2011 Sweet Spot

[LSI]

Where is the sweet spot on the 2011 Mp8 485hp 1750ftlb?I have been following the fuel mileage on other web sites and it looks like trucks with the 3:58,3:73 and maybe the 3:90 get the better fuel mileage than the ones with 3:32 or 3:42.It also appears if you lower the hp from lets say 515 with 3:55 to 460 or 485 and lower the ratio to 3:73 to 3:90 the fuel mileage goes up.I think the Mack sweet spot is higher than the ISX.Mine is about 1350/1400 with 515hp and 3:58's and 13spd.I am at 1350rpm at 62mph.Performance wise the 427 and 460 pass me all the time.The 350/400 run faster on short hills but I will pass them on longer hills,like 3 miles.

I have talked to maint managers of a few large fleets and they indicated no problem with the DPF or EGR on the 2010 or 2011 and the 2011 gets better fuel mileage.If this is true They won't be able to keep up with the demand(when this gets out) from fleets changing over.But a lot of drivers don't think the trucks are cool like the Petes and KW's. and the Macks are at a higher price.But cool doesn't pay the bills,Right?

Try to sell me on Mack!

Edited June 5, 2011 by LSI

[Mackpro]

I wish I had wrote down all the specs and tips on MPG and power I heard when we had a Mack engineer at our shop. I will talk to our Boss and sales guys and see what they say. Best I remember they talked like running a rear gear ration real high and getting the RPM down as low as 1200 or just high enough to cruise down the road. I really need to ask them and write it all down again.

[rhasler]

Read this morning that volvo ran a VN670 with D13 (MP8) against an International Pro-Star+ with Maxxforce13 and saw a 4% fuel economy (or "fluid economy") advantage, including the cost of DEF, over the International. The test was performed as follows:

These trucks were spec’d as closely to each other as possible. Each tractor

accumulated over 6,000 miles in identical operation. The test travelled the same

roads at the same time in the same weather and terrain. Trailers were identical

with identical payloads. Fuel was pumped from the same tanks and temperature

compensated. Test tires with identical tread depths were used. Cruise speeds

were GPS-calibrated to accuracy within a tenth of a mile per hour.

I would expect at least as much from a Mack.