compression+boost?

[billwot]

Originally Posted by ft_sjo

First google result: http://cochise.uia.net/pkelley2/DynamicCR.html

I'm not qualified to comment, it's a very complex subject and none of us will have the source data required to calculate it.

Actually, its very simple.

Final Compression Ratio (FCR) = (Boost / 14.7) + 1) x CR
Boost = Maximum Boost
14.7 = Psi. at Sea Level
CR = Engine Static Compression Ratio

http://www.xcceleration.com/cr-boost%20101.htm



And here's a calculator to make it even more simple:

http://www.gtsparkplugs.com/Effectiv...ssionCalc.html

[350matt]

so you guys are all on stock internals? all at 12.5:1 CR?

are you restricting the boost below 5000 rpm to avoid breaking rods?

[Reaper]

380ft pounds below 5000 on stock internals.

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[Mikeez]

So is it better to have a lower compression ratio?

12.5:1 (Stock Engine FRS) with 7PSI boost yields a 18:1 ECR (effective)

Is that good for pump gas

[Reaper]

I'm stock compression ratio and make 450+whp. Another local frs is 9.5:1 and can only make 350whp. My old tuners car is 13:1 and makes more power than me on e85. I've also seen stock compression cars make more whp on pump gas than my local buddy's low compression motor by a long shot. Don't go below 11:1 or you will lose power.