Dynamic compression

[Gussie]

Greetings;
I'm a little concerned my dynamic compression will be too high. My calculated DCR is 8.8:1. Is this too high for pumped gas?
Here is my specs:
Bore 4.03
Stroker 3.75
Deck clearance 0.015
Gasket 4.06 x 0.027
Piston +12 dish
383
64 cc trick flow 23 heads
See attached for cam card.

I considered thickening the gasket but then I might risk the squish range. Can't do any machining but worst case could swap a cam at this point. I'll be running the holley sniper 2 btw.

Thanks!

 

[legopnuematic]

I don't believe that to be too high, likely could not run 87 octane without pulling timing to prevent pinging, but should be ok on 93 octane.

 

[fast 99]

Cam design can relieve compression. 8.8 should be fine. A well-designed cooling system will help.

 

[Gussie]

Thanks everyone. I'll be ru Ning alliyworks aluminum radiator with dual electric fans

 

[vr1967]

What is your static cr?

 

[Gussie]

Please see below for what was calculated

 

[Craig Nedrow]

this does not look right. Is your piston -.015, (down) in the bore? Summit compression calculator has it right at 10:3. https://www.summitracing.com/newsandevents/calcsandtools/compression-calculator
Did you assemble and do the measuring yourself? Ideally pistons should be zero deck to minus a couple thou, as the smaller bore wont have much piston rock. Dynamic comp ratio will be lower as it takes into account the overlap @ BDC where the intake and exhaust valve is still open. Especially with fuel injection, you should be able to run 89 or 91 octane with that compression ratio, (10.3) with a good advanced tune, (30-34 degrees). If your gas is 87, you will loose some power, but your timing would need to be retarded. Tuning the A/F ratio will let you run more advanced with a "fat" (11.8-12.5) A/F. I do tune my own motors with a Wide band A/F gauge as you will be able to, so there is play room. Personally, I like a 9.5-10.75 street motor. You have a very nice setup for the street, gonna be snappy.