Mileage expectations with a Series 50 in a MCI 9.

[wissmannfamily]

I am considering a engine switch in my MCI 9 to a Series 50. I have read the previous comments on this subject and yet no one has given any indication of what mileage increases one can expect.  I presently run 35K miles a year and if I can increase my mileage from 6 mpg (current) to 9.5 mpg with todays fuel prices I can save $5-6 thousand annually.  This makes me look at this very seriously.  I would appreciate any testimonies of anyone that has done this swap.   

Loren

[belfert]

This may/may not help.  I have an 11.1L Series 60 in a 43 foot Dina.  I would suspect the Dina weighs a bit more than an MC-9.  I have a B500 tranny (5 speed version), not an HT series.  The Series 50 horsepower isn't all that much less than a Series 60 11.1L.

I got 7.8 MPG when I drove the bus home with a stiff headwind, but my air intake was also plugged so I expect closer to the 9.5 MPG that Busted Knuckle's buddy gets with his Dinas in charter service.

Brian Elfert

[MC7S50]

I get from 9.0 to 11.  Normally about 10.3 if no mountains.  I have an overdrive 10 speed and 3.73 axle.  I drive for economy, not speed.

[TomC]

Sort of a rule of thum.  Start with a mechanical 8V-71N and switch to a 6V-92TA-should be good for about 1.5 better mpg.  Switch to 6V-92TA DDEC, is good for another mpg.  Switch to a mechanical 4 stroke-same as an electronic 2 stroke.  Switch to a 4 stroke electronic and see another mpg.  So switching from a 8V-71N to a Series 50, you should see about 3.5 better mpg.  Personally, I think you'd be money ahead by just rebuilding the 8V-71N into a turbo engine with an air to air intercooler.  You need to put close to 200,000 miles on to see any real savings by changing to the Series 50, which is my favorite engine also.  Good Luck, TomC

[tekebird]

if you don't drive for speed I would keep your stone age simple 8-71 and put the money you would spend engineering the swap into your fuel budget.

of the buses in So Cal that were converted professionally into Series 50's.....they didn't do it for economy although they did see some gains, they did it becasue it was mandated by the government for emmision reasons.

as I recall there was quite a bit of organ transplant rejection issues when they did the swaps...and I think they were the tune of $50k each of course that included a new series 50.

I was looking at a A3 with a 50 transplant (one of the california mandated swaps) sopke to it's original owners maint director and he hated them...from a maint standpoint and he said they vibrated the back of the bus much more than the 2 strokes at highway speeds.

[Buffalo SpaceShip]

Fuel you pay on the installment plan. With the engine and tranny swap, you pay up front and wait for the savings to come back to you.

You'll have to ask yourself a few things:

• How much cash and time do you have for the swap?
• If you take both estimates and double them (not unheard of)... will it still be worth it?
• Will you hire it out or do it yourself? Changes the cost considerably.
• How long can you bus be down for engineering/ refitting?
• How long will you keep your coach?

HTH,
Brian B.