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CNG Retrofit
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I just read all I could find on the Volvo engine. There is a D13 and a D16 and they couple it to a fully automatic 12 speed transmission that they call the I Shift, controlled by a joy stick looking thing. Has D, N, R and manual where the driver can select the gears.
There is a testimonial from some trucking out fit that hauls 80,000 lbs with the combination and gets fleet wide average of 8 mpg. Now the guy I met and his mileage, maybe he travels light, after all it was specialized stuff that he carried and as an owner/operator he may well be extra careful with the vehicle but, suffice to say it apparently gets very good mileage. As for reliability, I haven’t a clue.
Wonder if the Volvo powered Prevosts have that I Shift……
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I am not sure if Prevost would put the ishift in, but I wouldn’t want it in my motorhome. The Allison is much smoother shifting and I see no reason to change. Granted, in trucks, the automated mechanical boxes work fairly well. We had 50 of the ZF-Meritor 12 speeds and they were a challange sometimes. They needed a voltage doubler since they were based on European specs (24v European vs 12v US) and these failed repeatedly. The TCU would also crap out more than it should. Even the shifter / paddle lever was troublesome. If I was still in the trucking business, I wouldn’t do the ZF-Meritor one again.
I can believe 8 mpg on an 80,000 truck that is driven properly.
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Arrow is testing the new Allison T-10 in some buses it is smooth as a baby behind a fully automatic with dual counters shafts they seem to think Allison has set a mark for Eaton and Z-F to try and climb,he has one of the T-12 Allison that is not in production yet it was nice behind the DD-13 in a MCI
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I currently have a 2013 X3-45 Prevost with about 18k miles, it turns about 1500RPM @ 65mph and I get 6 mpg consistently pulling a GMC Acadia.
The major differences that I have noticed with this engine compared to the series 60 in my last two Prevost coaches is that it is quieter, smoother at idle and has a lower center of gravity.
My opinion mileage is slightly worse, pulls about the same, costs more to operate (DEF), reliability about the same.
FWIW As far as RPM/speed Prevost offers 5 different rear axle ratios which will effect these numbers.
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The scuttlebut on the DD13 is that the compound turbo never produced the real world performance improvement that theory suggested. I think DD at one point advertised a 40 hp gain with the compound turbo. My DD mechanic tells me that Detroit Diesel Allison Service Centers often disable the compound turbo due to maintenance issues and the lack of real power gain.
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Jemcnx,
Good to see real world numbers on the new Volvo. I see tons of these trucks on the road and haven’t seen any stranded on the side.
As I’ve mentioned in a couple of threads, we are thinking of having a new Prevost bus built and I don’t want a headache with a new powertrain. There are certainly a few Cummins that bit-the-dust early but there many more that are reliable and strong. I would assume every engine manufacturer will have a few duds.
MM.
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One will never be able to compare the D13 Volvo to a DD13 thats not going happen in a Prevost Volvo is what you have in Prevost now.
Arrow tells me the 407 Setra’s they own are by far the best on fuel with the Mercedes/Benz OM471 engine 7.8 average, it looks like a revamped DD13 to me
The OM71 with 510 hp has 2500 lbs of torque at 1100 rpm it makes I 17 from Pheonix to Flagstaff seem like a flat section of west I 10 a super quite engine for it’s size I was impressed with the OM471
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2500 # torque?? I really question that number. What displacement is that engine. If it is 510 hp, I see no way to get that much torque out of it. Also, most transmissions would not handle that much…..
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The newest Mercedes (Daimler) heavy truck/bus engine I can find is the OM473, 15.6 liters, 625 HP, 3000nm torque (2200 and some change in foot pounds). I would venture to say that the 2500 number is for newton meters, that would put foot lbsat a little over 1800 which is more in line.
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