B3422w5
Well-Known Member
My W5 car had 727. Went from stock drum to aluminum drum, saw absolutely nothing on the ET slip.
727 Drum
- Thread starter Mopar Sam
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71Demon540
Well-Known Member
Had the same experience with my dad’s car, and uncles car. In my own car I went from aluminum to steel, didn’t see any difference on the time slip. Some people I know have had luck with the aluminum drums going faster. But it showed me nothing as well.
I hear lots of guys saying less rotating mass/weight equals faster et and mph. I know this goes for engines but on a tranny I’m not so sure by what these other guys are saying in posts 26/27. Kim
Possibly just weight overall
Gomer Pyle
Active Member
I've never heard of a ring gear breaking on a 727 trans. If your drum exploded call A&A and they'll make you a valve body that holds the low band in first, never happen again.
Reducing rotating weight helps acceleration, no matter where the weight is taken from. By how much depends on where the weight is taken from.
David Vizard did some testing, put lighter wheels on a Mustang & reduced the ET.
David Vizard did some testing, put lighter wheels on a Mustang & reduced the ET.
71Demon540
Well-Known Member
For sure. It all works better in theory. Some cars it works better than in others. Personally I’ve got a lot of comparisons for “theoretical” ET gain from weight savings in the engine or drivetrain, and been disappointed.
The aluminum drum vs steel drum is only one comparison in which we found zero gain in more than one car. Same goes for going from aluminum rods to steel rods. Zero performance loss in multiple cars.
B3422w5
Well-Known Member
Years ago I swapped from an 8.75 to a Dana. Fairly significant weight gain(65-70 pounds or so) saw nothing on the slip.
That’s because the Dana is more efficient at what it does. Kim
B3422w5
Well-Known Member
I was aware of that, but was still surprised it was enough to offset the weight, but it sure did.
That's a ring gear in a differential, over speeding the transmission
B3422w5
Well-Known Member
I went and did some research on the weight difference( been a long while since I did that swap) general consensus seemed to be 50 pounds.
I said earlier 60 or 70 pounds so I was off a little, and as you seem to love to quibble over most everything, I was off by 10 or 20 pounds.
The main point is the weight difference had no negative effect on ET, and the more effecient Dana 60 is why.
I also mentioned rotating weight helps the most [ post #31 ]. Removing static weight can help acceleration but it needs to be a substantial amount to be measured or felt.
There is reason Nascar racers use 6-8" clutches......
There is reason Nascar racers use 6-8" clutches......
I thought that the main reason for changing to a aluminum drum was safety, less chance of a explosion.
71Demon540
Well-Known Member
Either billet aluminum or billet steel. Both are safer than the stock, powdered iron drum. Lot of people used to go with aluminum because not only is it safer than the stock drum, but a lot have gained ET as well. I just have not had that experience with the aluminum vs steel drum as far as ET goes.
Did you ever go from a limited slip carrier to a spool? When I did I definitely noticed a consistent reduction in ET and added MPH. My guess is that rotating weight makes more difference than static weight.
B3422w5
Well-Known Member
No, that car I had a locker in it for a minute, then spool.
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