8.1 gas vs diesel.....

[hammersley]

OK folks - check this out... ... especially motorhomeguy towards the bottom... .



http://forum.thedieselpage.com/cgi-bin/ultimatebb.cgi?ubb=get_topic;f=15;t=000201



BTW - anybody have experience with 8. 1 towing heavy????

 

[GerryDrake]

Won't work

It would appear that one has to be logged in to view it

 

[pwerwagn]

yup, I cant get in either. :{

 

[AfterBurner]

"nor I" said the fly :{

 

[hammersley]

Sorry........

here's what the guy said... .



motorhomeguy

Newbie

Member # 14773



posted 21 January, 2005 03:01 AM

--------------------------------------------------------------------------------

I've got a 38' Class A (bus) motorhome with the 8. 1L GM engine and Allison transmission. Tips the scales at 22,000 lbs. solo, 27,000 towing my pickup behind it. Fuel mileage runs 7-10 mpg depending on terrain and weight, with comparable 350-horse Cat & Cummins diesels getting the same. No other gas engine can touch it for power and speed on the road, and only the high end diesels can run with it in the mountains.

Oil consumption on a recent 7000 mile cross-country trip was 1/2 qt.



No funny noises, no problems at all. GM rates the service life of the 8. 1 in the 26,000-30,000 lb. GVWR range at 200,000 miles. Judging by what I've seen with other RV'ers running 8. 1's I'm fairly confident mine will go 200k and then some. In a light-duty pickup truck it should last much longer- at least another 50k miles or so...



Happy trails!

 

[TPCDrafting]

My brother drives an '01 Cheby 2500 hd with the 8. 1 and ally. He loves it but hates the 9-10 mpg he gets empty. It pulls very well, but he had the block replaced at about 15k miles as it was loosing coolant and they couldn't find out where. Turns out the block was porous (sp?) He also had the ally out for major service as well. All under waranty, but still major problems. I've driven it a few times. It's far superior to any Ram V10 or Frod V10/460 I've driven. And yes in stock form, it would run away from my 12 valve.

 

[PRyker]

Well... All I have to say is "PISTON SLAP"



http://www.pistonslap.com/



I had a 6. 0 with it and it sucked. Sold it quick!!!!! Believe it or not I had people ask me if it was a diesel. It was that bad. What the heck was GM thinking when they made shorter piston skirts... blah!



Phil

 

[PRyker]

Oh... and I think that the 454's are (were) great engines, albeit they do use oil.



Phil

 

[Alan Reagan]

I'm sure the resale of a big motorhome with a gas engine is equivalent to a diesel, too. I would think that there is no way a diesel could stay with the devaluation of that hog.

 

[Bloomy]

Friend of mine has an 04 8. 1. I told him not to get it because of the mileage. So now he has 8,000 miles and is shopping with tomeygun for a Dodge/Cummins. My 12v dusted him pretty good from a stop for about 1/10th of a mile. Obviously on the top end he would beat me since my top speed is about 90 if I try. With the way he drives (short trips/town driving) he is averaging about 8mpg. No towing, but loaded with about 1500lbs of tools.



Thomas

 

[btanner]

yes I've seen a 8. 1 tow heavy (34k total weight) it towed like a champ (2000 chevy crewcab dually) but sucked gas like it was nobodies business (5 mpg constant) and the brakes weren't enough (trailer ended up having three of the four brakes bad) for that big of a trailer. it was pretty impressive up the grades but even with a 100 gallon tank we still had to stop for gas twice on a 1200 mile trip and fill up. The guy who had it sold it and bought a cummins empty it still sucked gas and it ate a little oil but all and all was a good truck with a strong engine.



-ben

 

[pwerwagn]

We (me, My uncle, and my bro-in law) haul tires here around albuquerque for disposal.

I use my 98 12V cummins, My bro-in law has a 97 F-250 crew with a 460, and my uncle has a newer 1-ton chev with the 8. 1. When we haul truck tires (semi tires) the trailer usually weighs somewhere in the 16-20K range (depending on the am't of tires). I have to say, I am very pleased with how my cummins hauls them on the freeway, I can leave both of them if I try. However, mine is nowhere near as nice pulling that much weight in town. theirs are much nicer from stoplight to stop light with that much weight. they both also average around 10mpg, while I average 14 with the trailer. also, both of their trucks brake better than mine.

I can out run both of them empty left and right.



--Jeff

 

[Billy Diesel]

We (me, My uncle, and my bro-in law) haul tires here around albuquerque for disposal.

I use my 98 12V cummins, My bro-in law has a 97 F-250 crew with a 460, and my uncle has a newer 1-ton chev with the 8. 1. When we haul truck tires (semi tires) the trailer usually weighs somewhere in the 16-20K range (depending on the am't of tires). I have to say, I am very pleased with how my cummins hauls them on the freeway, I can leave both of them if I try. However, mine is nowhere near as nice pulling that much weight in town. theirs are much nicer from stoplight to stop light with that much weight. they both also average around 10mpg, while I average 14 with the trailer. also, both of their trucks brake better than mine.

I can out run both of them empty left and right.



--Jeff

Do you think the in-town driving has more to do with the engines or transimissions (Manual vs. Autos) ?

 

[pwerwagn]

I think it is a combination of both. They both have autos, I have a 5-speed. however, I have used my grandpas 02 auto 3500 CTD once to pull the tires, and his was almost worse than mine (we all know the 47RE isnt that impressive from a stop though, especially with a load).

I had a V-10 dodge with a 5-speed, and personally I think it was a little better in town with a load than my CTD 5-speed.

However, I would not trade my CTD for the V-10, nor would I trade it for the ford or chevy. On the highway, it is untouchable. Plus I like the 20mpg empty.

Dont even get me started on the POS V-10 ford makes and dares to call an engine. I have pulled a pretty good load with one of those and it was bar none the most dissapointing truck I've ever driven. I'd put a 5. 7 hemi against one of those turds.



--Jeff

 

[Billy Diesel]

I found the same thing when hauling Jeeps to Moab. We had a new Ford V-10, an old Ford V-10,(both autos) and me, all Towing Jeeps. In town they were certainly quicker off the line than I was, but on the interstate I could pull grades in OD that had the V-10s in second gear and slowing down mightly. And that was when I just had the VA.



And lets not talk about how thirsty those things are!



--

-Will

 

[AfterBurner]

Have a freind that has a 4X4 crewcab 8. 1, that thing runs. they pull a dump truck with it all across Texas and it doesn't hesitate. The only problem they had was with the 4X4, but they got that taken care of under warranty. The truck has over 200k and is running strong. Test drove an 8. 1 3/4 4X4 extended cab- awesome acceleration! It was a blast and rode and drove like a dream, it was more comfortable than the dodge, and had more get up and go, and the dodge is far from stock.

But I still like the cummins, most of the time the fuel mileage is better than the 8. 1, but now that gas is cheaper than deisel and diesel engines cost so much to maintain, I couldn't tell you which is cheaper. But the cummins is definately a lot more fun

 

[DavidTD]

The 8. 1 is a great motor from what I have seen. They seem to make about 260hp and 360tq on the rollers which is comparable HP to the current diesels but the TQ falls short.



A good friend of mine had a 2500 with 8. 1. It ran low 16's in the 1/4 and pulled his trailer fine as long as it was allowed to rev. He sold it due to horrible fuel economy. The guy with the motorhome at 27k gross needs to check his mileage somewhere besides going down the mountains IMO.

 

[JLitton]

I had 2001 2500HD with 8. 1L and Allison. I live in WV and the motor and transmission handled my 31ft 5th wheel much better than my stock CTD/47RE combo in my 2003 Dually. The 8. 1L is definitely a strong motor when compared to a stock diesel.

 

[dodge cummins]

if i was in the market for a gas job, my first choice would be a chevy because i believe they make great engines. cummins is always slow from a dead stop especially towing a load. how many tractor trailers are fast off the line? i love my cummins and i would only trade it for a new cummins.

 

[pwerwagn]

I agree. If my CTD was stock, there is no way I could keep up with the 460/454 trucks we have. Even with a trailer.

I disagree with the cummins being slow off the line. When compared to other diesels, I have noticed that the cummis seems to be much lighter on its feet off the line that the other two options.