i went from a 2.0 4cyl to this current 2.2 4cyl ... like to minimize AC as much as possible driving around town... noticeable lag in throttle response...

at WOT the s2k stops AC compressor so its just the same. however, i dont drive around town at WOT

 

Alejo...you are a moderator, therefore you have a good deal of power on this board. I don't wish to be temporarily banned, which would probably have me pull an xviper and then another old-timer would leave the forum.

I will say that I was insulted by your response in the other thread, which put words in my mouth, and then locking it. So yes, I was insulted enough to respond.

But to answer your questions...yes, most modern cars shut the ac off when the throttle position is above some threshold. I don't recall the exact % throttle for cutoff on the stook...but definitely at WOT the ac shuts off.

When driving normally around town, and for me that is less than 50% throttle, I can feel the effect of the ac on my ap1, the ap2s I've driven and my m3...and any other car that I drive regularly.

And btw, my ap1 at a recent dyno day put down nearly the same hp & tq as the highest hp ap2 and a bit more hp than another ap2 with the same NA mods as my car. So if I notice the ac on my car...it is no wonder I can notice it on ap2s as well.

 

I always feel the difference when the A/C is on or off in my 07, and felt it in my 02, especially driving around town (I'd guess 75% or less throttle).

 

I don't take names.

Those who habitually divert threads into baseless AP1/AP2 arguments know who they are. The moderators constantly lock the threads they spoil, but they never get the message, and if that isn't fanatical, then nothing is. The guilty know who they are, and if the shoe fits ...

 

Has anyone ever run a dyno (AP1/AP2) with the A/C on and off, to show the difference?

 

well, I didn't mean to offend you and believe me - arguing with me over AC will not get you banned - no one here has power to be unreasonable.

 

you don't make sense either

we've missed your posts on the R&C threads, where did you go?

 

I dont think the a/c shuts of at any thottle position...
I was going 130mph and noticed the a/c was on... I turned it off as I was still in WOT and I felt a little more punch.

flamesuit on

 

most AC systems on most cars disengage once above a certain RPM. Like in my 3000GT the compressor is shut off somewhere around 4500-5k I believe. I would be surprised to find that in WOT situations in the s2000 the AC compressor is operating above 6000rpm.

 

If you are serious, you're going to have to be more specific, becaue I'm not at all sure what it is that you didn't understand.

I probably should spend more time in R&C, where there is less foolishness and a more knowledgable group of people, but I've always felt that I have more to contribute here and in UTH. If the amount of AP1/AP2 monkey business continues to grow in popluarity my infrequent visits to R&C are apt to become my primary activity here on S2kI, but I keep hoping (probably stupidly) that things will eventually return to the way they were back when XViper and RoadRage were here.

I'm still shocked that a quesiton about Miata AC vs S2000 AC could be perverted into another darn AP1/AP2 pissing contest, but if that BS is behind us now I think the topic has the potential to be both interesting and informative. I know exactly how the AC management logic works on our first gen Miata, but from both experience and some of the things said in this thread it seems that the S2000 AC management logic, like the VTEC control logic, is nontrivial. It may also be different in different MY cars, and it would be interesting to sort it out the way we did with the VTEC logic. So, getting back on topic ...

All modern cars have some sort of AC management logic. At the very leaset, the ECU will increase the idle speed setting when the AC is turned on, to maintain the correct idle speed. First gen Miata's and all other 90-91 Mazda's have a very primative AC management logic that simply ups the idle and shuts off the compressor under high loading (low vacuum). I haven't paid much attention to the AC management in the S2000, Benz, or Lexus, becaue the AC load is never an issue with any of them, but I have done quarter mile runs in the S2000, with the AC on, and off, and it makes no difference at all. I think we probably need to do the same thing we did to unravel the VTEC logic. If there is a test procedure for compressor disengagement, we need to look at it and see what factors have to come together to disengage the compressor. I know that on humid days my windshield will fog up during a hard pull through the gears, and that happens becuae the compressor stops running and the air coming from the defroster is no longer being dried out. I also know that the AC doesn't affect my quarter mile times or autocross times, but none of that actually tells us much about the control logic. I also know from some of what has been said in this thread that it has to be more complex than just vacuum/load.

As to the more general questions about feeling AC on and off, I have yet to see a car in which you cannot feel the load of the compressor when it turns on. Even with a long stroke Benz or Jag I-6 you can feel the extra load, but it's not an issue becaue all it takes is a tad more throttle to compensate, and you still have plenty of excess power left over. The same is true with the S2000, and if more throttle doesn't do it, a few more revs most certainly will, so again, it's a non issue around town. The same is true with shorter stroke V-8's. It's just as easy to feel the AC turn on in a 454 Chevelle as it is in an S2000, but it's not a problem in either of those cars in the same way that it's a problem with an underpowered car like a 1600cc Miata. We use to use a vacuum activated switch to disable the alternator on our autocross X-1/9, because when you've got less than 1300cc's every little bit matters, and it would actually be pretty comical if Honda had failed to put as much or more AC control logic in the S2000 as Mazda put in their cars as far back as 1990. I really don't think Honda is that far behind the curve.

Instead of comparing observations, we need to check the shop manual for a test procedure. As with VTEC, we are seeing conflicting observations, and the most likely cause is that we don't fully understand the logic behind the AC management. I'll try to remember to check the manual while I'm down at the shop later today.