I was checking out the 200 shot on the wideband and everything is good with cutout closed but when it's open it pops very loudly like there is gunshots going off. There is no knock and A/F is below 12.5-12.0. I put the 150 back on and it still pops but very lightly. I have tried the 150 many time before and never noticed this. ONly thing that has changed is cutout now has an electric baffle and it used to be manual.

 

As long as a/f is on and it feels like it should, I wouldn't worry about it. But, that is weird that it is popping .

 

Did you change your timing at all? Could be the fuel mixture is igniting too late and you still have unburnt fuel when your exhaust valves are opening maybe?? A 200 shot is a heck of alot of fuel mixture to add to the combustion chamber. Just a guess.

 

what are your plugs gapped at??? you may be blowing the spark out of the plug with that big of a shot, Mine did this on the 150 shot until I regapped the plugs to about .034" they are pretty tightly gapped, but the spark stays where it should now.

 

I'm leaning towards it running too rich and it burning when it leaves the cutout. I have gotten different answers from people as to what jets it takes for a NOS Ls1 plate to get me to 200. My 150 shot takes 63N and 38F but I was told to use 73n and 51F to get a 200 shot. IT seemed like to much of a jump in fuel but I still tried it. Anyone know the correct size jets? That recomendation was from nitrodaves.

 

I'd back the fuel down one jet size and watch the WB like a hawk... that should help too...

 

How old are your spark plugs?

 

How much timing are you running? Just curious.

 

Spark plugs are 3 months old, gapped at .035. My timing is at 27 degrees. I'll will change plugs tomorrow and see what happens.

 

nitro dave's plate
62N 38F for 150
78N 46F for 200