Power Lost Through ZF6
Thread Starter
Instructor
Joined: Oct 2000
Posts: 221
Likes: 0
From: Austin, TX
Power Lost Through ZF6
Can anyone explain how power is lost through a manual transmission? Is it because of a small amount of slippage through the clutch? Also has anyone ever measured the power loss through a ZF6? The most common generic power loss figure I hear is 15% for a manual 20% for an automatic.
Safety Car
Joined: Mar 2000
Posts: 3,620
Likes: 2
From: Hillsboro OR
Re: Power Lost Through ZF6 (Charles Klein)
The 15% - 20% includes:
Rear End:
1. trans
2. U-Joints on the driveshaft
3. Rear end
4. U-Joints
5. rear wheel bearings
6. tire rolling resistance
1,3 and 6 are the biggest sources of power loss.
The power loss factors also include:
Exhaust system components that were not used in the dyno test
Accessories bolted to the motor not that were not used in the dyno test
Rear End:
1. trans
2. U-Joints on the driveshaft
3. Rear end
4. U-Joints
5. rear wheel bearings
6. tire rolling resistance
1,3 and 6 are the biggest sources of power loss.
The power loss factors also include:
Exhaust system components that were not used in the dyno test
Accessories bolted to the motor not that were not used in the dyno test
Racer
Joined: Jan 2001
Posts: 322
Likes: 0
From: Liberty Township OH
Re: Power Lost Through ZF6 (Charles Klein)
Power is lost in the manual transmission because of the bearing & gear losses. There are no losses thru the clutch unless have one that is sliping. If this is the case you will have alot of losses thru the clutch, but this situation wont last for too long so I wouldn't wory about it. :p:
Safety Car
Joined: Jun 1999
Posts: 3,570
Likes: 3
From: Austin, Singapore, Kuala Lumpur, Houston, Dallas, Hong Kong, Elgin, etc.. Texas
Re: Power Lost Through ZF6 (AquaMetallic94LT1)
Today's net horse power ratings figures published by the manufacturers is at the fly wheel and includes full exhaust system, air intake system, and all accessories including alternator, water pump, A/C, and power steering pump.
FYI, the old gross HP rating sysem (prior to 1972) was whatever the factory wanted to publish but was without anything bolted to the engine and no air cleaner assembly.
FYI, the old gross HP rating sysem (prior to 1972) was whatever the factory wanted to publish but was without anything bolted to the engine and no air cleaner assembly.
Safety Car
Joined: Feb 2000
Posts: 4,564
Likes: 109
From: Austin Texas
Re: Power Lost Through ZF6 (Charles Klein)
According to Graham @ Lingenfelter, the ZF6 cars have a 17% loss through the drivetrain.
I'll take their word for it. They've engine-dynoed and then chassis-dynoed enough C4's to know their numbers....
I'll take their word for it. They've engine-dynoed and then chassis-dynoed enough C4's to know their numbers....
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Le Mans Master
Joined: Apr 2001
Posts: 7,410
Likes: 252
From: Little Elm TX
Re: Power Lost Through ZF6 (Joe90)
According to Graham @ Lingenfelter, the ZF6 cars have a 17% loss through the drivetrain.
I'll take their word for it. They've engine-dynoed and then chassis-dynoed enough C4's to know their numbers....
I'll take their word for it. They've engine-dynoed and then chassis-dynoed enough C4's to know their numbers....
Racer
Joined: Jan 2001
Posts: 322
Likes: 0
From: Liberty Township OH
Re: Power Lost Through ZF6 (No Go)
"friction in other words" could very generically be used as a label for most efficiency losses. In a previous post I said power losses in a manual transmission occured because of bearing and gear losses. These losses include churning of the lubricant, loading of the metel in the gears and bearings, etc. These losses can be further broken down as load dependent & load independent losses, load being defined torque to the input shaft. Additionally, most losses have some dependancy on speed, althought not necessarily a linear one. Temperature will also have an influence on efficiency, as the viscosity of the lubricant changes with temperature. To make a long story short, a gearbox will have a range of efficiencies dependent on speed, load, temperature, and a few other things that I have not mentioned. All these losses are a result of "friction". 15% is the number that I hear most often for a ZF6 which may be a very good approximation, but understand, this number will vary somewhat. Perhaps Lingenfelter uses 17% because his motors produce more than a standard L98/LT1/Lt4.
Safety Car
Joined: Feb 2000
Posts: 4,564
Likes: 109
From: Austin Texas
Re: Power Lost Through ZF6 (Polar LT4)
Perhaps Lingenfelter uses 17% because his motors produce more than a standard L98/LT1/Lt4.
NO, I think it is because they first run some of their engines on an "engine" dyno to tune it, then they drop it in the car and chassis dyno it. They have a power differential between the two dyno runs, and with some simple math you can come up with the loss of the drivetrain. Do that a few hundred times and I think you can come up with a pretty good average.... it has nothing to do with their engines making more power.
Thanks No Go. It has a long way to go, but the information is there to help. I'll have to go in and change it (if I ever get some time to just play again). I'm really pumped about the 427 SB with the 32v Arao heads....and I'll need to add that to the site as it's being done. Still waiting on Crower to send the balanced crank/rods to get the bottom-end put together.
Intermediate
Joined: Jul 2001
Posts: 46
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From: Austin, TX
Re: Power Lost Through ZF6 (Joe90)
Joe,
Nice pictures of your car on the track! I'm in Austin, also. Red 1989 w/chrome-plated stock rims; vanity plate "PFAST" (I'm a Pflugerville native). Can you tell me more about getting on the track? Was it a driving school? Did the 'vette club put it together?
Nice pictures of your car on the track! I'm in Austin, also. Red 1989 w/chrome-plated stock rims; vanity plate "PFAST" (I'm a Pflugerville native). Can you tell me more about getting on the track? Was it a driving school? Did the 'vette club put it together?
Safety Car
Joined: Feb 2000
Posts: 4,564
Likes: 109
From: Austin Texas
Re: Power Lost Through ZF6 (pfast89)
Yeah, the club put that event together in cooperation with NASA. You can go to their web site to get information at http://www.nasatx.com/html/main.html
You can also go to http://www.texasworldspeedway.com and they have a club that has races/lapping sessions at least once a month.
You can also go to http://www.texasworldspeedway.com and they have a club that has races/lapping sessions at least once a month.
