Which under drive pulley to buy/use?

[Brad Roberts]

Listen carefully: The 4inch will not turn the AC compressor fast enough at idle to keep the car cool!! So sitting at stop lights.. NO AC. This can happen also with the 5inch if the AC system is not 100%

[jb92563]

Originally Posted by Brad Roberts

Listen carefully: The 4inch will not turn the AC compressor fast enough at idle to keep the car cool!! So sitting at stop lights.. NO AC. This can happen also with the 5inch if the AC system is not 100%

I never read that anywhere or perhaps I missed that point.

Fortunately the car is rarely stationary for long, no traffic jams on my local routes, so I guess I'll try it out and see if I can live with that.

Do you know what the original pulley diameter is by chance?

I'd be interested in calculating the rpm difference that the accessories will see.

No issues with water pump speed at idle I hope as that is the more important thing.

I did buy a lower temp Thermostat and a new water pump that I will install while I'm in there as well.

[jb92563]

Update

I installed my Tarret 4" under drive pulley and all went well and better than predicted.

Particularly, I am happy to report that a 2001 S with the 4" under drive pulley still allows full operation of the air conditioning at idle!

Here is the Proof below:

With the Tarret UDP installed and the engine up to full operating temperature,
Ambient temperature 70 F as shown on the guage, and ~750 rpm at idle for over 5 minutes, airconditioning set at full the temperature of the air leaving the vent is ~38 F.


No disrespect Brad, but your information seems to be incorrect for the 2001 S scenario at least.
What model did you have that experience with?
Maybe we can qualify that statement and limit it to certain models?

Tarret UDP and Original

[thstone]

[QUOTE=jb92563;393339]

This might be on of the most informative pic's I've ever seen on 986Forum - OAT, Tach, Eng Temp, and A/C air temp all in one! Very clever. Great job!