Air temperature and performance

[sparks57]

I've been noticing that my truck runs like a stripped ape when the air temperature outside is around 60 degrees, but then when the temperature gets around 90, my truck runs like crap, to the point where I almost have to start in first instead of second (especially with AC)... is this normal?

 

[Diesel Freak]

Originally posted by CB_Parker

is this normal?

yes!

 

[RamAZ]

I have a 92 with auto that dosn't run the greatest at elevated temperatures. With the onset of summer here in the southwest, todays temperature is suppose to be 113+, I just give it a little more go pedal.



During the summer I also raise the idle speed on mine a little to compensate for the hot air. Just the way things go.



I'm going to California coast in September, Santa Maria area to visit, my truck really likes the cooler damp air.



It would be nice if there was a way to have the idle go up when the AC is on with out having to do a bunch of parts rigging and adapting.



Things sound normal to me.



Jim

 

[TSuter]

I've noticed on mine that high humidity is a killer also.



Tom

 

[bgilbert]

Start in 2nd?? they put that 1st gear there for a reason, its not called low its 1st... .

 

[Greenleaf]

Hot Air/Lower HP

It's true! Us diesel guys [on the state tractor pulling circuit] don't worry much about it. Come September it will put out more ponnies and some compensation is made, but not much. The folks who run the 3,000 HP blown engines and old Allison aircraft1710 cid do!!!!!!!



Think of it this way. Our CTD is 200-300HP. That's not much. When you'r putten down 3,000 and make a run, you must gauge ambient temp and barometric psi. Why? Because it means the difference between several HUNDRED HP. Especially so when your rig is powered by two Allison 1710's or five 3,000 HP Kieth Black's. They have to adjust fuel nozzles to compensate for air density.



The engines used in WWII employed a two stage supercharger [RRMerlin] to compensate for this very same thing. This gave us our high altitude fighters their name [high altitude]



Scott



Just because Sammy uses cork doesn't mean you have to.

 

[rkubicki]

Its totally normal CB... I tune my pump for warmer temps in the spring and then tune it again in the fall for the cooler temps... If its bad enough to make you use first gear then try cutting back some fuel just a little (1/4 turn CCW on the volume screw works well for me).





Rob