This being a six speed car, you did not get into high gear(4th as it is your 1:1) which means you did not ever put full load on the engine. When I say full load I mean the point where cylinder pressure is the highest. When you shift into fourth you're creating more cylinder pressure than you did in 1st, 2nd and 3rd with a M6. Thus putting more heat into the cylinder and of course the plug itself.

 

I agree the plug has not had much heat on it but there is enough info there to start the tuning process. Not everyone tunes the same way so just take this as another method.

If I were you I would give it a little more fuel before blasting it all the way through 4th gear. Most nitrous motors are hurt at the top end of the track. The tune gets more aggressive in that area because of the load on the engine.

Looking at your spark plug we have enough info to know its not overly rich. We have no black on the top of the plug, no black specks on the porcelain, and no hint of a fuel ring. The strap is chalky but is showing signs of what could possibly end up being your timing mark. I would take my thumb and wipe the strap. Then look at the strap to see if it shows any signs of a heat line. Using the info we see I would lean towards thinking it is possible that its aggressive on the tune up and it will only get worse on the top end of the track.

With that being said I like to take a safer approach. Which is why I have never blown up someones engine and I do a lot of nitrous tuning.

I would go from the 33 fuel jet to a 35 fuel jet. Then make another hit. I usually start off 330 the car and as I get the tune up close I move to 1/8 mile. Then if its a 1/4 car I move to the 1/4.

I like to see a tan fuel ring at the base of the porcelain. While getting the fuel ring to come around I watch the heat and timing mark on the strap of the plug. If it looks aggressive I pull timing to make sure the motor lives while dialing in the air fuel. Once I have the fuel ring where I like it then I make small timing adjustments watching the heat line on the strap, mph and ET.

Remember its better to play the safe side of things and have to make an extra pass or two than to get into a rush and hurt the motor.


Dave

 

That is good to know. Thank you very much. I was figuring that the short 1-3rd run won't be able to tell me the whole story but was hoping for a hint (for lack of better word). Your explanation of heat being induced to the plug under high load makes plenty of sense. Your help is very much appreciated.

 

Very good info Dave. Thank you very much. Your explanation is basically what I was looking for. I was not expecting to be able to fully tune the vehicle with such a short run on these plugs but was hoping to get a start. I did not want to jump in with an unknown tune and do a full pass in high gear. Through my nitrous research I know that most nitrous damage is caused at the end of the track.

Tonight I actually moved to the 35 jet and left the timing pulled at 7 degrees. I started another thread with my results and some decent pictures. I am hoping the pictures are clear enough for experts to be able to chime in.

Your guidance and advice is so appreciated. I know it takes a large portion of your day to come on these forums and respond to us users for basically no cost. Thank you for doing so. There is no way I could tune this car by just myself.