GM plans 3.9-liter V-6
By Richard Truett
Automotive News / April 11, 2003

General Motors will add a pushrod 3.9-liter V-6 engine to its lineup in the 2006 model year, the automaker said on Friday. The engine will be built at the automaker's Tonawanda, N.Y., engine plant.

The new V-6 and a 3.5-liter version using the same architecture will be equipped with GM's fuel-saving cylinder-deactivation technology that shuts down cylinders based on vehicle speed and engine load. GM says the system delivers an 8 percent gain in fuel economy.

GM is investing $300 million in the plant for new machinery and production lines. The upgrades are expected to be completed by the fourth quarter of 2004. The Tonawanda plant produces GM's 2.2-liter Ecotech four-cylinder; 3.1- and 3.4-liter V-6s; 8.1-liter V-8; 2.8-liter four-cylinder; and 3.5-liter five-cylinder engines. Employment is 3,340.

 

That 3.9L sounds like good news. I think this would be the new base Camaro engine.

We can assume that do to cost, the base V6 Camaro will not get a DOHC V6. So it will mose likly stick with a pushrod V6

The 3.5L pushrod V6 puts out 200HP so a good guess would be that the 3.9L version of this engine will have about 225HP / 240tq give or take a little. This would make a competitive base engine.

 

Is this 3.9L still going to be a 90 degree V or is it a 60 degree? Is this based of the 3.8 or is it a completely new design?

 

Yup, that was my first thought too... it would make a lot of sense.

Plus the timing is just about perfect.

 

Like the 3.5 in the new Malibu, this 3.9 will be an evolution from the current 3.4l, 60 degree V6.

 

The 60* V6 has had a long run. Didn't it get its start with the X-car? Kinda surprising that GM's going with the 60*, but I guess it makes sense when it comes to development/packaging costs.

 

I honestly dont know a lot about this motor. But mine has 116,000 on the clock and still runs great. Seems liek a good design to me!

 

Tell me about it. The 3.4 I had in my 95 Firebird had over 130k miles and never leaked a drop of oil. The one in my Grand Am runs pretty good too. Only problem I have with the one in my Grand Am is that it is harder to work on since its in there transversely.

 

Here's a stupid idea, at least for anyone who remembers the Cadillac 4-6-8. The 1982 cylinder deactivation concept failed in part because of the lack of technology, but it really wasn't the brightest way to fuel efficiency. Ever hear a V8 firing on four cylinders - not too smooth! Wait until you hear a V6 cruising on just three.

Sure Mercedes has been playing around with cylinder deactivation on the S-class for the last few years, but mostly on European models. I'm not saying that GM's move in this direction will be another disaster, but I would venture that anyone with an ounce of common sense will avoid these new V6s for the first few years.

It makes me wonder how many buyers have been complaining about the fuel economy of the old Buick V6. When a car like a Buick Regal or a Chevrolet Impala can pull 35mpg in real-world highway driving, that's pretty impressive

 

I doubt that analogy is accurate because from what I understand about the current cylinder deactivation is that the cylinder when shut off just pumps air freely and never gets compresssion in it.

 

WHY does everyone keep referencing the failed 8-6-4 Cadillac motors of 2 decades ago? This is NOT the same technology, do you really think GM would go down this road AGAIN if it hasn't been proven through extensive testing to work?

 

I've heard that the 60*(3.4) actually sounds better than the 90* (3.8), because of teh flow

 

Yeah the 3.4L sounds a lot better. Ive got Borla on my '95 and many non car people mistake my car for a V8. The 3.8L have a more raspy and ricey sound. This new 60* should be a great base motor for the 5th gen.

 

Maybe its because GM has continued to put out poorly engineered powertrains in recent years. Does anybody remember the 3.4 liter DOHC motor in the GM-10 cars? I know a guy who received a new Monte Carlo after they couldn't fix the myriad of problem with his Z34. How about the recent "Premium V6," otherwise known as the "Shortstar?" I've never seen a worse engine/transmission mating than in the 3.5 liter Olds Intrigue and Aurora.

Cylinder deactivation is an uneccessary technology. Worse yet, it leaves you with unresolved primary inertial forces in otherwise sound motors. Even if you remove the compression in deactivated cylinders, you hardly have a balanced engine.

 

I'm not sure how not firing 3 cylinders in a 6 cylinder engine makes it go from balanced, to unbalanced... It's not like the pistons and crank stop moving or anything...

FWIW, GM's DOD closes off the valves, leaving air in the cylinder (acts like a spring).

Assuming it works and is reliable (I don't see why not, with all the variable valve timing etc. these days) I think it is a valid technology. I don't think it makes sense to reference cars from 20 years ago, either. Why would you not want it? Wouldn't you like to burn less fuel and pollute less - with no loss of performance?? At minimal cost???