High-MPG Corvette

[hyperyaris]

Many cylinders + 6 gear ratios = low revolutions per minute on the interstate = good fuel economy

[dcb]

32 mpg = not that great

[hyperyaris]

I would humbly argue that for an 8 cylinder sports performance car, it is pretty darn good :/

[roflwaffle]

It's certainly good enough to avoid the guzzler tax, but getting a vehicle, especially something with a manual trans that's as small/low drag as a vette, to do better than 30mpg@55mph ain't too hard either. I'm hesitant to say it could be done w/ gearing alone, but it ain't like cylinder deactivation is anything new. It's just that people who are paying fifty grand and up for a sports car couldn't car less even if it could pull ~40-50mpg@60mph. All that's needed is a tall enough sixth, and a gear lockout in order to avoid the ~$8k ($10k?) guzzler tax.

[dcb]

hyper, my issue is that the OP wrote:

Originally Posted by Big Dave

MPG is more a matter of how you drive than what you drive

But now we have to qualify it with "good for a corvette", and even that isn't that good (because the engine has to fight itself and huge tires and downforce, basically it wasn't designed for MPG).

How you drive does make a huge difference, but only in terms of some percentage of what the vehicle is capable of getting in MPG, thus it is not "more important" per-se. If how you drive was really more important than what, then with the right driver, these two should be able to get about the same mpg, or within %50 anyway:



Of course if OPs point is to say "use what you got" then that is a very worthy consideration. Please do take the time to wring the most mpg out of your vehicles. Takes energy to build vehicles too. But, this looks like a commercial for new corvettes, with false logic, so I don't think that is the point. Worried stockholder? I dunno, what makes people jump to conclusions like that?

[theunchosen]

Cylinder deactivation is not really a good solution.

Even if those cylinders don't have any vacuum. . .have you tried to push a piston in a cylinder? Its not bad if you are just moving one piston through the cylinder, but even then. . .it requires a hammer and a block of wood. To turn the crank with no vacuum on a 4 cylinder I have to have a 2 footer and still pull hard enough that working out later would be a mistake. The engine is fighting that same force about once a second in a v8 if you disengage half the cylinders(by disengage lock the valves open during compression, intake, exhaust and expansion, shut off sparks and injectors).

If you really wanted to make a vehicle sporty but FE friendly as well you have pretty much 2 options. Forced induction from a supercharger that you can switch on and off with a secondary air intake that doesn't have to flow through the pre-cooler, compressor and extra piping or two small engines with the ability to completely disconnect either from the drivetrain completely and deactivate it.

Option one is obviously more simple. Its also obviously cheaper(especially if you do it yourself).

Option two is much more complicated. Its most likely 3-4x more expensive and you have to do it yourself.

Most people chose the charger and an on off switch, but those who chose the secondary engine have something thats really honestly worth bragging about. If you for example took 2 H22A redtops and dropped one in front one in the rear you'd have more hp than the 08 corvette(430 for the corvette and 437 for the twin engine). IT also still leaves you the option of integrating forced induction on whichever motor you won't be using for the FE runs(or both if you go with a supercharger-switchoff). Another large advantage to this over the standard corvette block. . .they have 2 valves per cylinder whereas the h22 has 4.

It also buys you awd that doesn't get bogged down at launch like every other awd system ever made. The problem with AWD arises with the differentials to split the power. Even the GTR's enormously expensive drivetrain bogs down as it switches power over from RWD at launch to AWD pull, given its much better than anything else but it still happens. The only expensive linkage to make sure each engine is sharing the load equally. . .is the billions of dollars of. . .asphalt.

Theoretically I am a fan of the twin engine idea, but practically. . .its not feasible. The advantages two engines buys couldn't be outweighed by the difficulties in manufacturing it. Yes if something goes wrong you could limp home on one engine without further damaging the other at all, but you would need to build a rear engine mount, move the fuel tank, and build a shift linkage that mated up to the transmission in the front as well.

[jamesqf]

Originally Posted by theunchosen

If you really wanted to make a vehicle sporty but FE friendly as well...

You'd buy a Lotus. Pretty close to the top of the US CAFE numbers every year, sometimes #1. Or you could update my old Austin-Healey Sprite.

But first you have to get away from the idea that stuffing a 400+ HP engine in a car is what makes it sporty. That's like trying to turn a bodybuilder into a gymnastics champion :-)

[theunchosen]

I agree the weight plays a huge problem. But if its going to be the size of a corvette and you rip what you can. . .the next and only thing to increase go is hp/torque.

But I agree with James, smaller lighter and more nimble feels sporty. If you have be heavy. . .

[dcb]

As long as we are discussing speed and weight:
Nascar (3400 lbs, lopsided distribution o)
Formula 1 (min 1334)
Rally racing, determined by natural selection

2 wheeled drifting in the snow anyone , though I think this drive has succumbed to inertial forces.

[MazdaMatt]

Nascar is muscle cars, not sports cars... ever watch those clowns try to run a road course... ha... what a crap shoot comedy show that is. I'm glad to see that they are at least trying for FE in a sports car. The big point here is that people paying that kind of money for that kind of car don't give a isht about FE - they ONLY want to tell their buddy's how many ponies are under the hood, and look cool with their mirror shades flooring it to the next stop sign. Kudos, IMO, for trying to boost the MPG.