Discussion in 'Small Block Tech' started by Mark Demko, Dec 25, 2020.
Me too, it’s the original from my GN, I’ll see if Guy wants to buy it
You might be able to re-stall that D5. I don't know how high it can be taken to.
Put in a 430 gear with the GV unit. The 430 will get you a high 11 shifting at 6800 and the GV will get you home with a 308 gear or so. it will be the only way to go if you want to keep the 350 trans. and beat the hell out of me
Now that will be a street terror 350
Your on buddy HAPPY NEW YEAR!!
Anybody read or hear how much power the GV eats? Just curious
I've never been able to get a straight answer on that Mark. I don't think anyone has ever done a back to back chassis dyno test. I think that would be the only way to know for sure.
I was curious as to the "taxable h.p."
IIRC in the '71 chassis manual, it lists the taxable h.p. of the 350 trans, and the 400 trans. at 27 and 37, or 37 and 47 respectively.
Yeah, I don't know. A back to back chassis dyno test is the only thing I would believe. It's an add on transmission. I think it probably takes a decent amount of power to turn it, and that probably goes up the faster you turn it.
"When designing transmissions and overdrive units, durability and reliability are often at odds with minimizing noise and parasitic power loss. Gear Vendors employs several techniques to reach a happy medium between these design goals. This is evidenced by the fact that our overdrive units require just 1 hp to turn for every 400 hp put through them. A large part of this efficiency is due to the Gear Vendors common vertex clutch design. This clutch is a single member, meaning that it shifts with very high pressure compared to the clutch pack in a conventional automatic transmission. The advantage of a clutch pack is that you can achieve a wider ratio spread, and slowly bring in ratio changes for smooth shifts that grandma would like. The single-element clutch is ideal for a short ratio. It results in a firm engagement, which is why a Gear Vendors unit doesn’t need a separate fluid cooler and operates on just 3/4 quart of ATF. Since a Gear Vendors unit does not share the same fluid as the rest of the transmission, if you break the trans, it will not hurt your Gear Vendors. Ultra-low parasitic loss is the key to long life, and Gear Vendors–equipped off-road race trucks have survived 7,500-mile events with zero reliability issues."
Wonder if that changes when it isn't engaged?
Why don't you put those heads on first and see what that does first speedy.
when the driver hits overdrive while in First gear, he has more torque multiplication than if he shifted into Second gear with a 4.56:1 rearend gear.
I dont quite understand how that could be so, putting the GV in overdrive while your in first gear, wonder if thats a typo and they meant underdrive?
If so that means my 3.42 rear would be like a 4.39?
I am I am, just toying with gear ratio options
The GV is not an "underdrive", it is "direct" and "over".
So, the torque multiplication is a misnomer.
When in first, say 2.51 and you engage the OD, you are now 28% "over" 2.51 or about 1.80.
Splitting gears gives you 28% over in each gear.
So, if you leave with the GV in "direct" (OD not engaged)** and then you engage near the shift point of 1st, you get an "extension" of first as you now have 28% more being in "1st over".
Hit second gear at the same time as you "button off" the OD, you are now pulling in second and then engage the OD again near the 2nd gear shift point, and you "extend" in "2nd over".
Then you shift into third (auto), and either run it out in 3rd OD, or you again, "button off" the GV back to "direct" and run through traps in 3rd without overdrive.
You can do the same thing with a manual in each gear.
** You can actually actuate the GV OD before launch, automatic trans, or manual trans, and the GV will engage at 20MPH as referenced from the speedo drive adapter/switch that GV provides. It is designed to do that. And be very consistent engagement.
Doing the "button off" is easy to do in a stick shift car. I had a shifter ball with button and was able to engage/disengage the OD at anytime with my thumb.
Thats not much at all!
I gotta head ache now LOL
A splitting headache?
If you have enough power the 3.42 hear and current trans would be fine.
Based on what Trunk-Monkey said, it's interesting that Gear Vendors definitely refers to under-drive and overdrive on their website? I wonder why?
Maybe they do offer some units with an "under"?
I see they offer a unit that lives behind the ST300. Has anyone tried this?
With the OD engaged in any gear other that nets less than 1:1, it can "technically" be called "under drive".
Since it cannot get you a reduction in 1st gear, it is not a "true" underdrive.
It is a "direct" 1:1 normally and then in overdrive (22% over)*
*I posted 28% earlier, but I meant 22%. (.78)
My uncle created true underdrive, and overdrive units, (Quick-Change) after he created the Shur-Shift two Speed LENCO that was actual under drive and direct using planet/sun rotating in "Low", and then "High" locked the sun/planet and gave direct.
Single unit provides 2 speeds. Underdrive, then direct. Adding another unit gives 3 speeds (as the next unit inline is already in low, and then after launching with the first unit in low, then shift to high, then the next unit is shifted into high. Always remember, with X number of units, speeds are counted as; "1(unit) is 2 (speeds), 2 is 3, 3 is 4, etc.
The Under drive and Over Drive.
Thats what Im hoping