How to build a muscle car for better fuel economy?

[Phoenix'97]

Originally Posted by Ecky

If your motor can produce more torque, it's simply capable of burning more fuel at that RPM. More fuel per mile = less miles per gallon. Torque ultimately comes from gasoline.

EDIT: That's not to say there aren't some things you can do which will improve how much usable energy you can get out of gasoline... but for the most part, it's true.

What I am trying to say is that I am burning a set amount of fuel yielding enough power such that the taxation from those two rear hub generators does not effect fuel consumption considerably enough to make much of a difference. In so doing, the goal behind AWD electronic assist is to help keep the V8 motor at very low RPM where it would normally be "lugging" but with the added power from the front electric motors, it can now operate with this notion of "efficiency" which helps to reduce overall gasoline or bio-fuel consumption.

So goes my logic.

[rmay635703]

Originally Posted by Phoenix'97

Well this University is in the process of perfecting this technology to apply to any vehicle. You see how excited I got over finding this product, although it is still in development. It beats the crap out of settling for a Prius! I want my V8 "gas guzzler"!

I have to watch the video again but I think he implies that one of these systems puts out 200 ft/lbs of torque, thus the two provide a combined 400 ft/lbs of torque!
.

Again on a 2’ diameter tire that is only 400/2 = 200lbs of thrust, I don’t know your weight but if you weigh about 200lbs this is only about equal to you pushing the car with moderate effort, less than what you can do if you push hard.

A normal economy car can put out thousands of foot pounds of force, even anemic ones

This is why gearing does wonders for any system

Now if Ecky wants to reveal the type of ebike motor he uses I would love to put one on the back wheel of my Insight but I bet the bearings wouldn’t survive even in my 1800 lb car, I also bet the gas motor would need to launch the car.

That said, a hub motor would work fine at steady speed on flat ground but I bet it wouldcrud up and fail.

I would love to be proven wrong, cause I have wanted a workable hub motor for years, just none thus far work for a car

[Phoenix'97]

Originally Posted by rmay635703

Again on a 2’ diameter tire that is only 400/2 = 200lbs of thrust, I don’t know your weight but if you weigh about 200lbs this is only about equal to you pushing the car with moderate effort, less than what you can do if you push hard.

A normal economy car can put out thousands of foot pounds of force, even anemic ones

This is why gearing does wonders for any system

Now if Ecky wants to reveal the type of ebike motor he uses I would love to put one on the back wheel of my Insight but I bet the bearings wouldn’t survive even in my 1800 lb car, I also bet the gas motor would need to launch the car.

That said, a hub motor would work fine at steady speed on flat ground but I bet it wouldcrud up and fail.

I would love to be proven wrong, cause I have wanted a workable hub motor for years, just none thus far work for a car

My car should weigh around 3000 lbs ish. I can't imagine that 200 ft lbs per hub motor, a combined 400 ft lbs, would be something to snub. At 4000 RPM my car produces 350 ft lbs torque, so think of the fuel required to get me there!

I don't know, the system offered by this University doesn't look cheap and under powered.

I suppose if worse comes to worse, I would have to figure out how to have this system programmed for those moments when my V8 starts to lose vacuum pressure under higher load conditions. This includes going from a stop, sudden acceleration, and even cruising on the highway and hitting a slight incline. I just thought it would make life easier to have the thing operating all the time and making sure that it was charging itself while it was in operation so that it wouldn't need to be manually recharged.

Certainly this is something that will require more time to research.

[Ecky]

Originally Posted by Phoenix'97

What I am trying to say is that I am burning a set amount of fuel yielding enough power such that the taxation from those two rear hub generators does not effect fuel consumption considerably enough to make much of a difference. In so doing, the goal behind AWD electronic assist is to help keep the V8 motor at very low RPM where it would normally be "lugging" but with the added power from the front electric motors, it can now operate with this notion of "efficiency" which helps to reduce overall gasoline or bio-fuel consumption.

So goes my logic.

I see two points here:

Q) Is the loss of this system going to actually be noticeable in my fuel economy? Because I'd really like to have AWD

A) Yes, I think it will. The amount of loss in fuel economy will be directly proportional to the amount of power that you add to the front wheels. If you only wanted 1HP up front, it would be miniscule. You could add 200HP up front, but you probably couldn't go 20 miles on a tank of gas trying to turn those generators. And, the more power you try to send up front, the less total power your car will have - because the system operates at a loss!


Q) Can I prevent my motor from lugging this way?

A) Lugging happens when your load is too high. This will add load to the engine - you're burning more fuel, after all, and your gas mileage is going down by doing this. The generators don't run for free, they're leaning heavily on the gas engine! If anything, it will lug worse.


You're asking to put extra load on the gas engine to give it to front motors, but you'll always load the gas engine more than you get from the front motors.

[Ecky]

Originally Posted by Phoenix'97

My car should weigh around 3000 lbs ish. I can't imagine that 200 ft lbs per hub motor, a combined 400 ft lbs, would be something to snub. At 4000 RPM my car produces 350 ft lbs torque, so think of the fuel required to get me there!

I don't know, the system offered by this University doesn't look cheap and under powered.

I suppose if worse comes to worse, I would have to figure out how to have this system programmed for those moments when my V8 starts to lose vacuum pressure under higher load conditions. This includes going from a stop, sudden acceleration, and even cruising on the highway and hitting a slight incline. I just thought it would make life easier to have the thing operating all the time and making sure that it was charging itself while it was in operation so that it wouldn't need to be manually recharged.

Certainly this is something that will require more time to research.

You can't charge it while simultaneously draining it. It's one or the other. If you're going to add a hybrid system, pick the times you'll be taking power out of the battery to put on the road, and the times you'll be taking power to put back in the battery. This usually makes the most sense when accelerating/decelerating.

[Ecky]

I'd like to add that the 200 ft-lbs of torque you see on the electric motors isn't the same as on your gas engine. Their torque curve looks something like this:




As you rev your gas engine up, it builds more power. That's not true of electric motors. Power is constant, so torque is actually highest at 0rpm. In an electric car, if you mash the accelerator, acceleration is constant because torque drops as RPM rises.

This is why they make a great compliment to gas engines - the produce the most power where gas engines produce the lease.

But you still have to get the energy to run them from somewhere.

[Phoenix'97]

So these motors no longer produce torque after 500 RPM? If that is the case I understand now why they are so limited.

[funkhoss]

Originally Posted by Phoenix'97

So, what do you any of you think about these ideas to modify my second-generation LT1 motor for better fuel economy and a good enough increase in the "seat of the pants" performance.

To be quite honest, I haven't read word for word through everything in this thread, but I've skimmed most of it. I have to wonder, though, that if this (above) is the main goal of the discussion, we haven't gotten a bit far afield.

To Phoenix'97, I humbly suggest that you take a look at the thread on my Caprice station wagon: 94 Caprice Wagon 5.7L project--46 MPG so far

My car has the same engine as yours, except for the cylinder heads and camshaft. The heads are iron instead of aluminum (although it's been well established in the performance community that the iron LT1 heads flow better than the aluminum ones) and the stock B/D-body camshaft favors low RPM torque over higher RPM horsepower.

My car is also significantly larger and heavier than yours. Considering that yours weighs about 1000 lbs. less, and has much less frontal area, in theory, you should be able to achieve significantly better numbers than I have.

I can consistently achieve 46 MPG with my wagon on long trips in warm weather. And the modifications that I have made are very simple and very inexpensive--no radical engine building, no hybrid conversion. I can even get well into the 40's MPG when I have my super-heavy, 14-bolt 4.10 ratio rear end installed!

In my opinion, the best thing you can do, given your goals above, is install a kill switch and learn how to pulse and glide with engine off coasting. You could "warm over" your car with a bunch of bolt on mods, increase its "performance", and still achieve 40+ MPG under normal "non-performance" driving conditions.

Just my two cents. This is probably all that I'm going to contribute to this thread, but...there it is.

-Funkhoss

[Ecky]

Thanks Funkhoss, your numbers speak for themselves. Conservative driving with engine-off coasting can go a very long way, and anything to keep RPM down, vaccum low and load high is going to improve efficiency.

Originally Posted by Phoenix'97

So these motors no longer produce torque after 500 RPM? If that is the case I understand now why they are so limited.

It depends on how the motor is wound. It might be 1000rpm, or 200rpm, it just depends on the motor. I was trying to communicate the shape of the torque curve for electric motors, that particular graph doesn't apply exactly to all electric motors. Ignore the numbers.

Anyway, the stock tires on your car have a circumference of 82.2 inches. A hypothetical hub motor that tops out at 500rpm at 24v will move your car along at 39mph, but will have a top speed of 78mph at 48v and 156mph at 96v. Electric motors play by different rules than gas engines do.

[Phoenix'97]

Originally Posted by funkhoss

My car has the same engine as yours, except for the cylinder heads and camshaft. The heads are iron instead of aluminum (although it's been well established in the performance community that the iron LT1 heads flow better than the aluminum ones) and the stock B/D-body camshaft favors low RPM torque over higher RPM horsepower.

My car is also significantly larger and heavier than yours. Considering that yours weighs about 1000 lbs. less, and has much less frontal area, in theory, you should be able to achieve significantly better numbers than I have.

I can consistently achieve 46 MPG with my wagon on long trips in warm weather. And the modifications that I have made are very simple and very inexpensive--no radical engine building, no hybrid conversion. I can even get well into the 40's MPG when I have my super-heavy, 14-bolt 4.10 ratio rear end installed!

In my opinion, the best thing you can do, given your goals above, is install a kill switch and learn how to pulse and glide with engine off coasting. You could "warm over" your car with a bunch of bolt on mods, increase its "performance", and still achieve 40+ MPG under normal "non-performance" driving conditions.

Just my two cents. This is probably all that I'm going to contribute to this thread, but...there it is.

-Funkhoss

So are you still using the stock B-Body camshaft? I have been posting in other forums trying to figure out the best set-up for my F-body LT1 which gives me the additional low end torque I seek while also giving me more seat-of-the-pants feel that I have been desiring, which is why I have been so adamant about the TPI intake. I don't drive beyond 5000 RPM when I have my fun so I figured the TPI intake was a perfect fit.

How the heck are you achieving 46 mpg on a 4.11 gear ratio?! Even when my car was in the best of shape I never could achieve that kind of mileage, and I have tried everything from detuning and experimenting with sucking in hot engine bay air to try to improve my mileage. How?!