Experience with GM454 and MPG

[Chas]

O.K. Kev,

I can see by your towing speed that you could be getting that good of mileage with your Burb'. Just be sure to let the rest of us pass! Sorry to have started the perpetual diesel vs. gas war again, I always seem to! But while I'm here, diesels run much cooler! Mine can idle with the a/c on in 100 degree weather and not even move the needle! Spark plugs, ha, shut it off at the propane dealer, no need, how bout' that torque baby!!

Chas

(btw, my k2500, a 4wd, had 4:10 gears in it)

[59toaster]

Originally posted by Chas
O.K. Kev,

I can see by your towing speed that you could be getting that good of mileage with your Burb'. Just be sure to let the rest of us pass! Sorry to have started the perpetual diesel vs. gas war again, I always seem to! But while I'm here, diesels run much cooler! Mine can idle with the a/c on in 100 degree weather and not even move the needle! Spark plugs, ha, shut it off at the propane dealer, no need, how bout' that torque baby!!

Chas

(btw, my k2500, a 4wd, had 4:10 gears in it)

My 75 GMC idles cold in high 90's weather and slugs around on steep grade never exceeding 5-6 mph for hours at a time (read as minimal air flow through radiator) and never gets past the 180mark. It all in how effecient your cooling system is. Deisels by defualt get 4 core radiators where as a base 350 without towing package gets a 2 core. Towing package on a 350 gets you a three core and a 454 gets the same 4 core as the diesel.

[74Tradewind]

My 2WD 1999 3/4Ton 454 equiped Freeway Frigate only gets 10 MPG. That's around town stop and go driving and on the freeway, towing the A/S or not.

This is not the best situation to be in where gas has hit $4.14/gal. is one area.

I bought a '71 VW Bus to tool around town in so I can save my gas money for camping.

The 3/4 T 'Burb has the full floating axle so I don't expect to have the recurring axle seal and bearing failure that happens with towing on a 1/2 Ton axle.

Let's see now... a 500 mile trip @10mpg=50 gallons X $2.50 gives me $125 in gas. If I got 18 MPG for the same trip I would be saving about $55. Oh well, I can bring more firewood from home in the back of the 'burb to make up the difference.

Ciao, Brian

[Silvertwinkie]

It's a personal choice. If you have the cash, the duramax/allison combo is a great vehicle (for towing).

If you want the same performance "towing" and don't want to spend the $5k, get the 8.1L (splurge the $1200--depending on vehicle for the same Allison transmission) that DavidZ71 has (engine not sure he has the trans).

The Diesel will get better gas mileage, but not the kind of great gas mileage to me that might warrant it. Pulling, the diesel has an edge on MPG and even a better edge when not pulling mostly because it gets most of it's torque in the low RPM band. Diesel fuel gels easier than gas, so you folks in the rust belt and/or frozen tundra need to be aware of this.

Gas on the other hand is everywhere local, everywhere remote, there are no problems finding stations. When not pulling, the 7.4L or the 8.1L big blocks can get out of their own way. Diesels are not quick vehicles. In the country, that might not be an issue. Living in the city where you need to merge onto the expressway and sometimes need "Scotty" to give you that power on a moments notice, the big block has it in gobs. The diesel doesn't.

In the end as I said it's a personal choice. You can't go wrong with either. If you look at the Chevy site, you'll find that the tow specs are very similar and from my exp, the diesel will only have a slight advantage in the MPG.

The idea that it costs more to operate a diesel is not true. But I will say to those that think diesels last longer, that might be somewhat true, but for each one that says, me too, I can also come back with people that have small and big blocks that have lasted the tests of time if properly maintained and not beat on. Also, consider 15 years from now on either, will the body still be there and accessories still work? Would either be worth rebuilding?

You cannot compare 18 wheeler truck to passenger car/truck diesels either. Those trucks cost upward of $100k in some cases. They get rebuilt because it's cost effective to do so. And although they do last well beyond 200-300k, the cost to do similar in a passenger truck is way different and is like comparing apples to watermellons. You really gonna sink $10k in engine, trans and body for a car worth less than $1k 15 years from now.

Gas or diesel? Personal choice. Does the same things, some pros and cons to each. Your lifestyle will dictate which is best for you. I do think the common ground we have is that both can do the same task quite well and in a very safe manner (driver habbits aside).

FWIW,

Eric

[Ira Iburg]

We have R2500, 454, 3.73, all options pulling 31 ft Airsream, 50 to 55mph,1334 mile 8.5 mpg, 1365 mile 8.7 mpg, 6236 mile 8.3 mpg. Never dared to ckeck without trailer but is one great tow vehicle

[davidz71]

Eric and Chas,
I use to be so anti-diesel that it was pathetic. I liked the smell of the exhaust but they were so slow and noisy. My eyes have been opened after hearing the Chevy Duramax and reading that the Dodge Cummins HP and Furd are quieter than previous engines. I cringe every time I hear a coworker drive his Ram 2500 with Cummins around the side of the building. NOISY but a good engine. OK, the Duramax has been run against the 8.1 and was almost neck and neck with it. Turbo has done wonders for this engine and other diesels. I won't get into the cost factor between gas and diesel but will tell you that the new generation of turbo diesel not only have pulling power but are fast. www.pickuptrucks.com did a pulloff with the Duramax, the new Furd diesel and the Dodge Cummins High Performance diesel. The Duramax did not fare as well as the new Furd and I can't remember how well the Dodge did. I like my 8.1 but there is one thing for sure, the Duramax can outpull the 8.1 up a hill with an equally heavy load. After saying all of this, has diesel exhaust killed most of my brain cells?

[Chas]

david,

Just give them a while to warm up and the diesel gets a better aroma, I agree that nothing stinks worse than a diesel warming up. I have heard of people putting a bit of Pine-Sol in the tank but maybe this is another one of those urban myths. As far as performance goes there was nothing wrong with my 95 Powerstroke "FORD" as it came out of the box but I just had to tinker with it so here goes.

On the engine i've added an ATS intercooler, BD 3'' turbo downpipe and BD 4" exhaust, Banks kwik spool turbo housing, a Hypermax chip and a K&N filter. On the tranny I have a BD billet steel torque converter, BD Pressureloc to increase the trannny pressures and a bunch of other mods done by my transmission shop. When it is unloaded it will do it all, smoke the tires, do donuts and perform any other juvenile actions I see fit. so much for the pokey diesel syndrome. Most people you hear that from probably drove or have gotten stuck behind a 240 diesel Mercedes at some point in their life.

Chas

[59toaster]

New Deisels are plenty impressive. I have had a chance to drive a Banks equipped 2000 F350 Dually and once that turbo spooled it was all smoke if you kept your foot in it. I have also drove several nearly new F250's with a dealer available chip that were darn impressive as well, once the Turbo got spooled up.
My problem is I'm paying Cash and I want pre air bags. I have two kids and extended cab is fine for short trip but it wont cut it for extended rides. I could live with a Crew cab short bed but they were not building them that way in the late 80's. That leaves the Burb. Honestly I would rather have a crew and then hav a bed where I could throw dirty junk without a care but I don't need a truck that takes a football field to turn around. Burb is still short enough that it doesn't have too bad of a turning radius. Just I don't care for 6.2 and 6.5 GM deisel's so that puts them out of the game. If I was buying new and cash was not an issue it would be a REAL hard choice between the Duramax and the powerstroke. I'd get a Deisel for sure then.

[davidz71]

Chas,
Sounds like tinkering with the PSD got you where you wanted. The used F250 I drove was either a '99 or '00 ext. cab short bed black with gold two tone paint. Sharp looking truck and that is what made me test drive it. Other than no get-up-and-go, the back seat was a fold down that resembled our stiff gym mats at work. Whoever rides back there has sore buns in short order. The '01 V-10 ext. cab had a nice rear seat with more room.

I would say that GM will tinker with the Duramax as far as programmer or bigger turbo to increase performance so that they can keep up with the other automakers.

[Ken J]

Hmmmmmmmmm diesels run cooler? My 6.5 heats up everytime it sees a hill. Have all kinds of work done to get it fixed. I realized that this overheating is probably unique to the 6.5.

I am planning to trade this one off for an 8.1 in the next couple of weeks.

The other thing I'm looking forward to is not having to sit in my Surburban while the turbo cools.

To me the diesel is nice if you do lots of long distance driving, Diesels like to run but as an in-town vehicle it's a pain.

I've also thought about replacing my motor if it ever came to that and its cost $6,700 just for the motor. In understand that a replacement duramax if $12,000.

Sorry I don't see the economics, I do agree that it does save fuel resources - which is a good thing.

Just thought I would give the persective of someone who has diesel and going back to gas.

[Silvertwinkie]

Not sure I like the smell of any exhaust, but to each their own.

Diesels do not run cooler.

I'll have to take your words on the off the line power of the new diesels. But I still find it hard to believe that a diesel has more SOP (seat of pants) performance off the line than a 7.4L or 8.1L.



Eric

[davidz71]

Eric,
You have the same feeling about the diesel vs 454/496 that I did. The pickuptrucks.com forum was talking about the Duramax vs 8.1 and I can't remember which magazine did the test. Some members on that forum apparently wondered also so they did their own tests and found that the Duramax held its own with the 8.1 pulling ahead by a couple truck lengths in the 1/4 mile (best I could remember). I have head a lot of discussion about the Allison transmission not transmitting all the 8.1 power to the driveline as it should. This was done, according to speculation, to cut down on drivetrain abuse and subsequent warranty work. I don't know but a trip to that forum might give more insite. Johnhd spends time there and maybe he might remember what they called it, something like "drivetrain management".

[j54mark]

"My 6.5 heats up everytime it sees a hill. Have all kinds of work done to get it fixed. I realized that this overheating is probably unique to the 6.5."

I've not heard this. Mine ('94) certainly does not. Coolant temp has climbed as high as 225 pulling up a 12% grade in summer with trailer in tow. The only time I worry about letting the turbo cool is on the extremely rare instances where I turn off the highway and immediately into a parking lot, or pulling the trailer up a large hill, and immediately arrive at my destination. Usually by the time I have waited through a light, or gotten through an intersection, and certainly by the time I have the trailer pulled/backed into place on leveling blocks, the turbo has had time to cool off.

Mark

[59toaster]

Nope not waiting as long as you should. I had a hot rod with a 2.3 pushing 18psi of boost and did in plenty of turbo's. My wifes dogging it and parking it didn't help either.
The big problem with turbos is the shear heat. If they are hot the oil cokes or boils on the bearing if it's not flowing. On start up this will sometimes blow the bearing and seal out. The flowing oil does just as much to help cool these as the water. Really more because it cooles the impeller shaft where the water cools the housing. The first turbo's were not even water cooled just oil cooled.
The seconday problem is since one end of the impeller is in the relitively cool intank path and the other in the intense exhaust is once you do shut them down the difference in the heat from one end of the turbo housing to the other is different and it will warp the impeller shaft. Keepingthem spinning helps keep them true till they cool.

I'm really surprised that so few people use "Turbo Timers" on deisel trucks. The hotrod turbo car crowd has used these for a long time an it's usualy the first upgrade they do. It goes a long way to help prevent premature turbo failure. It's a timer that delays the engine shutting down so you can get out and go without having to wait for the turbo to cool. It lets you lock up the truck and set the alarm but will let the vehicle idle for 2-3 minutes. If somebody opens the door to try to steal ithe truck it kills the engine. Most can be tied into the alarm systems and dely their automatc arming or if the alarm triggers before a door is opend it shuts down at that point. Not expensive at all when you concider a Turbo cartrage (just the impeller and center If your buying a whole assembled turbo your paying to much) will set you back at least $300 just for that part. If your not able to do the install yourselft it's a easy $800 repair at the typical shop.

www.google.com and put in "Turbo timer" and your city and should pull up a number of shops that sell them local. Or find a online shop. Bet you could get them from Banks as well.

[Chas]

Toaster,

I've got 150k miles on the original turbo in my 95 Powerstroke and have never had any problems with it. I change the oil every 5,000 miles and use either Rotella or Delo. I think you are referring to engines which had turbos added to them, hot rods with gas engines and the like and being such they probably have insufficient oil supply and run much hotter than the diesel to begin with. I guess you are talking about an SVO Mustang?

Chas

[59toaster]

Originally posted by Chas
Toaster,

I've got 150k miles on the original turbo in my 95 Powerstroke and have never had any problems with it. I change the oil every 5,000 miles and use either Rotella or Delo. I think you are referring to engines which had turbos added to them, hot rods with gas engines and the like and being such they probably have insufficient oil supply and run much hotter than the diesel to begin with. I guess you are talking about an SVO Mustang?

Chas

Close, Merkur XR4Ti. Same engine.

[Ken J]

Mark

I also have a 94 6.5 - its in perfect condition, but on long grades in Colorado it gets up to about 240 or more degrees rather easily. I've been told that heat is the killer of these engines, so I've tried all kinds of stuff and has not worked. Following the diesel pages, this seems to be a problem with these engines. I've received all kinds of opinions on how to fix/improve it but at this point since its a buyers market for vehicles, I've opted to just get a new one with a monster (gas) motor.

Ken J.

[j54mark]

Do you undertstand the 6.5 overheating problem to be general or altitude related? In know of many here in Missouri, and whatever other problems they may have, overheating has never been one of them. These engines are used in a lot of high stress situations (every Humvee ever made, Chevy Stepvans).

In re: cooldown. "Nope not waiting as long as you should". Waiting for what? These are very low boost turbos. Too low, by some people's estimates. If it hasn't cooled down in 10-15 minutes of low rpm, low load idling and creeping through a campground, it ain't gonna cool down in another 10 min. of idling. Mine is original, never rebuilt, and I turned over 160,000 mi. yesterday.

I do realize, of course, that other turbo motors are different.

By the way, you will not hear me extoling the virtues of the 6.5. I hold only that they are a decent engine capable of giving quite acceptable service - you just don't want to pay much money for one.

Mark

[Ken J]

I don't know if high altitude is causing it or not....However, everything I have read is that these engines are prone to heat.

[Chas]

I don't profess to be an expert on the 6.5 but have heard that the early to mid 90's models did have a problem in regards to overheating. They supposedly fixed it in the late 90's. A friend of mine had a 95 GMC dually with the 6.5 and it would run hot at times. It was a great truck, got better mileage than the Powerstrokes but not nearly as much power. I heard that some people had ruined their engines by installing fog lamps into the air intakes in the bumper. Guess they need all the air they can get.

Chas