A/C Horsepower numbers?

D

DeadGeneration

Member
Contributor
:
'04 RX8
I was driving around in hot-as-balls-sandwhiched-in-a-toast-oven florida with the A/C on full blast on "recycle" mode. The A/C system isn't strong enough, but that's not the point of this thread. I decided to floor it with the A/C on full and I would estimate what "feels" like a 20whp loss. I was wondering if there is a more exact figure out there some where. I hit 4-6k in 1st gear and it was a dog, where as without the A/C on the car starts picking up around that area. I have AEM SRI and Thermal CL Catback (which really opens up that power range). Any one else have experience noticing that much different when the A/C is on vs off?
 
i wouldnt say 20HP, but it is a noticeable diffrence, and our AC sucks so bad i shouldnt of even gotten it. oh well, just get more performance parts and go faster to cool off
 
What is more interesting is that most modern (Last decade or so) AC units are designed to decrease engine strain during hard acceleration. This is especially true on smaller engines. I learned this first hand from an engineer who lived in AZ. On a hot day, the WORST thing you can do is lay on the gas in hopes to get the RPMs up for your AC. All you will do is get the car to reduce the AC output!
 
I dont notice it too much actually. It might be my driving style though. I tend to keep the engine pretty high up in the RPMs a lot of the time, probably around 3000 unless Im cruising on a long stretch of road. Like someone mentioned earlier, the AC compressor gets shut off when you really mash on the gas, The ECU either senses a vacuum drop in the intake, or it does it purely on RPM. Once you reach this point you wont have any AC power loss. Lugging around town I notice a very slight loss, hard acceleration is the same as without AC.
 
camrycev6 said:
What is more interesting is that most modern (Last decade or so) AC units are designed to decrease engine strain during hard acceleration. This is especially true on smaller engines. I learned this first hand from an engineer who lived in AZ. On a hot day, the WORST thing you can do is lay on the gas in hopes to get the RPMs up for your AC. All you will do is get the car to reduce the AC output!
Click to expand...


You are absolutely right; Many modern cars have the A/C pulley disconnect every time you go WOT then re-engage when you let off. It will continue to function throughout the rev range but will temporarily stop driving the A/C compressor while you are demanding all the power the engine has to offer. I think it's a safety feature more than anything especially on cars that are so brutally underpowered to begin with... I am pretty sure the P5 does not do this. I have had a chance to test out the AC and yes, it's ok for my moderately warm summer days but i can imagine it being inadequate in a so-cal traffic jam. Best get energy efficient window tint to give it a fighting chance in those clime's
 
i live in FL as well. never use it. just roll all the windows down and if i want cooler air, i go faster. just my .02
 
Everytime I turn on the AC in my P5, a little part of me dies. Plus there is this rattling nosie from the passenger side that DRIVES ME NUTS! Strangely it goes away when I turn the temp to heat.
 
I can't imagine not having AC. It is 90+ here in the Summer, with 70 - 99% humidity. (Maryland) No amount of wind blowing in the car is going to make me feel cool with those conditions. Only AC will do...
 
It also doesn't help that I have that problem with the A/C shutting off in the 2nd and 3rd fan speed settings. Owell, POS.
 
A/C, what's that? So far, I think i've used it once. What I DO have is a really new type of A/C that doesn't affect the engine's power output at all. They're actually prototyping it on my car. It's called 80-4. 80-5 if the sunroof is open.
 
the AC in my p5 sucks,i try and use it and it never gets very cool. I just roll my windows down most of the time.
 
I tell all my girl friend that A/C is the bomb in my car, it's just me that's making them hot... chicks dig it :rolleyes:

"you spent how much on this car and the ******* A/C is balls?" - anon.
 
For P5 owners, turning off the AC is Like engaging VTEC. Anytime I'm losing a race at the strip I just hit the AC off button and BOOM! An extra 20whp!!!!

(drive2)
 
I really must have a freak P5, the AC works REALLY well in my car. I have to turn it down and turn the cold to the between cold and hot setting (and I love it freezing). The UR UDP pulley really helped the AC from draining as much power. I mean yeah, if I am AutoXing I will have it off and the windows down any way. Though everyday, the AC does not hurt as much now. The mod also helps with freeway cruizing. Maybe you guys should get your AC systems check out for low coolant or leaks.

Magus
 
Please log in or register to reply here.

Similar threads

C
The dreaded A/C Issue!
Replies
6
Views
3K
BenjiHoggi
BenjiHoggi
CTt3P5
    • Like
CX-50 A/C Issues
Replies
5
Views
2K
CTt3P5
CTt3P5
K
DFW floods - High water and car running rough now
Replies
11
Views
2K
katapaltes
K

Latest posts

Back