Hooker LT Dyno Atap questions...
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Joined: Jan 2002
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From: Lincoln Park Mi
Hooker LT Dyno Atap questions... Got the A taps from my dyno runs, and one bank looks like it is runnign leaner than the other, which side of the car is B1? I would think drivers side...
B1S1 B2S1
0.365 0.415
0.895 0.990
0.905 0.975
0.905 0.970
0.910 0.975
0.910 0.960
0.910 0.965
0.915 0.960
0.910 0.965
0.910 0.960
0.905 0.970
0.905 0.965
B1S1 B2S1
0.865 0.900
0.840 0.875
0.835 0.865
0.815 0.850
0.805 0.855
0.805 0.850
0.805 0.850
0.805 0.860
0.820 0.870
0.810 0.870
0.820 0.870
0.825 0.895
I know I got a little anti sieze on one of the O2 sensors during the header install, I wiped it off but Im beginning to wonder if that might be affecting it. can the front and rear sensors be switched? i might try one of the rears.
also L trims were 4.7 B1 and 8.6 B2 and 1.6 B1 7.8 B2.. is that a normal spread?
sorry bout all the questions, i dont know much about the A Tap, i dont even have it.
B1S1 B2S1
0.365 0.415
0.895 0.990
0.905 0.975
0.905 0.970
0.910 0.975
0.910 0.960
0.910 0.965
0.915 0.960
0.910 0.965
0.910 0.960
0.905 0.970
0.905 0.965
B1S1 B2S1
0.865 0.900
0.840 0.875
0.835 0.865
0.815 0.850
0.805 0.855
0.805 0.850
0.805 0.850
0.805 0.860
0.820 0.870
0.810 0.870
0.820 0.870
0.825 0.895
I know I got a little anti sieze on one of the O2 sensors during the header install, I wiped it off but Im beginning to wonder if that might be affecting it. can the front and rear sensors be switched? i might try one of the rears.
also L trims were 4.7 B1 and 8.6 B2 and 1.6 B1 7.8 B2.. is that a normal spread?
sorry bout all the questions, i dont know much about the A Tap, i dont even have it.
Re: Hooker LT Dyno Atap questions... Freak, everytime I have been on the dyno for some reason the first pass always looks richer on the 02's. Yours appears to be the same. Based on this pay particular attention to your second pull....it is running very lean!
Do you have a MAFT? You need to set your base fuel richer and see if your LTFT's come down to "0" or at least closer. What was your WOT timing doing? Any knock retard?
Do you have a MAFT? You need to set your base fuel richer and see if your LTFT's come down to "0" or at least closer. What was your WOT timing doing? Any knock retard?
Thread Starter
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Joined: Jan 2002
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From: Lincoln Park Mi
Re: Hooker LT Dyno Atap questions... i ran lean on both runs, according to the wide band O2 at the dyno around 13.8 or so, I dont have a MAFT yet, i have since replaced my ported MAF with my stocker, to try and get myself a little richer, My buddy has a MAFT that we are gonna try out before I go buy one, if it doesnt work I might just go ahead and get tuning, or maybe i wont need it with the stock MAF.
no real KR to speak of, had a touch (like .3) on one of the first run, but that was it...
so setting base settings will cause WOT to be richer? and i want them at about 0?
Do you know about the O2 sensor and anti sieze? what about switching the front out with a rear one?
Thanks a bunch
no real KR to speak of, had a touch (like .3) on one of the first run, but that was it...
so setting base settings will cause WOT to be richer? and i want them at about 0?
Do you know about the O2 sensor and anti sieze? what about switching the front out with a rear one?
Thanks a bunch
Re: Hooker LT Dyno Atap questions... One other critically important item that you didn't mention, did you allow your PCM to "re-learn" the idle mixture after the header installation? Also, did you allow it sufficient "idle re-learn" time before dynoing?
I was basing my comments above about running rich on your first run by looking at your bank 2 O2 readings for your first run..... .960-.970 range is very rich but the wide band is the right thing to use if you have access to one by all means rely on it since our O2 sensors aren't always very accurate.
What happens with the LS1 PCM is that at WOT it no longer makes continuous fuel trim adjustments like it does at part throttle where it is using continuous data feedback using the O2's. When you nail it WOT, the PCM typically will make a stab at a one time fuel/timing table for WOT use and you get what you get. Thus, the PCM will select the fuel/timing map based on running lean at part throttle and this means you will get a rich condition at WOT. If you are getting a lean condition at WOT, like you indicate, the PCM thinks you need more fuel because it could have thought that it observed richness at part throttle. Do you know what your part throttle O2's are reading?
The reason you want you WOT LTFT's at or near zero is because the PCM will not be looking for a substitute fuel/timing map table at WOT and you should get the optimum power table.
I would try switching the O2's side to side between S1 & S2 before going to the rears.
I was basing my comments above about running rich on your first run by looking at your bank 2 O2 readings for your first run..... .960-.970 range is very rich but the wide band is the right thing to use if you have access to one by all means rely on it since our O2 sensors aren't always very accurate.
What happens with the LS1 PCM is that at WOT it no longer makes continuous fuel trim adjustments like it does at part throttle where it is using continuous data feedback using the O2's. When you nail it WOT, the PCM typically will make a stab at a one time fuel/timing table for WOT use and you get what you get. Thus, the PCM will select the fuel/timing map based on running lean at part throttle and this means you will get a rich condition at WOT. If you are getting a lean condition at WOT, like you indicate, the PCM thinks you need more fuel because it could have thought that it observed richness at part throttle. Do you know what your part throttle O2's are reading?
The reason you want you WOT LTFT's at or near zero is because the PCM will not be looking for a substitute fuel/timing map table at WOT and you should get the optimum power table.
I would try switching the O2's side to side between S1 & S2 before going to the rears.
Thread Starter
TECH Regular
Joined: Jan 2002
Posts: 400
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From: Lincoln Park Mi
Re: Hooker LT Dyno Atap questions... I unhooked the battery, and drove for about 125 or so miles, about 50 was open header though, at normal cruise my O2s were all over the place.
thanks for hte help
thanks for hte help
