gearbox

iTrader: (95)

the ac system is gonna break on its own anyway. the r134a is very corrosive and eventually the system telds to fall apart. sometimes i wish i didn't have ac, the only time its good is when you have 100% humidity and the car fogs up.

AzNTiG3R

Most compressors are driven faster than engine speeds (overdriven), due to a smaller diameter compressor pulley versus the crankshaft pulley. Engaging a compressor at engine speeds above 1500 rpm with high discharge (head) pressures places extreme loads upon the compressor's components. To add to this destructive process, most newer vehicle designs employ lower hood lines and little or no grill openings. As a result, compressor head pressures increase due to limited airflow over the condenser. Like a high compression engine, abnormally high A/C head pressures place excessive loads upon internal components of the compressor. So lets think about this for a second like running the engine at high rpm’s with the a/c compressor engaged (it produces a substantial load), and anyone knowing anything about racing cars would know that a load is what you don’t want when racing. Plus think about it if you are turning on and off the a/c while driving hard that causes a jerk and when excessive jerking starts happening motor mounts begin to prematurely wear out. Not only are you robbed of performance due to the drag of the air conditioner compressor, but you are risking the health of the compressor by driving it at such high RPM. A couple people have actually had the compressor "explode" when they missed a shift and ended up driving the compressor at over 7000 RPM (note I said compressor NOT the engine / think about the smaller diameter of the a/c pulley). Which Honda’s can easily get up to with there engines, Honda’s can see around 8000+ RPM’s with no problems just from there engines plus if you have ever looked at a power curve from a dyno chart you would see that the typical shift points on most Honda’s are around 8000 RPM’s, with this in mind the little pulley on the a/c compressor on Hondas is about a quarter or size smaller than the crank pulley, which is say spinning around 8000 RPMs, which then means that the a/c compressor is spinning at least 10,000+ RPMs.

S2000man01

iTrader: (1)

right. that's all fine and dandy except.

if you have the throttle open at WOT like when you're flooring it and getting up to say 7000rpms, the compressor is NOT ENGAGED, therefore it is NOT SPINNING. so if your engine is spinning at say 8000rpms, why on earth do you think the compressor is spinning at at least 10,000+ rpms when the compressor clutch isn't even engaged??

i think you're missing the fundamental fact here that the compressor is not spinning if you have it floored and are driving at such a high rpm.

S2000man01

iTrader: (1)

not really to the extent you are claiming. take a look at the pulley driving your civic's compressor. i'm willing to bet it's almost just as big as the crank pulley.

last time i checked, honda looks like they know what they are doing. not to mention i have yet to see or hear about a modern car blowing their compressor from the causes you list here. not on any forum, nor in person, have i seen anyone do what you're saying. technology has updated immensely, and there is much more to the engineering here than what you're claiming.

if you're running at high rpms, the compressor is not engaged, since you're likely at high rpms at WOT. and if you're not WOT and at high rpm, the ECU limits the load. for example, above 6000rpm (may be 5000rpm on the civic), whether you are WOT or not, the ac's magentic clutch driving the compressor is disengaged. so what you're claiming is a totally moot point.

no it doesn't, since it won't engage the compressor while you're driving hard. not to mention you put more wear and tear on the mounts from shifting at redline. lol.


see above

the compressor pulley on my S2000 is just about the same exact size as the crank pulley. the compressor on hondas is NOT a quarter size or smaller than the crank pulley. where are you getting this information from? have you looked under your hood?

not to mention that as i said, in high rpm or WOT, the compressor is disengaged.

some guys even race their S2000's with the AC on in extreme heat. and they never blew any compressors.

Other safety controls are:

High/low pressure switch that will turn off the compressor if the pressure is out of range.

Thermal protector on the compressor that turns off the compressor if temps are too high.

Pressure relief valve on the compressor that will open if other means fail at turning the compressor off, high pressure is released to the atmostsphere.

AzNTiG3R

YOU have an S2K....most of us one this site have civics, so yeah if we were to race w/ the AC on, there'd be a drag on the engine, as opposed to the S2K.

S2000man01

iTrader: (1)

no, i'm telling you there isn't. there is no drag on the engine if you have the AC on.

the civic will cut the AC compressor if you are either WOT or above 5100rpm. to be honest just about every car made today has this kind of feature for the AC.

Curiouz_G

iTrader: (1)

s2000man, how do you know all this? lol it seems like whatevers posted on the forums, u seem to know the answer. blah =)

S2000man01

iTrader: (1)

i dont know the answers to everything, and often times ask questions of minds far greater than me.

this particular question I fielded to a former honda engineer who is an s2ki.com member, S2000 owner, and moderator on s2ki. (i moderate there too). he was the one who gave me the information so i could write the full detailed answer you see above.