I don't know about the engines you've mentioned above but Subaru offers 2 engine options in their Outback.

1. 2.5L turbocharged I-4 : 243hp/241lb-ft tq. 20/26mpg with 5spd auto and 23/28mpg with a 5spd manual. Car weighs 3605lbs with auto, 3535lbs with manual.
2. 3.0L N/A flat 6 : 245hp/215lb-ft tq. 19/26 with a 5spd auto. It weighs 3610 with auto (no manual option).

That's about as close a comparo as i've seen. 2 different engines with similar hp outputs in similar cars with similar weight. But the fuel economy and tq output favors the turbo 4. And from the performance #'s i've seen, the turbo 4 was significantly quicker as well.

I don't mind a smaller turbo 4 or 6 vs a larger N/A 6 or 8 as long as the performance and fuel is comparable or better. As in the case of the Subaru above, i'd rather have the turbo 2.5 over the N/A 3.0L any day of the year.

 

With 140HP??? That could end up with an SS badge

Seriously though, once the warranty is up, could you imagine even thinking of increasing the boost on that thing???

And 38mpg??? Woot!

 

Yeah. It will make an awesome engine in the Aveo. And a good one in the Cobalt.

 

My thoughts exactly.

Think about it. A 140hp 1.4L turbo Ecotec puts out 100hp per liter. The only production V8 GM offers with similar numbers is the LS9, and the only engine that bests it is the 260hp 2.0L turbo Ecotec in the Cobalt/HHR SSes.

The 2009 Aveo5 is a nice looking little car. Packaged with this engine, a six speed (A6 or M6) and a suspension/wheel package would make for a neat little pocket rocket for under $15k. I'd think they'd sell like hotcakes.

 

My 1986 Cutlass weighed 3400 lbs, and the 307 put out a whopping 140 hp. The thing merged with traffic just fine. Fuel mileage wasn't great, but it never felt sluggish, just not fast.

 

You can't compare lawnmowers to cars.
Let's put it this way, you drive a V6 Camaro @ 75% max power, what 5,000rpms? like 2nd gear....on the interstate, and I drive a V8 @ 1,600rpm in Overdrive.
You're saying you'd be more efficient, using less fuel to travel the same distance????

I'm no engineer but, doesn't sound right to me.
And I believe car "B" will last longer too.
Not trying to be smart, I just don't see it.

 

No, you have to stretch it a bit further to get close to the comparison Eric is alluding to.

In your car at 1600rpm in overdrive, you're pushing maybe 20 road hp. Your typical LS1 is going to get 28-30mpg in this scenario.

To operate as Eric pointed out- Engine "B" would have to be something really small- say a 400cc engine with a 25hp rating. Operating it at 80% load to maintain the same speed noted above, it would most certainly do better than 28-30mpg.

To compare to a big rig- our cars get 30mpg rolling down the highway carrying 3700lbs, including the weight of the vehicle. You have almost no throttle angle, and the engine isn't loaded. Compare that to my Dad's Freightliner, which knocks down 6.5mpg with 80,000lbs gross weight. And, at that weight, the turbo is spooled up- way up- almost the entire time. So, he loses 75% efficiency to our cars in terms of MPG, but is pulling 40x the weight.

 

Todd and Eric are Correct. All other vehicles use alot smaller engines at a higher state of use. To use the big rig example again, the total weight 80,000lbs is being pulled by a 400hp 15.0L engine. What if that was a 3200lb car with a 800lb load equaling 4000lbs. Thats 5% of the semi's weight, give it 5% of the power (20hp) and 5% of the displacement (0.75L or 750CC). In a perfect world the mileage would be 20 times greater than the semi's(6mpg) for a total of 120mpg. Problem is no one want to do 0-60 in 60 seconds and lose 10mph everytime you go up a hill.

GE locomotives are another shining example of efficiency. They can move 2000lbs 400 miles on 1 gallon of diesel according to the latest Union Pacific commericals.

Whats up with all this aveo talk? Have any of you seen the Astra? Much better looking car, I'd be happy with a 140hp 1.4T 6spd in an Astra.

As for the 3.0L vs I-4 turbo question, it can be a mix up once you add in the extra cost for premium fuel for the turbo. Point in case, my 3.0L maxima calls for premium, I switched over to 87 this year. I would be very hestiant to switch a turbo car over to 87. At $3 per gallon for 87, 91 cost $3.20 or more. You should add in the 7-8% increase cost in using premium to the added mpg that the I-4T might provide.

A great example of this is the epsilion. Saab 9-3 2.0L turbo, 19/26mpg, 2.8L turbo 16/26mpg. Thats on premium.

Chevy malibu, 22/30mpg 2.4L, or 17/26 with 3.6L. So its really hit or miss. The real way to increase mpg on the cheap is to buy a car with a manual transmission. I think cafe will mark the return of the stick. On the Saab 2.0L turbo the mpg jumps to 29 highway instead of 26. Thats 11%, which if you are really **** will make up for the 7-8 percent cost of running premium.

 

I just want to point out that it takes quite a bit more than 20hp to move a 3500lb car down the road at ~60mph. Probably 50-60hp.

Your point is still valid.

 

Actually, it's not as high as you think.

Car and Driver used to publish "road horsepower" numbers with all of their road tests, which described the amount of power required to move the car at 55MPH. Going from memory, most passenger cars were under 20 HP.

 

That's your opinion. While attractive, the Astra is a Saturn (Opel in europe). Chevy is the low price/ high mileage brand for GM. A pocket rocket Aveo5 would fit perfectly in their lineup. It'd be kind of like the turbo Dodge Colts from the 1980s.

Valid points. I'd be interested in the numbers a turbo 4/A6 Malibu could put out. Either with the 1.4L or 2.0L versions.

 

I wouldn't trust those numbers. It's somewhat common for A/C systems to use more than 20hp in warmer ambients.

 

CAFE does not care what type of gasoline you require.

 

I recently purchased a 2008 G6 with the 2.4L I4 that gets like 164 or 169 HP (can't remember which one of those two). I would gladly give up 30 HP to gain 5 MPGs. I was spoiled by my last car, a 99 Saturn SL with a 5 speed and I loved the 39MPG highway. My girlfriend's 2001 Saturn SL is an auto and only gets like 33MPG highway. Why the hell don't they have more 5 speed automatics so there isn't such a disparity?

I'm guessing that between dropping 30 HP (maybe a 2.2L instead of 2.4?) and adding a 5th gear to the auto tranny, my G6 would go from 30-32 MPG highway into the 38-40MPG range. That would be EXACTLY what I'd want out of my daily driver.

 

Even modern compressors? If so, evidence? AFAIK, a modern A/C compressor requires at most 1-2hp.