Drove a 3900 Impala, MY '08 today...

[DEI37]

I got to drive one of these today. I was alone, so I got on it some. This was the first vehicle I've driven with DOD. It was seamless for sure. But, the car was so weak. The car itself was nice. It rode nice, and had good brakes. But the engine was weak, and the trans was sloppy. I think the ONLY way I'd get an Impala would be if it was the SS.

Maybe they are faster than they feel, but I know my Olds would rape one. Even a stock '97-03 GTP probably would, even with the same HP rating. Oh, how I wish they would have just reworked the 3800. GM could have worked up some good aluminum multivalve heads, incorporated DOD, and still retained the blower if they wanted too.

Sorry guys, but the W-Body 3900 is a let down.

[IsaacHayes]

New cars now are super heavy. You'd be surprised how heavy they are. The SS is limited in power by the ECM too, so it doesn't blow apart the trans. However people that have cracked the ECM have made them run very fast with just ECM tuning.

[DEI37]

Oh, I know, but still. I'm not sure what they are gaining with this engine. Not fuel mileage, that's for certain. The EPA numbers are worse than a L67 GTP is. I'm not sure of the L32 GTP/Comp G's.

The LS4 car has a different trans than the 3900, too. I know they are PCM limited. It is still very much in its infancy as far as being able to be worked with. Cracked? Yes. Usable? Limited. From what I was understanding, those PCM's are write once only.

[gpse3400]

Actually those New impalas are very cush riding and can be decieveing. They are good for a mid to low 15, at least thats what the police cars do.. Also the EPA reworked its economy tests all cars for '08 will have a much lower fuel economy rating.

[DEI37]

Still, going back to new '06 magazine numbers, the weight is the same as a GP GTP, an with MORE power than the L67, is substantially slower, and would even get edged out by a standard GT with a 200HP L36...at very similiar weights.

Admittedly, I'm partial to the 3800 family, primarily because of the superior reliability (my own experience), but if these engines are the future for GM...I dunno.

I did not know that about the EPA numbers. Thanks for clarifying that.

[IsaacHayes]

The DoD version of the 3900 is not 240hp. It reduces the power some. And I bet that impala weighs more than a 97 era GTP. And the GTP's had 240hp, and then in 2004 or whatever when they got the better SC they went to 260hp.

That impala does NOT have more HP than the old l67 GTP, it has 7hp less.

http://media.gm.com/us/powertrain/en...VV6/08_LZG.xls

EDIT: Edmunds lists the 07 3900 impala as 3649 lbs. A 2000 GTP is listed as 3396 lbs, and has 40more ft/lbs of torque and 7 more hp.

And chevrolet.com lists the LTZ 3900 2008 impala as 3,729lbs.

So yeah its heavier and less HP than the L67. It's not that the 3900 sucks :P

[DEI37]

Based on the '06 numbers from MT, the 3.9 was 242HP, and weighed 3550-3700 pounds. I know an '06 GTP was 260HP, and about the same weight.

I do know that the '08 power number is 233HP after reading a little further after the initial post. I didn't this afternoon, though. Sorry 'bout that. I realize that the torque from the L67 is a bit more. But, with a 2.93FDR, it is soft off the line, and has a dead spot around 40mph. It can be tuned out, but stock, it's there.

2003 GTP: 240HP @ 5200rpm, 280ft lb torque @ 3600rpm, 3559lbs, 18/28mpg (taken from Edmunds.com)

2008 Impala LTZ: 233HP @ 5600rpm, 240ft lb torque @ 4000rpm, 3649lbs, 18/28mpg (taken from Edmunds.com)

I really don't want to get in to a pissing match...was more or less sharing my thoughts with the car. To me, it's just not as impressive. The power is smooth, and the engine sounds good. Don't get me wrong there.

I am not finding performance stats for these cars on Edmunds, but MT had the '06 3.9 Impala to 60mph in 7.8 seconds. That was a 242HP engine. Those same people have hustled a GTP to 60mph in 6.6 seconds (without traction control) and a GP GT in 7.7 seconds. The GT is lighter, but was only 200HP and 240ft lb.

I think there is a lot more in these engines than GM is pulling from them, likely for transmission durability. I won't dispute that. But, from the factory, it just didn't seem like what it was gonna be cracked up to be. Somebody put 15psi from a turbo on it, then we'll talk. :P

EDIT: And, the 3900 has variable valve timing AND aluminum heads on top of being a slightly larger engine.

[PCGUY112887]

I had a chance to ride in a new Roush Mustang the other day (had the roush body but not the blower). Even with a 300hp 4.6L, between even sloppier transmissions nowadays and heavier cars (this was a convertible as well), they just aren't as fast as older cars with lower HP numbers.

[SappySE107]

And its NA, why must we still compare apples to oranges.

[PCGUY112887]

And its NA, why must we still compare apples to oranges.

?

HP is HP.

[DEI37]

Then use the numbers for a GP GT. But, the picture is that much worse when you do. Lose a hundred pounds, 40HP, and 40ft lb torque, and it's still just as quick with better fuel economy. That's what I'm having to point out now.

My initial thoughts were simply that the 3900VVT/DOD just wasn't up to what I thought it would be. After hearing all the hoopla...I was anxious to drive one. I did, and was left wanting...A LOT more.

EDIT: What I DID like was that power did not seem to fall off past 5300rpm or so. In fact the tach indicated 6100 or so, and it was still pulling alright.

[SappySE107]

So an S2000 that makes 200 hp is the same to you as the 72 corvette that makes 200hp.

[SappySE107]

Id like you to show some proof on MPG after what lorenzo has said on the ratings. I woud also like to see a timeslip or video of these 2 setups racings.

My suggestion, go drive a G6.

[DEI37]

I'm simply pulling rating from Edmunds, as I've already stated.

To post #12, not hardly. This is all in regards to a "new & improved" engine versus an old and "outdated" platform. I am now simply implying that with a lot less money, I think GM could have done better. And, like I've already said, my first post was simply a driving impression. I didn't say anything sucked. It was just a let down.

I would love to drive a G6 3.9. Especially with a 6M. Lighter, and better gears...that should be a hoot to drive. I drove a 3.5 G6 with an automatic, and it was nice enough. I guess that car had been through the ringer, so I won't comment on it.

I don't have vids or timeslips of them racing, obviously. All I've got is my Olds versus a LS4 MC.

Here's the link for that: http://vids.myspace.com/index.cfm?fu...deoID=11414494

BTW, I still get just shy of 30mpg on the highway. At 72mph, all four windows open, and about 300HP/335ft lb torque on tap.

[gpse3400]

Here's a couple of tests.

http://www.motortrend.com/roadtests/sedan/112_0108_family_sedan_comparison

http://www.motortrend.com/roadtests/sedans/112_0704_police_car_comparison

http://www.caranddriver.com/roadtests/6746/2004-pontiac-grand-prix-gtp-competition-group-page3.html

When I'm in the Monte it always gives a sensation that I'm going slower than I really am. They really reworked the chassis very well in '06.

One thing you'll notice is the speed is in the quarter is right up there with a 3800sc so the power is definataly there. just one steps off the line harder than the other. 3800 isnt really a top end engine in its stock form....which explains alot...