6 pinion Planetary?
Thread Starter
Safety Car
Joined: Jan 2009
Posts: 3,736
Likes: 56
From: anchorage ak
6 pinion Planetary?
As the title says 6 pinion Planetary, is any one running it in there 700r4? I know it closes the gap between 1st and 2nd gear by lowering the first gear ratio from 3.06 to 2.84 plus with 6 pinions is supposed to be stronger. I know having the 3.06 for first gives ya plenty of low end in first, but does create a pretty big gap rpm wise between first and second gears and the difference between the two is for lowend is a small .93% loss. I'm thinking on trying it but am curious as to if any of yall had tried it? If so what what are your thoughts on it, good and bad. P.a.t.c's web site says that closing that gap decreases the E.T. by .3 to .5 tenths and that might just be marketing. Thanks Blue
Melting Slicks
Joined: Oct 2002
Posts: 2,317
Likes: 111
From: St Louis MO
The lower your power-to-weight ratio (heavy vehicle), the more important it is to have a very low first gear ratio (think large trucks needing very low gear ratios just to get moving). As the power-to-weight ratio becomes higher (think dragsters), the first gear ratio can even be eliminated (1:1 high gear only). The overall ratio, first times the rear end ratio, is often quoted as ideal when it is 10, but it is also dependent on your torque and horsepower - so, is traction a problem on starting? If you spin the wheels readily when you try to start quickly (such as at the dragstrip), you may do better with a higher first gear ratio (lower number) as it will promote better hook to the track.
As an example, with my former '78 Vette, I turned many 11.50s with 3.08 rear and a TH350 with a 2.52 first gear with a strong 406 SBC because it hooked well; with 3.36, traction was a problem. So, how much torque multiplication do you really need?
As an example, with my former '78 Vette, I turned many 11.50s with 3.08 rear and a TH350 with a 2.52 first gear with a strong 406 SBC because it hooked well; with 3.36, traction was a problem. So, how much torque multiplication do you really need?
Le Mans Master
Joined: Oct 2002
Posts: 7,098
Likes: 378
From: Las Vegas - Just stop perpetuating myths please.
I'm not sure the $700 cost of the lower 2.84 ratio is justified. If u have traction problems a better fix may be a early 4L80. U can buy them used in usable condition for that kind of money. But the conversion parts like trans mount, driveshaft and cooling line maybe another $700.
BTW I thought it was a 5 pinion gear planetary. Maybe u know a cheaper unit?
BTW I thought it was a 5 pinion gear planetary. Maybe u know a cheaper unit?
Thread Starter
Safety Car
Joined: Jan 2009
Posts: 3,736
Likes: 56
From: anchorage ak
I'm not sure the $700 cost of the lower 2.84 ratio is justified. If u have traction problems a better fix may be a early 4L80. U can buy them used in usable condition for that kind of money. But the conversion parts like trans mount, driveshaft and cooling line maybe another $700.
BTW I thought it was a 5 pinion gear planetary. Maybe u know a cheaper unit?
BTW I thought it was a 5 pinion gear planetary. Maybe u know a cheaper unit?
