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koda59 · 10-21-2020, 06:30 PM

When I was at the Cummings dealer picking up some filters, I asked about have my HP raised to 450. They recommend no. I then asked about 425 and again they said they do not recommend it. I am already at 1250 torque and all I would gain was less MPG. The 3000 transmission is already maxed out for torque.
Gaining 100 FT torque is self defeating for cost to expected improvement.

Ray,IN · 10-21-2020, 08:59 PM

It is what it is, accept slowing down on hills and driving 60-62 MPH. The only other option is getting upside-down on MH loan.
Concerning your Escalade, look at the Motorhome towing guide to determine if it may be flat-towed. It will not accumulate miles on the odometer while being towed.

Ray,IN · 10-22-2020, 04:03 PM

FWIW, virtually all aftermarket "tuners" will void the factory warranty.

Pnakhoul · 10-22-2020, 04:22 PM

I was told this morning by my local Allison shop that they make variations of the 3000. Some are maxed. Some have more leg. Some can be adjusted. Some can’t. This is a 21 mh. Most of the time the guts stay the same but I’m going to find out for sure before making an assumption. I was told by Cummins that even a 100 foot pound of torque would be felt and could be the difference between doing 40 up a hill or 55. The majority of my travels will be in Colorado. I was there the first two weeks of this month and encountered hills and trouble passing ( at almost 63 feet long ) others multiple times a day. There are also a ton of 10 mile+ 2 lane roads where I’m holding up 25 cars because of trouble going up hill. If I’m not mistaken, the 44B is a tag axle with the same motor, Allison 3000 and is pushing 450 hp and 1250 pounds. At the end of the day if I’m unable to get the upgrade or if the upgrade doesn’t do at least 50% better for me than I will chose another coach. Sucks but I know for a fact that if I don’t enjoy driving this then I will go on many many less vacations.

BillJinOR · 10-22-2020, 05:22 PM

I can almost guarantee the 100 ftlbs won’t be 50 % better. Sounds like a new coach is in the wind. I’d do that and forget the 3 grand experiment. Good luck with whatever you do.

jcussen · 10-22-2020, 06:40 PM

Had a 99 coach with the ISM 450 1450 ft/lbs torque, got the cummins reflash to 500 hp and 1550 ft/lbs. Found it had slightly better acceleration in 2 and 3rd but on a 6% grade in 5th, would only maintain about a 5 mph increase in speed at a higher rpm. I do have a pyrometer and boost gauge so I can see when engine is overloaded. Towing 10000 lbs, would want in a new coach at least a X-12 or X-15.

MrAlexander · 10-22-2020, 08:16 PM

If you have an Allison, it should be a 3000MH series which can handle the 450 HP and 1250 lb-ft from the Cummins L9's maximum uprate. While the peak torque only moves up by 100 lb-ft, there is a much greater improvement at higher engine speeds. The maximum difference in torque is at 2100 RPM where the 450 makes an additional 205 lb-ft which is also an additional 82 horsepower available or about 22%. At normal cruising speeds, you are probably going to see more like a 10% improvement. So, it isn't a small increase but you also have to consider that you are in a very large vehicle and even that considerable increase isn't going to make it climb mountains at the speed limit fully loaded.

Pnakhoul · 10-23-2020, 02:46 PM

Quote:

Originally Posted by MrAlexander

If you have an Allison, it should be a 3000MH series which can handle the 450 HP and 1250 lb-ft from the Cummins L9's maximum uprate. While the peak torque only moves up by 100 lb-ft, there is a much greater improvement at higher engine speeds. The maximum difference in torque is at 2100 RPM where the 450 makes an additional 205 lb-ft which is also an additional 82 horsepower available or about 22%. At normal cruising speeds, you are probably going to see more like a 10% improvement. So, it isn't a small increase but you also have to consider that you are in a very large vehicle and even that considerable increase isn't going to make it climb mountains at the speed limit fully loaded.

Thanks. I’ve been looking to see if anyone had some data like this. I’m going to give this a shot. If its not any better then I will go back to the last resort of renting a car at my destination. I wish I was full time but I’m not anywhere near that with a large family of small kids. I would that if I trade this 21 discovery LXE that I would take at least a 40k loss even after buying it at invoice. IMO for the 40k, I can rent cars for the next 5-7 years and make my trips quicker as I won’t be towing anything.

fagnaml · 10-23-2020, 03:50 PM

Pnakhoul --

Welcome to the forum! There are many great forum members willing to provide help at any time.

Per the sales brochure for your coach, you have a 380 HP Cummins IS9 engine with an Allison 3000 MH transmission. Your coach is very similar to mine in length except I have a 360 HP ISB engine with the same transmission. Your coach's GCWR is 46,400# compared to my GCVR of 41,000#. We both have a similar GVWR of ~$36,000#

I have no problems towing my 4,000# Jeep Wrangler Unlimited but I do know it's behind me. Your Cadillac Escalade from what Mr. Google says has a curb weight of ~6,000# which shouldn't be a problem for your coach. However if you are towing it in a 4,000# trailer pushing the total weight near 10,000# I think the capabilities of your coach of your coach would be stressed.

Presuming your Escalade is a a two wheel drive model, it can not be flat towed. However, in lieu of putting it in an enclosed trailer, an option to investigate is modifying it to be flat towed by installing a "drive shaft disconnect" device such as this one --> https://www.remcodsc.com/ The drive shaft disconnect would allow your Escalade to be flat towed saving ~4,000# of towing weight.

If you choose the drive-shaft disconnect modification, there are several options to protect the Escalade from rocks, etc. that could be "kicked-up" by your coach including rock deflection shields, front bra, windshield protector, etc. --> https://www.amazon.com/Camco-45401-V.../dp/B0024ECGZC

Hope this info is helpful! Enjoy your coach and let the forum know what you decide to do.

Finally, I guess I don't know "everything" about Texas geography. Where is Shavano Park located?

**pasdad1** · 10-23-2020, 04:20 PM

If it were me I would simply have the wife follow the motorhome and drive the Escalade. You say you are only gone 5-7 days on a trip, so hopefully only 2 of those are driving days.....otherwise you aren’t getting to enjoy your trip.

Much better than renting.....much better than towing 10K pounds. Don’t worry about the highway miles on the Escalade.....that big engine is hardly working cruising at 65 on the highway, and 200K+ miles is no sweat ....you don’t need to be worried about wearing it out.

Ray,IN · 10-23-2020, 05:38 PM

Allison Transmission specs. Now you know the standard torque and HP limits of their transmissions. There is a retired Allison engineer who posts in the Allison transmssion forum and freely offers his advice if you are interested.

grantmnc · 10-23-2020, 06:07 PM

Stupid question, but are you keeping the RPMs up on the motor when pulling the hills. I noticed much better performance when I downshifted to keep the RPMs up I did much better on the hills.

Kenvb · 10-26-2020, 10:19 AM

wow.. 500 some HP we have older 5.9 Cummins with 190 HP and the 4 spd Allison. only pull 2500 lb 4 dr Suzuki tracker and it slows down on hills..but who cares..we not in hurry.

JohnBoyToo · 10-26-2020, 10:52 AM

I think the cheapest and quickest fix for you is ....
patience

I know, I know... believe me I know - both the wife and I drove sports cars coming into the coach, so it was a big adjustment... her less than me, since she drives it like a grandmother she's so tense when driving

After patience, as you learn your coach, you will get to anticipate the driving style you need... accelerate before the hills and keep rpms UP...

Consider lessening your weight in coach and toad... get supplies closer to your destination so you are not hauling around 1000 lbs of food and drinks

Getting rid of the trailer and maybe get a smaller/lighter dolly for the toad? or equipping your car for 4 down seems next in line...

Driving the toad separately sounds like a non-starter with all the kids in the coach and you trying to drive without someone to tend them

good luck and be sure to let all other potential buyers know the concerns you have...