NOS jetting + tuning chart.......

I think you might be swapping cause and effect. You can get away with a little more timing on a combo that's already overly rich because the excess fuel acts as a crutch helping to keep any detonation & extra heat generated from excess timing (over an "optimum" timing setting) in check......to a point.

If you picked up by cranking in a bunch of timing that shows that either......

(A) Your fuel & nitrous jetting was close to optimum, but your original timing was too low to begin with. And increasing the timing was getting it closer to "optimum".

(B) Your fuel was rich to begin with, and increasing the timing past an optimum setting was a crutch trying to deal with the excess fuel.

Are you pulling any timing back out in high gear?

DILLIGASDAVE wrote:I think you might be swapping cause and effect. You can get away with a little more timing on a combo that's already overly rich because the excess fuel acts as a crutch helping to keep any detonation & extra heat generated from excess timing (over an "optimum" timing setting) in check......to a point.

If you picked up by cranking in a bunch of timing that shows that either......

(A) Your fuel & nitrous jetting was close to optimum, but your original timing was too low to begin with. And increasing the timing was getting it closer to "optimum".

(B) Your fuel was rich to begin with, and increasing the timing past an optimum setting was a crutch trying to deal with the excess fuel.

Are you pulling any timing back out in high gear?

No. But how do you know how much timing your car wants on nitrous without adding it and watching the mph and plugs. If the plugs look good and you add more timing and the car picks up that means the car wants more timing. If you raise timing you have to raise fuel unless your rich already, ask Steve Johnson. You can't just take away the timing that NOS recommends, every engine is different and will want a different total timing. Let's say for example your motor runs it's best on 36 degrees total timing on motor and you take away 2 degrees, it will slow you down but if you add it back and it picks it up it will also richen the tune up when you pull the timing, if you don't believe me then try it yourself. You all act as if having the timing that your car wants doesn't make hp and that is just crazy and every one will be different as to how much it wants on xxx of jets. If your just pulling how much the chart says you should and then setting your fuel to it then you could be missing out on a lot of hp. There will be a certain point in which your car will start to slow down because your adding to much timing and the fuel could keep it from detonation as a crutch as you say but you will slow down and your mph will fall. Here is a quote from one of the threads I showed you all from a very good tuner. Read it and see if you don't understand better what I am trying to say.

[QUOTE=Monty Mikho;88723]Here a plug taken from a motor running a .040 and .042 pill (fogger)
Clean plug below..

The arrow on the left shows the heat mark which is near the base of the ground strap (Start of the thread). Anything hotter will make this mark go lower (down onto the threads). Anything colder will move this mark up
(towards the radius of the ground strap).

The arrow on the right shows the fuel ring. Notice it is at the base of the plug. It falls between the inter metal part of the plug and the base of the plug. Anything richer will move up the plug (Like picture # 2). Anything leaner will work towards the metal part of the plug.

Please remember if the fuel ring is in the right spot and you need to add timing. That it will need added fuel as well. Remembering adding timing will give the fuel more time to burn. If the fuel isn't there it will eat a piston. If you remove timing and the fuel is rich remember to remove some fuel.. I think you get the picture.. Let us know how things work out for you. Make you best judgements on which way to move and how much. Try little moves.. Never make two big moves..




This picture is mid rich. It also shows some oil on the plug. Lets discount that at the moment. Notice the fuel ring us 1/3 of the way up the porcelaine? this fuel ring means it is rich. Removing fuel will lower this mark. Adding fuel will raise this mark (Like picture #3)



This plug is fuel rich. Notice the fuel ring at the top of the porcelain near the electrode?




The following plugs show timing heat marks. The marks are identified by the red mark.

The picture below shows the target timing mark for nitrous motors.





The picture below shows not enough heat in the combustion chamber. Adding timing will allow more time for the fuel to burn producing more heat in the chamber. You will need to add around 1.5 degrees of timing if the timing mark falls in this area. Please remember to look at the fuel ring and make adjustments if needed.




The picture below is too much timing. Removing timing will move this mark off the threads back on to the ground strap. If the timing mark falls in this area. You will need to remove around 1.5 degrees of timing. Don't forget to look at the fuel mark to see if changes are needed




Please note that lean fuel mixtures will add heat to the combustion chamber as well. Use the standard 1 degree of timing per 25 HP and the jet spread/fuel pressure recommended with your kit. Work your way to a better tune up from there. Personally I like to remove the fuel and add timing (if needed in that direction) in very small increments. Making big moves will make a lot of wasted aluminum...

The plug below is an oiled down plug. Notice the glaze look to the porcelain. The dark spot at the base is the fuel ring. The tan/gray is the oil. Please do not confuse the two. They look totally different.



Play safe, make small moves and take it easy. This stuff will come with time. Use a new set of plugs after reading the first set. Using a used set of plugs will mislead you down the wrong path. Save these plugs till your tune up is done then you can reinstall them in the motor (unless they are wasted of course). Take your time with reading. 5 minutes of time will save you $1000 in broken parts and hours of rebuild time.[/QUOTE]

DILLIGASDAVE wrote:I think you might be swapping cause and effect. You can get away with a little more timing on a combo that's already overly rich because the excess fuel acts as a crutch helping to keep any detonation & extra heat generated from excess timing (over an "optimum" timing setting) in check......to a point.

If you picked up by cranking in a bunch of timing that shows that either......

(A) Your fuel & nitrous jetting was close to optimum, but your original timing was too low to begin with. And increasing the timing was getting it closer to "optimum".

(B) Your fuel was rich to begin with, and increasing the timing past an optimum setting was a crutch trying to deal with the excess fuel.

Are you pulling any timing back out in high gear?

After reading your post a few times I think you have the right idea. It would be A in my case and could be in anyone's case. You don't know how much timing your motor will want on a certain nitrous hp level until you raise your timing till the mph falls off. B would be when one went past the optimum timing level and the fuel is crutching it from detonation. Your mph will fall off at this point and you will know when you reach B.