Fuel
#1
Fuel lean in cold temps
I am running HTA green on E85 tuned for 31 psi and af basically at 11.8 ratio.
Power Mods: HTA Green / o2 housing & TBE / LICP and Intercooler / MBC & 25 psi wga / 1250 cc injectors / 84mm intake & cone filter
Lately its been running too lean. Around 13 af ratio area when WOT. Decreasing the boost to 22 psi and I am back to the normal area of 11.8 . I havent done too many runs yet but I'll try to see if it holds a good a/f at the boost level or just a one run thing.
Concidently with the falling temperatures, I have removed the EGR system and installed a block off plate (my tune allows it to be removed). I have vacuum capped the intake manifold nipples and routed the FPR straight from the intake manifold nipple.
Things i have changed or checked:
-Replaced walboro 255 pump with new pump
-Double checked FPR line
-Injectors are spotless from Gunk build, but I'll again in the next couple days.
I did also change my clutch, but disconnecting the battery shouldnt mess with the tune correct?
Since my car got stolen and found next day back in August, they took my tactrix cable so I cant data log unless some locals can help with that?
Am I missing anything to double check? Also is it normal to bring down the boost by 8-9 psi for colder temps? Seems kind of excessive.
Power Mods: HTA Green / o2 housing & TBE / LICP and Intercooler / MBC & 25 psi wga / 1250 cc injectors / 84mm intake & cone filter
Lately its been running too lean. Around 13 af ratio area when WOT. Decreasing the boost to 22 psi and I am back to the normal area of 11.8 . I havent done too many runs yet but I'll try to see if it holds a good a/f at the boost level or just a one run thing.
Concidently with the falling temperatures, I have removed the EGR system and installed a block off plate (my tune allows it to be removed). I have vacuum capped the intake manifold nipples and routed the FPR straight from the intake manifold nipple.
Things i have changed or checked:
-Replaced walboro 255 pump with new pump
-Double checked FPR line
-Injectors are spotless from Gunk build, but I'll again in the next couple days.
I did also change my clutch, but disconnecting the battery shouldnt mess with the tune correct?
Since my car got stolen and found next day back in August, they took my tactrix cable so I cant data log unless some locals can help with that?
Am I missing anything to double check? Also is it normal to bring down the boost by 8-9 psi for colder temps? Seems kind of excessive.
Last edited by BluEVOIX; Nov 3, 2010 at 08:11 PM.
#6
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Still, FedEvo8 may have a point. If the oxygen level of the fuel has changed and the average ambient air temps are significantly lower, then you may have to compensate by doing a complete fuel map tweak.
#7
Maybe, but e70 contains more gasoline than e85. So if the ethanol content drops then the richer the a/f ratio should be. Now, colder air would mean more dense with oxygen and leaner a/f ratios. But a 20-30* F drop in temps shouldn't require an adjustment decrease of 8-9 psi. I could be wrong, but it just doesn't make sense in my mind for that large of an adjustment.
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