cdoggy81

iTrader: (6)

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

PREDATOR-Z

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)

cdoggy81

iTrader: (6)

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

oange ss

iTrader: (50)

I got

SCR = 11.56
DCR = 8.67

assuming the cam is advanced 2* for 112 ICL

DrkPhx

iTrader: (15)

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.

oange ss

iTrader: (50)

in that case...


114 LSA / 112 ICL

SCR = 11.56
DCR = 8.63

114 LSA / 110 ICL

SCR = 11.56
DCR = 8.79

Gh0st

iTrader: (3)

What are the numbers for the following setup:

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

oange ss

iTrader: (50)

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

studderin

iTrader: (28)

do you have any chamber work done?

cdoggy81

iTrader: (6)

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

PREDATOR-Z

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?

cdoggy81

iTrader: (6)

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

cdoggy81

iTrader: (6)

Any ideas?

oange ss

iTrader: (50)

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

cdoggy81

iTrader: (6)

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

david vericker

iTrader: (1)

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.

oange ss

iTrader: (50)

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

oange ss

iTrader: (50)

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

cdoggy81

iTrader: (6)

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...