Burning back 2 plugs on 200 shot
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From: Fort Worth Texas
Burning back 2 plugs on 200 shot Every time I spray a 200 shot, I burn #7 and #8 plugs. All other plugs look fine. Its a nx single nozzle with 78 n20 and 43 fuel pills. A/F is at 11.5 and only have 18 degrees of timing. Im not sure if fuel is just not reaching the back two cylinders or what?? Here are the mods-
408 - compression ratio around 10.5
Callies magnum xl crank
eagle rods
diamond pistons
ported 317 heads
fast 90/ nw 90
42# injectors
comp cam 23x-24x, 612-615
And this only does it on the 200 shot, 150 is fine... Any suggestions?? Direct port time?
408 - compression ratio around 10.5
Callies magnum xl crank
eagle rods
diamond pistons
ported 317 heads
fast 90/ nw 90
42# injectors
comp cam 23x-24x, 612-615
And this only does it on the 200 shot, 150 is fine... Any suggestions?? Direct port time?
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Colder would or might help, thoug this will not fix the seemingly lean condition. Going down the neck, a dry would and will give better distribution. I also have gone to DP, though dry. I have had no distribution issues running up to a 300rwhp shot down the neck with the dry nozzles. Fuel drop out is a reality on the front mount wet hits. maybe colder plugs and refrain from going bigger? Make sure you run the best gas you can get as an added safety measure. Depending on how lean, this could be a recipe for a lean back fire, been there done that, lol. Good luck anyway, the 408 and a 200 shot is a beast. 
Robert
Robert
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From: Fort Worth Texas
If you are pulling fuel off the rail and/or t-ing it before the rail and still have stock lines, you are starving the injs of fuel. Not due to pressure but due to the volume of the stock lines.
First varify fuel pressure and make sure its not droping.
If fuel pressure is not droping and you are running a solid 11.5 airfuel across the board those runners are not flowing as efficiant as the others. The best fix would be a directport so that you can individually tune those cylinders.
Tuning wise with what you have you can run a colder plug in those cylinders and richen up your over all nitrous tune untill those plugs start reading right.
The best fix though is to go directport.
Dave
If fuel pressure is not droping and you are running a solid 11.5 airfuel across the board those runners are not flowing as efficiant as the others. The best fix would be a directport so that you can individually tune those cylinders.
Tuning wise with what you have you can run a colder plug in those cylinders and richen up your over all nitrous tune untill those plugs start reading right.
The best fix though is to go directport.
Dave
How about flowing your injectors and putting the 2 richest ones in the back 2 holes.
Or even buying them with say 5% more for the back two. I know you can buy them like that from racetronics.
Or even buying them with say 5% more for the back two. I know you can buy them like that from racetronics.
Thread Starter
TECH Fanatic
iTrader: (10)
Joined: May 2007
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From: Fort Worth Texas
First varify fuel pressure and make sure its not droping.
If fuel pressure is not droping and you are running a solid 11.5 airfuel across the board those runners are not flowing as efficiant as the others. The best fix would be a directport so that you can individually tune those cylinders.
Tuning wise with what you have you can run a colder plug in those cylinders and richen up your over all nitrous tune untill those plugs start reading right.
The best fix though is to go directport.
Dave
If fuel pressure is not droping and you are running a solid 11.5 airfuel across the board those runners are not flowing as efficiant as the others. The best fix would be a directport so that you can individually tune those cylinders.
Tuning wise with what you have you can run a colder plug in those cylinders and richen up your over all nitrous tune untill those plugs start reading right.
The best fix though is to go directport.
Dave