Any one have any experience with a Gear Vendor? Thinking about one for me 1976 Dodge 360 with TBI. I get 9.5-10 mpg now, hoping for more.
What are your thoughts?
Good morning, Jack;
The Gear Vendor 3D0475 Over Drive bolt-onto-the-back of the 3L80 three speed automatic transmission is what I am working toward also. The plan is to do the engine modifications first to make sure the engine can pull the 22% higher gearing on the level ground, and be able to drop back to standard 3rd for the grades and then 2nd-Over for the steeper climbs. The calculations say that with this full package, I should be able to go up the West side of Steven's Pass in 2nd-Over at about 50 MPH or maybe 55 MPH instead of the 35-40 MPH that I can climb that hill now with the 15,000 pound weight that I normally run with the P37 motor home chassis.
If the C-172 comes to an end this winter, and it is looking like it will, because I am not able to pay for the full MOH the O-300B engine is looking at right now, then completing the P37 engine-driveline conversion should be possible by this coming spring. That will be nice.
While there is hope for an improvement in fuel economy, my main goal is the use of the over-drive on 2nd and 3rd gears for climbing with 2nd, and hopefully flat land fuel economy with 3rd.
One thing that I noticed is that I will need to recalibrate the speedometer, or somehow move the speed0meter-odometer cable off the transmission and back to the driveshaft where it will not change as gears are shifted. One possible work-around I can do right now is to use the GPS box speed display for complying with the speed limits. Besides, while the speedomoter is accurate, the odometer in my P37 is about 10% optimistic and makes it seem like the 454 in the P37 is getting much better fuel economy than it actually is. Using the GPS box for a more accurate indication of actual miles traveled was disappointing when I first calculated the fuel economy that way. It seems that the C-172 actually does get better mileage than the P37.
Enjoy; Ralph, Latté Land, Washington