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V-Drive

Junior

Well-Known Member
#1
Could one of you guys explain to me how a V-Drive works or what exactly is a V-drive? I have seen river boats referred to as V-drive. These boats have the motor facing the rear of the boat, I believe. What is the benefit of this setup in an offroad machine? Does this setup allow for more driveline articulation? Why does this setup require the rear chunk to be offset so far to one side? Please excuse my ignorance and enlighten me.

Thanks in advance.

Junior
EJR Racing #244
 

Donahoe

Well-Known Member
#2
Junoir, Think of a v drive like a tranfer case on a 4wd truck. But with only one drive flange on it. A V-drive system allows the builder to put the motor Almost to the rear end of the truck (backwards) and still use a drive line that is long enough to get big wheel travel in the rear.... The reason the rear diff is off set is becuse you now have a motor in the place of where your drive line would normally go.. Hope that helped..

NEVER LIFT!!!!!
 

Greg

Well-Known Member
#3
The reason the builders dont use a transaxle like a buggy is cause a big live axle is soo much stronger and the only way to mount a V8 motor/ transmission combo in the rear is to bend it in the middle. the reason they use them in boats is to get the angle of the prop more verticle and to keep the engine in the rear of the hull.

Greg
 

FABRICATOR

Well-Known Member
#4
Junior,
How about at least three of us? The reason these units from boats are called V-Drives is because the input shafting and output shafting are at a slight angle to each other, usually around 160 to 170 degrees. The gears are also slightly beveled. Most of them are water cooled and some have a forced oiling system. As mentioned above, this is to get alot of power underneath the engine to the propeller. The bottom line reason they are used on some off-road racers is because it allows for a "mid" engine location, and there simply is no transaxle readily available which can handle over about 400 horsepower in this type of application. Several road racing transaxles have been tried and all failed. The weakest point is the case itself and the ring-and-pinion area. Even the Fortin unit is overworked when coupled to a healthy V8 in a mid to heavyweight vehicle. This is not to say that a capable transaxle cannot be built. But that's another story. The V-Drive in off road racing has been around for several years. It allows the drive shaft to run back from about the middle of the car along the side of the conventional but backward facing transmission and engine. This is why the "pumpkin" part of the live rear axle is radically offset to one side. The advantages of this system are brute strength, and it is somewhat friendly to long travel suspension. The main disadvantage is that it is very heavy. It adds alot of weight to the chassis that would not otherwise be there. It also causes a large, very offset weight to be placed on the rear axle. This does cause stability problems, although some designers and builders deny this. Hope this helps with why-the-V-drive.
 
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