 octane fuel will not become a serious issue until the engine is put under max load (WOT). If you mix 103 and 93 at a 50/50 ratio = 98 octane which will be more than enough to protect the engine from detonation when running it hard. Yes, that is somewhat more expensive, but de-tuning is like taking two steps forward then taking one step back. Just my 2 cents.

 

had an 01 motor that was -.008
the 98 motor i have now is right at the same, that's why I was using that deck height, i believe the older the graphite gaskets were .053, the new GM MLS i read are suppose to be .060, but cant confirm that measurement

 

i used the .053 gasket for the initial DCR calc..

 

I'm not de-modding. I'm building an engine with parts I have.

Thanks for the help oange SS

It looks like I need to call Futral & TSP...