A new gas engine for GM heavy duty trucks is coming

colliehauler wrote:

ACZL wrote:
GM had a darn good set up with their 8.1 gasser few years back. Too bad they did away w/ it. How many folks long for the days of Ford's 460, GM's 454 and want to say Dodge/Ram's 460 cu in engines?

They were good engines in their day but inefficient by today's standards. I owned several BB Chevy's, and a 428 and 429 Ford's.

I agree, my current 6.0 is miles ahead of my old TBI 454.

noteven wrote:
Ib516 - thanks for posting your experiences.

What does your 2014 do for daily driver economy?

Wish I could remember. Lost it in the divorce process. It wasn't horrible, and was almost identical to my work mate's 2014 Ram 1500 5.7L Hemi. He added a leveling kit to his and Goodyear Duratrac tires. Before his mods, he was about 1 mpg better.

Ib516 - thanks for posting your experiences.

What does your 2014 do for daily driver economy?

harmanrk wrote:

ib516 wrote:
I'll pay a 2-3 mpg penalty at the pump (for less expensive fuel mind you), for a bit less power and gain reliability, and avoid the OMG repair costs that are inevitable in any engine.

You 2-3 MPG loss may be a bit optimistic. Also, you definition of 'a bit less power' and mine are wildly different. (HPs may be close, but 400 ftLbs vs 900+ is not a bit less)

The 2-3 mpg is based on my 2007 5.9L Cummins 3500 SRW Megacab 3.73 truck and my 2014 2500 Crew cab 6.4L Hemi 4.10 truck pulling the same RV over the same route I took every summer. The Hemi got 7-9 mpg at 21k combined load, and the Cummins got 9-11 mpg. The lower number for both is into a headwind or in the mountains, and the higher is on the flats with very little to no wind. 2-3 mpg difference in my personal experience, and I tracked every tank with the fuelly app.

Interestingly, my current set up is also 8-10 mpg, and the RV is only 17 feet long and 3500# (but is a full 8 feet wide).

And yes, you're right, the torque gap is a huge, but I was speaking in terms of overall performance. I could crest the same mountain passes at 60 mph with the Hemi and a 12k RV as I could with the Cummins, but I used more RPM to do it. The overall performance gap isn't as wide as is represented by the torque figure. Like I said, the Hemi was faster to 60 mph with a 14k load than the Cummins was for whatever reason, part of that likely due to the 3.42 the Cummins truck had compared to the 4.10. But, like I said, similar overall performance, just higher RPM and more fuel used in the process.

noteven wrote:
Ib516 - stock spec Cummins 6.7 /5.9 reman injectors are being advertised for C$495. Approx US$376. each.

Don’t put cow pee in your DEF tank. How do you even collect it? :) :)

Interesting that my numbers were that far off. Maybe the number I heard was new vs. new? I do know how much they were for my 2002 5.9L Cummins because I bought them. And maybe the 6.7L ones have come down in price since I did my research when trying to decide what one to buy (Cummins or 6.4L Hemi) in 2014. More of them on the road would make the parts cost decrease for sure.

Hammerboy wrote:

ib516 wrote:
They're all going to put more money into developing new gas engines due to the initial cost, complexity, and huge repair costs of the modern diesels. What's one injector worth these days? $1500? I bought a set of 6 new Bosch (RV275) injectors for my 2002 5.9L Cummins for $300 a few years back.

Customers like me have decided diesels aren't the reliable anvil they used to be. They are fragile, delicate, and costly when compared to their predecessors. You won't find a 5.9L Cummins or a 7.3L IH that will limit you to 5 mph because it's out of cow pee, or because the exhaust choking device is clogged. Yes they're powerful, but no thanks.

I'll pay a 2-3 mpg penalty at the pump (for less expensive fuel mind you), for a bit less power and gain reliability, and avoid the OMG repair costs that are inevitable in any engine.

You sound overly optimistic about gas and overly pessimistic about diesel I must say.

Dan

Fair enough, and yes I may be. I'm basing my opinion on what I have read on these forums, and my experiences. YMMV :)

noteven wrote:
So what do Big Gasohol engines return for fuel economy towing a 18,000lbs x 40ft 5th wheel anyway?

The mpg would be pretty poor - about 35% or so less than a diesel in the same truck.

I did tow a 40' cedar creek 5er that weighed 14,000# as a test with my 2014 6.4L Hemi and it did fine. I couldn't tell much difference between it and mt 37.5' 5er that weighed about 12k. I towed that one through the mountains with my Hemi no problem. I also did a 0-60 test with that cedar creek 5er behind my truck at the time an a buddies 2014 3500 SRW Cummins (370p/800tq). The Hemi was faster to 60.

Not many people want to tow that heavy though. Diesels (at least in a 3/4 ton and up) are by far the best choice when you only judge by performance when towing (mpg, power, ease of towing). If that is your primary purpose, or you tow almost all the time, I'd say buy the diesel, suck up the higher maintenance cost, and hope you avoid expensive repairs over your period of ownership.

However, for most weekend warriors, and those who still work full time (and don't use their truck for work), a big gas engine may be the better choice overall. It was for me, so I'm excited for the new gas engine offerings by the big 3.

You have to think the bean counters at the big 3 think there are more people out there who agree with me - otherwise they wouldn't sink the money into developing more big gas engines for trucks.

George3037 wrote:

Turtle n Peeps wrote:

George3037 wrote:
More HP and torque of this new gas 6.6 should make it work less in GM trucks where the truck weight is similar to previous years. It would be nice to see this 6.6 get a few more MPG than the 6.0.

Maybe GM should build a 1,000 HP gas engine. That would really work less and get super mileage.

But then someone would come out with a 2,000 HP engine and that would work less than the 1,000 HP engine and get even better mileage. :B

Kind of like when you're running out of gas so you drive faster to get to the station faster so you won't run out of gas. :R

I'd just like to see GM come out with a gas engine for use in 3/4 & 1T trucks that gets better than 13 MPG empty without having to switch to a diesel truck.

It takes a certain amount of energy to push a vehicle down a road. The more HP an engine has and uses, the more fuel it will take to make that HP. Every time a cylinder goes bang it wants a 14 to 1 fuel ratio in it. In simple terms the more RPM you have the more that cylinder goes bang and the more fuel the engine will use.

The more heavy a vehicle is the more fuel it will burn. Seems like everybody wants a quad cab and 4 wheel drive and every single gadget money can buy on their trucks. (heavy)

No matter what some may tell you it takes fuel to make HP and it takes lots of fuel to make big HP. One of my engines makes about 750 HP and it uses about 1 gallon of gasoline to make a 1/4 mile run. (5 quarts for the run and return)

I want to win the power ball and you want a big truck that will get 15 MPG. Your chances are a lot better than mine! :B

So what do Big Gasohol engines return for fuel economy towing a 18,000lbs x 40ft 5th wheel anyway?

Turtle n Peeps wrote:

George3037 wrote:
More HP and torque of this new gas 6.6 should make it work less in GM trucks where the truck weight is similar to previous years. It would be nice to see this 6.6 get a few more MPG than the 6.0.

Maybe GM should build a 1,000 HP gas engine. That would really work less and get super mileage.

But then someone would come out with a 2,000 HP engine and that would work less than the 1,000 HP engine and get even better mileage. :B

Kind of like when you're running out of gas so you drive faster to get to the station faster so you won't run out of gas. :R

I'd just like to see GM come out with a gas engine for use in 3/4 & 1T trucks that gets better than 13 MPG empty without having to switch to a diesel truck.