Is it just me, or does the AC rob 100 HP?
 

Not really 100 HP, of course, but it seems like when the AC is on the car feel MUCH less responsive.

The one thing that I was noticing today was that when cruising, I feel the compressor turning on and off every minute or so. The air blows ICE COLD, but when the compressor engages and disengages, it makes the car almost lunge forward or backward.

"Lunge" may be a bit strong, but it is definitely noticeable and somewhat annoying.

What are your experiences?

it was a cool day today here so i would get the freon level checked. you may be getting a bit low.. does it always cycle alot? and yea the ac does make it seem like you are towing a civic. you get the rear sorted out?

Its just you.

Thanks for the input!

The freon was just checked. Scott changed the position of the AC condenser this past week and said that it was getting too hot and turning off originally, but he changed fan placement (I have 2 extra) and it was fine. This frequent cycling could be this problem? If so, I'll give him a call tomorrow. I really don't use the AC all that much, so I'm not sure if it's a chronic problem.

Scott says he didn't notice anything strange from the rear, and now that I drive it again, I think I was just being paranoid. Now, I just need to get some tires so I can run a good time at the Tampa Racing Track Day next Saturday!

My car would do the same thing with the A/C on, and it happens to be a MB also, maybe thats a common problem with MB's. haha


SO now I just open the sun roof leave the windows down and hope for green lights

No, Its just you man. Probabily because when you have 400+ hp to feel the loss to :p:

My old stock setup didnt really change much.

It's a good reason to get rid of it! ;) Anyone want to buy A/C parts?

X2

well anyone knows running the a/c robs hp since there is another load being added on the belt thats running the engine..im sure you knew that..

and yes, this past summer when driving my work truck, i would have the a/c on, when i get to a big hill, it would feel sooooo sluggish, i turn the a/c off and it felt like i hit boost and i would start moving again.. it was soo fun LOL

My '95 is completely stock. When the compressor is on, it feels a tiny bit (barely noticeable)more sluggish at less than 3krpm at low throttle. Anything above 3krpm and/or more than 1/3rd throttle isn't noticeable. On any car I've driven weighing less than 3000 lbs and appropriately powered (a few Miatae & early 80's BMWs), I notice the same deal. My old '82 320's AC could be used as a secondary e-brake. :p: It had problems, though.

I don't know about the PFC, but the stock computer should cut the compressor at WOT under all conditions.

We ran my car on the dyno once with the A/C on (accidentally) for one pull. It cost me 20 HP. Down from 320 to 300.

I've noticed very little difference when my A/C is running. I can't tell or feel any sort of loss, but I usually only use it on long highway trips, not around town.

a/c robs me of power and makes my idle stupid

I don't notice a huge loss in power with my A/C on.

On my R2 when the compressor kicks on the car seems to bog for a moment. The car feels like it has less power, which makes sense because of the engine having to run the compressor (as mentioned above). Maybe once doesn't notice it as much when you are near stock HP levels?

I wonder how much my 9.5 lb flywheel affects this.

i have a lightened flywheel, since the change, when i have my ac on, i find that my car will stall out more easily because of tendency to drop below idle

My car runs like shyt when the A/C is on. Only use it on the highways, and sometimes around the city (FL gets hot)

If you are really feeling the compressor kicking in like that, you need to put in some A/C compressor oil. This will help lubricate things and make it less noticable. A compressor that doesn't have much oil will be very noise when it kicks in and you will loose more hp. I can hardly hear mine run when I'm outside the car and when it kicks in while driving, it's hardly noticable.

duno, i dont have it

Ditto here. Running stock Flywheel and sequential, even around town. I notice the fan speed and elevated idle, but performance drop is very slight.

My '94 R2 has ~68,000 miles, AC blows ICE cold, and seriously you can NOT tell the AC is even on. Car is just as easy to drive as with it off - very little if any change in response and power. Idle bumps up to about 800-900 RPM when the compressor is running - that's about the only sign.

I agree with the above - the compressor might be near death or needing oil.

Seriously, the AC is far more noticeable on my SC300 than on the RX-7. On my convertible, though, it's like the anchor is thrown out when the AC is on - it becomes a DOG.

I would have things checked on it. Don't ditch the AC on a street-driven car - chicks like AC :).

Dale

We also had a dyno day where the guy had turned his A/C on to get the fans on to cool off the engine, but left it on during the run by mistake. Next run he turned it off and picked up about 25 rwhp. High 250 range to low 280ish with it off.

Tim

Whiners
 

Man... I'm sure you guys are experiancing a loss in power.. but damn, I drive a Civic with like. 170 FLYWHEEL horsepower. Air conditioning is like a KILL SWITCH. I can't drive on hilly streets - i.e. Seattle - with A/C on at all. it is VERY noticable. It's most noticable with the cruise control on set to a certain speed, the car feels like it hits road kill for a second.

if you have 300hp and take a loss down to 280hp, i'm not going to shed any tears. Its the 135hp down to 115 hp that is a PITA.

It would be very interesting to do a dyno run with AC on VS AC not.

Ok who wants to step up ;)

tim already batted/\ thanks for asking

Not really... the A/C turns off at WOT.

"An A/C cut-off system is used to improve idle smoothness immediately after starting the engine and to improve acceleration performance."

Pages F-130 to F-132 in the service manual cover the A/C cut-off system.

I wonder if the Microtech has such a function, or if the Microtech would even control that...

my pos loses about a million hp when I have the a/c on
what a pos

sorry for brining back the dead, but my AC unit haves the same problem but a bit different.
1
while driving on a constint speed (ie on the freeway ) lets say 80mph

and i turn on the AC, i can feel the compressor kick on,AC blows cold.
but right after a few seconds i feel the car going forward and backward .

like the compressor is turning on and off every other second. it is very annoying.
what could cause this ? a bad dieing compressor ? i see some people say it needs some oil in it. where do i put the oil in and what typ of oil ?

2
with the AC on the car stalls almost every time when i pull up to a stop light or if im trying to take off from a stop.

i have HALTECH ps1K

^ Have you tried turning the compressor by hand when the car is off? Should have some resistance but not to difficult, and should rotate fairly smooth.

What RPM does your car idle at with the haltech? Do you have the ISC installed? Is this a recent problem? You may have multiple issues. I am not familar with how the haltech controls idle when the engine is under load. I.E. a/c on.

I agree with Dale Clark.. When my ac is on I can not even feel it. All I notice is the increased RPM and the higher fan speed.

Is your Haltech configured for an A/C input signal and then an A/C output signal (like the stock ECU or Power FC) or is the Haltech completely bypassed? Can you post the current map in your PS1000?

whining about whiners..

i'm keeping my eye out for that monolith to pop up.

i will go ahead and try this that , my car idle at 1000-1100 rpm

with ac on it just drops to the floor like 400 and dies. what is a ISC?

it was never a problem ,cause my AC never worked,and now i got it to work and its doing this.

i will have to ask my tuner ,:(

ISC= Idle Speed Control basically helps smooth out and regulate the idle speed of the car by bypassing air around the throttle body. This is useful because when the A/C is turned on and the compressor is spinning it is causing a load on the engine and that may be why your car is stalling.


John