LilJayV10

iTrader: (39)

I was reading a good article from Engine Labs this weekend about quench on a nitrous motor. The normal thinking seems to be for a N/A motor the tighter the quench the better(to a point obviously, around .035-.040)

The article was talking about on a nitrous engine a larger quench is better, around .060 to help with flame travel/speed. They talked about softening the, increasing the quench my modifying the cylinder head.

For a street car that will only on spray occasionally is it worth running a thicker head gasket(I'm running a .045 now)to help it out or at a 200 shot does it even matter?

Thanks for the replies.

ATwelveSec02Z28

iTrader: (17)

increasing the quench will give you a wider tuning window.

Id look at 0.051 gaskets, you don't want too much quench, and at only a 200 hit you're not in dangerous territory with a sensitive tune up

G Atsma

.051 is the stock size gasket in case any don't know.....

98cherrySS

iTrader: (2)

I am no expert on the matter however, an engine builder explained to me about 6 years ago, that tighter quench will reduce detonation because the air that is squeezed out of the quench area cools the chambers. The tighter the quench the more cooling effect, to a limit I'm sure. This in turn is supposed to provide timing "head room" in nitrous applications. With that said, my engine builder suggested .041 MLS gaskets for my application which yields .036 quench. Planning to run a 200 shot max.

ATwelveSec02Z28

iTrader: (17)

If your engine builder told you that, Id be looking for a new builder. Thats pretty much the opposite of what is known. Increasing quench gives a wider tuning window and allows for more timing.

On a 200 hit, you're not really in a dangerous/sensitive area with your run of the mill LS engine.

On the other hand, my engine and heads are very sensitive especially when spray close to 600hp. The chambers are softened, and the quench is loose in an effort to slow the combustion flame.

98cherrySS

iTrader: (2)

Thanks for commenting. I've been looking into quench this AM and see that what you are saying is widely accepted as the truth. I won't name names but the builder I discussed this with is a very successful and very large pro mod engine builder. One of the largest in the US. His typical builds start at 2,000hp and go up from there. His company did all of the machine work on my block before they went exclusively pro mod so I am a little surprised to see that his guidance is in opposition to most of the published articles that I found on this subject. I'll be reaching out to him for some clarity on why the tight quench was recommended for my build.

'68LT1camaro

iTrader: (1)

Which plugs? What fuel do you run?

ATwelveSec02Z28

iTrader: (17)

I run Brisk Surface Gap plugs and C23.

My engine isnt a run of the mill LS, Mozez heads are very timing sensitive because the chamber is very efficient. I wouldnt recommend using surface gap plugs unless you absolutely need to, and if using them you need to find ways to monitor your tune. On an efficient head though the lack of a strap will allow more timing safely - theory is the strap remains hot, eventually acting like a fuse for detonation.

Before BES did some updates on my heads/engine it would never "nip a plug"... If a plug got burned, there was at least a hole in the piston.

MaroonMonsterLS1

so @ATwelveSec02Z28 Could you explain why less quench would be better for nitrous?
typically a tighter quench helps fend off detonation. The squish zone helps get more even fuel distribution and temperature gradients and it usually allows a couple degrees more timing before detonation.
Why would that not be the case with nitrous

KW Baraka

iTrader: (7)

What's most important to you; optimal tuning for everyday, NA driving.....or optimal tuning for nitrous (racing)?

KW

ATwelveSec02Z28

iTrader: (17)

The tighter quench will increase the flame front and burn rate - while great for an NA engine, its not optimal for large amounts of nitrous.

If you're spraying upwards of 1600pph of nitrous, you don't want a fast violent burn. When spraying that much nitrous and more, you're trying to keep the engine alive. The more quench allows for a larger tuning window - not more timing, just more of a cushion before the engine starts eating itself.

NA engines are more about efficiency... Less efficient engines respond better to nitrous, and are more forgiving if you miss on the tune up.