automatic overdrive
Curious, does anyone make a a programmable control box that would operate a GV's unit so it would split each gear automatically? I like the idea of using a 727 but wouldn't want to be splitting gears manually all the time. Sometimes, hell, most times, I just want to cruise.
There are very few Mopar transmissions that will get any advantage out of such a feature.
They are;
For M/Ts; the A833od, the Commando A833, and
For Autos; the A999/998 wide ratio TFs. All others split the 1-2 not bad, but the 2-3 is messed up.
> Furthermore; if you have a good amount of Torque AND an automatic, it's kindof silly. Really, a stout-360 doesn't need it. With my Commando box, I rarely split it.
For you;
"hell, most times, I just want to cruise",
I see NO advantage in it. Run whatever hiway gear you want, and just stall it up until you get the take off performance you want. If yourstall-rpm gets to be higer than your cruise rpm, then a loc-up will solve that.
More math;
The A999 has ratios of 2.54-1.54-1.00
With a cruise gear of 3.23s,
your Road gear ratios would math to;
8.85-4.97-3.23
But hang on, at WOT, there are different slip ratios in each gear depending on torque input, and Rpm, and Roadspeed. Plus at a Dead-Stop, the TC has a superbig torque-multiplier inside it. And the Loc-up brings it all back to 3.23.
So Lets assume a TC ratio of 1.8. and slips in each gear of 20%/15%10%
>So then First gear starts off at 1.8 x 8.85=15.93, which begins to diminish as soon as the car starts moving. At peak torque it might be down to 1.2 x 8.85=10.62
Second will be 1.15 x 4.97=5.72, and
Direct might be 1.1 x 3.23=3.55.
Loc-up of course is 3.23
So when you stack it all up, you get; 15.93 to10.62-5.72-3.55-3.23in loc-up. How many gears is that? I count 5( FIVE), lol. The first one, 15.93 to 10.62, of course, you don't get an actual shift, you just get a 50% longer flight-time, before the 1-2 shift.
If you put a GVod on a 727; by the math the ratios are
2.45-1.45-1.00-.78od, splitting it gets you
2.45- 1.91-1.45-1.13-1.00-.78od, and the splits are .78-.76-.78-.885-.78
So you can see the tight 2od to Direct of .885 is kindof silly. If I had this combo, I would split from Second to 2od, then 3od; like this ; 2.45-1.91-1.45-1.13-.78od
for splits of .78-.76-.78-.69, badaBoom! That's nice tight splits.
But I can guarantee you that for your stated purpose, you would only split the 1-2 when showing off. For a Hiway-cruiser this wants a rear gear of 4.10 or less, 3.55d will get you a final drive of 2.77, and 65=2240 with 27" tires. Like mine.
This is the very minimum cruise rpm for which you can still give a hopped up engine nearly the cruise-timing it wants. If you cannot engineer it to run what it wants, it will not get any better fuel economy than say 3.73s or even 3.91s......... unless you drive faster.... lol.