Is GM getting smart?
 

The new GMT900 pickups are nice looking, but GM really didn't have FE in mind when they selected powertrains.

Finally, a year after their introduction, they're offering the old 4.3 liter V6 option. Now, if they would just add a cam phaser and cylinder deactivation from its V8's to the V6, along with a manually tranny, I could dump my Ford P.O.S. for a truck that gets 25 mpg.

I should start another contest to see if GM ever does it.

4.3s are awesome engines. I like your idea for the cam phaser, cylinder deactivation, and manual tranny. That would be a truck I'd like to own as well. :thumbup:

what do you do that you need a full size for? i have a 2.2L 5speed s-10 that gets 28mpg around where i drive (alot 55mph highway)...no aero mods whatsoever.(a bed toneau cover could add 1-2 mpg). even the 4.3L s-10s are getting mid 20's or so.

what is a cam phaser? something having to do with variable cam timing? What if you dropped in a cam that has a low end power band and call it a day? Like a RV cam.

Very few people who drive trucks actually need them. Most people just want them and find excuses to buy them. My own opinion is that the guy in the shiny F-350 doesn't really need a truck. If he really needed the truck, it wouldn't be all shiny. It would be doing truck stuff.

For the 2 or 3 times a year I need to haul stuff, it's a LOT more economical to rent a U-Haul, and save on gas the rest of the year.

As for GM getting smarter, I think they are. I have a few friends who work for them, and I don't want run my mouth about stuff I shouldn't, so I'll just say that they are working on things to make their engines more efficient.

MA4T

The 4.8L in a regular cab can get into the mid 20s stock, and has almost 100HP and 100TQ more than the 4.3L. The 4.3L is old technology, it's the same engine they've been running since the late 80s. With the right engine, drivetrain and computer mods, a 4.8 in a regular cab could get into the low 30s. A friend of my dad had a 4.8 in a 99 that got a rock solid 25MPG, and it had the mechanical fan up front. This is the engine I was going to install in my S15 before GM announced their new 4.5L diesel. Sometimes GM gets it right, but then other times...

GM's cylinder shutdown is one place where they are NOT smart. It's activated by OIL PRESSURE. That's right, it depends on the quality of oil used and how dedicated the owner is to keeping the oil changed. Two years into China-Mart brand oil changes every 6 months, the passages that control the cylinder deactivation are going to be full of gunk, and the system will fall flat on its face and the system will be blamed for it, because "that's the same way I've always changed my oil and I never had a problem." Or, wait till the engine has 100K or more miles on it and the oil pump starts getting weak. The system depends on the computer being able to shut down 4 cylinders at the exact same time to run seamlessly, all it'll take is a little gunk to block one cylinder's control port or not enough pressure not quite shutting everything down to kill the system, and shortly after the engine from harmonic distortions. I think they are going to wind up having to shut the programs down on the engines when people start bringing them back with complaints.

I just don't think they will be able to work out the bugs on a multidisplacement system until they perfect electronic valves. Of course, when they do this they will solve many of the problems of the internal combustion engine. Imagine having an engine that accelerates like a dragster on WOT, yet sips fuel at cruise because the "cam profile" is determined by load on the engine and throttle position, not by an unchanging, heavy chunk of steel going through the engine. With electric valves, a multidisplacement system might be able to fire as few as 2 cylinders on a V8 to maintain speed since you won't be limited to a specific valve event as you are with a camshaft. Electric valves are a dream come true for me. :D

The 3.9L V6 in the new Impala has cylinder deactivation, thery should transplant it into the GMT900....

Do you mean it's controlled by oil pressure, or actuated by it? Honda's VTEC has been using oil actuated, computer controlled mechanisims since 1990. While comparing Honda and GM engineering-wise is like apples and oranges, using oil pressure for mechanism control isn't an inherently bad design.

Under low load, the resulting low oil pressure collapses the lifters which keeps the valves from opening, thus deactivating half the cylinders.

my dad had an 81 ford f150 with the 300 inline-6, 2.73 rear end, the HE package and OD, it was a 2wd stepside and got 25 mpg.. in a full sized half ton, in 1981.

so don't give me all this need modern (read: expesive) technology stuff to get halfway decent fuel milage in a truck

light-duty diesels would be nice though

Jeff

A 4.8 liter GM getting mid '20s for FE is ludicrous at normal speeds. My son had a 4.8 in a 2wd Chevy and it got 18 mpg tops. And check the EPA ratings for the GMT900s......Are you telling me that your relatives are hypermiling?

I absolutely agree that old tech can get good FE. But just try to get 2.73 axles in any new truck today. The salesman will look at you like you're from Mars.

I've been deploring the lack of FE trucks at Gassavers for as long as I've been posting. I don't care whether it's old tech, new tech, or unobtanium.

GM could build a FE Sierra from its own parts bin, equipped with a 2.73 to 3.23 axle, 15" wheels instead of those ridiculous 17's, electric power steering, water pump and fan, manual tranny and a 3.9 liter V6. It would get 25 EPA mpg without breathing hard. With gas over $3, ya gotta wonder why they don't.

yeah, that ford had plenty of power with the 300, that was a really nice motor.

if you could get an FE tuned version of the 4.2 inline6 in the chevy with a 5 (or better yet 6) speed trans and a fairly tall readend (the 3.08 8.5 inch 10-bolt comes to mind) with a t56 in 2nd od (6th gear) and 235/70-15s about 65 mph would only be 1200 rpm and i think you could build enough torque with a FE/lowend cammed 4.2 to pull that out of the freeway, you would just have to not use 6th on slower roads, but you would have a second overdrive that was less tall to use the rest of the time

Jeff

2.73 seems awefully low for a fullsize pickup that'll probably be used for hauling quite a load or trailer. They really just need a 5 or 6 speed so you can more correctly control revs at speed.

I haven't read anything about it (to know if they're even trying or close), but I too saw the merits of the electric valves years ago and have been waiting eagerly. I've even thought about attempting it myself a few times but really don't have the time or money.

Other added benefits, you no longer need to pump oil into the head, there will be nothing to lube up there. I think I read the main place oil gets heat sheered is the head because of temperatures there and the lack of fluid (much less resevoir up there compared to the oil pan), so this should instantly increase the milage you can get from regular oil between changes.

Also we can finally get an efficient cylinder shutdown. Displacement on demand isn't much different than just killing the injectors to half the cylinders, during compression you're still stressing and losing energy you won't regain with ignition. With electric valves you can just make the intake open during every downstroke (assuming sequential injection so you would only be drawing fresh air) and open the exhaust valve on every upstroke, while the injector or cylinder is 'off'. This would drastically decrease how much energy an engine draws when not igniting.

I work on the LS4 engine in the W cars. We have never had a problem with the lifters clogging due to oil breakdown. The oil pump is a higher displacement pump then normal to compensate for the new style lifters. When tested for durability the ecm is used to calculate needed oil changes. I know on our Buick that means 6500 miles. With todays oils even cheap ones this should not be a big problem. One of our engineers drove a Buick Lacrosse Super from Michigan to D.C. and he is no light footed driver and recorded 27.8 MPG not bad for 300 hp and as heavy as it is! I think most of us could see over 30MPG. I hope since my pay check is directly affected by GM's programs and with their 100,000 mile warranty in place, having them clog or shorten the life span of the engine won't be true. Remember that Chrysler also has a similar system, so does Ford I think?

Forgot to add that all of these systems default to max. number of cylinders they have.

I was talking about "supposed" 1/2 ton diesels which are coming in '09 with a cousin who works for Ford in their advanced planning area. I had read that Ford, GM, and Dodge were introducing small diesels in their light trucks starting in '09. Well....he sees designs out to 2013 right now, and they don't have any diesel on the docket in that time period. Obviously this doesn't say anything about GM or Chrysler, but if one of the 3 were introducing a 30+ MPG truck, you'd think the other two would be right there as well. I think this whole small diesel rumor is just that....a rumor. I asked my cousin why they weren't already building small diesels, as they would sell more of them than they could make if the price was not much more than a gas truck. He said they did many surveys,and there is no customer demand. Well...if there isn't an oil exec. standing behind the curtain of that decision I'd be shocked...
Spence

I'm pretty sure that oil companies make money on diesel sales too. Otherwise they'd register the diesel sales as some sort of "charity" thing, and take a write-off...

The survey question was probably written like :
If you could have paid $3,000 more and gotten a diesel with the exact same performance and 3 mpg more, would you have?
And so people said no.

Yeah, there was no customer demand for the EV-1, either. :rolleyes:

Rick

Every single time I read the title of this thread:
"Is GM getting smart?"

I think
"Doubtful."

Every time...

one thing I noticed , my 99 ford ranger with 125k miles has the original exhaust , you can see the steel and a little bit of rust spots inside the pipe. I just checked out a 06 Chevy Colorado 4cly 6k miles, the inside of the pipe is full of black carbon. is this just a fluke? I'm going to keep my eyes open on all makes, I know Nissan's have a light tint of carbon build up and they all have blue smoke when its cold and you first start driving. It makes me gag when the shop first opens and all the techs are driving in the shop to their bays. I never noticed that smoke on fords unless their was a problem with the engine.

I very very rarely see smoking nissans of any type car or truck. my friends 330k maxima never even let out a single puff, nor does my 240sx, or my ex-gf's dads old d21 hardbody, or my other friends altima...

Jeff

Might be normal for a Colorado. But the one on my 04 Element is still just about clean enough to eat out of. I mean, if you were into that...

Black carbon indicates a rich condition, right? Maybe the one you saw is used mostly on short trips?

coulda been driven around the lot alot or alot of shorter test drives (or alot of test drives in general)

my 95 s-10 has suit in the inside of the pipe, same with my chevette but thats an exception(fully carbed no emmisions finicky air fuel ratio setting)

I should hope not! When I buy a truck, it's not because of fuel economy...it's because I need it to do certain things that a car can't.

My Dad's Ram has MDS cylinder deactivation...not only does it not really help, I can't help but think of the Cadillac V8-6-4 debacle...if you ask me, I say less fancy schmancy technology, not more. I was already chagrined to find out my car had variable cam timing, even though it's a mechanical system...

On a side note, I drive a truck at work. It's an '07 Ranger fleet model with the Mazda-designed Duratec 2.3l 16v, power nothing, automatic, a/c. I get about 20mpg in it with the a/c almost permanently on, though I've seen as low as mid-16's when my co-workers drive it...mostly city driving with some highway-ish stretches.

GM's base 900 gets better FE than the Toyota Tundra. For better or worse in that size vehicle it is an industry leader. I feel all of them should try harder!

Unless you have driven a 4 6 8 Cad. you can't know how bad they really were! Most people can't tell when AFM is even happening and it has been mentioned on this site there should be a light when it is. You had no problem knowing with the old Caddy! People use to think the trans. was shifting into different gears.
AFM and Chyslers MDS is not a cure all. Most people don't see any difference because there pushing there trucks at75 plus. Which immediatly cuts the system off. And you deafeted what it was designed for.
All of these veh. have a narrow window were they work, push them and your in 8 cylinder mode. If someone really tries to drive to see a gain in FE they will. Would they do better with lighter weight, better gear ratios, smaller engines? Yes but thats not what the truck industry builds for the masses!
Have you seen the Tundra commercials? performance is key and lets pull a small house while were at it! I have read over and over how GM, Ford and Chrysler should build more FE into trucks. Seems to me Toyota learned the hype from the big 3 very well! And is going for uncharted territories to perpetuiate the overkill war.
My design for trucks would be this. Quit punishing the average consumer with the ability to tow anything! What happened to towing packages? If you towed you bought the package to do it. Now everyone is forced to because the marketing people feel for resale everyone needs it. Thats crazy but until people change their buying habits, current marketing practices won't either.

I think my Dad's Ram is just so heavy that I doubt MDS ever even kicks in; he's not really fond of driving 75, though, usually stays between 65 and 70 on the freeway. Haven't had any freeway time in the Ram though, since we don't have one in town...

35 mpg CAFE standards applied to trucks would make them absolutely brilliant?

I must have missed your test results. Can you post the experiments you ran and the variables you controlled for, and the variables you were not able to control?

I read an article in a magazine, think it was Motor Trend, last year where they were interviewing a GM engineer. He said that the truck fuel injection programming was set to run a lot richer than on a car across the board. I wish I could remember which mag it was, it was sometime about a year ago while at the doctor's office. Anyway, from the way the article was reading it looked like a person could just get a car computer that uses the same style of fuel injection along with a pinout diagram for both the car and truck, wire the truck to accept the car computer, then get better mileage just off that. It would also explain why a Camaro was able to pull down mid 20s when driven easy, when a truck driven the same way could only get mid teens. And no, weight and aerodynamics wouldn't play that much of a role at the speeds I'm talking about. I always wanted to try it to see if it would work, never actually got to it (I'm pretty lazy). I was going to try this with my 96 Tahoe, but after some heavy soul searching decided that no matter what I did with it I'd not be able to get more than 30MPG and about 13 second quarters out of it, but the same work to a smaller, lighter vehicle could turn 40+MPG and maybe 11 second quarters. Yes, my goals are as high as my a$$ is heavy :D.

No need to get snippy.

If you must know, it gets around 11.5, and close to 15 if it spends any time on a highway. Considering this is about what the 360 Magnum the Hemi replaces used to get, it doesn't look to me like MDS is doing a whole lot for these trucks. Check out the EPA estimates or other drivers' results, and they're still significantly below competitors' results (Ford 5.4, Chevy 5.3, or 5.7 Vortec for that matter). Add to that the fact that my Dad's truck is nearly 6000lbs and the engine's relatively high volumetric efficiency for a truck engine makes it a tad bit revvy, I'm really not sure the MDS is ever even engaging. The way I see it, it's one more thing to break while jacking up the base cost. No thank you on MDS.

Okay, just checking.

Dodges do seem to really suffer on FE.