Hi all.

I just wanted to see what the general consesnus was.

My 3.9 -Elk Conversion - with the AC on is a dog. I pretty much have to floor it to obtain acceleration that doesn't get me run over.

Is yours like that?

thanks...

 

I notice a difference in acceleration between A/C on and A/C off but not enough to be concerned about. How many miles on your engine?

 

115k...

I guess what I am trying to say is how does it compare?

My van with the AC on feels like it has the accelleration of a VW Bug (if you have driven on of those) or a older Toyota Tercel.

It just seems a little slow.

 

Mine is a 2000 5.2L V8 but I too experience noticable power loss in the summer, esp in bumper-to-bumper traffic in town.

After a great deal of investigation I have decided this is due to multiple issues. The a/c compressor design is pretty efficient and only pulls 10 - 12 hp. Add another 1 hp loss for running the blower fan. The bigger loss comes from the fan clutch which is easily 15 - 30hp. I removed my engine fan and replaced with an electric but the van still doesn't accelerate like it does in cooler weather.

What I think is happening is that the hot incoming air charge is sensed by the IAT, which causes the computer to lean out the fuel mixture. This lean mixture is then sensed (by the O2 sensor) and the computer must retard the iginition timing in order to prevent detonation (pinging). All of which results in much lower engine power output.

I plan to play with IAT modifications when I have time. Currently I am replacing my van's carpet.. the old carpet was glued down and it's already taken 3x longer than I estimated