GM's NA small engines

[cmattson]

Ok, we know that GM's had a substantial investment into their transmissions - with the 6speed fwd and 6speed rwd just hitting the markets. The Allison transmission simply cannot be beat. For engines:

6-speed pushrods:

I know that the 3.5l (as used in the Impala) and the 3.9l have been getting active displacement & variable valve timing.

6-speed DOHC:

The 3.6l variant of this engine is rumored to be getting direct injection - and should push around 300hp. I haven't heard anything about the 2.8l, 3.2l. This engine was designed so that you could have different bore sizes through the use of cyl. sleeves. It can displace anywhere from 2.8l to 4.0l. I'd imagine that the 3.6l's DI system could be ported to any of the other engine sizes in this family.

Now, here's where I get to my point:

What is GM doing with small engines? I know it's hard to get worked up over 4cyl's. They aren't terribly exciting, but let's face it: with $3.00+ gasoline, having a peppy, smooth, reliable, gas-sipping 4cyl should be tops on GM's powertrain to-do list.

The Ecotec 2.0/2.2/2.4 variants routinely get panned by the auto press as being 'course'. The power output is just average amoung similarly sized competitors engines - as is it's fuel economy. DI will help it's fuel economy and it's power output, but something needs to be done in terms of refinement. How about a smaller engine (1.5l-2.0l range). The Aveo should push 40mpg+ - that's inexcusable -- especially since you have GM Europe to leverage.

I'd harp on small diesels as well, but with new emission laws taking place, it's substantially harder for a manufacturer to make a profit on the clean-small diesel/compact-car combo-platter -- so I won't question GM waiting for the dust to settle on this one.

[Drew Dowdell]

Ok, we know that GM's had a substantial investment into their transmissions - with the 6speed fwd and 6speed rwd just hitting the markets.  The Allison transmission simply cannot be beat.  For engines:

6-speed pushrods:

I know that the 3.5l (as used in the Impala) and the 3.9l have been getting active displacement & variable valve timing.

6-speed DOHC:

The 3.6l variant of this engine is rumored to be getting direct injection - and should push around 300hp.  I haven't heard anything about the 2.8l, 3.2l.  This engine was designed so that you could have different bore sizes through the use of cyl. sleeves.  It can displace anywhere from 2.8l to 4.0l.  I'd imagine that the 3.6l's DI system could be ported to any of the other engine sizes in this family.

Now, here's where I get to my point:

What is GM doing with small engines?  I know it's hard to get worked up over 4cyl's.  They aren't terribly exciting, but let's face it: with $3.00+ gasoline, having a peppy, smooth, reliable, gas-sipping 4cyl should be tops on GM's powertrain to-do list.

The Ecotec 2.0/2.2/2.4 variants routinely get panned by the auto press as being 'course'.  The power output is just average amoung similarly sized competitors engines - as is it's fuel economy.  DI will help it's fuel economy and it's power output, but something needs to be done in terms of refinement.  How about a smaller engine (1.5l-2.0l range).  The Aveo should push 40mpg+ - that's inexcusable -- especially since you have GM Europe to leverage.

I'd harp on small diesels as well, but with new emission laws taking place, it's substantially harder for a manufacturer to make a profit on the clean-small diesel/compact-car combo-platter -- so I won't question GM waiting for the dust to settle on this one.

175421[/snapback]

I think the 2.8 CTS with DI should be the "greenline" model. Bump up the HP to around 220hp and leave the rest of the improvements to better fuel efficiency.

The Aveo still uses a Daewoo motor... it doesn't benefit from any of GM's engine technology.

I've never found the ecotechs to be *that* bad. The Alero I borrow from time to time is smooth, quiet, and efficient. I want to point out that the GM Ecotechs typically do much better than their EPA rating while the Asians to worse than their EPA rating. 36 mpg highway in a 2005 Alero is pretty easy to do. A 6-speed and DI in a similar size/weight/aerodynamic car should easily see over 40.

<wishful thinking>Wouldn't it be nice if, through the combination of VVT and DI, you could press a "sport mode" button on the dash and get an instant boost in HP. This would be interesting in the 2.8 CTS with VVT and DI. Normal mode gets you 215hp and 30mph highway, sport mode gets you 255hp and 23mpg highway.</wishful thinking>

[cmattson]

I think the 2.8 CTS with DI should be the "greenline" model. Bump up the HP to around 220hp and leave the rest of the improvements to better fuel efficiency.

The Aveo still uses a Daewoo motor... it doesn't benefit from any of GM's engine technology.

I've never found the ecotechs to be *that* bad. The Alero I borrow from time to time is smooth, quiet, and efficient. I want to point out that the GM Ecotechs typically do much better than their EPA rating while the Asians to worse than their EPA rating. 36 mpg highway in a 2005 Alero is pretty easy to do. A 6-speed and DI in a similar size/weight/aerodynamic car should easily see over 40.

<wishful thinking>Wouldn't it be nice if, through the combination of VVT and DI, you could press a "sport mode" button on the dash and get an instant boost in HP.  This would be interesting in the 2.8 CTS with VVT and DI.  Normal mode gets you 215hp and 30mph highway, sport mode gets you 255hp and 23mpg highway.</wishful thinking>

175429[/snapback]

I drive an Ecotec-powered Malibu daily and I agree with you that (1) it's not as course as the press touts, and (2) it's mileage is generally better than advertised. That being said, improvements can (and should be made). I've definately driven smoother engines. There is no reason why the Aveo should still be straddled with a relatively inefficient (for it's size) engine.

As for your wish, turbo-charging is probably the closest to your design. When the engine isn't working hard, the prop in your exhaust isn't spinning as fast. The turbo charger isn't providing as much boost and your engine is as-close-as-possible to being normally aspirated. Goose it up and that increased engine exhaust will spin that turbo that much faster, the unit will provide that much more boost, and your engine will output that much more power (and correspondingly, that much more exhaust pressure -> rinse, wash, repeat). The use of a turbo isn't bad at all. I suspect that more manufacturers will be open to it as it's technology that's been around forever and gas prices increasingly put pressure on manufacturers to deliver a blend of power and fuel economy.

[76ChevyTrucker]

My only complaint about using turbos for power increases is the hell that it puts engine oil through, and if you're like some normal "Joe Blow"s you won't change the oil and create havoc in your engine.

[razoredge]

I still havent drivin an Ecotec but I did have the 2400 Alero loaner, I was impressed.

Oldsmoboi - I believe the 3900 with the variable intake and VVT does just what your talking about by simply pressing the gas pedal. I also know for a fact that the SC 38 (L67) does exactly what your talking about. Its as tame as a pony for Grandpa driving and spirted as a Stallion when you put her down.

Which brings me to supercharging. Cmattson = I though supercharging was much more fuel conscience when no demand was placed on the engine and then it just keeps giving and giving as RPMs increase. I have been led to believe turbo charging is not fuel conscience for typical driving, am I wrong?

This 260/260 turbo DI Ecotec engine for the Solstice is awful impressive at least from reading about it. But thats from a performance aspect, not sure about milage. Use this tec and apply it to a 1.5 for compact commutor cars and you might have something

Ive seen this TDI Audi R10 race car in action (on TV screen) and its quite impressive. Set record laps at LeMan. Its so quite you can hardly hear it and it doesnt smoke. Unfortuanantly the R10 was not at Limerock when I went but it will be next year, then I can get a better look, listen, smell. We loved our VW diesel from a mileage standpoint but thats about it. It vibrated, rattled and smelled a bit. Those days are over, diesels have come a long ways. The US government needs to give them a chance to get a foothold

Once again I will say we need to get the weight back out of these fat pigs if we really want to commit to performance and fuel mileage in the same breath. VW Rabbit as I recall was 1800 or 1900 some odd pounds. Seems we could find a happy compromise. High belt lines and "raised ride height" plus "screw areodynamics" is certainly not the answer. It all takes time and trends sometimes do our thinking for us, not our brain

[thegriffon]

…The Aveo still uses a Daewoo motor... it doesn't benefit from any of GM's engine technology.…

175429[/snapback]

The Daewoo engine in the Aveo is a development of GM's Family 1 engine family from many years ago, so it doesn't genefit from any of GM's recent engine technology. GM do Brasil builds another generation of primarily SOHC FlexPower Family 1 engines, and GM Europe builds the latest DOHC Ecotec generations. The newest uses a smaller, lighter block and features turbocharging, TwinPort or Dual-CVVT technology. Older Family 1 blocks range from 1.4 to 1.8 L, but the latest is only built in 1.6 and 1.8 L capacities, as a newer, more efficient 1.4 has been added to the latest Family 0 block (1.0 3-cyl to 1.4 4-cyl). GM Daewoo has its own S-Tec sub-Family 1 engine family (0.8–1.2 L), even smaller than GM's Family 0.

[Dsuupr]

Maybe part of Lutz's comment about GM products getting better gas mileage has to do with them advertising the Ecotecs actual mileage rather than devaluing them.