Possible driveline update OM352A to OM906LA

[Christian]

The 900 series develop peak hp at 2200 but they are happiest cruising at 17-1900 rpm. Over 2100 is ridiculous. 2600 or 2900 is even worse.
I’ve owned one for 15 years.

I hoped you'd reply, I know you have one. The 100km/h is illegal anyways here, I can go around 90km/h without getting pulled over instantly. The big rigs go down the freeway at around 86-88km/h. That'll put it at around 1,900, so that sounds perfect.
The OM352A will go at 2,900 all day, but noise and fuel consumption is horrendous! If I keep it at around 75-80km/h it's a lot more civil, but that's too slow, and the big rigs will try overtake you all the time.
So to me it sounds like it'll be er good match?

Having spent a lot of time driving a truck with the om906 and G85-6, I'd agree. It's a nice refined package, but at 2,100 rpm you can tell it's working hard. I had no qualms about pegging it at 2,100 on steep grades, but fuel consumptions goes skyward and it makes a lot of noise. 1,700 rpm is perfect cruising speed, but it's certainly down on power there, and you won't be able to hold grades in an 11 tonne truck at that engine speed.

Remember I come from 168hp, and 423nm with a very narrow powerband. My truck has a registered GVW of 7,5T

We have a 906la with an allison b300r in our bus.
5th gear 2100 rpm at 55mph.. have not driven with the 6th gear unlocked.
Very nice engine..420000 miles, no smoke , no leak ..gave us 9 mpg on a 9000 miles trip with 22000 lbs and a toad.

That all being said.. just swapped an TDI in a 404 unimog and it takes a long time. Life is fast and short.
Better to first finish the conversion , take it on the road, have some fun and then start hacking if you still feel like it.

Good luck,
Johan

I get your point! And it's a really good one. I might do that.

I used to jump head first in to projects. and often ended up bumping my head several times. I try to be a bit wiser and plan ahead now. I try to plan projects, research, sometimes I drop them, because there's a better way, or the end result isn't worth the effort.

In this case I originally planned on updating what I had. First a new gearbox to lower rpm, there's a guy who does a S6-36+GV36 gearbox conversion, not simple or cheap. Then I found the G56-6, simpler, cheaper, but I'd need a custom bellhousing and custom clutch. Then I'd look at updating turbo, adding an intercooler, that would possibly make the OM352A run hot, so better cooling, you get the picture, I'd be chasing my tail all the time, trying to achieve something I get in the OM906LA/G85-6 package with less effort.

I ask your advise to get a sanity check, If the answer is positive, I can start looking for parts, and plan the details without rushing, and keep an eye out for the perfect offer.





My point is, I might not do this right away, but an important step for me is maturing the plan and get some peer review, since I know my abilities to convince myself that what

 

[nick disjunkt]

I'd say that if you want more speed and power, there's not much to recommend against the powertrain you've chosen. It's reliable and efficient, without being overly complicated, and you can get a running 1823 truck in decent condition for less than € 5K to take all the parts from. For sure there is added complexity over your original engine, but that's the price you pay. I managed to get a cheap Mercedes Star/Xentry diagnostic system off eBay to work with my truck, which was very helpful. For an overland truck I'd try to make sure whichever donor vehicle you get is one of the earlier Euro 2 or 3 chassis without emissions equipment. My Euro 3 truck had no EGR, DPF or SCR system.