moregrip

iTrader: (8)

do these seem like reasonable guidlines?

9.0:1 BLACK SMOKE (NO POWER)

11.5:1 RICH BEST TORQUE @ WOT

12.2:1 SAFE BEST POWER @ WOT

13.3:1 LEAN BEST TORQUE @ WOT

14.6:1 STOCHIMETRIC AFR ( CHEMICALLY CORRECT )

15.5:1 LEAN CRUISE

16.5:1 BEST FUEL ECONOMY

18.0:1 CARBURETED LEAN LIMIT

22.0:1 EFI LEAN LIMIT

parish8

iTrader: (6)

i am not complaining, actualy i am thrilled that it isn't slowing down form the days when it was real cold and infact is quicker now on pump gas than before. i was sure some of the good numbers i was seeing before was due to the cold but that doesn't seem to be true.

here is the best comparison gtech i can find. it was 20deg that day and 50deg today. almost identical i was running the same a/f ratio and the same timing.

edit >> that run on the cold day had some race fuel in it and would not run without knock retard at that boost on pump. the warm day run is on pump.

moregrip

iTrader: (8)

Cold engine guidlines; at 10deg you may be seeing engine requirements similiar(but not exactly) to a totally cold engine, see below:

THE COMBUSTION PROCESS REQUIRES VAPORIZED FUEL. MOST OF THE VAPORIZATION OCCURS AFTER THE AIR AND FUEL DROPLETS HAVE MOVED PAST THE INTAKE VALVE, BUT A LARGE PORTION MUST OCCUR BEFORE THE INTAKE VALVE OPEN. IN A COLD ENGINE THE AIR, FUEL AND ALL THE COMPONENTS CONTACTED BY THE FUEL ARE AT TEMPERATURES THAT DO NOT PROMOTE VAPORIZATION, SO ADDITIONAL FUEL MUST BE ADDED SO THAT THE PERCENTAGE THAT DOES VAPORIZE WILL SUPPORT COMBUSTION. THE AMOUNT OF THIS ADDITIONAL FUEL (COLD ENRICHMENT) DEPENDS ON THE TEMPERATURE. IF THE STARTING CLIMATE IS VERY COLD (-20F) THE A/F RATIO MAY NEED TO BE 4.0:1, AS THE ENGINE WARMS UP, THE A/F RATIO MUST BE LEANED TO NORMAL VALUES.

NovaTime

PV=nRT.

I'm just being theoretical here

I don't know if the fuel being cold makes it slightly harder to combust or not, but it makes sense that the lower the temperature is, with volume remaining constant, that pressure will have to decrease. Coupling this with colder air (more dense; d=m/v), maybe that has an effect.

NovaTime

if we apply PV=nRT with a totally cold engine, that means that manifold pressure will DECREASE because the volume is CONSTANT!

parish8

iTrader: (6)

that kind of makes sence. i am not sure if that is what i am experiencing but it offers a prety good explanation. running it at those super cold temps is something that i will seldom do and will probably just turn down the boost when that cold.

lm7

iTrader: (8)

why not just try to add fuel like whitt said in the first place next time its that cold...maybe if your truck is tuned right for the weather u can run some better times...? wouldnt hurt to try.. its not like u dont tune that bitch everyday...

moregrip

iTrader: (8)

I think it was the running lean statement.
Parish is not running lean, however it seems that more fuel is the logical direction for more power under those extremely cold temps.

parish8

iTrader: (6)

i might try it but there isn't much of a point. i will never see 10deg at the track and there is no one to race on the street when it is that cold. i would be doing it just for the gtech and no one count's those as meaning much. the only reason i was out beating on it when it was that cold was i just got it running and had to see what it would do.

here is what i want to do.

hop in my truck. fill it with pump gas, drive to the track, dont even get out, just pull right up to the staging lanes. open the electric cut out as i stage. run a 10.xx, go get my slip. THEN, crank it up wouldn't that be sweet

James B.

iTrader: (1)

Once you figure out what the optimal intake temperature is you can electrically regulate your intercooler pump.