i do not run anywhere near that much compression with our procharged stuff. i wouldnt do it, but maybe others have some first hand info

 

You care to share compression ratio numbers or cranking compression? I’ll guess 11-11.5 static and something in the 160-180 range cranking?

 

If you were at 11:1 compression 10psi would put you at 18.5:1. If you follow the average of .85:1 additional compression for 10psi of boost, 15:1 would put you at 21.4:1 compression ratio for your engine. Drop the compression down and let it eat.

 

My math puts 15:1 at 10lbs of boost at just over 25:1

 

Maybe try diesel fuel LOL

 

I saw I tried once. Made it through the burnout then blew it apart at launch. Looked like a top fuel motor after a bad run. Only thing left good was intake

 

Bad idea to run that much CR PROCHARGED or any other boosted application.

 

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Pistons are way too cheap to even think about it as the expert posted!!

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I have no experience with a pro charger but, I had 15.35:1 on an injected alky 496 BBC and stuffed an 8:71 roots blower on it to run a supercharged class. Talked to a few different blower mfgs and Littlefield told me as long as I kept it down to 5-6lbs of boost it would live. It did live, but I suspect the blower consumed more HP than it added. I pulled a couple head studs along the way, but did not torch the head gasket. I say go for it, the pro charger probably takes less HP to spin than my old heavy roots blower.

 

Put a 300 NOS shot on it.
it’d probably pick up 500 😳

 

What length rod? I have a set of pistons.

 

Plenty of 14-15:1 boosted engines out there but they aren't NA engines with boost. They don't have H beams..

 

I heard of Hemi guys running insane CR, and a blower, but they also bring spare engines for every round!!!!


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To me (with my limited understanding) calling that chart above effective CR is false, that is still static # based on math but other variables play a role too.
Here's a true effective CR calculator Wallace Racing - Effective Compression Ratio Calculator and this for dynamic CR is nice also Wallace Racing: Dynamic Compression Ratio Calculator
I want to believe these two are more accurate determining how much boost is your limit with chosen fuel.

 

Charts are always interesting. But never tell the entire story. From about 2005 to around 2012 raced a F3-139 ProCharged Gas deal. 9/1 CR and finally worked up to 42 psi boost without an intercooler. Was not easy and with a pile of burnt pistons and rings. But in the end it was reasonably happy. Chart says that's impossible🤔

 

Good luck and weld the heads to the block.

 

so it can be thrown away in one nice compact piece????lol

 

It was top alcohol F/C, and I was just visiting a buddy's pits.
Trust me I never said a word and stood in the corner & listened.

I was building a 509" Pro-Charger engine for my T/S, so I was interested,
but when they started talking about 13-1 & 14-1 I knew better.
Plus they were talking about sky high boost, so nothing they were discussing would help me.

My guy said 11-1 on meth, so that was my plan.

.

 

Even if you did have a blown motor with that much compression that wouldnt self destruct your tuning window would be miserably small. You would have to have a dead on tune every time to keep it together

 

On our hemi with the 140 we have 13.31 .050 gasket With BBC big chief heads 12.1