Does anyone have first hand experience with confirmed ZF losses? I've read that they are in the 20% range.
Has anyone dyno'd their engine, then had the car chassis dyno'd to compare?
Will
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I believe the number was 75hp. It isn't a percentage. It won't take more HP to run the transaxle if you have 600hp rather then 300hp. The loss is the same.
quote:Originally posted by 4NHOTROD:
Does anyone have first hand experience with confirmed ZF losses? I've read that they are in the 20% range.
Has anyone dyno'd their engine, then had the car chassis dyno'd to compare?
Will
I should have some chassis dyno numbers soon and will be able to get a good idea of what the ZF power loss is. I already know what the engine dyno numbers are but I have alway been told that it is close to a 80 horse power loss through the ZF. It seems like we have debated this question before on this forum and there is also a 22 percent to 25 percent figure out there.
Yes, Ive read 22-25% many times. Never actually heard of it verified, though.
When do you plan on going to the chassis dyno?
What were your engine dyno numbers?
Will
When do you plan on going to the chassis dyno?
What were your engine dyno numbers?
Will
quote:Originally posted by 4NHOTROD:
Yes, Ive read 22-25% many times. Never actually heard of it verified, though.
When do you plan on going to the chassis dyno?
What were your engine dyno numbers?
Will
The engine produced 534 horse power at 6500 rpm with a 830 cfm Quick Fuel carb that was untouched. It is a 388 cubic inch Fontana block with CHI 3V heads and matching CHI single plane air gap intake manifold. My numbers are going to be somewhat off now, because the chassis dyno tuning will be done with a F.A.S.T XFI 2.0 fuel port fuel injection system installed. Pantera Performance Center in Castle Rock Colorado has the car and should have the engine installed and run on the chassis dyno sometime in September. The power maximum horse power may not go up with the fuel injection installed, but it should not be less either.
Pantera Performance Center claims that there is about a 80 horse power loss through the ZF. They have done a lot of engine and chassis dyno runs on Panteras through the years and that is the figure that I have been given. The real proof to myself will be when we actually put mine on the dyno.
sorry, but what do you guys mean with power loss trough the ZF ? if i'm right , power can't go away ... so just be converted to heat due friction i suppose ?....now i don't think a small box like the ZF can dissipate that amount of heat equivalent to 80 HP ... sure not without a massive oil cooler ???
i estimate : ZF box max 2 m2 x (120°C oil temp - 20° ambient temp ) x 50 Kcal/h ( high wind speed ) = 10.000 Kcal/h... that ZF box would act as a 12 KW stove... ! and this is what ??? 15 HP??? or i'm i wrong ????
i estimate : ZF box max 2 m2 x (120°C oil temp - 20° ambient temp ) x 50 Kcal/h ( high wind speed ) = 10.000 Kcal/h... that ZF box would act as a 12 KW stove... ! and this is what ??? 15 HP??? or i'm i wrong ????
I wish it was only a 15hp loss? You can reduce the loss some by using full synthetic lube. It reduces the drag on the gears. That's somewhere between 5 to 7 hp.
75hp loss is not really a big power train loss at all.
It's been pretty much documented on a dyno.
You would have to go to something like a VW Bug transaxle to get the loses that low.
I've seen the Corvair take the SB Chevy without breaking with the Crown Corveight kit. I can't believe the VW could.
75hp loss is not really a big power train loss at all.
It's been pretty much documented on a dyno.
You would have to go to something like a VW Bug transaxle to get the loses that low.
I've seen the Corvair take the SB Chevy without breaking with the Crown Corveight kit. I can't believe the VW could.
Of the few instances when I've seen engine dyno & chassis dyno sheets for the same Pantera motor, the loss has computed each time to 19%. How much loss was due to the engine breathing warmer engine compartment air, how much loss was due to the Pantera's exhaust system, and how much loss was due to the ZF? That I can't say. But the total loss computed to 19% each time.
quote:Originally posted by Belgiumbarry:
sorry, but what do you guys mean with power loss trough the ZF ? if i'm right , power can't go away ... so just be converted to heat due friction i suppose ?....now i don't think a small box like the ZF can dissipate that amount of heat equivalent to 80 HP ... sure not without a massive oil cooler ???
i estimate : ZF box max 2 m2 x (120°C oil temp - 20° ambient temp ) x 50 Kcal/h ( high wind speed ) = 10.000 Kcal/h... that ZF box would act as a 12 KW stove... ! and this is what ??? 15 HP??? or i'm i wrong ????
Thats exactly what my engineer/Pantera buddy said to me. Thats why I asked the question.
George brings up some very good points, as well
Will
It does seem that 75 to 80 hp is a high number. Perhaps it also accounts for the air filter, higher engine bay temp and full muffler system often not included on a bench dyno.
I can turn my ZF by hand; heck, out of the car, my drill would turn it. I certainly think my 5 hp lawn mower could spool it up pretty nicely, although I admit I've never tried. :^)
I recognize that at higher RPM, it would experience higher frictional losses. It just seems that the figure is overstated. I owned two opels that had 100 hp engines. I don't think 3/4 of their power would have been lost to the ZF. Just doesn't pass the sniff test.
JT
I can turn my ZF by hand; heck, out of the car, my drill would turn it. I certainly think my 5 hp lawn mower could spool it up pretty nicely, although I admit I've never tried. :^)
I recognize that at higher RPM, it would experience higher frictional losses. It just seems that the figure is overstated. I owned two opels that had 100 hp engines. I don't think 3/4 of their power would have been lost to the ZF. Just doesn't pass the sniff test.
JT
Dyno and find out yourself. Simple. I can't think of a car that only took 50hp?
The power loss will always be a percentage, not a set figure of 75 or 80 hp etc.
The more power your engine produces the more power you will lose through the drive train.
More power equals more friction in gears, bearings & driveshafts, as well as the tyres.
The lost energy turns into heat, hence the requirement for items such as transmission oil coolers on high output engines.
As George has stated, from his experience it has always worked out at around 19%, which is pretty good.
That equates to a fairy efficient transmission.
It’s possible if you had 930 CV joints instead of the Uni’s the losses may be a touch less.
As with better synthetic oils decreasing the friction.
So a 500 hp engine would have around 405 hp at the rear wheels, (95 hp loss).
A 350hp engine would be around 284 hp at the rear wheels, (66 hp loss).
If your engine was down a few cylinders & you filled it up with diesel by mistake & it was running like a real pig, put out only 90 hp, then the losses through the ZF would only be 17 hp.
Going to the extreme, if you had a twin turbo 427 monster pumping 1000 hp at the crank your ZF & drive train would be sucking up a good 190 hp & leave you with 810 hp at the rear wheels.
(still going on the 19% loss)
That’s why gearboxes let go with lots of power & torque.
Too much torsional twist on materials that were not designed for the increased power, too much friction on gear tooth faces leads to prematurely worn gears, shearing of teeth or bearing housings split from too much outward pressure & oil overheating & failing to do the job required.
So you need to beef up the transmission to handle the power, wider gears, bigger bearings, heavier shafts…..gearbox now holds up, but friction has increased, as has the inertia of the heavier rotating parts & so losses increase.
Gearbox is now good, but you start to suffer from a loss of traction, so fit bigger sticker tyres……….more power lost due to the increased frictional loading of the tyres.
And because your now loading the engine & not spinning the wheels, yep, more power is again lost due to increased friction in the drivetrain.
It’s said that a 7000 hp Nitro drag car requires 450 hp just to drive the supercharger.
It’s all relative.
You want more, you have to lose more…….it does not come for free.
But remember, your only losing all that power due to friction when your on full noise, & really, how often are you producing full power when you go for a Sunday drive?
5%.........10% of the time?
So the heat generated by the transmission is relativly low.........unless your on the race track, & thats when your losing 19% power 80% of the time.
As opposed to the Sunday cruise..... 19% of the power 5% of the time.
Regards,
Tony.
The more power your engine produces the more power you will lose through the drive train.
More power equals more friction in gears, bearings & driveshafts, as well as the tyres.
The lost energy turns into heat, hence the requirement for items such as transmission oil coolers on high output engines.
As George has stated, from his experience it has always worked out at around 19%, which is pretty good.
That equates to a fairy efficient transmission.
It’s possible if you had 930 CV joints instead of the Uni’s the losses may be a touch less.
As with better synthetic oils decreasing the friction.
So a 500 hp engine would have around 405 hp at the rear wheels, (95 hp loss).
A 350hp engine would be around 284 hp at the rear wheels, (66 hp loss).
If your engine was down a few cylinders & you filled it up with diesel by mistake & it was running like a real pig, put out only 90 hp, then the losses through the ZF would only be 17 hp.
Going to the extreme, if you had a twin turbo 427 monster pumping 1000 hp at the crank your ZF & drive train would be sucking up a good 190 hp & leave you with 810 hp at the rear wheels.
(still going on the 19% loss)
That’s why gearboxes let go with lots of power & torque.
Too much torsional twist on materials that were not designed for the increased power, too much friction on gear tooth faces leads to prematurely worn gears, shearing of teeth or bearing housings split from too much outward pressure & oil overheating & failing to do the job required.
So you need to beef up the transmission to handle the power, wider gears, bigger bearings, heavier shafts…..gearbox now holds up, but friction has increased, as has the inertia of the heavier rotating parts & so losses increase.
Gearbox is now good, but you start to suffer from a loss of traction, so fit bigger sticker tyres……….more power lost due to the increased frictional loading of the tyres.
And because your now loading the engine & not spinning the wheels, yep, more power is again lost due to increased friction in the drivetrain.
It’s said that a 7000 hp Nitro drag car requires 450 hp just to drive the supercharger.
It’s all relative.
You want more, you have to lose more…….it does not come for free.
But remember, your only losing all that power due to friction when your on full noise, & really, how often are you producing full power when you go for a Sunday drive?
5%.........10% of the time?
So the heat generated by the transmission is relativly low.........unless your on the race track, & thats when your losing 19% power 80% of the time.
As opposed to the Sunday cruise..... 19% of the power 5% of the time.
Regards,
Tony.
quote:you filled it up with diesel by mistake
This was done by one of our club members a couple of years back. And in good fun we gave him a trophy for the first diesel powered Pantera in Arizona.
quote:Originally posted by JTpantera:
It does seem that 75 to 80 hp is a high number. Perhaps it also accounts for the air filter, higher engine bay temp and full muffler system often not included on a bench dyno.
I can turn my ZF by hand; heck, out of the car, my drill would turn it. I certainly think my 5 hp lawn mower could spool it up pretty nicely, although I admit I've never tried. :^)
I recognize that at higher RPM, it would experience higher frictional losses. It just seems that the figure is overstated. I owned two opels that had 100 hp engines. I don't think 3/4 of their power would have been lost to the ZF. Just doesn't pass the sniff test.
JT
I believe the 75 to 80 horse power loss figure has come from using the 20 percent calculation, which is linear. If you have a Pantera engine with 375 fly wheel horse power, then you will lose about 75 horse power though the drive train. I would love it to be a fixed maximum 75 horse power loss, but after some detailed research, it is based on a percentage. The more horse power you have going into the ZF or any drive train, the more you will lose.
Chassis dyno time is not very expensive and if you really want to know what your Pantera is putting to the ground, then hook it up to one. They don't call those things "The great disappointer" for nothing.