# A/C benchmarking **URL:** \ **Category:** Maintenance/Repairs\ **Created:** [June 24, 2009, 5:23pm UTC](https://community.cartalk.com/t/a-c-benchmarking/32328 "2009-06-24T17:23:16Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![Jeffmw05](https://avatars.discourse-cdn.com/v4/letter/j/74df32/32.png) [@Jeffmw05](https://community.cartalk.com/u/Jeffmw05)\ **Post date:** [June 24, 2009, 5:23pm UTC](https://community.cartalk.com/t/a-c-benchmarking/32328/1 "2009-06-24T17:23:16Z")
Does 42?F @ the duct sound about right on a 90? day? Conditions: Car stationary, max A/C, partial shade. jmw ---
**Author:** ![mcparadise](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/mcparadise/32/32_2.png) [@mcparadise](https://community.cartalk.com/u/mcparadise)\ **Post date:** [June 24, 2009, 5:27pm UTC](https://community.cartalk.com/t/a-c-benchmarking/32328/2 "2009-06-24T17:27:07Z")
42 F sounds pretty good to me. What does your service manual say the temperature should be? ---
**Author:** ![Whitey](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/whitey/32/24680_2.png) [@Whitey](https://community.cartalk.com/u/Whitey)\ **Post date:** [June 24, 2009, 7:20pm UTC](https://community.cartalk.com/t/a-c-benchmarking/32328/3 "2009-06-24T19:20:24Z")
Agreed. You don’t get much better than that. Without knowing the year, make, and model, nobody can tell you if it meets the manufacturer’s specifications. Does your owner’s manual list a specified temperature range? ---
**Author:** ![americar](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/americar/32/42_2.png) [@americar](https://community.cartalk.com/u/americar)\ **Post date:** [June 24, 2009, 8:50pm UTC](https://community.cartalk.com/t/a-c-benchmarking/32328/4 "2009-06-24T20:50:20Z")
That is cutout refrigerant pressure converted to temperature plus ten degrees. Sounds good to me. ---
**Author:** ![Jeffmw05](https://avatars.discourse-cdn.com/v4/letter/j/74df32/32.png) [@Jeffmw05](https://community.cartalk.com/u/Jeffmw05)\ **Post date:** [June 24, 2009, 10:33pm UTC](https://community.cartalk.com/t/a-c-benchmarking/32328/5 "2009-06-24T22:33:10Z")
Thanks for the replies. I’ll check out my O-manual and the Haynes and see what they say! ---
**Author:** ![oldschool](https://avatars.discourse-cdn.com/v4/letter/o/e19adc/32.png) [@oldschool](https://community.cartalk.com/u/oldschool)\ **Post date:** [June 24, 2009, 10:41pm UTC](https://community.cartalk.com/t/a-c-benchmarking/32328/6 "2009-06-24T22:41:08Z")
The figure fits very well with my GM performance test chart. GM lists humidity as a major factor to consider when determining system performance. I know we have been down the humidity doesn’t matter path before because some say testing should be done on recirculate. Two things, for my 2004 performance test (2004 Envoy) GM specifies to not use recirculate and I did download a very good book on the affect of humidity on AC performance. The material is for a single user so Ican’t post the entire document but humidity should not be discounted when making a call as to whether the system is performing correctly. [autoACsystem.com](http://autoACsystem.com) the material is not free. ---
**Author:** ![ok4450](https://avatars.discourse-cdn.com/v4/letter/o/e9bcb4/32.png) [@ok4450](https://community.cartalk.com/u/ok4450)\ **Post date:** [June 25, 2009, 4:57am UTC](https://community.cartalk.com/t/a-c-benchmarking/32328/7 "2009-06-25T04:57:57Z")
I agree; sounds pretty decent for a stationary car. Get it rolling down the road at speed with additional air blowing through the condenser, the high side pressure will climb a bit, the low side will drop, and the temp at the ducts should drop even more.