Electric AC compressor?

[EcoCivic]

Originally Posted by California98Civic

On my Civic that air is not hot if I have the HVAC temp setting on the "cold" side. On the 6th Gen Civic, the temp selector cuts off the hot coolant from circulating into the heater core.

The air isn't noticeably hot as if it is being heated since I blocked off the underhood part of the HVAC air intake, but since it is outside air it is still hot and humid in the summer and therefore adding load to the AC system and forcing me to use it more.

My 7th gen Civic had a heater control valve also, but I removed it when I installed my oil cooler/warmer since I needed constant coolant flow. Last summer I bypassed the heater core, but I didn't notice any difference in air temp or AC performance so I didn't bother this summer.

It seems like heater control valves are becoming a thing of the past, lots of newer cars such as the 8th gen Civic and newer don't have heater control valves. I suppose the manufacturers decided that the extra cost wasn't worth it since very little/no air flows through the hot heater core when the heat isn't on anyways since the blend door blocks the airflow.

I have heard that the main point of the HCV is to extend the heater core's life by preventing the erosion caused by constant coolant flow when it isn't needed and to improve emissions by speeding up the engine's warmup by reducing the volume of coolant that needs to be heated when the heater isn't on, but I don't know how true that is.

[California98Civic]

Originally Posted by EcoCivic

... I have heard that the main point of the HCV is to extend the heater core's life by preventing the erosion caused by constant coolant flow when it isn't needed and to improve emissions by speeding up the engine's warmup by reducing the volume of coolant that needs to be heated when the heater isn't on ...

I always start the car with the heater on the cold side. It warms up faster. Years ago I found that I could start the car with the heater core bypassed by the cold setting, drive until it hits running temperatures on my UltraGauge, switch the heater select to "hot," and watch the coolant temp drop 10 or more degrees F (depending on how cold it was to begin with). Then it would creep back up within about a minute. So, the difference is significant, but not huge.

[cRiPpLe_rOoStEr]

Even though most people would not be so willing to wait until the engine builds up enough heat nowadays, maybe it could make more sense to recover heat from the exhaust.

[EcoCivic]

Originally Posted by California98Civic

I always start the car with the heater on the cold side. It warms up faster. Years ago I found that I could start the car with the heater core bypassed by the cold setting, drive until it hits running temperatures on my UltraGauge, switch the heater select to "hot," and watch the coolant temp drop 10 or more degrees F (depending on how cold it was to begin with). Then it would creep back up within about a minute. So, the difference is significant, but not huge.

I think the heater core only holds about 1/2 of a quart of fluid, so I wouldn't expect the difference in warmup time to be huge. The effect from actually using the heater during warmup is very significant though, so I wait until the coolant is fully heated up before I use the heater. Fortunately I live in the south and park in a garage, so my coolant is always fully heated up by the time I get to the expressway about 2 miles from my house and the oil is pretty warm by then too (140+ degrees).

I did notice that the oil to coolant heat exchanger I added delayed the coolant's warmup by about a minute or so since some of the coolant's heat is being used to heat the oil during warmup, but I'm sure that heating up the oil much quicker and more completely during the winter more than offsets any additional fuel consumption or engine wear from the slightly delayed coolant warmup. It also keeps the oil nice and cool when I'm beating on it in the middle of the summer

[EcoCivic]

Originally Posted by serialk11r

Another method is an underdrive pulley.

The more I think about it the more I think you might be onto something with that idea. I don't spend much time idling or sitting in traffic, so giving up a bit of cooling performance at idle for significantly more efficiency during normal driving may be an acceptable tradeoff. I would think reducing the short cycling would be better for the compressor's longevity too.

The only problem is that I'm not aware of any simple way to underdrive the compressor. To slow the compressor down, I would either need to get a smaller crank pulley or a larger AC compressor pulley. All the underdrive crank pulleys that I have seen for these engines are missing the rubber damper, so that wouldn't be an acceptable option. And unlike the other pulleys, finding a larger compressor pulley that would fit would probably be impossible since the pulley has an integrated clutch assembly.

[Ecky]

Not long ago, I swapped the crank pulley on my 2.4L engine for the pulley from the 2.0 Type R engine. I believe it was ~11% smaller in diameter.

I imagine you probably have an OEM option.

[EcoCivic]

Originally Posted by Ecky

Not long ago, I swapped the crank pulley on my 2.4L engine for the pulley from the 2.0 Type R engine. I believe it was ~11% smaller in diameter.

I imagine you probably have an OEM option.

Thank you. The K series crank pulley won't work, I have a K24A2 TSX engine siting in my living room and already checked.

The problem is that the D17 engines don't have aftermarket support like the K series and OEM parts aren't generally interchangeable like with the D16's, crank pulleys included. However, I have heard that the B series crank pulleys will fit, but I would have to look into that.

[California98Civic]

Originally Posted by EcoCivic

Thank you. The K series crank pulley won't work, I have a K24A2 TSX engine siting in my living room and already checked.

The problem is that the D17 engines don't have aftermarket support like the K series and OEM parts aren't generally interchangeable like with the D16's, crank pulleys included. However, I have heard that the B series crank pulleys will fit, but I would have to look into that.

Geez I wish I knew people like you two out here, interested in Hondas and FE and swaps and such. Seems like all the coolest kids are elsewhere...

[Ecky]

Originally Posted by California98Civic

Geez I wish I knew people like you two out here, interested in Hondas and FE and swaps and such. Seems like all the coolest kids are elsewhere...

I understand it's kinda hard to do engine swaps in California.

On the other hand, you have nice weather.

[EcoCivic]

On the subject of the AC system's efficiency, when would be the best time to use it? I assume that other than only using it while braking in DFCO, the next best scenario would be using it at idle while coasting rather than while cruising or climbing hills?

According to my Scangauge, my idle fuel consumption is around 0.2 GPH with the AC off and turning the AC on increases that by about 1/3 to around 0.3 GPH.