In anticipation of an arguement

[Jsup]

I am anticipating an argument with an idiot.....I know it's coming

So the question is....

RWHP number....

1. From what I understand a manual transmission is more efficient than an automatic. How much difference in HP, percentage wise, is the difference between automatic and stick.

2. How much is an AC delete worth in terms of HP.

I just want to slam this idiot to the ground.

The only differences between the two are listed above, what would you anticipate they are worth in terms of HP?

Thanks.

 

[turtlevette]

do you have any paticular idiot in mind? I'll argue with you.

 

[Jsup]

do you have any paticular idiot in mind? I'll argue with you.

Yes I do.....I have had the idiot in mind for some time. Just waiting for the email

My response is....."well take off XX HP for the manual and the AC" I have in mind what that number should be. Just want to verify with opinions.

I can't post "there" so if you want, once I get the answer, you can respond in a particular thread with this information and see how the cast of idiots responds. Would be entertaining.

 

[big2bird]

do you have any paticular idiot in mind? I'll argue with you.

:rofl::rofl::rofl:

 

[big2bird]

I will leave the answers to the REAL egghead engineers, but on point #2, the A/C, I suspect it depends on the HP of the engine in some ratio. A higher HP engine will try to rev up faster, and will try to accelerate the compressor faster, therefore, the larger the HP of the engine, the more parasitic loss of HP. Make sense?

 

[big2bird]

I will leave the answers to the REAL egghead engineers, but on point #2, the A/C, I suspect it depends on the HP of the engine in some ratio. A higher HP engine will try to rev up faster, and will try to accelerate the compressor faster, therefore, the larger the HP of the engine, the more parasitic loss of HP. Make sense?

Another way to think of this
1)1,000 HP 2,000 RPM diesel engine. Engage the A/C clutch, and I doubt you could measure the loss.

2)2,000HP fuelie running 7,000 RPM. Engage the clutch, and the belt snaps off.ush:It would try to accelerate that standing still compressor so fast, it would be like a big brake.

Engineers, Am I full of s**t, or is that correct?

 

[turtlevette]

I would ventue that a/c delete is worth 0 hp. I don't even know if i buy the argument that automatic trans consumes more hp. It can't be that much more. 5 - 10 hp?

 

[mrvette]

I will leave the answers to the REAL egghead engineers, but on point #2, the A/C, I suspect it depends on the HP of the engine in some ratio. A higher HP engine will try to rev up faster, and will try to accelerate the compressor faster, therefore, the larger the HP of the engine, the more parasitic loss of HP. Make sense?

Another way to think of this
1)1,000 HP 2,000 RPM diesel engine. Engage the A/C clutch, and I doubt you could measure the loss.

2)2,000HP fuelie running 7,000 RPM. Engage the clutch, and the belt snaps off.ush:It would try to accelerate that standing still compressor so fast, it would be like a big brake.

Engineers, Am I full of s**t, or is that correct?

I would ventue that a/c delete is worth 0 hp. I don't even know if i buy the argument that automatic trans consumes more hp. It can't be that much more. 5 - 10 hp?

Non engineer here, but I used to play with Lionel....Bird you must be right above, when the compressor is not running, it's another idler pulley, bet not a dyno in the land could measure it's loss off the loading, especially with a serp belt, it was explained to me once that a serp belt actually is worth some lo single digit HP on a typical car engine,

Jim, on that auto tranny thing, I am flat out shocked at the power lost in the drive train 25% is astounding....for one thing, hp lost must be due to friction, I can't see the surface area of a stick shift and diffy as dissipating that amount of heat without flaming the mess into a glowing red ball at freeway speeds....much less NASCAR, say 200 hp would be 750 watts/hp is 150,000 watts....way over ten kitchen ranges on full blast, tops and ovens too, take a hell of a cooler/radiator to kill that power off, that's insane...

I know thats what everyone claims across the board, so I presume it's correct, I just can't see how RWD balls out race cars kill the heat off without flaming it up.....

I do know a diffy runs hotter'n hell after a goodly freeway blast...

don't ask....:cussing:

 

[010752]

Don't know how true it is, but the th400 was always said to need 25hp, supposedly quite a bit more than others.
There is a figure for the A/C compressor, and if I remember right the bigger displacement A6 was around 8-9hp at full load.
Not engaged, I doubt you could even measure the belt/pulley drag easily.

 

[mrvette]

Don't know how true it is, but the th400 was always said to need 25hp, supposedly quite a bit more than others.
There is a figure for the A/C compressor, and if I remember right the bigger displacement A6 was around 8-9hp at full load.
Not engaged, I doubt you could even measure the belt/pulley drag easily.

Especially with serp drive....and it was funny that on a 455 Pontiac, the engine did not seem to care much at idle, if that comp was running or not, but my vette SBC damn sure did....

:gurney:

 

[turtlevette]

Jim, on that auto tranny thing, I am flat out shocked at the power lost in the drive train 25% is astounding....for one thing, hp lost must be due to friction, I can't see the surface area of a stick shift and diffy as dissipating that amount of heat without flaming the mess into a glowing red ball at freeway speeds....much less NASCAR, say 200 hp would be 750 watts/hp is 150,000 watts....way over ten kitchen ranges on full blast, tops and ovens too, take a hell of a cooler/radiator to kill that power off, that's insane...

I know thats what everyone claims across the board, so I presume it's correct, I just can't see how RWD balls out race cars kill the heat off without flaming it up.....

I do know a diffy runs hotter'n hell after a goodly freeway blast...

don't ask....:cussing:

You are right. The energy has to be dissipated in the form of heat. I don't buy the claim that there is that much loss, especially if the torque converter locks up. These trannies would catch on fire after sustaining WOT for 20 minutes.

My torque converter locks up around 30 mph and the thing never gets that hot. You can put your hand on the cooler after a 20 min run around the track and its just luke warm.

 

[mrvette]

Jim, on that auto tranny thing, I am flat out shocked at the power lost in the drive train 25% is astounding....for one thing, hp lost must be due to friction, I can't see the surface area of a stick shift and diffy as dissipating that amount of heat without flaming the mess into a glowing red ball at freeway speeds....much less NASCAR, say 200 hp would be 750 watts/hp is 150,000 watts....way over ten kitchen ranges on full blast, tops and ovens too, take a hell of a cooler/radiator to kill that power off, that's insane...

I know thats what everyone claims across the board, so I presume it's correct, I just can't see how RWD balls out race cars kill the heat off without flaming it up.....

I do know a diffy runs hotter'n hell after a goodly freeway blast...

don't ask....:cussing:

You are right. The energy has to be dissipated in the form of heat. I don't buy the claim that there is that much loss, especially if the torque converter locks up. These trannies would catch on fire after sustaining WOT for 20 minutes.

My torque converter locks up around 30 mph and the thing never gets that hot. You can put your hand on the cooler after a 20 min run around the track and its just luke warm.

I have not done it yet with this 200 auto, but some years ago, I stuck a thermocouple probe down the dipstick tube on the 700 in this '72, and it ran a easy 180f+ on oil temps, after a 95F ambient freeway run, through traffic and into the garage here....that was a rad cooler, plus another in front in series after that....:shocking:

I really should measure this 200 4r, already 82f out, maybe if I think of it, I can do that today....

:ill:

 

[big2bird]

I would ventue that a/c delete is worth 0 hp.

So an A/C compressor uses 0HP?" I don't think so Tim."

 

[big_G]

Don't forget that the auto trans had a front pump. It takes some power too.

 

[mrvette]

Don't forget that the auto trans had a front pump. It takes some power too.

Yeh, but for a stick shift to suck up 15% of engine HP, and another ~10% for the diffy?? something like that.... it's nutz....

I can't see how in hell they all stay alive doing that shit, by my rough guesstimations on power, electrical is the way I go as I understand it best, and relate to a electric range cause that's the shit I most familair with, as most guys are, I suspect....

tossing off even FIVE electric ranges as waste heat???

:fishing::stirpot::sos:

 

[turtlevette]

I would ventue that a/c delete is worth 0 hp.

So an A/C compressor uses 0HP?" I don't think so Tim."

a/c delete as an option from the factory? How is that going to get you any extra hp? Guys with a/c have it off when driving hard. Where's the difference?

Does anyone run a/c under WOT conditions? The new cars have a cutout switch. Right?

 

[mrvette]

I would ventue that a/c delete is worth 0 hp.

So an A/C compressor uses 0HP?" I don't think so Tim."

a/c delete as an option from the factory? How is that going to get you any extra hp? Guys with a/c have it off when driving hard. Where's the difference?

Does anyone run a/c under WOT conditions? The new cars have a cutout switch. Right?

not my setup now, the computer is told the a/c is requested, and so it knows to add rpm to the engine AND turn on the Spal fans, but the comp is wired direct to my dash switch....computer has no output I know of to control the compressor clutch so I have no disable on the compressor for engine demand....

NOW on my '87 I know the compressor was disabled when WOT happened....the a/c would get warm if I floored it....the only way I could tell....

only times I have ever done a serious power run is with top down anyway....

damn little use for the a/c...but I have been known to run windows up, top down, a/c blowing....

:hissyfit:

 

[JPhil]

Yeah, "A/C delete" has nothing to do with horsepower in and of itself. As an 'option' it reduces weight, removes unneccesary controls & systems, and lowers the initial purchase price. It just makes the car cheaper, simpler & lighter. There is horsepower loss is when it is engaged--but there is no horsepower gained by not having the A/C system. The only peformance gain is through reduced weight.
I installed "A/C delete" on my car just to reduce the amount of bullshit I don't feel the need for.

 

[BBShark]

From Wikipedia:

Hydraulic automatic transmissions are almost always less energy efficient than manual transmissions due mainly to viscous losses in the torque converter. A relatively small amount of additional energy is also required to pressurize the hydraulic control system which uses fluid pressure to determine the correct shifting patterns and operate the various automatic clutch mechanisms.

Manual transmissions use a mechanical clutch to transmit torque rather than a torque converter thus avoiding the primary source of loss in an automatic transmission. Manual transmissions also avoid the power requirement of the hydraulic control system by relying on the muscle power of the vehicle operator to disengage the clutch and actuate the gear levers, and the mental power of the operator to make appropriate gear ratio selections. Thus the manual transmission requires very little engine power to function, with the main power consumption due to drag from the gear train being immersed in the lubricating oil of the gearbox.

The energy efficiency of automatic transmission has increased with the introduction of the the torque converter lock-up clutch which practically eliminates fluid losses when engaged. Modern automatic transmission also save energy and complexity by minimizing the amount of shifting logic that is done hydraulically. Typically control of the transmission has been transferred to computerized control systems which do not use fluid pressure for shift logic or actuation of clutching mechanisms.

 

[big2bird]

I would ventue that a/c delete is worth 0 hp.

So an A/C compressor uses 0HP?" I don't think so Tim."

a/c delete as an option from the factory? How is that going to get you any extra hp? Guys with a/c have it off when driving hard. Where's the difference?

I assumed he was discussing the HP required to turn the compressor. I also assume the HP difference between the disengaged A/C clutch and an idler is equal.
HP required to "start" the compressor turning would most likely be equal to locked rotor requirements of an electric motor. I.E.: It would require 6 times the HP to accelerate the A/C compressor vs running speed.