Mercedes MBE 926 Motor

[Warpath]

I mentioned this in another thread, but figured I post the full story here.

From the day I drove my rig off the lot I have been disappointed in the power of my Mercedes motor. I had alot of travel plans scheduled last year and with the delay in getting my rig which was do to a blown head gasket on the brand new motor, I did not get a chance to get it in to service to see if something could be done.

Finally got around to driving the rig to a W.W. Williams to have them plug the motor into there computer and see what options I had. Normally I could have given them my serial number off the motor and they could have told me over the phone, but some loser put a hokey computer sticker over the Mercedes motor placard which read Motor Rating = 300 hp. I should have known something was up with that when I saw it, but what ever.

Anyway it turns out that someone put the wrong motor in the truck, should have been 300 but is 280, still don't know if it was Freightliner or Detroit's fault, but Detroit is paying for the parts & labor to have the motor rated to the original 300 hp. Which is actually just a injector change and a re program from what I have been told. I don't believe anyone anymore.

The reason I say this is because when WW original thought it was the 300 hp version of, they said I could have it turned up for $400 with a reprogram. Now I am being told that the 300 hp version and the 330 hp version would require a block change, since the 330 version has a additional water jacket in the block for the water cooled turbo.

The funny thing is that now that I have uncovered the real motor spec info located on the motor in 2 locations they both read 7.2 liter 330 hp / 1,000 ft-tq at ?? rpm (can't remember what the rpms where). So I don't understand that, and no one can tell me why it has this info on motor.

One thing that does seem to be consistent is that everyone I talk to at Detroit says that the motor even rated at 280 should be a pretty stout motor for my application. And I do have to say that from 5 mph up 50 mph it is very good. But from 50 to 70 mph it's a dog. 70 to 75 are very good even in the mountains.

So next Monday I will take in to have the work done and I am also having it dyno'd to make sure it is what it is.

The thing that bugs me more than anything is that if I would have done my own checking I would have found out that Freightliner was making changes to the M2-106 to accommodate bigger motors. Changes that my truck received and for an extra 2 grand I could have had the 330 hp version motor and not had any power issues.

So as I go through my Harvard education in truck conversions, learn from my mistakes.

Next week I'll let you know if a true 300 hp motor is sufficient power for a motorhome conversion weighting in at 30,000 lbs

[Marc]

Hey Warparth,

The whole mess sounds like a complete circle jerk. Did you purchase the truck from the dealer and then have the conversion done?? Or did the truck come from the conversion company?? If you purchased the truck direct from the dealer what does the Line Sheet/Build Ticket say in regards to the motor model etc.etc.???? If the Sheet/Ticket reads that it is the bigger motor when in reality it is not, I bet you could get what you were led to belive it was for "FREE" This whole thing sounds
like "One of Two Things/Cut & Dry" and they would be: "HONEST SCREW UP OR FRAUD" I have heard of this in two other
incidents but not in as much detail as you put it.If you do not get what you want, ??????Might be time to Lawyer up???????

Good Luck & Keep us Updated

[Gary Atsma]

Like I said before- I would be P----D to the max if it happened to me, just as Warpath is, I'm sure. It does sound, however, like Freightliner (or Daimler-Chrysler) will make good on it, as they should. Best of luck to you on this fiasco, Bill, and please keep us posted. It IS appreciated!
Gary

[Wick]

We had a similar thing happen when we bought our first bus style motorhome. We were told over the phone that it had an ISC Cummins in the coach and when we drove down to Florida to pick it up we discovered that it had the ISB. Quite a difference in size and hp. The coach had stickers for the ISC on the outside but when I lifted the bed I saw the ISB. I have had the ISB engines in my yard tractors so I was very familiar with them. I pointed this out to the salesman and he did not believe me. It wasn't until we threatened to leave without the coach that he checked into it. Seems that Monaco ran out of the ISC engines and at the time just started offering them in this coach so they put the smalled engine in and never changed the markings. We were able to get another coach a few weeks later like we had ordered and made them deliver it......
Just shows you never know.....
Wick

[Warpath]

The truck goes in tomarrow night to get the motor updated.

I let ya know what happens

[Warpath]

O.K. Here is the update. Motor received new injectors and program update to get it to the 300 hp & 860 ft/tq, my rig weights (approx)30,560 lbs. towing a jeep wrangler weighting 3,300 lbs. Total = 33,860

Got a chance to run the rig on a rolling stretch of turnpike for about an hour and here are my thoughts.

First take off from a stop has improved about 25%. Still slow to launch but not bad, and not even a issue to me. It's a truck.

From 5 mph on up to 55, about a 50% improvement. Now I get the feel of the motor pulling pretty hard, don't care how good you are at shifting a manual there is no way your beating this automatic. If required you can really lay into it and it will get to 55 surprisingly fast.

At 55 to 65 mph which was the main issue, about 90% improvement. Awesome! Got a chance to hit a decent long grade and no issue anymore holding speed as well as slowing on the hill and than building speed back to 65. I am really happy with the improvement here.

I find it very hard to believe that a 20 hp & 60 ft/tq increase could make this big of a difference. I have to imagine there was some other issue.

I did contact Detroit (many times and many different individuals) about pushing this motor to 330 hp. I have been given a number of different answers to this question, which really pisses me off. I hate when people are not straight up honest with me.

Sifting through all of the BS I have been given, here seems to be the answer. It can be done with new fuel nozzles, unipump, turbo, cooling lines & ECU update. But Detroit will not authorize it unless the motor is out of warranty. They won't even do it if you told them you wanted to cancel your warranty.

I will say if this rig runs as nice as it does with 300/860 it would be awesome with 330/1000.

As some of you have on your rigs I will be adding a engine monitoring system next week which will monitor everything from rolling MPG and torque to trip info and engine diagnostics. The diagnostic feature is what I need right now, since I didn't get down the road but a few miles and the dang check engine light popped on. At least I can determine if it is a big issue or something that can be handled on the next service.

More info on the unit here --> VMS

I will be running the VMS 240 CL and will give a full report in a few weeks.

[DrFun]

Thanks for the update, Bill!

FWIW... I got the same story from my Freightiner dealer... no engine upgrades after the truck leaves the factory.

I kinda wish I'd splurged for the 330/1000 option when I spec'd the M2. Oh well.

Did you find out if any changes to your Allison 3000TRV would be required if you upped the engine's peak torque?

As a cheaper alternative to the VMS unit, consider the CANTrak. I don't have one yet so I don't have any user experience to share. But, the price is attractive at about $400.

[Gary Atsma]

Hey Alan-
While 330HP is always good, I have a feeling that your unit should fairly well fly down the road with 300 HP, especially not pulling a trailer. That is gonna be a FUN rig to drive, I'll just bet. I'm looking forward to hearing more about your new rig! Upon seeing the pics, I feel justified in thinking about doing a rig very close in size to yours. The main difference for me will be in the truck used, probably a used Freightliner FLD112 or 120, or Century Class 112 or 120, either one with a 38-48" sleeper with captains chairs, sorta like an extended cab. One question- What is the Cab-to-Axle measurement of your truck? Thanks in advance!
Gary
PS Hey Bill, glad to hear the rig is up to snuff on power. It has to feel GOOD!

[Camping Dutchman]

you need 450hp, no issues

[Gary Atsma]

you need 450hp, no issues

You and I BOTH know this, but hey, these guys already have their trucks, must live with the limitations inherent to them, thus must somehow feel good about their decisions. I'm only trying to help.....a little......(uh oh, here come Bill and Alan to kick my butt...;-)
Gary

[Warpath]

No butt kicking here, I totally agree a 450 hp motor would be ideal. My issues with the first conversion was it had to long of a wheelbase and no over the cab bunk room. So my best option to solve this was to use the M2-106 chassis.

Unfortunately it is horsepower is limited. And for me at that time it was 300 hp. Now 330 hp.

For someone trying to make a decision on what chassis to use, in my opinion if your using at a motorhome and live anywhere but in the mountains I would say the M2-106 with 330 hp would be a great choice. But for racers towing trailers and traveling extensively along with anyone prone to be in the mountains often, you have to go with the a bigger chassis and bigger motor.

We'll be doing some mountain travel this year and although I won't be winning any races, at least now I will be able to maintain the speed limit it most cases.

[DrFun]

Originally posted by Gary Atsma:
One question- What is the Cab-to-Axle measurement of your truck? Thanks in advance!
Gary

Wheelbase: 210"
Cab-to-axle: 144"

[Gary Atsma]

BOY am I glad WE have a sense of humor!?!?!
Actually I couldn't resist, and am glad butt is still intact......
Carry on........
Gary
PS- OHH!! and thanks Alan for the info! I was curious, 'cuz the rig looked pretty balanced. Again, NICE!