I never felt our m11 drove correctly power wise. Too many other high line coaches I have driven had a less revvy higher torque feel to them versus this coach.
But never having driven another m11 myself and being out of the Rv biz by 1997 made any driving opinion suspect.
But never felt "right" somewhat disappointing.
So I started going through every part in the engine compartment. If everything was as good as it could be that would be fine but sad.
52 months later I finally got what I like/wanted in the driving power of the coach.
Originally the coach would downshift every time at large throttle inputs. Revvy. Wrong for a large Diesel engine IMO.
Hmmm. And as it revved out it was not faster. Typical large Diesel engine is where the torque makes the coach accelerate faster than the rev out hp does. Not this one.
Hmmm.
Had to fix the bad stuff first. Winn system. Cam position sensor. Altitude sensor upgrade. Adjust valves and injectors.
Still down on power on the cummins dyno in Los Angeles. No blowby.
Limited power upgrades on a m11 celect plus. Too old. Replaced by the ISM.
the help and info here made my project possible. Thanks to everyone.
I have no idea for sure what of my changes could be eliminated and not alter the results but I doubt that the results would be the same if any steps skipped IMO.
Had the local cummins shops expert welder remove the oem muffler and install and 5050xl resonantor. Beautiful expensive job.
Helped but not done yet. Added a Donaldson blue foam airfilter after the Pittsburg power guys mentioned it helped on their web site in these.
Intermittent large RMPG increases on flat non windy roads got my interest up. Why?
Turns out Foretravel opted for a low temp hydraulic fan controller. Full max fan speed at 180 degrees. 40 or more hp continiously drawn off the engine if warmed up.
Never got a straight answer from the cummins guys as I think they do not know the answer to my temp questions.
My thought was that the engine will not produce full torque if not fully warmed up. No one to ask on 20 year old stuff.
Found a beaver owner selling a new 199 degree hydraulic fan controller off his c15 cat on Craigslist.
Had the cummins shop install the controller. And had the alternator rebuilt as the LN had a bad diode and bearings.
Less power off the motor.
270 watts of solar make the alternator work less when driving during daylight. No residental refer.
Left Orange County bound for sequoia Sunday. Two electric bikes on a rear rack and a Toyota Solara convertible tow car and full water and fuel. Full gvwr.
New Michelin xza-3+'s at 90 rear/100 front. No alignment issues. No dead spot. No truck sway at all.
No brake pad drag.
Ahh. Coach now torques harder in each gear. Pulled in the mountains at lower rpms without downshifting.
Agressive throttle made the coach accelerate in the higher gears without downshifting. Wow. Real torque.
At 7,000 feet in the Sierras the coach would accelerate up grades without downshifting and at medium throttle. Never floored.
Totally different drive.
Also like every big Rv I have driven I think this was was not broken in yet.
Sounds crazy but the truckers mentioned that their m11's did not fully seal up until 150k miles.
That's at 80k weight.
Round trip mpg was 7.6 and I mostly was at 68 mph.
Flat ground at 68mph showed 9.5 RMPG. S!ight downhill, on I99 out of Bakersfield headed towards Los Angeles showed 10 RPMG.
Full power up grapevine showed 52-54 mph with trans in non mode operation.
Engine temp never hit 220. 92 degrees ambient. Engine temp is noticeably lower. I assume the oem muffler made it run hotter from the high back pressure.
Yes it's noisier. Sharper toned.
Better mpg, lower temp, much better torque,
If I was not towing and no wind sucking bikes on the coach I think it would get 10mpg pretty easy.
Funny enough the RMPG got better at 68 or 69 versus low 60's. I think the engines torque and hp curves and Foretravels rear end gearing are perfect at 70.
Yes I know that's not possible as you lose 1 mpg from 60 to 70. Unless the motors more effecient at 1450 rpm than at 1300.
Tested this a half dozen times. At 60 I got 8.5 RMPG. at 68 I got 9.5. You tell me.
All the pieces together worked out.
The exhaust work may be part of this as the welder used better flowing curved sections versus flex hoses. Maybe.
Not sure why and what contributed, slightly higher temp allowed the ECM to allow more torque? Less loss at norms temp from the lower power consumption from the fans higher temp max speed?
Less restrictive air filter? Lower power consuming tires?
How does my numbers match up with other owners is necessary.
Quite possible every other one always drove like mine does now? No way to know.
No reason to ever sell this one.
25 pounds max boost revved hard.
I assume the turbo and injectors are ok. But who knows for sure. Not worth the time and money so far to have them checked.
Hope this helps someone. Almost said nothing. My secret.
Sounds great Bob - I love the 5050 Aero too, nice work on the detective stuff.
Hope the replacement filter doesn't let in more dirt like a K and N - more air (specifically oxygen) = more power but in the case of the K and N it also = more dirt, causing more than one expensive overhaul
Keep riding and rejoicing!
Bob, what is your rear end ratio? When I went out in march I found that my coach would not go into 6th until 62-63 mph. could that be the reason on your coach for better mileage at 68?
The Donaldson website shows a 90% reduction in passed abrasives using the finer weave "blue" filter.
Well aware of the k&n issue. Last ten years I have been building KTM four stroke dirt bike engines as a hobby biz.
Same as everyone else's. 3.91.
The trans shift points are adjustable by a dealer. My cummins shop asked if I needed it. No.
I think the oem muffler was that restrictive or rusted up inside or both that it killed the engines power and made it run hotter,
And the fan controller sucked 40-50 hp from the motor every time it got to 175 degrees.
Vpms temp indication on my laptop shows a four degree temp increase on flat running conditions. 175 to 179.
At 179 the fan controller is at "idle" speed not off. So the charge air cooler is getting enough volume through it to work correctly.
Intake manifold temp runs roughly the same as before the controller change.
Hard to wipe the grin off my face driving the coach in twisty, turny mountain roads.
Plus the mpg.
15-20 degrees cooler engine temps up the tejon pass floored. Couple of miles per hour better.
I assume that is the back pressure reduction.
Pulled out many times to pass trucks that were running 65 or so and the coach easily pulled to 73 or so.
Before the changes it would need to be floored and slowly pick up speed. Not does it at part throttle.
The benefits come from using nanofiber rather than cellulose. I've been using one on my FT for the past couple of years but can't say that I've noticed any huge increase in power.
http://www.donaldson.com/content/dam/donaldson/engine-hydraulics-bulk/literature/north-america/donaldson-blue/F111411-ENG/Donaldson-Blue-Air-Filters-Off-road.pdf
Probably a small increase but enough for Pittsburg power to show it as an power improvement for a m11 on their website.
Your 8.3 sucks less than a m11. May or may not be a factor. It's a system. Everything works together.Be an interesting test to swap back and see some day.
trans seemed to run cooler using the retarder hard. 223 or so max. No idea if correct or why.
Less hot engine makes the trans cooler work better? Probably. Win/win.
Someone asked me what it took to change my m11 to an ism. I did not do that.
Csn be done but the change would run $15k or so.
Bottom end is the same. M11 red top has the stellite valves and the block supporter at 450 hp the ISM has but the head, cam, turbo and injectors would need changing.
Much higher pressure injector system and a variable turbo on the ISM.
Lots of EGR complaints on the later motors. Enough that the trucking industry is building new trucks without motors and instilling m11 engines rebuilt in new trucks. Gliders is what they are called. Big volume