The Dieselfication of FMC #1046
A number of you are aware of the project that I have going on with my 1976 FMC as there has been a link to the photo album that follows the project in my signature for some time. I have also done a l...
Forum Discussion
wildmanbaker wrote:
You should see a great improvement in fuel mileage. I am wondering if you will notice much difference if drive ability.
Based on the experiences of other FMC's that have been converted to other diesel engines, I expect that my mileage will go from 7.5mpg to about 12mpg. I am crossing my fingers and want be surprised when it goes even higher due to the efficencies of this engine relative to engines from the '90's and earlier.
There are basically two aspects to driveability: One is how it accelerates onto the highway and up mountain grades (I live in the West!). The other is how stable the steering is on a crowned road and in cross winds, etc..
The first one is a given as HP will go from 225 to 360 and torque from 350 to 650 ft.lbs.
The second one is what I believe you are refering to in your post. The first thing to understand is that these coaches were originally built to handle very well. A key feature that helps with this is that it has 4 wheel independent suspention. That means that the differential does not move up and down - it is locked into position and is attached to the same frame members as the engine. This enables a very short driveline (6 inches in this case) which then enables the rear wheels to be moved closer to the rear than is possible with virtually any other coach.
That said, I AM adding weight behind the rear wheels. Due to all the aluminum, the Duramax is about 150 lbs more than the Chrysler 440-I that was removed. The Allison transmission is about 200 lbs more than the original Load-flite three speed. I had previously replaced the Load-flite with an Allison 540 so my transmission weight is very similar to what has been in the coach.
This is the lightest diesel conversion that can be done to this coach! However, if necessary, I am prepared to do a little rebalancing of the unit. Others with heavier engines, have been able to maintain the historic FMC handling after a little rebalancing.
You asked a very important question and one that I explored extensively prior to starting this project.
