Gear vendors OD
I drove a car with one for a long weekend. It was just too little of a good thing with that set-up's overdrive ratio. I wish Gear vendors would offer in a deeper overdrive, but they don't.
I ended up using a built up 2004R, which has a .67 overdrive and a lock-up torque converter. Aside from that, it's also the best automatic transmission I've ever driven.
With an A904 automatic, the ratios are
2.45-1.45-1.00-.78 with splits of .59-.69-.78 It's actually a great set of progressive splits, keeping your engine in the powerband, IF you have a decent rear gear..... Like 4.10/4.30s.
It works even better with a 4 speed; the ratios are;
2.66-1.92-1.40-1.00-.78 with splits of
.72-.73-.71-.78
But if you shift 1-2-3-3od, then 4od, you get a nice short 4th, and a deep overdrive. It looks like this
2.66-1.92-1.40-1.09-.78 and splits of
.72-.73-.78-.71. If you combine that with a Commando box, the ratios are;
3.09-1.92-1.40-1.09-.78 with splits of
.62-.73-.78-.71 This work really well with 3.23s or 3.55s
But it doesn't stop there! I split those gears like so;
3.09-2.41-1.92-1.50, and then into 4th-over for splits of
.78-.80-.78-.52. This works awesome with 3.55s cuz 93=6150 in 1.50 gear, which is what my combo traps at in the Eighth. The starter gear is 3.09x3.55=10.97,, which compares well with 2.66x4.10=10.91.
The result of this is 4 very close-ratios with a deep low, and then that .52 split at the top makes 65=2240rpm
But it doesn't stop there;
Going back to autos, the A904 ratios are
2.45-1.45-1.00, splits of .59-.69.. If you split those, you get
2.45-1.91-1.45-1.13-1.00-.78 with splits of
.78-.76-.78-.88-.78
In this case you would shift; 1-1od-2-2od, them 3od for splits of .78-.76-.78-.69
That 2-od would get me 93@6150 again,now with 4.30s, the starter is 4.30x2.45=10.54, and 65=2710.. That's all very doable. But I will never have an auto.
The A999 ratios are slightly better at the top, and slightly not as good at the bottom. And the split from 2od to 3od is .65, and you can run 4.10s(or even 3.91s) instead of 4.30s
My point is this: if you buy a GVod strictly for the cruise-rpm reduction, yur leaving a lot of performance on the table. Install a bypass on the GV computer, and start splitting gears; the thing shifts like lightning. My combo gets to 93 mph with one pull on the stick, and two electric shifts. After the tach hits 7200 in first, it stays there all the way. Then later, I cruise home at 2240.
But it doesn't stop there. When cruising around I never split gears, so with enough torque, I shift at 2800, and pretend I'm a tractor.
The thing is, with a 230*@.050 cam, if I cruise at any less than 2240, the fuel mileage just gets worse, as the cam don't work right for that down there. My combo actually gets better mileage at a lil higher rpm
