Down some power, summertime temps?

[spederman]

I just upgraded to GI joes 8 rib setup with a 3.2 RR pulley. Previously my setup was the 6 rib w/ 3.25 vortech pulley. I was getting pretty bad belt slip. Now there is none which is sweet. But for some reason i am down quite a bit of power and was wondering if summertime temps/humidity can affect the numbers this much:

6 rib 3.25 vortech pulley @9psi= 400rwhp/403rwtq (dyno'd in march when temps were prolly in the 60-70's here in TX)

8 rib 3.2 RR pulley@9psi= 377rwhp/375rwtq (dyno'd yesterday temp in the high 90's & about 80% humidity)

What do you think, is this normal summertime power loss? or should i look into something with the car?

 

[Tim2002GT]

The temperatures are most likely to blame. That and the high humidity. I have heard of FI cars losing up to 5% hp in the hot summer air.

 

[Stan Weiss]

The temperatures will only be to blame if the numbers are uncorrected. Most times you get corrected numbers. What do the dyno sheets say?

 

[spederman]

I am getting the dyno sheet emailed to me tomorrow since their printer was broke. I'll take a look and see what other info i can get from the dyno and post them. How do i know if the numbers are corrected or not?

 

[Stan Weiss]

Normally printed on there will be something like "CF 1.03". It should also list the temperature, humidity, and barometric pressure.