Nitrous help===fouling plugs i think.
11-03-2013, 04:11 PM
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Nitrous help===fouling plugs i think. I have this problem after running a bottle or two thru my engine. AI 243 headed stock shortblock with cam and exhaust/ bolt-ons. The car will run great after changing plugs BR6efs or BR7efs. Spraying 150 shot with a stand alone with 109 octane in it. Then all of a sudden after some runs and 1.5 to 3 bottles it will fall off on ET by .8 to 1.2 seconds on a qtr mile run. It will feel lazy and butt dyno is very noticeable. It will crank right up and idle and seem to run fine on motor but it gets sluggish and has no pep like it should. It almost seems like when you spray it it doesnt spray nitrous but I know it is. Its like not very much improvement in HP. Then change the plugs and it goes back to jerking a knot in your neck and hauling *** on the spray like it should. Its not consistent on when it does this as it can be after a bottle in a half to up to 3 bottles later so its a puzzle to me. You never know when its going to go slow. I tried a test and turned the stand alone pump off and just hit the nitrous to see if it changed and it hit harder but still off some then sprayed it with both on and doggggy. Take the plugs out and they look fine but they are fouled some what because I install new plugs and it runs like a Different car. GURUS is this in the tune or whats causing the issue. The car has been dyno tuned and had laptop hooked to it and everything in tune is good. Im spraying 58 psi from the stand alone with high octane unleaded. I guess its getting pig rich when i spray. Using jets that company recommends on fuel with that shot size. I have a LNC200 and pull 4 degrees but have pulled zero timing on the dyno and it all looked good spraying it. Any ideas??? Thanks
11-03-2013, 08:10 PM
#2
I have this problem after running a bottle or two thru my engine. AI 243 headed stock shortblock with cam and exhaust/ bolt-ons. The car will run great after changing plugs BR6efs or BR7efs. Spraying 150 shot with a stand alone with 109 octane in it. Then all of a sudden after some runs and 1.5 to 3 bottles it will fall off on ET by .8 to 1.2 seconds on a qtr mile run. It will feel lazy and butt dyno is very noticeable. It will crank right up and idle and seem to run fine on motor but it gets sluggish and has no pep like it should. It almost seems like when you spray it it doesnt spray nitrous but I know it is. Its like not very much improvement in HP. Then change the plugs and it goes back to jerking a knot in your neck and hauling *** on the spray like it should. Its not consistent on when it does this as it can be after a bottle in a half to up to 3 bottles later so its a puzzle to me. You never know when its going to go slow. I tried a test and turned the stand alone pump off and just hit the nitrous to see if it changed and it hit harder but still off some then sprayed it with both on and doggggy. Take the plugs out and they look fine but they are fouled some what because I install new plugs and it runs like a Different car. GURUS is this in the tune or whats causing the issue. The car has been dyno tuned and had laptop hooked to it and everything in tune is good. Im spraying 58 psi from the stand alone with high octane unleaded. I guess its getting pig rich when i spray. Using jets that company recommends on fuel with that shot size. I have a LNC200 and pull 4 degrees but have pulled zero timing on the dyno and it all looked good spraying it. Any ideas??? Thanks
-plug gap
-nitrous/fuel jetting, and which system it is
-nitrous pressure
-fuel pressure
-mph gained from spraying
You should probably not need to change plugs very often on a 6 or 7 series plug. Sounds a little like nitrous pressure or lack of nitrous.
11-03-2013, 09:34 PM
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78 MM Harris speed works wet plate kit. 58psi fuel pressure, 950-1050 N2o pressure. Im using the HSW 150 shot fuel and nitrous jets that came in their kit.
Plug gap could be an issue maybe. I went with .030 to .032 for a long time and it took longer to foul out the plugs than when gapped at .035. I just put some BR6efs gapped @ .028 in her tonight and she runs very good again NA and on the spray. Those plugs are gapped very tight from NGK out of the box and always have to open them up a bit. May go .025 or lower as an experiment on the next set and may put BR7efs in it. I tried the plug gap as its an easy cheap experiment.
The car has run 124 mph but other night it went 118.5 on full dope hit. It went 119.3 on 125 shot on pretty much stock bolt on Ls1 yrs ago.Still fishing for answers.
Plug gap could be an issue maybe. I went with .030 to .032 for a long time and it took longer to foul out the plugs than when gapped at .035. I just put some BR6efs gapped @ .028 in her tonight and she runs very good again NA and on the spray. Those plugs are gapped very tight from NGK out of the box and always have to open them up a bit. May go .025 or lower as an experiment on the next set and may put BR7efs in it. I tried the plug gap as its an easy cheap experiment.
The car has run 124 mph but other night it went 118.5 on full dope hit. It went 119.3 on 125 shot on pretty much stock bolt on Ls1 yrs ago.Still fishing for answers.
11-04-2013, 10:39 AM
#4
78 MM Harris speed works wet plate kit. 58psi fuel pressure, 950-1050 N2o pressure. Im using the HSW 150 shot fuel and nitrous jets that came in their kit.
Plug gap could be an issue maybe. I went with .030 to .032 for a long time and it took longer to foul out the plugs than when gapped at .035. I just put some BR6efs gapped @ .028 in her tonight and she runs very good again NA and on the spray. Those plugs are gapped very tight from NGK out of the box and always have to open them up a bit. May go .025 or lower as an experiment on the next set and may put BR7efs in it. I tried the plug gap as its an easy cheap experiment.
The car has run 124 mph but other night it went 118.5 on full dope hit. It went 119.3 on 125 shot on pretty much stock bolt on Ls1 yrs ago.Still fishing for answers.
Plug gap could be an issue maybe. I went with .030 to .032 for a long time and it took longer to foul out the plugs than when gapped at .035. I just put some BR6efs gapped @ .028 in her tonight and she runs very good again NA and on the spray. Those plugs are gapped very tight from NGK out of the box and always have to open them up a bit. May go .025 or lower as an experiment on the next set and may put BR7efs in it. I tried the plug gap as its an easy cheap experiment.
The car has run 124 mph but other night it went 118.5 on full dope hit. It went 119.3 on 125 shot on pretty much stock bolt on Ls1 yrs ago.Still fishing for answers.
11-04-2013, 10:42 AM
#5
I'm guessing you dont have a wideband so the next step will be reading the plugs for Air/Fuel and also timing. Most companies will recommend jetting that is on the rich side. Its really just a starting point. You want to be in the 11.8 to 12.0 range.Feel free to shoot me a PM if you'd like help getting the tune up lined out.
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11-04-2013, 12:17 PM
#9
11-04-2013, 03:53 PM
#11
I would definately recommend a wideband. You may want to also try the jetting for 60 PSI. I think we all need to wait and see what the wideband is showing, to help further diagnose the problem. We looks for about a 12.8 A/F ratio on nitrous, and 1000 PSI bottle pressure. The car may pick up more by adding a degree or two back into it, FWIW. Usually problems like this are caused by too much timing pulled, and too much fuel. What Brandon said is correct, most companies jet rich out of the box, for safety precautions, I know that we do. The plug pics definately looks rich. Are you pulling global timing or is it actually a tune that pulls timing when the nitrous comes in?
-Garrett
-Garrett
Last edited by NitrousExpress; 11-04-2013 at 04:03 PM.
11-04-2013, 05:53 PM
#15
You are low 10s or even 9.x AFR from looking at those plugs if they are NGKs.
If my car would reduce fuel to 33 and try again same spark. Basically when it's not 100% black on base ring and starts getting color you are closer.
If my car would reduce fuel to 33 and try again same spark. Basically when it's not 100% black on base ring and starts getting color you are closer.
