Highest MPG V8?

[GasSavers_Dust]

I've heard 34 from a C5 z06 owner. Don't know the particulars of it. I know that they have a lean burn system in the PCM. I'm sure with hptuners more could be squeezed out of it.

[monroe74]

My dad swore that he could get 25 mpg with his '66 Dodge Polara, 318 V-8, two barrel carb. But I never personally verified that.

[96hb]

My dad owns an '03 Corvette, so I know for a fact that they can get 30+ mpg if you drive it easy. The RPM's are so low while cruising. I think at 55mph it only turns something like 1500, but tons of power on demand, if/when you need it.

[Wyldesoul]

Yeah. I've always heard a lot of good about the FE that LS1 could get

[GasSavers_RoadWarrior]

Originally Posted by jcp123

Similarly, the Cadillacs with Northstar V8's are known for getting ~27mpg on the open road with little effort.

I knew there was a good reason to drop a Northstar in my minivan....

[bobc455]

Originally Posted by 96hb

My dad owns an '03 Corvette, so I know for a fact that they can get 30+ mpg if you drive it easy. The RPMs are so low while cruising. I think at 55mph it only turns something like 1500, but tons of power on demand, if/when you need it.

Having the RPM so low just astounds me. You still need some power to move the car, but I guess if you have so little aerodynamic resistance the engine doesn't have to produce much torque, so it's okay to run it "down in the mud". I'd be curious to know what kind of timing numbers they use under load at 1500 RPM, since the piston speed is so slow.

I guess a lockup converter is also helpful with the automatics (crown vic & northstar), of course the 5-speed manual (i.e. mustang) being the odds-on favorite.

-Bob C.

[bobc455]

Originally Posted by monroe74

My dad swore that he could get 25 mpg with his '66 Dodge Polara, 318 V-8, two barrel carb. But I never personally verified that.

I've heard lots of claims like that also, but they also sounded like "wives tales" to me too...

-Bob C.

[monroe74]

Originally Posted by bobc455

Having the RPM so low just astounds me.

It's not that shocking that a Vette can do 55 mph at 1500 rpm, when you consider that a VX is only turning 1852 rpm at that speed. 1.5 liters.

[dkjones96]

Originally Posted by bobc455

Having the RPM so low just astounds me.

If you look at the torque on that engine (2001 Corvette test results) you'll see why the engine is able to turn so low.

Obscene amounts of torque everywhere. Over 300Ft-Lbs as low as 1500 rpm!

It's also why this car can cost only 65K and not only keep up but in a lot of cases beat 200K+ sports cars in performance, feel and fuel economy. This is actually the only car GM makes I would buy.

[bkrell]

The mpg numbers in the Vette are not strictly because of a fuel efficient engine. It's a combo of the gearing and the aerodynamics of that thing.