I am looking into purchasing a used motorhome. A 1992 30' Barth has interested me, but I'm uncertain about the 160 Cummins deisel engine having enough power for the 30 foot motor home. Can anyone enlighten me as to the difference in performance and power between a gas and the 160 Cummins deisel engine.

Hi Pooh,

Welcome to the website. First of all, don't hold us to this but we know of this coach and I would think that most of us feel that this is probably a 190 hp Cummins 5.9.

The big deal on a diesel coach is not the horse power but it is the torque. That's what will pull you up the hills. Now I have talked with a bunch of folks with this exact coach. The all tell me the coach is a dog. A 30 foot awesome, wonderful 12 mpg, dog. And they are all giggling when they tell me this and say they love their coach. I believe that this 1992 has an electronic turbo-charged which can be electronically pumped up to around 250 hp. Check it out though. Just because it is a 1992 coach doesn't mean it has a 1992 engine. This 5.9 has around 620 ft lbs of torque. I think the 454 has around 500 ft lbs. So that diesel will give you more torque up the hill plus when you are going 65 with a gas coach you will be turning around 2500 rpms, the diesel will be around 1700 rpm at the same speed. That equals fuel savings.

Plus isn't diesel around 30 cents a gallon less than gas right now???

[This message has been edited by davebowers (edited June 27, 2004).]

Torque figures on the gas Chevies are pretty easy.

The LE8 454/V8 installed in 81-86 Chevy gas MHs had 230 hp and 360 ft lbs torque.

The LT9 454/V8 (TBI) had 230 hp and 385 ft lbs torque.

The ht502 Chevy crate motor develops 338 hp and 512 ft lbs torque at 2800 rpm. A chevy can be made to produce even more torque, but it will be at an rpm unsuitable for motor homes.


Figures vary on the 5.9 Cummins. Here are some for later 5.9s:

From
http://www.cumminsnorthwest.com/Cummins/Dodge.asp "The current 5.9-liter I-6 24-valve Cummins Turbo Diesel engine provides 235 horsepower and 460 pound-feet of torque. The 5.9-liter I-6 High-Output Cummins Turbo Diesel engine provides 245 horsepower and 505 pound-feet of torque."

From http://www.therevshop.com/shop/scripts/prodView.asp?idproduct=692 "The 98-02 5.9 produces 556 ft lbs".

According to Banks, http://www.bankspower.com/test_results_AM01.cfm

The 93-98 5.9 produces 170 hp and 521 lb ft of torque.


Any discussion of torque in motor homes needs to consider the weight of the vehicle and toad.

It boils down to an individual's tolerance for slowness up the hills. If you are doing 45 and pass other MHs, all is well. If you are doing 45 and the others pass you, well, how is it?

Will you be climbing 6 and 7 percent grades?

Perhaps a test drive is best.

The issue for a vehicle this size, "Diesel vs. Gas" is IMHO, a no-brainer. Diesel wins, hands-down. Fuel savings, lower maintenance, (more expensive when you DO need to perform any major maintenance, however) longevity... the Diesel engine, especially these CUMMINS', is just getting broken in when it's typically re-build time for a 454. No exaggeration. Now it's true these "early" 5.9 Cummins' are not as good as the later ones ("B" and "C" versions), and you don't have as many after-market boost options, but they are still pretty good, regardless. No, you won't be able to drop the pedal to the floor for a quick(er) on-ramp blast, like you might be able to with a 454, but when you do that with a 454 your gas mileage drops to 3-4 MPG. Your CUMMINS is going to get 12-13 no matter what you do, 14-15 if you really squeeze it and behave yourself. If the Cummins is a "B" model (12 valve, usually found in '93 or later machines) you are in MUCH better shape. You can really boost the power with products like BANKS Engineering make:

http://www.bankspower.com/app.cfm?appid=AM01

Call them, their techs are VERY helpful, and will hold an informative discussion with you. Ask them what you are getting, ask how to identify a "B" model, what to expect if it's an "A" model, etc.

My first choice would be CAT, then CUMMINS, then Detroit (which I have!)... and they all have their strengths and weaknesses.

Good Luck! Buy a DIESEL!

P.S. You can, with practice, get good at building momentum down hills (ie. haulin' ass) and make it up with little drop in speed... like the truckers do. You can hold your own pretty easily except for the longest grades. Believe it or not, when you drive a DIESEL like that you get WAY better fuel mileage! And when you go to BANKS' web site, and they claim more HP, more TORQUE, and better fuel mileage, that's true. I've had a "STINGER" equipped system and got 2-3 MPG better with it. It makes the engine so much more efficient it's not funny. Amazing. Good products, those BANKS'...

There are other alternatives to Banks such as BD Performance Diesel http://dieselperformance.com/mhome/index.php have kits for older Cummins without electronics.

[This message has been edited by EddieChevalier (edited June 28, 2004).]

[This message has been edited by EddieChevalier (edited June 28, 2004).]

quote:

Originally posted by duteman:

My first choice would be CAT, then CUMMINS, then Detroit (which I have!)... and they all have their strengths and weaknesses.

Chris, do you prefer a CAT 3208 over both the Cummins 5.9 and 8.3? Or just one? Would you expound on why you prefer CAT?

Hmmm. Well, these "baby CUMMINS's" have a good pedigree, but they are known by some as "disposable engines". Need a re-build? Don't bother. That's but an opinion. Not mine, I'd love to have one. They aren't sleeved. Now "real" CUMMINS engines, like the "big block" one seen in some Regency's, (https://www.barthmobile.com/ubb/Forum9/HTML/000356.html) are bred from better stock, the CUMMINS truck and equipment engines. It's true, some of the 8.3 blocks were forged in Brazil, I think, and had some cracking problems, but it's all relative... early CAT 3208's and D.D. 8.2's had head bolt issues... (just don't ever let them overheat...), so, every maker has engineering issues from time to time. Big Cummins' usually ARE sleeved, so re-building is a reasonable proposition. CAT 3208's are not sleeved either, I should say, nor are Detroit Diesel 8.2's. BOTH 3208's and 8.2 are really old technology, worth up-grading when the re-build decision needs to be made... So, a "big-block" CUMMINS would be a fabulous unit. A million miles, no problem. Even the 5.9's can go a very, very long time... just keep changing oil and filters, and use synthetic, like MOBIL DELVAC 1... you can get it from a CAT dealer... it's their CAT synthetic. Keep water out of the fuel, your fuel system will go forever.

But back to the question... I build this perception based on a number of factors... I used to work construction and in the trucking industry... hands-down the most "fun" to drive are the 2-cycle Detroit Diesels... Loud, powerful, snappy throttle response! There are the 6V's and 8V's... put two 6's together and you have a KILLER 12 cylinder beast! Wooof! But these don't make great coach motors, too noisy. But that PREVOST that passed you on that long grade, screaming as it went by? Probably a 2-cycle Detroit!

When you were a kid, were you into go-carts? Everyone in my neighborhood had Briggs and Stratton engines, or Techumsas' (sp) snagged off of lawn-mowers, except the rich kid, who had McCullochs... 2-cycle screamers that would just out accelerate and smoke everything else. That's what driving a Detroit 8V equipped truck is like! These aren't turbo-charged, the are SUPERCHARGED, gobbling air as fast as they can, shoving it down eight hungry throats, every stroke a power stroke! WOOOF! But to drive them right, you have to keep the r's up... smaller power band, can't lug em as far down as 4-stroke engines... so, they are higher revving engines, run in the high rev's most of the time, a formula for disaster, or at least, more frequent re-builds.

CUMMINS' are four stroke, strong, powerful, tourqe to die for... but they are a bit stodgy. Now the CAT's, sort of in between... not many trucks used them, too expensive, kinda "elite", and well, they are just so damn well built... engineered very well. I ran parts warehouses in construction shops in ALASKA for a long time, and one was re-building Detroits all the time. Then the CUMMINS', but especially rare was the need to re-build the CAT. I guess my opinion is based on the years of experience with the CAT "system". You will never be without a part from CAT. They will have it, tomorrow, no matter where you are on this planet. No lie.

But CUMMINS's are all over the place, and the "B" or "C" version, electronically controlled, with a BANKS system, and an ALLISON 6 speed, would be one fabulous combination. Especially in a "smaller" rig like a Breakaway... Wow. Now that 34 ft. Breakaway on the website is a killer unit. (https://www.barthmobile.com/ubb/Forum9/HTML/000360.html). Really the perfect combination. I think when I get my next rig is will be a mid-90's unit, with 6 spd ALLISON. Nice to have those two extra gears. I just need to wait another ten years for the price to meet my wallet!

But ALL the manufacturers have gone to newer technology... I've spoken to the CAT dealer here about some day re-powering my REGENCY. He does not want me to consider a 3208, as they are only available as re-mans now. Now, they will if I so choose, and will support it... (try getting a Detroit Diesel dealer to do that for an 8.2!) but they want me to go with a new 6 cyl (I forget the model... 3216?)because it is WAY better engineering... it is sleeved, WAY better efficiency and pollution control... but close to 14 thousand bucks to have the job done. Yikes. Half of that for a 3208T.

Did I answer your question? or just confuse the issue? I do that well, I think...

Let me summarize a bit: I'd prefer a 3208 over a first generation 190 CUMMINS. The "B" or "C" model CUMMINS, with BANKS's "POWER PACK" would be better than a 3208. Way better, simply because it's better technology, electronically controlled, 12-valve, more efficient and cleaner. My LEAST preferred motor package is the one I OWN! A Detroit 8.2T. I did disparage them a bit above, but the Detroit Dealer will get you any part you need for an 8.2, and/or a re-built one from the factory... it's just a loosing proposition. Dirty running engine, smoky... If (when) mine needs replacing, I'm seriously considering re-powering with the CAT or perhaps even a CUMMINS. Problem is that the ALLISON transmissions are very torque sensitive, so it's quite likely a tranny replacement is needed too...

Yeah, Detroit says that the 8.2 was killed also because of emissions... they just couldn't get it to burn clean enough for the new millenium. Both the 8.2 and the 3208 are similar, V8 4-stroke, Turbocharged medium duty engines. Both had early problems with head/head bolts... both were fine eventually, but like you said, CAT just kept developing the 3208 while DETROIT just did "bug fixes". There's even a 3208DI, direct injected head set up. CAT only recently stopped making new ones... a testament to it's soundness. It's a good engine, and if I ran into a real nice used one, I'd consider swapping my 8.2 and not look back. retro-fitting a CUMMINS would be more of a project. Hey, anything is possible, but there is a point of dimishing returns...

A 5.9 CUMMINS will push a 30' motor home OK. I've test-driven a 1992 34' Gulfstream... 5.9, and it drove fine. It's torque and tranny, really.

I really think I'd hold out for a 93 or better "B" model... put a BANKS PowerPack on it, and really be doing great. They claim huge numbers, and I believe them. Plus, they claim 10-12% better fuel mileage, and that's been my experience too. Couple that with a 6-speed ALLISON, and it's probably the best solution, in my book. For my money, any coach that size that can get 15 MPG is doing DAMN GOOD. I like to travel, not just drive down to the lake for two weeks. Not that there's anything wrong with that from time to time and, heck, you can find those coaches that have been driven to the lake and back each year for 20 years, and sometimes get a killer deal! Hey, these "B" model units are 11 years old now, and somewhere out there is a deal waiting with YOUR name on it! I don't think I'll be able to afford one 'till it's 15-20 years old... like my 84 MCC REGENCY. But then you have to fix all the stuff that happens to a 20 year old chassis... even though it's only got 53,000 miles on it, I'm going through it, belts, hoses, rubber, shocks, rust repair/undercoating, electrical, seals, water pump, gaskets, etc. etc. So it's always something. Like someone said, UNDERuse can be as bad as MISuse...

A REAL nice mechanical set up was that 40' all-electric puller we saw a while back. THAT was a "real" CUMMINS motor... big-block like in a semi. That was literally a "million mile" rig. Someone got a great rig, and I was even trying to figure out how I could afford it, but the weirdness of the all-electric and huge doghouse was a bit too much for me, 'cause I happen to like propane, being self-contained for a few days without having to run the generator, etc. I would have had to do a bunch of $$ work to IT... so, hey, I'm doing that now to my MCC for a HELL of a lot less money...

It's always something...

I was always told that you ran the Detroit 71 Series diesel like you set at the kitchen table ..... both feet fat on the floor.and you were mad at it. Run it between 1800 and 2100rpms all the time.
Never ran a 3208 Cat. Had a couple 3406's and a couple Cummins NTCs big blocks

HA! Those 8V-71's were a blast to drive... hot rodding a belly-dump building roads... spreading gravel one stone thick at 40 miles an hour! Fun. We had a great crew, all real good drivers, and a company that would let us know if the job was a "hard money" or "cost plus" job. We liked the hard money jobs the best, 'cause you needed to haul-ass to make money!

You do need to keep them revved up, though, as the symmetrical design of the engine makes it easy to lug it to the point where, when you're real heavy, in a gravel pit, trying to get moving, the engine coughs for a split second, then starts running BACKWARDS! Freaks you out when it happens. Exhaust spitting out of the air filter, all of a sudden you lurch backward without changing a gear... that happens no more than ONCE, I can tell you! All the veterans bust a gut at the sight of a rookie doing THAT! It amuses a crew for days. Not much else for entertainment in ALASKA!

We had an eight V-71 in one fire truck I worked on. I was on the tailboard and the driver went to start the engine and got it running backwards. The wall behind the truck was coming at me real fast. He got it stopped just in time. We got to the fire in good shape. Those two cycle engine sure make a great sound roaring down the road with the siren and airhorn going.