Problem with fuel..
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From: Port Tobacco, MD
Problem with fuel.. I have had a problem for the last 2 weeks and can't seem to figure it out. The first pass the car went a very rich 10.1:1. I followed it up by leaning out the PE table by 6% and still went ~10.0:1, later that night we found out the bottle was near empty so we linked the 2 together. We come back this friday and run it again and runs another 10.1:1, lean it out 6 % and it seems like it gets better but its still FAT!
http://home.comcast.net/~pthomas1077/10.07.JPG
leaned fuel out 6%
http://home.comcast.net/~pthomas1077/10.6-135.JPG
Phil
http://home.comcast.net/~pthomas1077/10.07.JPG
leaned fuel out 6%
http://home.comcast.net/~pthomas1077/10.6-135.JPG
Phil
Are you sure that you have the correct jets on the gas? I know its a shot in the dark, but I've seen this happen plenty of times. And even tho the jets have the size stamped on them its always good to really check them and make sure they are right.. Here is an example..
My friend has a ProModified car and he kept having problems with the nitrous.. He tore the car apart 2-3 times and replaced all the electronics, rewired the whole car, checked the nitrous/fuel solenoids, etc etc and then after burning a hole completely thru 2 pistons and the cylinder wall he checked the nitrous jets and the nitrous jets in the 2nd stage of his system were WAYYYYYYYYYYY to big. Were suppose to be like a .032 and measured out to a .088!!!! Thats an expensive **** up and cost him 2 Vanolia pistons and had to re-sleeve a Donovan 706 aluminum block.. ouch!
My friend has a ProModified car and he kept having problems with the nitrous.. He tore the car apart 2-3 times and replaced all the electronics, rewired the whole car, checked the nitrous/fuel solenoids, etc etc and then after burning a hole completely thru 2 pistons and the cylinder wall he checked the nitrous jets and the nitrous jets in the 2nd stage of his system were WAYYYYYYYYYYY to big. Were suppose to be like a .032 and measured out to a .088!!!! Thats an expensive **** up and cost him 2 Vanolia pistons and had to re-sleeve a Donovan 706 aluminum block.. ouch!
Phil. I have read your other trend also. Just double check the fuel AND nitrous jets. 1st couple of runs this year, I couldn't understand why the car just didn't pick up last year, just kind of laid over. The nitrous jets were the 75 shot, vice the 100 shot. Everything was good after the switch.
The only other thing (re-checked the jets, syn operation, and the lines -- check on the syn to actual jet side not the incoming line) would be possible NR on the initial hit where it is pulling timing which would richen up the mixture. Pull your spark plugs - or just change them out. How much timing are you running? Gas - 91 octane or race?
You are so close to 9's. Good luck.
David
The only other thing (re-checked the jets, syn operation, and the lines -- check on the syn to actual jet side not the incoming line) would be possible NR on the initial hit where it is pulling timing which would richen up the mixture. Pull your spark plugs - or just change them out. How much timing are you running? Gas - 91 octane or race?
You are so close to 9's. Good luck.
David
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From: Port Tobacco, MD
I am running rich on all of my jet settings 150 200 250. 28 degrees of timing with 150 and 23 on 200 and 250. My car was tuned on 93 octane for motor and I am running a 50/50 mix of 111 race gas and 93 at the track. I wonder if the race gas is throwing the tune off.
Phil
Phil
Maybe. 1st of this year, I ran 104 unleaded. Decided to change to 114 - straight no mixing. I was able to run 30 degree of timing with 100 shot and 28 degrees with 150 shot with no NR or detnation. I'll be dropping to 26deg on the 200 shot. We aren't 2 far off on timing. My A/F on the dyno and with the O2 wide band in the car stays right at 11.9-12.01. Possible that the A/D (temp and so forth) is forcing the car to run richer? Correct me if I'm wrong, but with cooler air, you can run richer and push through more gas. If you keep pushing the same amount of gas with hotter temp (worse AD) than the car would run richer. If all else remains the same (shot, your tuning) would this make the car actually run richer?
David
David
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From: Port Tobacco, MD
Ya know, thats a good question. On my old FWD turbo car when we went to straight race gas C16 the car fattened up ALOT. Tune on the street was -15% and at the track it was -30% on race fuel. When you refer to A/D what do you mean? I wonder if my nitrous supply line is restrictive? Its the small line maybe -4 that came with the TNT F1 kit. I thought I read somewhere that there is a point when the -4 line simply can't flow enough to support a large shot of nitrous. Someone was also talking about line swell.
Phil
Phil
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AD - DA - air density. Sorry. I have read/heard the -4 should be fine up to at least a 250 shot. I had no problems last year running 200 shot with the stock TNT F1 kit lines.
Also, last year I had 2 set-ups. One for good air (cold temps) and one for hot temps. I would lean out the set-up by an additional 5%.
Again, just a thought
David
Also, last year I had 2 set-ups. One for good air (cold temps) and one for hot temps. I would lean out the set-up by an additional 5%.
Again, just a thought
David
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From: Port Tobacco, MD
Its got to be in the tune. The car runs very fat on all of the jet settings. I was thinking about trying a 50 shot smaller fuel jet and see what that did. 200 nitrous with 150 fuel.
Phil
Phil
Last edited by Phil99vette; Jun 25, 2005 at 06:58 PM.
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Anytime you alter the Spec gravity of fuels you will alter the tune..
you can easily see +/-10% in going from different 93 octanes when one contains 10% ethenol vs one that does not. since your mixing and matching fuel I suspect that would be the first place I would look. Also, I would stop mixing fuels Unless your mixing them out of the vehicle. The ratio of the mix is important and you have no control when dumping it into the tank with the fuel remaining in the tank at an unknown volume and mix ratio.
Dave
you can easily see +/-10% in going from different 93 octanes when one contains 10% ethenol vs one that does not. since your mixing and matching fuel I suspect that would be the first place I would look. Also, I would stop mixing fuels Unless your mixing them out of the vehicle. The ratio of the mix is important and you have no control when dumping it into the tank with the fuel remaining in the tank at an unknown volume and mix ratio.
Dave
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From: Port Tobacco, MD
Could the tune be 10% rich due to the ethanol and possibly another 5% rich due to how cold the high octane fuel burns?
And another thing, when I was driving down to the track, the car was running ~13.0:1 crusing and if you correct that back to the normal 14.7 you get a 13% correction factor.
Phil
And another thing, when I was driving down to the track, the car was running ~13.0:1 crusing and if you correct that back to the normal 14.7 you get a 13% correction factor.
Phil
