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Re: Power difference between transmissions [Re: volaredon] #3096695
11/23/22 11:17 PM
11/23/22 11:17 PM
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Originally Posted by volaredon
I don't get the "percentage of power" thing. Don't make sense to me. You're not changing what parts weigh, (centrifugal force) or the fluid, it would seem it takes "x" quantity of power to run the trans. No matter what size engine is in front of it. More HP available, less percentage of the whole.

I asked what I did in the most general of terms, I'd think one 727 would eat up the same #of HP as the next, unless that "next" one was modified vs stock (rollerized, whatever)
Or one 904 vs another, or one 500, or one a833od vs another one just like it, etc etc.


But more specifically in my exact case whatever trans I run on this project will be run by a built up /6. I don't see something like that "8hp-whatever" coming close to a possibility.
If I decide the a500 is my trans of choice I'm gonna have to find a /6 to small block trans adapter as it is. The truck currently has it's original and working 727 in it. The only thing I have to do to that is find the leak(not the pan or the input or output shaft seal) and add a mild shift kit so I can stop the converter drain back situation it has. And drive the snot out of it from there.
But I just got an 833od with flywheel, bell housing, pedals, linkage and everything I'd need to swap that in except for a new, fresh clutch which I believe I may have in the attic. And I have an a500 here too, that worked when pulled, that I'd rebuild before I use it just because of age and past maintenance being an unknown.
But being a 500 is '904 based" it seems a downgrade vs a 727 in terms of durability. I don't have a 518 at present. I'd like to run something I have. If it's the 500 is definitely have to do some beefing up just for my own piece of mind.

If I'm gonna make a change from the 727 it's gonna be a change to the least power sucking option I have available and on hand.



The percentage is because you are acceleration a load. Think it through. It takes more power (a greater number because the percentage stays the same) so it’s not a fixed number but a fixed percentage. (a powerglide is about 19-19.5% and a TF is about 21%). That means that it robs the same PERCENTAGE of power no matter what. 21% of 500 hp is 105 hp and 21% of 1000 hp is 210 hp.

So the percentage stays the same but the actual power consumption number goes up because you are dealing with a percentage of how much hp it takes to drive a gear box.

Look at NHRA Pro Stock and Mountain Motor Pro Stock. One is 500 CID and about 1500ish hp. The other can be some really big CID, BUT the power doesn’t go up as a percentage of CID because friction losses are also a percentage.

So let’s say you are looking at a 500 CID engine and comparing it to a 700 CID engine. At 1500 hp, you get 3 HP/CID. And the 700 CID engine makes 1750 hp which is 2.5 HP/CID. Because the friction losses are a percentage of total hp, the bigger engine makes more hp but is less efficient (2.5 HP/CID rather than 3.0 HP/CID).

If you made the bigger engine even bigger, the flywheel hp would (should) go up but the HP/CID would go down.


Just because you think it won't make it true. Horsepower is KING. To dispute this is stupid. C. Alston
Re: Power difference between transmissions [Re: Ray S] #3096861
11/24/22 03:17 PM
11/24/22 03:17 PM
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north of coder
moparx Offline
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Originally Posted by Ray S
Originally Posted by volaredon
Original to the truck... 727 lockup,


727 with locking TC?
Rare as hens teeth!


i have two on the shelf, big block units from newyorkers.
beer

Re: Power difference between transmissions [Re: moparx] #3096862
11/24/22 03:20 PM
11/24/22 03:20 PM
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ILLINOIS
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volaredon Offline OP
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My son still has one out of an 80 ramcharger that originally had a 360

Re: Power difference between transmissions [Re: volaredon] #3096876
11/24/22 04:11 PM
11/24/22 04:11 PM
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moparx Offline
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i was originally going to use one of the lock up units in my humpback project as a kind of fourth gear, but i ended up with two A518's, one of which is a rebuilt unit, and a JW ultra-bell for a big block.
i will use the A518 and the adapter now, for the true fourth gear, and a "kind'a" filth gear with a high stall lock up [expensive] converter.
beer

Re: Power difference between transmissions [Re: 360view] #3096958
11/25/22 06:56 AM
11/25/22 06:56 AM
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So, everyone on Moparts contribute $20 and buy a “transmission dynomometer” to test efficiency and power consumption?

https://powertestdyno.com/product/transmission-service-450e-series/

Or maybe give a “shout out” to trans shops that already own and operate units?

Re: Power difference between transmissions [Re: 360view] #3097050
11/25/22 01:13 PM
11/25/22 01:13 PM
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PINE VALLEY
Ray S Offline
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Originally Posted by 360view
So, everyone on Moparts contribute $20 and buy a “transmission dynomometer” to test efficiency and power consumption?

https://powertestdyno.com/product/transmission-service-450e-series/

Or maybe give a “shout out” to trans shops that already own and operate units?


Nice
I have seen results from DIY dynos for moto and bike drivetrains that simply use an electric motor input with current meter and generator head on the output, calibrated with a solid shaft.
For a decent HP test one would need an engine dyno - test the engine direct, then with trans.

Re: Power difference between transmissions [Re: 360view] #3097227
11/26/22 10:32 AM
11/26/22 10:32 AM
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ILLINOIS
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volaredon Offline OP
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Originally Posted by 360view
So, everyone on Moparts contribute $20 and buy a “transmission dynomometer” to test efficiency and power consumption?

https://powertestdyno.com/product/transmission-service-450e-series/

Or maybe give a “shout out” to trans shops that already own and operate units?


I would have figured theres a westech/Steve Brule type of person somewhere out there that has already run such tests and that there would be a published list out there "somewhere" that already exists with such info.

In the 80s when I went to a local community college in their automotive program they had a trans test machine, that could be used to test a transmission, usually after a rebuild. It had lotsa adapters for bellhousings and tq converters, I only ever saw it actually get used once in the time I was there, it had a 4 banger (1.6?) Toyota engine to power it, that I remember hearing was donated by a local wrecking yard to power it. It had a bank of pressure gauges that could monitor pressure at any of the pipe plug test ports but I don't think there was any "dyno" function on it to test power used by a given transmission

Re: Power difference between transmissions [Re: madscientist] #3097249
11/26/22 11:54 AM
11/26/22 11:54 AM
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Originally Posted by madscientist


The percentage is because you are acceleration a load. Think it through. It takes more power (a greater number because the percentage stays the same) so it’s not a fixed number but a fixed percentage. (a powerglide is about 19-19.5% and a TF is about 21%). That means that it robs the same PERCENTAGE of power no matter what. 21% of 500 hp is 105 hp and 21% of 1000 hp is 210 hp.

So the percentage stays the same but the actual power consumption number goes up because you are dealing with a percentage of how much hp it takes to drive a gear box.

Look at NHRA Pro Stock and Mountain Motor Pro Stock. One is 500 CID and about 1500ish hp. The other can be some really big CID, BUT the power doesn’t go up as a percentage of CID because friction losses are also a percentage.

So let’s say you are looking at a 500 CID engine and comparing it to a 700 CID engine. At 1500 hp, you get 3 HP/CID. And the 700 CID engine makes 1750 hp which is 2.5 HP/CID. Because the friction losses are a percentage of total hp, the bigger engine makes more hp but is less efficient (2.5 HP/CID rather than 3.0 HP/CID).

If you made the bigger engine even bigger, the flywheel hp would (should) go up but the HP/CID would go down.


Are you saying that with no other changes to a car, other than stepping up to 1000 hp from 500 hp the transmission will require more power to move the car?

Re: Power difference between transmissions [Re: volaredon] #3097250
11/26/22 11:55 AM
11/26/22 11:55 AM
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Michigan
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Originally Posted by volaredon
Originally Posted by 360view
So, everyone on Moparts contribute $20 and buy a “transmission dynomometer” to test efficiency and power consumption?

https://powertestdyno.com/product/transmission-service-450e-series/

Or maybe give a “shout out” to trans shops that already own and operate units?


I would have figured theres a westech/Steve Brule type of person somewhere out there that has already run such tests and that there would be a published list out there "somewhere" that already exists with such info.

In the 80s when I went to a local community college in their automotive program they had a trans test machine, that could be used to test a transmission, usually after a rebuild. It had lotsa adapters for bellhousings and tq converters, I only ever saw it actually get used once in the time I was there, it had a 4 banger (1.6?) Toyota engine to power it, that I remember hearing was donated by a local wrecking yard to power it. It had a bank of pressure gauges that could monitor pressure at any of the pipe plug test ports but I don't think there was any "dyno" function on it to test power used by a given transmission


That’s because there is no trans “Dyno”. There are transmission test stands as you describe here.

A dynamometer measures output. Transmissions make no power.

Re: Power difference between transmissions [Re: Transman] #3097273
11/26/22 12:59 PM
11/26/22 12:59 PM
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PINE VALLEY
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Re: Power difference between transmissions [Re: Transman] #3097456
11/27/22 07:40 AM
11/27/22 07:40 AM
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Oakdale CT
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Originally Posted by Transman
Originally Posted by volaredon
Burned up


That’s not breaking the trans from power.

Most likely a leak, low fluid, misadjusted throttle pressure, lack of maintenance (misadjusted band/s), etc.

/6 wont “break” a 500.


I have one (42RH) behind a 5.9 magnum with upgraded heads, 500+ lift roller, headers, RPM intake and headers. So far I have not broken it though it is fortified with upgraded parts.




"I think its got a hemi"
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