[Tone]

Popular Hot Rodding recently did an interview with GM Engineering on the upcoming displacement on demand (DoD), next generation smallblock V8.

They also offered some interesting details on the upcoming 3.9 V6, including power ratings ("Rated at 240hp at 5900 rpm and 245 lb.-ft. of torque at 2800 rpm, the 9.8:1 compression LZ8 will make 90 percent of its peak torque between 1800 and 5800 rpm.") and the fact that the engine will be engineered for both FWD and RWD applications.

See - http://www.popularhotrodding.com/features/.../0405phr_gmdod/

 

[Butta]

Great article! Thank you.

 

[tgagneguam]

Much appreciated post; I hope more like this follow. I'm not an engineer, though I do have a yearning to understand these types of things better. Articles like these help me to move toward a better conception of engine technology, albeit at a glacier's pace.

 

[T-Keith]

I've been waiting for more details on this engine.

Here are my thoughts and observations:
They talked only about the aluminum LH6 for the LWB TB & Envoy, but it also says "Both iron and aluminum versions of the engine block have redesigned oil galleries to support DOD oiling requirements." We can asume from this that the larger trucks are staying cast iron, and also getting DOD.

Their resoning for not offering the DOD on the Corvette and Rainer was that the muffler system used on the TB and Envoy would not package well. This is a poor excuse for the Rainer, perhaps the exact muffler used will not fit, but there should be plenty of room for another muffler to be designed. This may be something they are working on and will debute sooner or later. As for the corvette, It's a sure thing that Vette buyers are concerned about exhaust note, and packaging is tight on the sports car. But would the buyers care about a change in note when cruising in 4 cyliner mode? Perhaps a quieter note would be welcome on long trips?

Lastly, with the V8's mileage going up and the I6s mileage not very favorable on the heavier LWB models will they, or should they, drop the I6 on these trucks? How about DOD on the I6?

 

[MelvinJ]

Originally posted by T-Keith@Apr 22 2004, 02:04 PM
Lastly, with the V8's mileage going up and the I6s mileage not very favorable on the heavier LWB models will they, or should they, drop the I6 on these trucks? How about DOD on the I6?

I think you may be right about this. The extended models are so heavy that the V8 should be standard. Personally, I think the whole extended line of 360's was ill-conceived - top heavy, with ungainly handling, and mileage barely any better than a Suburban but with less room.

But, I see them everywhere these days, so they are definitely selling. Goes to show what I know.

 

[T-Keith]

Originally posted by MelvinJ@Apr 22 2004, 12:00 PM

But, I see them everywhere these days, so they are definitely selling. Goes to show what I know.

Heh. Just because they sell doesn't mean they make sense.

 

[hpmartin]

I have to disagree on the 360's. I never wanted a SUV until those came out with the I6 4200; it gets great gas mileage especially when you compare it to the power output. I wouldn't want one with the V8, though, it gets numbers like the behemoth Tahoe/Suburban, so why bother? The 4200 does fine for those, bumping the highway mpg into the low 20s. And even though it doesn't look like it's much improvement over the V8's MPG, when you drive a lot of miles, it makes a huge difference. IMHO, of course.

 

[usa1]

Great article. Does anyone know how Chrysler beat GM to market with this technology. GM announced this years ago.

Mark

 

[Ming]

Nice! Hope DOD doesn't "eventually" appear in 2010...

The LH6 isn't the only engine that will receive the benefits of displacement-on-demand. We've already mentioned that Daimler-Chrysler's Hemi will be getting some form of DOD in the near future--but we don't have exact details of that yet. What we do know is that GM is coming out with a 3.9L V-6 (RPO code LZ8) which is scheduled to first appear in the 2005 Pontiac G6.

The "high value" 60-degree OHV V-6 will become the staple engine in vehicles which typically had the old 3100-, 3400- and more recent 3500-series engines (on which the LZ8 is based). Rated at 240hp at 5900 rpm and 245 lb.-ft. of torque at 2800 rpm, the 9.8:1 compression LZ8 will make 90 percent of its peak torque between 1800 and 5800 rpm. That compares very favorably with the venerable supercharged 3800 (RPO L67) which, in most iterations, makes 240hp at 5,200 rpm. What's more, the LZ8 does it with only 100cc more displacement, two valves per cylinder, pushrods and no supercharger.

Like the LH6, the LZ8 will have electronic throttle control and cylinder deactivation (running on three cylinders to the LH6's four), but will also throw into the mix variable valve timing and a variable intake manifold for dynamic runner tuning. Variable valve timing will be accomplished electronically by a gear-driven camshaft phaser capable of altering timing by as much as 40 degrees. As a happy coincidence, this feature will also allow the elimination of EGR control.

For the time being, the LZ8 will only be available in non-DOD form, but we've been assured that it will eventually appear. What's more, the LZ8 is designed to work in a rear-wheel drive configuration, which would pave the way for its use in a future base-model Camaro. If that occurs, the LZ8 would trump the '05 Mustang's base V-6 by nearly 40 horsepower while returning the same fuel economy.

 

[AmericanRevv]

GM is still planning on having the DOD in the 2007-8 (can't excatly remember off the top of my head) malibu, right? And I think the E-nox too the year before... right? Or am I thinking of a different Advanced Engine?

I hope the Malibu is still on track. I begged my panrets for 2 years to get me a Colorado when come [came] out... nothing's happend. My dad was guessing I'd be in it in less than a year, but I'd wait to get the malibu, that's how cool I think it is.

 

[silverado_13]

Will we see this technology in the Next generation of Chevy/GMC Full sized trucks?

Also how much of an advantage do u think this will give them over the competition?

 

[AmericanRevv]

Last I heard it is out. But only for commercial use. And maybe only in Canada. It might be either, both, not at all. Last I knew it was supposed to be avliable to the public this fall...maybe. Please don't take my word for this. It's on GM's web site. I don't know if everything still on schedual or not. And I have no idea where I heard the Canada thing, but I did. Can someone else please help him if you know more than me. I'm just going off of what I've heard in the past.

 

[MelvinJ]

Originally posted by hpmartin@Apr 22 2004, 06:53 PM
I have to disagree on the 360's. I never wanted a SUV until those came out with the I6 4200; it gets great gas mileage especially when you compare it to the power output. I wouldn't want one with the V8, though, it gets numbers like the behemoth Tahoe/Suburban, so why bother? The 4200 does fine for those, bumping the highway mpg into the low 20s. And even though it doesn't look like it's much improvement over the V8's MPG, when you drive a lot of miles, it makes a huge difference. IMHO, of course.

Were you talking about the standard length 360's, or the EXT and the XL versions (and the 7-passenger Ascender, for that matter)? I don't have a problem with the regular length ones, and the I6 is a fine performer, although I had hoped for better than 15 mpg city.

I've never driven an extended one, but every report I've read mentions that handling is tippy and very soft, and the I6 has to struggle against the extra 350 pounds that they weigh. The difference EPA ratings are 15/20 for an I6 extended 360, and 14/18 for the Suburban, which is almost negligible.

Of course the 360's do cost several thousand less than a comparably equipped Suburban, and they do turn a bit tighter, so that's probably enough of an advantage to make people buy them.

 

[T-Keith]

Originally posted by hpmartin@Apr 22 2004, 01:53 PM
I have to disagree on the 360's. I never wanted a SUV until those came out with the I6 4200; it gets great gas mileage especially when you compare it to the power output. I wouldn't want one with the V8, though, it gets numbers like the behemoth Tahoe/Suburban, so why bother? The 4200 does fine for those, bumping the highway mpg into the low 20s. And even though it doesn't look like it's much improvement over the V8's MPG, when you drive a lot of miles, it makes a huge difference. IMHO, of course.

I was refering to the extended models only. On these trucks the I6 gets similar mileage to the V8. With DOD, the V8 might be the same as the I6. 14/18 plus 8% equals 15.12/19.44

Trailblazer 2WD LT I6 16/21
Trailblazer 4WD LT I6 15/21
Trailblazer 1WD EXT I6 15/19
Trailblazer 4WD EXT I6 15/20
Trailblazer 2WD EXT V8 16/19
Trailblazer 4WD EXT V8 14/18

-T

 

[hpmartin]

I have no use for the extended models, so I probably wasn't thinking of those. I was impressed with the fact that I could sit in that third row seat quite comfortably, and I'm almost 6 and a half feet tall. But I don't need that extended version; I definitely agree that the standard wheelbase version drives better.

 

[jro4566]

Cool!