Opinion on my compression ratio for PD boost

[CobraRed_96_GT]

my shortblock has manley 18cc pistons .20 over - which up untill now i though was pretty low compression. But that's basically what most centri guys run, i'm running a 1900 TVS and guys running PD blowers usually aim for less. So i was thinking maybe a thicker headgasket? What type?

Guess i shoulda went with 23cc's, but all i heard was people telling me that modulars likesome compression with boost when i was considering them. I want to be able to run pump gas.

My guess is with ported heads i'd be around 9.6 with stock gaskets.

 

[Midnight2V]

A little more information is necessary to figure out what compression ratio you have. What kind of heads do you have? If they are ported, what is your chamber volume? You said you have 18cc dish pistons, but do you have valve reliefs cut into them? With these questions answered, I should be able to get you a rough idea of your CR. FYI, determining an optimum CR depends on how much boost and timing you want to run (so please include this figures as well).

If you would really like to get specific, i.e. power goals or et time/trap speed, answer these questions.

What is the flow data on your heads?
What cam profile are you using?
what intake manifold do you have?
What exhaust setup are you using?
What is the ring gap on your .020 over-bore is?

If you would like some recommendations, don't hesitate to ask. I would be happy to help. Maybe it will be less expensive for you than it has been for me. If nothing else, I can tell you what didn't work for me.

Hope I can help.

 

[CobraRed_96_GT]

Sure, i just didn't want to overload people with specifics just wanted a general opinion.
In my sig it describes my heads.
Stage II PI heads - should be close to stock cc but my guess is a little lower since the low rpm emissions lip isn't there and the chamber is smoothe.
No fly cuts
Heads flow roughly 229-231/299-202
Stock manifolds with 2.5" exhuats after that
I'm pming you the rest of the info since it's secret squirrel stuff.

 

[Stan Weiss]

One of the difference between a thicker head gasket and more dish in the piston is the amount of piston to head clearance or squish. You normally want to run more clearance in a boosted motor than a N/A motor, but this does depend on the amount of boost.

 

[CobraRed_96_GT]

One of the difference between a thicker head gasket and more dish in the piston is the amount of piston to head clearance or squish. You normally want to run more clearance in a boosted motor than a N/A motor, but this does depend on the amount of boost.

Should be a healthy amount of boost. Wont a thicker HG make that more clearance which = better?
Anyone know the stock head gasket compressed thickness? .036"?

 

[CobraRed_96_GT]

Talked to MMR and they said 9.6:1 shouldn't be a problem, and thet PD blowers don't mind the compression too much. Hmm. I'm still looking at a thicker gasket just because we only get 91 octane here, anyone know where i can find a Cometic or MLS gaskets that are thicker?