Your old Honda have less torque, and peak is probably higher in the rev range. Also, as mentioned, modern compressors are more efficient.
Reduced power with A/C on
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Back in the 80s most of our cars were 4-cyl. The VW van had something like 80HP (waterbox) and we had a subaru wagon with about the same 80 HP or so. It could have been less. Tennessee interstates are full of rolling hills. We'd often ride the AC button to run the compressor down hills and cut it when going up. In the VW especially, it was helpful. in the subaru, it had an impact but was more of an amusement.
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Originally Posted By: OVERKILL
Well, your 1998 had 106HP, your 2010 has 140HP. That's a big difference. Also, the compressor on the 2010 is probably more efficient, making the difference seem even larger.
Even worse: at cruise speeds the 1998 might only have 60 bhp available (lower revs) and 20-25 bhp is needed just to maintain speed. If you want to accellerate slightly you have to do that with the remaining 30-35 bhp, and with the AC on this might very well be reduced to 20-25 bhp...
That'll feel like you have 25% less power available, and you wouldn't be far off.
Well, your 1998 had 106HP, your 2010 has 140HP. That's a big difference. Also, the compressor on the 2010 is probably more efficient, making the difference seem even larger.
Even worse: at cruise speeds the 1998 might only have 60 bhp available (lower revs) and 20-25 bhp is needed just to maintain speed. If you want to accellerate slightly you have to do that with the remaining 30-35 bhp, and with the AC on this might very well be reduced to 20-25 bhp...
That'll feel like you have 25% less power available, and you wouldn't be far off.
Originally Posted By: mclasser
A little off topic, but I wish Honda started using variable displacement A/C compressors. My Infiniti has a VDC and it's nice not hearing the annoying on/off cycling like in my Hondas. I remember reading that VDCs create less drag on the engine as well.
They are now - Honda's using them in newer cars. Nissan and Subaru have been using VDCs longer than Toyota or Honda - mostly because CalsonicKansei(their HVAC supplier) stopped making compressors of their own design and started licensing Delphi's compressors.
When the Accord Hybrid and 2nd gen Civic Hybrid was released, Honda used a weird "twin compressor" setup from Sanden, half the compressor was mechanical and the other half was electric. The electric half was fed off the 144V DC circuit to allow the HVAC to work even with the engine stopped. Not as elegant as the Denso hermetic scroll compressor used on most Toyota hybrids.
A little off topic, but I wish Honda started using variable displacement A/C compressors. My Infiniti has a VDC and it's nice not hearing the annoying on/off cycling like in my Hondas. I remember reading that VDCs create less drag on the engine as well.
They are now - Honda's using them in newer cars. Nissan and Subaru have been using VDCs longer than Toyota or Honda - mostly because CalsonicKansei(their HVAC supplier) stopped making compressors of their own design and started licensing Delphi's compressors.
When the Accord Hybrid and 2nd gen Civic Hybrid was released, Honda used a weird "twin compressor" setup from Sanden, half the compressor was mechanical and the other half was electric. The electric half was fed off the 144V DC circuit to allow the HVAC to work even with the engine stopped. Not as elegant as the Denso hermetic scroll compressor used on most Toyota hybrids.
My '81 Accord really bogged down when the AC kicked in, so I got a vacuum switch from J.C. Whitney to disengage the compressor below ~5" vacuum.
One of the few really useful gadgets they sold
One of the few really useful gadgets they sold
For what it's worth, the wife's old Cavalier started doing the same thing when the A/C came on, and the compressor died shortly after. Replaced it, and you barely noticed the drag on the new one.
My Father's cousin (a Toyota-trained mechanic from 'way back when') can recall the late 70s and early 80s when air-conditioning became more common on the Corolla... He said coupled with a 3sp automatic of the time, you'd generally hear the things screeming their [censored] off just driving around in traffic
Indeed, even in a '92 Landcruiser in the family with a 1HZ N/A 4L diesel six, the A/C does take a toll on the vehicle's oomph. And there is a noticeable effect in my '93 BMW, but that could also be VANOS seals - flooring it having next-to-nothing happen isn't just limited to A/C operation (although there is generally a link, LOL), but once you start moving, it opens up and is fine again.
Indeed, even in a '92 Landcruiser in the family with a 1HZ N/A 4L diesel six, the A/C does take a toll on the vehicle's oomph. And there is a noticeable effect in my '93 BMW, but that could also be VANOS seals - flooring it having next-to-nothing happen isn't just limited to A/C operation (although there is generally a link, LOL), but once you start moving, it opens up and is fine again.
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Over on the Ford Escort forums, we refer to the A/C button as the drop anchor button.
Originally Posted By: zzyzzx
Over on the Ford Escort forums, we refer to the A/C button as the drop anchor button.
LOL! That's how it was with my 2014 Subaru XV Crosstrek 5spd. You REALLY noticed every time the compressor cycled on. With the CVT/AT equipped Subarus, you don't notice it at all oddly enough.
Over on the Ford Escort forums, we refer to the A/C button as the drop anchor button.
LOL! That's how it was with my 2014 Subaru XV Crosstrek 5spd. You REALLY noticed every time the compressor cycled on. With the CVT/AT equipped Subarus, you don't notice it at all oddly enough.
Originally Posted By: mclasser
A little off topic, but I wish Honda started using variable displacement A/C compressors. My Infiniti has a VDC and it's nice not hearing the annoying on/off cycling like in my Hondas. I remember reading that VDCs create less drag on the engine as well.
Or better yet, electric A/C compressors.
A little off topic, but I wish Honda started using variable displacement A/C compressors. My Infiniti has a VDC and it's nice not hearing the annoying on/off cycling like in my Hondas. I remember reading that VDCs create less drag on the engine as well.
Or better yet, electric A/C compressors.
Originally Posted By: tig1
You'll lose around 4-5 HP with the AC on, and around 1-2 MPG. Stayin cool ain't free.
Right you are tig, pumping heat uphill requires energy, which in this case is gasoline.
You'll lose around 4-5 HP with the AC on, and around 1-2 MPG. Stayin cool ain't free.
Right you are tig, pumping heat uphill requires energy, which in this case is gasoline.
My Jaguar X-Type with 2.5L V6 simply becomes slow when the AC compressor is on. Normal for this car. It's a very powerful AC system, and the compressor pulley is small, and spins it quickly at idle.
Selecting the compressor "off" during full throttle acceleration results in a noticeable surge of power. Strangely, it does not have any form of full throttle disconnect.
Selecting the compressor "off" during full throttle acceleration results in a noticeable surge of power. Strangely, it does not have any form of full throttle disconnect.
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Haven't read each post so smack me me if already said but starting with the advent of drive-by-wire throttle systems (gas pedal is a potentiometer, electronic actuator for the throttle body butterfly, etc), the ECU compensates for A/C drag. I know that with my '09 Forester throttle response is actually slightly crisper with the HVAC controls are set to A/C or defrost. Not sure if the ecu is tweaking the throttle sensor scaling or injection quantity or what but something is going on.
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