Nitrous Dry Shot GOES LEAN!!!!
11-29-2006, 08:24 PM
#1
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Nitrous Dry Shot GOES LEAN!!!! I just dont understand what is going on here. Here is the nozzle setup:
Nozzles are about 3" from the MAF which from what I understand, should register a pretty dense shot on the MAF and should bump the airflow registered pretty high thus adding a lot of fuel
Jetted for 70hp, the nitrous system is working 100% as it should.
On the dyno tonight, I dialed in the WOT N/A tune to 13.0 across the chart and about 26-27* advance up to .76 g/cyl. Above .76, I made the timing 21* for the spray.
So, on the spray runs I had to let off each time because it would start spraying at 13:1afr and work its way up to 14-15afr.
SO I would let off at about 4400rpm where the AFR was about 15:1
W T F???
I have done every single power adder on a car known EXCEPT Dry nitrous. And I have to say, I am about ready to just convert this to WET.
BTW, car is completely stock so no, I doubt I am running out of fuel pump on a 70 shot. And also, I have 42# injectors in.
Nozzles are about 3" from the MAF which from what I understand, should register a pretty dense shot on the MAF and should bump the airflow registered pretty high thus adding a lot of fuel
Jetted for 70hp, the nitrous system is working 100% as it should.
On the dyno tonight, I dialed in the WOT N/A tune to 13.0 across the chart and about 26-27* advance up to .76 g/cyl. Above .76, I made the timing 21* for the spray.
So, on the spray runs I had to let off each time because it would start spraying at 13:1afr and work its way up to 14-15afr.
SO I would let off at about 4400rpm where the AFR was about 15:1
W T F???
I have done every single power adder on a car known EXCEPT Dry nitrous. And I have to say, I am about ready to just convert this to WET.
BTW, car is completely stock so no, I doubt I am running out of fuel pump on a 70 shot. And also, I have 42# injectors in.
11-29-2006, 08:47 PM
#3
at risk of sounding retarded i will state the obvious from that pic. the maf is unpluged. with that being said maybe you should clean the wires on the maf as they will get oil build up from you oiled air filter. also make sure the screen is out of the maf as it can easily ice up due to the extream cold from the nitrous. thats about all i have gotten so far as i am a nitrous noob also. good luck
11-29-2006, 08:57 PM
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Sory, but nothing comes to mind whay that would be lean.
Aren't you glad you dyno'd it, and found that out, instead of assuming it was ok.
Heres to you, Mr.TestedAFR-guy
Aren't you glad you dyno'd it, and found that out, instead of assuming it was ok.
Heres to you, Mr.TestedAFR-guy
11-29-2006, 09:11 PM
#5
OMG! I know the problem! Your MAF is unplugged! I see it in your picture. That's probably the problem, eh?
On a more serious note, is that a SLP MAF? Looks like it from behind. I don't know if that plays any role, but I never sprayed with my SLP MAF for fear of something messing up.
On a more serious note, is that a SLP MAF? Looks like it from behind. I don't know if that plays any role, but I never sprayed with my SLP MAF for fear of something messing up.
11-29-2006, 09:34 PM
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Originally Posted by volksmech1
at risk of sounding retarded i will state the obvious from that pic. the maf is unpluged. with that being said maybe you should clean the wires on the maf as they will get oil build up from you oiled air filter. also make sure the screen is out of the maf as it can easily ice up due to the extream cold from the nitrous. thats about all i have gotten so far as i am a nitrous noob also. good luck
Thanks for the feedback, but I do have all those bases covered just for the record.
11-29-2006, 09:42 PM
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Originally Posted by 860 Performance
Sory, but nothing comes to mind whay that would be lean.
Aren't you glad you dyno'd it, and found that out, instead of assuming it was ok.
Heres to you, Mr.TestedAFR-guy
Aren't you glad you dyno'd it, and found that out, instead of assuming it was ok.
Heres to you, Mr.TestedAFR-guy Aside from the MAF being unplugged (assuming it was plugged in for testing and you snapped the photo after you put your nozzles in)...your nozzles I think are in a better location than mine on my Blackwing.
W/ the 42's already in place it should not be a problem. Are the nozzles indexed so you know they are pointing at the MAF and not away from the MAF/are your nozzles 90 degree/70 degree or straight shooters?? .76 g/cyl is near what I was intending to use (above) when I got around to the dry tune, I am totally stock but am working on my VE and MAF tuning before I do the NA runs for the final max NA G/cyl.
Vin and I easily got to a 175 shot on a combo wet/dry on the stock fuel system on my 99, so I agree the stock vette pump on the stock motor likely is not the culprit. Since your into the tune can you log fuel pressure just to verify?
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11-29-2006, 09:48 PM
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Originally Posted by 860 Performance
Sory, but nothing comes to mind whay that would be lean.
Aren't you glad you dyno'd it, and found that out, instead of assuming it was ok.
Heres to you, Mr.TestedAFR-guy
Aren't you glad you dyno'd it, and found that out, instead of assuming it was ok.
Heres to you, Mr.TestedAFR-guy
11-29-2006, 09:53 PM
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Originally Posted by Beer99C5
LOL Vin!
Aside from the MAF being unplugged (assuming it was plugged in for testing and you snapped the photo after you put your nozzles in)...your nozzles I think are in a better location than mine on my Blackwing.
W/ the 42's already in place it should not be a problem. Are the nozzles indexed so you know they are pointing at the MAF and not away from the MAF/are your nozzles 90 degree/70 degree or straight shooters?? .76 g/cyl is near what I was intending to use (above) when I got around to the dry tune, I am totally stock but am working on my VE and MAF tuning before I do the NA runs for the final max NA G/cyl.
Vin and I easily got to a 175 shot on a combo wet/dry on the stock fuel system on my 99, so I agree the stock vette pump on the stock motor likely is not the culprit. Since your into the tune can you log fuel pressure just to verify?
Aside from the MAF being unplugged (assuming it was plugged in for testing and you snapped the photo after you put your nozzles in)...your nozzles I think are in a better location than mine on my Blackwing.
W/ the 42's already in place it should not be a problem. Are the nozzles indexed so you know they are pointing at the MAF and not away from the MAF/are your nozzles 90 degree/70 degree or straight shooters?? .76 g/cyl is near what I was intending to use (above) when I got around to the dry tune, I am totally stock but am working on my VE and MAF tuning before I do the NA runs for the final max NA G/cyl.
Vin and I easily got to a 175 shot on a combo wet/dry on the stock fuel system on my 99, so I agree the stock vette pump on the stock motor likely is not the culprit. Since your into the tune can you log fuel pressure just to verify?
Needless to say, this dry bs is pissing me off, Im about ready to go WET and be done. But the reason I went dry is because Ive tuned these cars for years with LS1 Edit and HP Tuners, and I love that one simple idea of how you can do a full blown N/A tune and then edit another part of the timing table for spray. And yes, that part of it worked fine...so I know the MAF was picking it up...but why the fuel? At 4400rpm on a 70shot, there is no way my stock fuel pump is the culprit. HIGHLY doubtful.
11-29-2006, 10:08 PM
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Vin and I had the problem with my 26 pound injectors: 50 shot was fine, 75 shot was an AFR above 13...Injectors 106%+ with the 50 shot.
The 42's fixed it in my case. CRC makes a MAF cleaner maybe the oil from the BWing has fouled the MAF a bit (not likely as .76 is the upper end of my NA g/cyl too), or maybe a kink in the hose before it goes through the firewall or pinched by something???
Here is my nozzle position, yours looks in a better location than mine for sure.
NX 90 degree that collide right in front of the BW opening (they are not spraying directly at the MAF).
The setup pictured was high 10's low 11's for AFR on the stock tune (just modified the IRC for 42's).
The 42's fixed it in my case. CRC makes a MAF cleaner maybe the oil from the BWing has fouled the MAF a bit (not likely as .76 is the upper end of my NA g/cyl too), or maybe a kink in the hose before it goes through the firewall or pinched by something???
Here is my nozzle position, yours looks in a better location than mine for sure.
NX 90 degree that collide right in front of the BW opening (they are not spraying directly at the MAF).
The setup pictured was high 10's low 11's for AFR on the stock tune (just modified the IRC for 42's).
11-29-2006, 10:24 PM
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Originally Posted by Beer99C5
Here is my nozzle position, yours looks in a better location than mine for sure.
The setup pictured was high 10's low 11's for AFR on the stock tune (just modified the IRC for 42's).
Damn now Im jealous of your AFR.
Honestly, if the problem is that my MAF is dirty, I dont even want to risk doing the dry shot...because I saw the maf wires when I took the maf off to install the nozzles...and they appeared fine to the naked eye. So if cleaning them works, then I really dont care because I dont want to risk it if lets say all of a sudden a spurt of air filter oil gets on a MAF wire and then my AFR spikes to 15:1...c'mon that sucks.
I would rather run with a wet kit and live with the very small risk of a fuel noid locking up than having to worry about a maf wire.
11-29-2006, 11:17 PM
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Originally Posted by Todd157k
Beer, What is your timing set at?
11-30-2006, 05:16 AM
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100 shot running 28 degrees. Bottle pressure 1000 or less.
When we did the combo to 175 shot, we pulled 3 degrees based on KR we saw.
On two logsout of maybe 8 sprays, playing with the new injectors, with the 100 shot I saw some false knock after the shot (about 1050 on the bottle pressure), and once I saw 4 degree's KR with a bottle pressure of 1100.
When we did the combo to 175 shot, we pulled 3 degrees based on KR we saw.
On two logsout of maybe 8 sprays, playing with the new injectors, with the 100 shot I saw some false knock after the shot (about 1050 on the bottle pressure), and once I saw 4 degree's KR with a bottle pressure of 1100.
11-30-2006, 06:24 AM
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Originally Posted by Beer99C5
Are the nozzles indexed so you know they are pointing at the MAF and not away from the MAF/are your nozzles 90 degree/70 degree or straight shooters??
He has NX nozzles, which have the logo on the injection side. I can see from the pic they are in correctly.
Vinny
11-30-2006, 09:03 AM
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Originally Posted by 99FRC
Stock pumps are designed for stock injectors. Sounds like you need a pump with the 42lb injectors.
If I had stock injectors, the only difference would be that they would be pulsed much more frequently to deliver the same amount of fuel.
BTW, how is Dave's plate kit? I am considering just buying his plate kit conversion since I already have his dry kit installed. I am really considering just going wet...but in the mean time I do want to find out WHY this is happening.
11-30-2006, 09:15 AM
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hey man..just another idea..not sure if anybody has mentioned it or not, but what about your fuel filter?? Have you changed it recently?? That could definately be a possible cause of fuel starvation..
11-30-2006, 09:34 AM
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You need to either log fuel pressure while spraying, or have a buddy hold a fuel pressure gauge while on the dyno.
That will rule out any fuel supply issue.
Vinny
That will rule out any fuel supply issue.
Vinny
