Convert from 8V-92 to Series 60

[antioch01]

Tony,
I wondered about that, if the mileage is that close it would not be worth it. And I quite frankly love the sound and performance of the 8V92. Your coach is probably a 45' which may make some difference. I assume you flat tow your Jeep Liberty which should be next to nothing in weight and wind. Our Liberty weighs 43000 lbs. and with the smaller trailer and our diesel beetle we can get about 5 mpg. We need the enclosed trailer because we put the Harley in front, but we sometimes tow a stacked trailer that adds another 9000 lbs. If we travel out West we plan on taking the stacked trailer so we can take the toys. That drops the mileage to 3-4 which is where the S60 would maybe help with its torque. I would like to see what a 40' prevost S60 pulling a stacked trailer gets for mileage.

[travelite]

The front compartment in our coach has two boxes and ports for checking the ADEC and DDEC systems and the harness runs to the rear. I need to know if this harness will plug into a world trans and a DDEC4 ? I am thinking as I am typing this, I can check the DDEC4 on the S60 in my yard now and compare to the DDEC 2 on the 8V92.

Robert,

There's a bunch of very knowledgable DD folks over at: www.dieselenginetrader.com. Go to the DETROIT subforum. There's a man there who goes by the name of gonefishen. He's a wealth of knowledge as are many other folks over there. They can answer your questions related to ECM and wiring harness compatibilites, etc.

[antioch01]

Headed there now, thanks

[Jon Wehrenberg]

Robert, I will let the experts address the DDEC issues. When you look at your underside. compare the length of the driveshaft between the U joints on your 8V92 and a Series 60 40 footer. Also see if the tag axle has been modified. I think it is very important to maintain the geometry Prevost built into the 40 footer with Series 60 to avoid vibrations and the damage than can ensue.

As to the mileage, why don't you run some numbers. For example, let's say you drive 15,000 miles. My 8V92 was geared so top speed was 69 MPH, 72 downhill. I drove it at around 60 MPH and I got 5.6 MPG. My Series 60 coach is 5000 pounds heavier, and I drive it 62 MPH and originally got around 8 MPG, but since the change in fuel to the low sulfur I more consistently get 7.5 MPG. These are not guesstimates, but actual numbers since I record every gallon of fuel ever put into the coaches. How you drive will have a substantial impact on your fuel economy.

So lets pretend fuel costs $5.00, which is much higher than it is today. On my 8V92 my fuel cost would have been $13,393. On my Series 60 my fuel cost $10,000 for a savings of $3,393. Now that is not chump change, but if you drive less than the 15,000 miles the savings, even at $5 per gallon is not so significant. Only you can decide if the cost and effort to swap engines and transmissions will be justified based on fuel savings. In today's dollars the savings, even at 15,000 miles per year is down to $2375.

If you are right about fuel going out of sight, maybe you can justify it, but your biggest expense even with a coach of your vintage is still going to be depreciation. Personally, we loved our 87 Liberty and had no intent to replace it, but when it was damaged by a fire and we faced 9 months without it, we bought our current 97 45 footer and will never go back to a 40 footer. The changes Liberty made in the 10 model years was significant and despite how much we liked our 87, it just could not compare.

[Mark3101]

I second the notion that you may not see the increase in mileage you are looking for. My S60 usually gets around 5.50 to 5.75 mpg. I have only seen it better if I drive much slower than I the speed limit. If you have a working 8v92, I would think you would be hard pressed to ever recover any of the costs involved in a swap just in fuel. FYI, my 45' weighs in at just under 51000 lbs. and I flat pull a 2010 Tahoe.

[travelite]

Hi Mark,

As I'm sure you're aware, the emissions controls on the later S-60's do have a cost in terms of fuel mileage; nonetheless, Robert made it very clear in his earlier posts that he's a talented fabricator with a complete fabrication shop at his disposal and that he likes his bus and wants to keep it. This is great project and will provide a wealth of information and expertise to the forum. I'm looking forward to lots of pics. Robert, good luck!

[antioch01]

Thanks to all for the great input. I am definately looking at this project with eyes wide open. Having the S60 for 0 $$ is a plus but if I have to swap trannies to a world the cost could be prohibitive. After reading several threads from the Diesel Talk forum it sounds like the world trans is needed. I did some measuring today and the clearance is not an issue. The length of the S60 to the trans looks like it needs about 3 to 4 more inches, like Jon said earlier.
As a plus though the engine rotations are the same.
Another issue I noticed today was the intercooler needed for the S60. More to think about.
I am going to raise it up tomorrow and look at the drive shaft, tag and trans mounts.

[ajducote]

This may have some real information you need. Scroll down to "HardHeadKens" post.

http://www.busconversions.com/bbs/in...topic=12909.15

[Jon Wehrenberg]

I forgot to mention my Series 60 is DDEC III. Mileage figures you should rely on are for those who have DDEC !V. Later versions had different mileage. It may in fact turn out the improvement in mileage may not be so great, but with the Series 60 there is one distinct advantage. While a guy is waiting for the 8V92 turbo to spool up the Series 60 with its low end torque will get the bus and that stacker off the line and moving.

And welcome to POG. I hope you know by now we will always answer your questions, and on certain rare occasions we may actually offer the correct answer. If you don't take any of us too seriously, and don't mind hanging out in this asylum we call POG you will fit right in.

[antioch01]

Jon,
I have run some numbers and if I pulled my small enclosed trailer with diesel VW beetle, I can get about 5.5 MPG and I would not be as interested in the swap. My concern is when I load my stacker (which is what we would like to take out West) my MPG drops to 4 at best. I do run 60 - 65 MPH. If I can pull that trailer and get 7-7.5 MPG I would be happy and say it was worth it. Not to mention the value of the coach would be better. If I do the conversion I intend to make the S60 look factory or better. The issue with the 45' in my mind is the extra 5000 lbs. My stacker is 9000 lbs. but only adds 4000 lbs. if I deduct the extra 5000 lbs of a 45'. So I should be able to get the same mileage and performance as a 45' pulling a 4000 lbs. vehicle.