Quench for 4.125", 16 psi?
Normally, for a naturally aspirated or nitrous engine, you can set quench distance at about .040" and be okay.
However, on a boosted engine, some people have claimed that larger distances (.050-.100") actually help make more power.
However, on a boosted engine, some people have claimed that larger distances (.050-.100") actually help make more power.
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12 Second Club
Joined: Mar 2006
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From: Sarasota, FL
Anyone have any comments as to why this might or might not be true?
A lot of the big nitrous guys are saying the same thing....running .080"+ gives a bigger tuning window and makes more power than the tighter stuff NA motors usually run. I'm not smart enough to know why though.
With a super/turbocharged engine, the cylinders are much more densely packed with fuel and air, and the combustion is a lot quicker. Imagine lighting a brush fire in the desert, versus a dense forest. Which fire speads quicker?
I would guess, that the crevices in the quench area cause peak pressures to be a lot higher than the rest of the chamber, probably inducing detonation. That could probably even explain why the Hemi chamber is the standard in T/F and T/A classes, as there is basically no quench area at all.
I'm probably wrong though. lol
I will run the quench around .060" on alot of BBC N20 engines I do for the reason of minimizing the speed at which the burn across the chamber/piston heads takes place. The 'theory' is it helps control detonation, if that is possible on a N20 engine. I have also had good luck on 400 shot and bigger BBCs with the larger combustion chambers - 115cc and up. Sometimes to good/small of a chamber design and quench can promote too fast of a burn and make it more of an explosion than a slow burn leading into detonation.
I would assume these things would apply to the LS engines.....
I did my 403 Procharged engine at .041" quench because I didn't want to spend for special thickness H.G.'s and it was fine at 14-15 psi - pump gas and meth - when I tore it down. It didn't like more than 16* WOT.
Would have been interesting to play with the quench (open it up) and run it again to see if it would tolerate more timing.
I would assume these things would apply to the LS engines.....
I did my 403 Procharged engine at .041" quench because I didn't want to spend for special thickness H.G.'s and it was fine at 14-15 psi - pump gas and meth - when I tore it down. It didn't like more than 16* WOT.
Would have been interesting to play with the quench (open it up) and run it again to see if it would tolerate more timing.
