Nitrous Timing

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Apr 10, 2014 | 09:38 PM

stevecritt

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Nitrous Timing

Im getting ready to run the nitrous on my car. gonna start off with A 100 Shot and work up and stay at 200 shot. I run 36* max at about 3500rpm. What should I back off to?

Apr 11, 2014 | 04:42 AM

Doug G

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From: Harford Co. Maryland

Rule of thumb for starting out is -2* for every 50.
This is just for baseline.
No projected tip plugs.
Will want a few degrees colder plug.

READ YOUR PLUGS !

Apr 11, 2014 | 08:23 AM

newschool72

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From: georgia

Quote:

Originally Posted by stevecritt

Im getting ready to run the nitrous on my car. gonna start off with A 100 Shot and work up and stay at 200 shot. I run 36* max at about 3500rpm. What should I back off to?

That looks like a bunch of timing for a head as efficient as we run on these LS engines. Did you come up with 36* on a chassis dyno, or the drag strip? My point is, you don't really hear the detonation that comes from too much timing very well, so before you start spraying, you might want to nail down your base timing. If you found that timing with the dyno or strip, then Doug nailed it down pretty good, IMO. If your timing came by the butt-o-meter, dropping 2* of timing on an engine that's beating it self to death with too much base timing is going to beat it self to death much quicker on spray!

Apr 11, 2014 | 08:32 AM

70shortwide

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mine is 36 from 3500 on. If i went down the time would fall off at the track.

Apr 11, 2014 | 08:55 AM

newschool72

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From: georgia

Quote:

Originally Posted by 70shortwide

mine is 36 from 3500 on. If i went down the time would fall off at the track.

How far down have you gone? Mine runs good at 34*, but I haven't experimented below 31-32* and those test were under less than ideal conditions. Im going to drop a ton of timing off mine (starting at 25*) and see if the real sweet spot is closer to what the EFI guys run. There are a lot of players in what the individual engines timing will be, but compression and combustion chamber shape are the 2 biggest . Contrary to what we were all taught by our dads, more timing isn't better. The right timing is always best, and the closer to TDC the advance is, the better the push on the piston and the less the piston has to fight the flame front to get over the hump. If it needs 36*, then that's what it needs and that's where you should run it. Based on all the high timing I see on carbed setups, I wonder if our 34 to36* timing is the best our engines will run in the high timing window we start our testing in. In other words, 36* might be the best it will do between 30 and 38*, but it might be better in the 25-29* range. I wont know till I try it, but it makes sense, based on what the factory and the EFI guys run. The low timing is what these heads were designed to run best in, so its worth a try.
OP, I hope this is related enough to your question to not be a highjack.

Apr 11, 2014 | 02:46 PM

TXsilverado

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From: Humble Texas

here we go....

Apr 11, 2014 | 06:02 PM

stevecritt

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Just the butt dyno. Im going to track tonight, gonna bump down the timing to 34. No nitrous tonight just motor. I was thinking 28* for a 100 shot to start off with