AJ/FormS
Well-Known Member
- Joined
- Apr 26, 2016
- Messages
- 1,292
- Reaction score
- 306
Again, for your application, which automatic you install, makes as good as no never mind. This is because the power loss is not instantaneous through the tranny, but rather a percentage, as the rpms rise.And it is only somewhat linear.
For instance; if the absolute powerloss through the tranny was say 25hp at 6500 rpm, then at 5000 one might expect (5000/6500)x25=19.2hp loss. And at 3000 one might expect (3000/6500)x25 = 11.5hp loss. In reality this is just no so. Further more these are WOT numbers. At say 50% power application, one might expect 50% the power loss. So now the numbers are 9.6 and 5.7.
But here's the catch. The absolute loss through the tranny is directly related to the input power. If you are inputting 400hp. you might lose that 25. But if you are inputting 200,You will not also be losing 25.
So again for your application, I doubt you would notice a powerloss.
However, the mass of the rotating parts in the big 727 are considerably more. And that mass takes a wee bit more time to spin up. In a drag car, this is important on account of that car will suffer three accelerations and two decelerations during the course of the race.
Your car on the other hand will suffer only one acceleration, on account of first gear with 3.23s and 27" tires will hit the speed limit; 65 =6400 plus TC slip;say 6650.
So again, which tranny you use should probably be more related to what you have available, and what your chassis is already set-up for, and what you can afford.
Now for the wild card; there is available a 904 with ratios of 2.74-1.54-1.00 and a loc-up. This will give you a starter gear of 3.23x2.74=8.85 plus the momentary TC ratio. This will get you off-the-line quite a bit more briskly, than the 2.45 low in the standard box;about 12% better torque multiplication. The only downside is the rpm drop between shifts. But again at your power level, this is not a big deal. Another nice thing is the loc-up feature, which will eliminate the TC slip while cruising, and might be good for 1 or possibly 2 mpgs on straight point-to-point hiway useage.
These are the real reasons to opt for a 904variant.
Oh and it is a few pounds lighter. Plus the TC is usually lighter.
And if you are confused about some of this, consider that Chrysler put the 727 behind slanty's too, for HD use. In they often had reargears in the 2.xxs. If you had a 140hp slanty and you stuck a 25hp loss tranny behind it, you would turn an already sucked out combo into a total pig of a car.Ok, maybe sucked-out and pig-of-a-car, are a bit harsh.But after you drive your car with a 360 come back and tell me I was wrong,lol.
Anyhow, more ramblings from AJ, peace/out.
For instance; if the absolute powerloss through the tranny was say 25hp at 6500 rpm, then at 5000 one might expect (5000/6500)x25=19.2hp loss. And at 3000 one might expect (3000/6500)x25 = 11.5hp loss. In reality this is just no so. Further more these are WOT numbers. At say 50% power application, one might expect 50% the power loss. So now the numbers are 9.6 and 5.7.
But here's the catch. The absolute loss through the tranny is directly related to the input power. If you are inputting 400hp. you might lose that 25. But if you are inputting 200,You will not also be losing 25.
So again for your application, I doubt you would notice a powerloss.
However, the mass of the rotating parts in the big 727 are considerably more. And that mass takes a wee bit more time to spin up. In a drag car, this is important on account of that car will suffer three accelerations and two decelerations during the course of the race.
Your car on the other hand will suffer only one acceleration, on account of first gear with 3.23s and 27" tires will hit the speed limit; 65 =6400 plus TC slip;say 6650.
So again, which tranny you use should probably be more related to what you have available, and what your chassis is already set-up for, and what you can afford.
Now for the wild card; there is available a 904 with ratios of 2.74-1.54-1.00 and a loc-up. This will give you a starter gear of 3.23x2.74=8.85 plus the momentary TC ratio. This will get you off-the-line quite a bit more briskly, than the 2.45 low in the standard box;about 12% better torque multiplication. The only downside is the rpm drop between shifts. But again at your power level, this is not a big deal. Another nice thing is the loc-up feature, which will eliminate the TC slip while cruising, and might be good for 1 or possibly 2 mpgs on straight point-to-point hiway useage.
These are the real reasons to opt for a 904variant.
Oh and it is a few pounds lighter. Plus the TC is usually lighter.
And if you are confused about some of this, consider that Chrysler put the 727 behind slanty's too, for HD use. In they often had reargears in the 2.xxs. If you had a 140hp slanty and you stuck a 25hp loss tranny behind it, you would turn an already sucked out combo into a total pig of a car.Ok, maybe sucked-out and pig-of-a-car, are a bit harsh.But after you drive your car with a 360 come back and tell me I was wrong,lol.
Anyhow, more ramblings from AJ, peace/out.
