Dynamic compression?! Tony and the big dogs needed!

[blackbird1084]

JE 181920

[05hd]

JE 181920

Those are 5cc valve relief, like most JEs. 11.5:1 static and 10.1:1 dynamic.

If my other post gets approved by a moderator, it has a lot more info.

[96LT1355Z28]

I know its not answering your question but 11.5:1 compression won't require a conservative tune myself and many others run 12.5:1 with 91 just fine.

[05hd]

I know its not answering your question but 11.5:1 compression won't require a conservative tune myself and many others run 12.5:1 with 91 just fine.

Intake valve closing at?

[blackbird1084]

The problem is that the cam I have builds a ton of compression. I still don't have a cut and dry answer.

[quik95lt1]

you should be fine with that......people freak out over DCR numbers just like "head flow" and "dyno" numbers.......dynamic compression values work great if our motors never turned and were not affected by Volumetric Efficency.......my motor is at a mere 9.3:1 DCR according to my numbers yet i cant even go near 93 octane with my static cr of 13.9:1, a very efficent top end and a peak VE of around 100%

also when you calculate are you using your ABDC @ .004 or @.050 numbers? if you use ur .050 numbers your DCR calc will be through the roof.......mines at 11.90......this is incorrect make sure you use the advertised number where it comes off the seat......

[blackbird1084]

No I used the the intake closing degree. I used the calculator on Wallace racings website. Check yours on there and see if it's close so I know if it's in the ball park.

[quik95lt1]

yup its right on the money at 0 altitude it says im at 9.36:1

[blackbird1084]

Ok I'll probably veer on the side of caution and use 93 with an octane booster at first before I use just 93.

[quik95lt1]

with a good tune you should be fine........to get the most out of it a race gas tune will prob yeild some extra power.....