lean after 6k
lean after 6k Went to the dyno today and we couldnt figure out why my car went so lean after 6grand and up to my 6600 shift point. The a/f looks good all the way up to(11.7 range) 5800-6000 and starts to fall on its face to 14.0
and just not sure what to do . We data logged and never did have one bit of knock either. My NA a/f is on the mone and the jetting seems ok. Mods are in sig and it is a wett shot and a 150shot. Fuel rail ? Plugs? Let me know if you guys have any suggestions or need some more info to help. Im running tr6 plugs ,racetronix pump with hotwire kit.
and just not sure what to do . We data logged and never did have one bit of knock either. My NA a/f is on the mone and the jetting seems ok. Mods are in sig and it is a wett shot and a 150shot. Fuel rail ? Plugs? Let me know if you guys have any suggestions or need some more info to help. Im running tr6 plugs ,racetronix pump with hotwire kit. Last edited by 2001z; Oct 25, 2008 at 09:02 PM.
I figured a 255 pump would keep up with 551rwhp ? I dont think the fuel pressure went below 58 on the dynotune guage in my car but not 100 percent sure . It was weird my first run i did with a 32 jet in the run looked straight all the way across but was a touch lean so we put in a fatter jet like a 33 and it helped it all the way up till it got to 6grand and then spiked the a/f . It was def weird. On the 3rd run we tried a 34 jet but fron running so much somehow some fuel must have puddled up and had a backfire and shot my lid and maf across the dyno room so thats when i called it a day lol. Right now i have my 125 jets(59and a 31) in with and plan on running it from 3400-5800 on the window switch and shiftlight at 6k and 6600 on motor runs till i figure out this issue.
trouble shooting If it is the pump/rails......no jet is going to help.
with the fatter jet in, seems like it would be richer all the way across the rpm range on the nitrous, up untill you were having the fuel issues before. With the larger jet your lean issues would arise a few rpms lower due to the more fuel flow through the jet, than with the smaller jet installed, therefore dropping the fuel pressure sooner.
The nitrous/fuel should take care of itself with the jets with a wet kit. If the bottle pressure is pretty consistant, and the fuel pressure is consistant, then your afr through your rpms should be constant also.
I wouldn't think it is in the PCM or injectors, due to your N/A numbers being on the money.
with the fatter jet in, seems like it would be richer all the way across the rpm range on the nitrous, up untill you were having the fuel issues before. With the larger jet your lean issues would arise a few rpms lower due to the more fuel flow through the jet, than with the smaller jet installed, therefore dropping the fuel pressure sooner.
The nitrous/fuel should take care of itself with the jets with a wet kit. If the bottle pressure is pretty consistant, and the fuel pressure is consistant, then your afr through your rpms should be constant also.
I wouldn't think it is in the PCM or injectors, due to your N/A numbers being on the money.
If it is the pump/rails......no jet is going to help.
with the fatter jet in, seems like it would be richer all the way across the rpm range on the nitrous, up untill you were having the fuel issues before. With the larger jet your lean issues would arise a few rpms lower due to the more fuel flow through the jet, than with the smaller jet installed, therefore dropping the fuel pressure sooner.
The nitrous/fuel should take care of itself with the jets with a wet kit. If the bottle pressure is pretty consistant, and the fuel pressure is consistant, then your afr through your rpms should be constant also.
I wouldn't think it is in the PCM or injectors, due to your N/A numbers being on the money.
with the fatter jet in, seems like it would be richer all the way across the rpm range on the nitrous, up untill you were having the fuel issues before. With the larger jet your lean issues would arise a few rpms lower due to the more fuel flow through the jet, than with the smaller jet installed, therefore dropping the fuel pressure sooner.
The nitrous/fuel should take care of itself with the jets with a wet kit. If the bottle pressure is pretty consistant, and the fuel pressure is consistant, then your afr through your rpms should be constant also.
I wouldn't think it is in the PCM or injectors, due to your N/A numbers being on the money.
What valve springs? You have to remember its an oxygen sensor not a fuel sensor. so it reads unburned oxgen . if for any reason combustion does not hapen you will get a lean reading . not that it 100% but look at the dyno graph for any signs of valve float. A intake backfire is also a sign of valve float.
how did the 125 jets look on the dyno?
can you post the graphs?
what was thr a/f when it backfired? can you post that graph?
how did the 125 jets look on the dyno?
can you post the graphs?
what was thr a/f when it backfired? can you post that graph?
What valve springs? You have to remember its an oxygen sensor not a fuel sensor. so it reads unburned oxgen . if for any reason combustion does not hapen you will get a lean reading . not that it 100% but look at the dyno graph for any signs of valve float. A intake backfire is also a sign of valve float.
how did the 125 jets look on the dyno?
can you post the graphs?
what was thr a/f when it backfired? can you post that graph?
how did the 125 jets look on the dyno?
can you post the graphs?
what was thr a/f when it backfired? can you post that graph?
Last edited by 2001z; Oct 26, 2008 at 09:44 AM.
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So with the valve floating what do i need to do to look for to help fix this? Do i need to go in and retq my rockers ?I also know i could feel the car fall flat on its face on the dyno after 6 grand on the 150 shot .
Last edited by 2001z; Oct 26, 2008 at 09:59 AM.
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Verdad Gallardo Ok here is the update with the 125 shot i went out with my brother and tried the spray again today and had the 59/31 jets and did a 3rd gear roll with it spraying 3400-5800 in it and it was lean the whole way through like 12.7-13.0. Felt like a 50 shot lol so i put the 33 jet in and bamm mid 11s all the way up to 5500 then it went to 11.9 and that is it . we did it 3 times and perfect every run and felt a ton stronger . I guess im gonna stick with the 125 for a while since it seems to work good.
What jet were you using for 150? 62 or 63? what fuel? what nozzle?
I don't think it is valve float just throwwing it out there. valve floate will look like W"s on a slow downward path. The intake valve floating will cause combustion to go back threw the intake when theres nitrous pressent.
I don't think it is valve float just throwwing it out there. valve floate will look like W"s on a slow downward path. The intake valve floating will cause combustion to go back threw the intake when theres nitrous pressent.
I can tell you a single 70 jet is alot more then a 150 hit, that's more like a 175.
It sounds like you're running out of injector/fuel system. I dunno how that could be possible unless the filter is clogged, becuase I'm running the same pump, stock rails with 42 lb injectors and a wet Nos plate kit off the stock rail and have gone 9.5 with it on a consistant basis, and am having no fueling problems at all. I am running race fuel, and my jetting is alot different then what yours is, but that could just be one manufacturer to another I dunno.
It sounds like you're running out of injector/fuel system. I dunno how that could be possible unless the filter is clogged, becuase I'm running the same pump, stock rails with 42 lb injectors and a wet Nos plate kit off the stock rail and have gone 9.5 with it on a consistant basis, and am having no fueling problems at all. I am running race fuel, and my jetting is alot different then what yours is, but that could just be one manufacturer to another I dunno.
70 is not a 150.
The Fuel jet size should be 0.036" with A Nitrous jet size of .070" making 221.29 FWHP with 1 port(s)
Actual HP to the wheels: 188.10 HP
the 150 is
A Nitrous jet size of .062" and The Fuel jet size should be 0.032" making 173.60 FWHP with 1 port(s)
Actual HP to the wheels: 147.56 HP
Per ww.robietherobot.com ...
Unless the kit has some crazy lines or noids or something thats why your lean it needs a 36 jet and your probably out of fuel system. although with a holley 255 and a hot wire kit we made 625 and went 9.8.
The Fuel jet size should be 0.036" with A Nitrous jet size of .070" making 221.29 FWHP with 1 port(s)
Actual HP to the wheels: 188.10 HP
the 150 is
A Nitrous jet size of .062" and The Fuel jet size should be 0.032" making 173.60 FWHP with 1 port(s)
Actual HP to the wheels: 147.56 HP
Per ww.robietherobot.com ...
Unless the kit has some crazy lines or noids or something thats why your lean it needs a 36 jet and your probably out of fuel system. although with a holley 255 and a hot wire kit we made 625 and went 9.8.
With a regular racetronix intank pump, and the hotwire kit (well, sort of I redid the hotwire kit, I ran a heavier wire inside the bucket out to the connector, and with my battery in the trunk the wire is alot shorter, and it's 10 guage right to the pump itself for both power and ground) I don't know what I am making on the jug for power, but the 3350 lb car with full exhaust goes 9.5 @ 142 repeatedly and I haven't had any issues at ALL with running lean, car runs fat if anything.
I'm a little different on the jetting though, and by the robbie site I'm way rich. (I'm running a 65 nitrous jet and a 42 fuel jet)
But the plugs look great, distribution is very good, and the car's got 200 passes on it with no more then oil changes and a set of valvesprings (probably due for another set now but the season's over so it can wait)
I'm a little different on the jetting though, and by the robbie site I'm way rich. (I'm running a 65 nitrous jet and a 42 fuel jet)
But the plugs look great, distribution is very good, and the car's got 200 passes on it with no more then oil changes and a set of valvesprings (probably due for another set now but the season's over so it can wait)
Everyone jets their kits differently. I found a manual online for the nitrous works kit here: http://www.barrygrant.com/fromBarryG...it%2013075.pdf
I would double check the jet sizes...125 looks to run a 55N and 31F. Thanks.
Nick
I would double check the jet sizes...125 looks to run a 55N and 31F. Thanks.
Nick
Everyone jets their kits differently. I found a manual online for the nitrous works kit here: http://www.barrygrant.com/fromBarryG...it%2013075.pdf
I would double check the jet sizes...125 looks to run a 55N and 31F. Thanks.
Nick
I would double check the jet sizes...125 looks to run a 55N and 31F. Thanks.
Nick
And being a nitrous "Expert" you would knwo unless something is screwy a jet makes x hp and needs x fuel if a kit called for some jet 4 sizes larger than it should there is an issue with that kit!
"Nick"
I got the actual slip with the jet sizes on them from barry grant and that is where im geting my jetting it actually says a 76 for 175. for the 150 it says 70/33or35 and the 125 i have 59/33for 40psi or31for 50psi for fuel. I tried the 31 and it was to lean so i tried the 33 and it was 11.5-11.9 with my wideband . The nozzle i have is the upgraded nozzle kit from 125-175 shot from barry grant. On the dyno on the 150 shot my fuel pressure never dropped below 57 pounds at the fuel rail according to my dynotune guage it stayed 60 through most of the way till around 5500-6600 where it was 60-57psi. Injectors maybe? plugs? I doubt its my fuel rail.
