Cummins ISC 8.3 Turbo w/Allison 3000

January 20, 2014, 03:48:55 am

Just ran across this article where the question was asked of Banks about the ISC Cummins with the Allison 3000 series.
Thought it might be of interest to our hot rodders.
Dave M

Here is what Banks answered when someone asked about using their products:

Quote:
We have two levels of products for ISC powered motorhomes, the Stinger and the PowerPack. The PowerPack offers a gain of about 119 HP and 284 lb-ft torque, but is only intended for use on vehicles where the ISC is mated to an Allison 3000MH. The 3000MH is rated to handle 1200 lb-ft and 400 HP at the input shaft. The Stinger is designed for use on vehicles with the MD3060 or MD3066. It is calibrated to not exceed the maximum torque capacity of those transmissions, but to optimize the performance of the engine to achieve the maximum torque value through a broader RPM range. A look at the torque and power curves in our literature will make that more clear. The MD3066 is rated for somewhere between 1100 and 1250 lb-ft depending on how you read the spec sheets, and 370 HP. The MD3060 is rated for 935 lb-ft and 310 HP (recreational tow vehicle spec). This presents a problem even before you start considering power improvements; if you have a 330 HP ISC mated to an MD3060, your engine already has a HP rating that is higher than the transmission's rating. How do they get away with selling a new vehicle that has this mismatch of ratings?

I can't really answer that question (which is more or less the issue that
this person raises), but it does force us to look at some other issues.
What really becomes the point is not so much the horsepower ratings as much as the torque ratings. Allison transmissions are pretty much invulnerable, but their weak link is large amounts of torque under heavy load. A classic example is a garbage truck. Those vehicles are under heavy load all the time, because they are constantly accelerating from a stop with a large amount of weight, always repeating the process. I have been told that the majority of failure problems with Allison transmissions occur on garbage trucks for this very reason. Allison and Cummins use a strategy to prevent problems with excess torque under these high load conditions in vehicles equipped with an ISB or an ISC. In 1st and 2nd gear, before the torque converter clutch is locked (which is when torque will be highest due to torque multiplication through the unlocked torque converter), power is
de-rated in the Cummins electronics to prevent the occurrence of high torque loads. This de-rate of the power is actually quite evident to the driver of one of these vehicles. Since our electronics are essentially an overlay of the factory calibrations, this protection phase is preserved when our product is active.

The two different products (Stinger and PowerPack) are offered to
accommodate the three different transmissions and their ratings, but in
reality, the torque capacity is much more important than the horsepower
ratings, as Cummins and Allison have demonstrated by ignoring those ratings in some cases. The nature of the calibration in the Stinger is available to offer peace of mind to those ISC owners with the MD3060 or the MD3066. As a sidebar, if I were the owner of an ISC with one of these transmissions, knowing the durability of the Allison units and the way they operate, I would consider putting the PowerPack on even though that is not the recommended product. In all my time working with customer service issues, I have never known of a situation where an Allison MD3060, MD3066 or 3000MH had any kind of a mechanical failure, with or without power enhancing product.

________________

Re: Cummins ISC 8.3 Turbo w/Allison 3000

Reply #1 – January 20, 2014, 07:34:18 am

Interesting, I had a 350 hp 8.3 with the 3060. It was a bit slower in first and second but still ran fine.

Re: Cummins ISC 8.3 Turbo w/Allison 3000

Reply #2 – January 20, 2014, 09:57:23 am

Interesting to note that Foretravel used a 400hp ISL with the MD3060R in U295's in 2003 or thereabouts...
Don

Re: Cummins ISC 8.3 Turbo w/Allison 3000

Reply #3 – January 20, 2014, 10:43:19 am

Quote

The MD3060 is rated for 935 lb-ft and 310 HP (recreational tow vehicle spec). This presents a problem even before you start considering power improvements; if you have a 330 HP ISC mated to an MD3060, your engine already has a HP rating that is higher than the transmissions rating. How do they get away with selling a new vehicle that has this mismatch of ratings?

It's been my understanding that not all the horsepower will get to the transmission. You have to subtract all the loads for the hydraulic pump, alternator and air conditioning compressor. My guess is those loads can range from 20-50 hp.

Foretravel Owners' Forum For owners and Fans of Foretravel Motorcoaches September 10, 2025 ...