Sayin' Hi'

[TheMonacoans]

Hi All,
Wife and I just traded our Chevy truck and trailer across for an 89 Monaco motor home. With this set-up I figure I can install an hydraulic tailgate and bring my GoldWing Trike along with us.

Anyhow: Motor coach is a Diesel Pusher powered by a 5.9l Cummins, 6BTA5.9 There is no HP rating anywhere that I can see. Probably 160 or so? Transmission is a 4 speed Allison AT 545. There's an after market over/underdrive transmission by Gear Vender. Sounds like a 2 speed rear-end sorta gizmo? Allows you to split gears.

With only 69,225K miles on it, it seems like a decent rig. I wonder if any of you could give me any insight into any of the components that you have any experience with.

My only diesel experience is the power plants etc. at work. All they do is drone.

We don't get the machine till next week so I haven't had much chance to drive it get any real feel for it yet. Might be wanting to put a little more fire in her.

 

[ameristar1]

Getting power out of the Cummins B series is pretty easy, yet with your situation the thing that I would not do is get too aggressive with the tune.
The easy stuff is all about uncorking every bottleneck in the system. Install the biggest air filter and piping going to the turbo that will fit, and make sure that it has a source of fresh, cold air. Then do the same on the exhaust side: big downpipe and muffler, as large as possible that can fit with an acceptable sound. Install a FASS System for the fuel to make sure that it doesn't starve with larger lines (Bosch VE pumps don't like to be starved for fuel). Now the foundation is good to make more power.
At this point, you have to decide how strong you want to make the combo. Since torque is what you need, with all that weight you're pulling you need a good 650 lb/ft or better at the wheels to make it half way liveable. Good thing that you can get way more than that out of a B series without even trying.
I'd upgrade the turbo, injectors, install an intercooler and tune the VE pump.
Turbo: HX35 or if you want to go aftermarket an ATS Aurora 5000
Injectors: Get a stock set Extrude Honed for a 100hp increase
Intercooler: If it doesn't have one, a liquid to air unit with a high flow pump and roof mounted radiator will drop the egt's nicely and allow more boost.
VE pump: Go conservative on the timing, install a higher rpm governor kit (put a 4000 rpm kit in and hold on) and tune the fuel to suit. VE pumps fuel heavy down low (can be smoky when you hit the throttle), but the power hits hard down low to get all that weight moving.
If everything is tuned right, the power will go way up, and so will the mpg. Plus you won't have to pray hard every time you need to make a passing manuever. Oh, be sure to get a full compliment of gauges (boost, egt, fuel pressure) and learn to drive by them. The lower the boost that can be maintained on the highway, the higher the mpg.

 

[argve]

That Gear Vendors will really come in handy. It's a direct drive 1:1 ratio then it will be an overdrive (I don't know what ratio you have) but once you are on the highway it will be like another gear that can be switched under FULL POWER. My brother has one on his motorhome and it makes his not suck as much fuel (his is a 454 gasser in a 33ft Fleetwood). Should be a switch somewhere to turn it on then after that it will take care of it's self, it will switch in and out of overdrive as needed all by it's little ole lonesome.

As for power I would wait and see how she does then start turning up the power as you need. You might be happy with how she is currently. In a motorhome your not looking to break speed records - it's an enjoy the ride type of thing.

 

[TheMonacoans]

Thanks for the info. We aren't real 'in a rush' types to begin with. I don't plan to go charging into retirement passing everything by....

 

[TheMonacoans]

Well you sure gave me what I asked for! It's good to know it's do-able for a reasonable amount of $$ and labour if it turns out to be necessary. I will keep this info.

Thanks,

Bob

 

[ameristar1]

Thanks for the info. We aren't real 'in a rush' types to begin with. I don't plan to go charging into retirement passing everything by....

Nah, nothing like that. The more powerful you make a turbodiesel, the better the mileage will be and the easier it is to drive. I used to drive OTR with a KW W900 that had a 3406B Cat motor that was mildly tuned and I will tell you it made life easier.
When you get that thing out on the road and the wind and mountains don't affect how she rolls you'll see what I mean. You can set the cruise and she doesn't slow down no matter the grade, no matter the load. That's what makes driving enjoyable.

 

[FordGuy100]

Also, if you plan to up the power, that Allison will suffer. Dont go to crazy, or you will cook it. You can play with the pump some and get it tuned to not smoke much, and have decent power. It will make life in the mountains a little easier.

 

[TheMonacoans]

Pretty hard to argue that kind of logic, my wife might even agree!
Doing it in increments, are there steps I could do without having to do the bigger $$ items? Where's a good place to start?

Thanks miles,
Bob

 

[TheMonacoans]

So, should I take from your post that my tranny is 'the' weak point in my drive-line? Considering that it's a DP make any difference in that equation?
I sure don't mean to push this machine at all, just want enough power and dependability to be able to cruise easy.

Thanks for the info, 3 miles from Silverton, BC

Bob

 

[ameristar1]

Install the gauges first. Then do the intake, filter and exhaust. Tune the pump and install the high rpm governor kit. Drive it around and see how you like it. Watch the egts and drive by the gauges.
The vehicle being a diesel pusher means that cooling is critical since there is not a lot of air circulating around the engine compartment. Make sure everything is up to *****, and change the coolant over to Evans Zero Pressure coolant. It has a very high boiling point, eliminates hot spots inside the engine and will last 10 years. Your mpg will improve slightly also. It's not cheap, but for peace of mind you can't beat it. Put the biggest trans cooler that will fit with a fan (you can't over cool an automatic).
I'd also do the water/methanol injection at this time, just for safety, if it's not intercooled.
The turbo and injectors are not as expensive as you may think, an HX35 Holset is a late model Cummins turbo that can be had for peanuts ($200.00 maybe) and the injectors can be Extrude Honed for 37.00/piece. Airflow and fuel must be matched for best performance, so they should be done together.
If you get an opportunity to take a late model, high power diesel pusher out for a drive, use it as a comparison. The vehicle you have can perform just as well, just without all the electronics.

 

[FordGuy100]

Guage, intake and exhuast. If done right, would be around $750. YOu can then tweek the pump by turning it up some, but not to awful much. The Allison AT 545 is a good tranny at stock levels, but goes downhill once you turn it up. But they go behind DT 466 and they put out more power, so I think doing these simple mods will net you a good increase in power, and it should still be reliable.

Guages involve Boost gauge, 0-30psi should be fine. Pyrometer, to measure eghaust gas tempertures, if you go above 1200* for to long at the exhaust manifold (where you should drill and tap for the thermocoupler, right before the turbo where they all meet up), you run the risk of melting it down. Lastly you need a transmission temperature gauge, cause you want to make sure you tranny stays nice and cool, a hot tranny will decrease the life of it. Go with a name brand gauge like ISSPRO, autometer, extra...you get what you pay for here, dont skimp out.

 

[crashnzuk]

Go with a higher boost gauge than 30. You can max out a 30 easy with a B engine. Get a 50psi gauge so you have some room (my truck will make 30 psi). Guages are most accurate in the middle of their range. Once you get it going and have a baseline of boost and EGTs, find out what exhaust housing is on the turbo. If it is one of the large ones (18 or 21), you can pick up a lot of performance just chaning that one part to a smaller one.
Travis..

 

[ameristar1]

Go with a higher boost gauge than 30. You can max out a 30 easy with a B engine. Get a 50psi gauge so you have some room (my truck will make 30 psi). Guages are most accurate in the middle of their range. Once you get it going and have a baseline of boost and EGTs, find out what exhaust housing is on the turbo. If it is one of the large ones (18 or 21), you can pick up a lot of performance just chaning that one part to a smaller one.
Travis..

You think a 12cm or a 14cm might work well on a big vehicle like this without getting too hot?

 

[FordGuy100]

Yeah but I dont think he wants to put that much fuel through it though, so I would think he wouldnt boost more than 30psi, but then again he might.

 

[crashnzuk]

I bet a 14 would be good, not too small and it would be fairly quick to spool. I also think a boost gauge higher than 30 is a good idea. It would be easy to max out a 30 psi gauge (my truck would, and it's not that cranked), and it really doesn't cost any more to get a higher gauge from the get-go.
Travis..