Anyone know how much Hp it takes, to drive a 914 across flat ground? Options

[ClayPerrine]

Having a brain fart (don't want to talk about this idea yet).. and I want to know if anyone knows the HP required to drive a 914 down a level road at 60 mph? Let's assume that it is bone stock. I know it takes less than 76 HP.. or the 1.7/1.8 would never be able to hold freeway speed.

[Aaron Cox]

it takes alot of hp to get moving, takes very little to sustain speed (IMG:style_emoticons/default/smile.gif)

[type11969]

what is the frontal area of the 914? With that, you should be able to come up with a pretty good estimate. My guess is about 20-30 hp though.

-Chris

[Otmar]

About 180 wh/mile if everything is just right, so that's 10,800 W which is also about 14.5 HP.

[lapuwali]

A test done my Car & Driver awhile back showed a number of normal sedans with numbers under 10hp at 60mph. Something like 8-9hp was the average. Most motorcycles (small frontal area, but terrible aero) use up something around 15hp. I'd place the 914 at 10-12hp, as a wild guess. I'd doubt it's as high as 20hp.

[skline]

Why would you want to know this? I always figured the more the merrier. (IMG:style_emoticons/default/driving.gif)

[nebreitling]

hybrid 914?

[ClayPerrine]

Why would you want to know this? I always figured the more the merrier. (IMG:style_emoticons/default/driving.gif)

I was reading the thread on the electric 914, and it reminded me of a car I saw years ago. It was a Huge Lincoln Town Car, but it got approximately 100mpg. To do this, the owner had removed the drive train, and put in hydraulic motors at the wheels. Then he put an huge accumulator and a l briggs and stratton engine from a lawn tractor driving a hydraulic pump. On level ground the motor could push enough fluid to keep the car at freeway speed, and slowly fill the accumulator. With a full accumulator, the available torque would absolutely roast the tires. But when the accumulator emptied, it wouldn't pull a sick whore off a commode.

What if a 914 were done this way? I did some calculations, and a 17HP motor attached to a pump that will push about 50Gallons per minute could run 2 5.06 cubic inch hydraulic motors without a problem, driving a 914 on stock tires about 60 mph. IF we add an accumulator to the mix, we should be able to really make it accellerate fast. Each motor is capable of about 125 ft/lbs torque. That's Per Wheel. The 17 horse engine would run at a constant speed, which is more efficent than accellerating and decelerating. With the proper valving, we could even make "closed throttle" coasting refill the accumulator.


Kinda hare-brained, but anyone else think this is doable?

[lapuwali]

Question is, what's the efficiency of the hydraulic motor? Would it be more or less efficient to have the 17hp engine power a generator, which charges batteries, which run electric motors? The advantage of the hydraulic system is the accumulator is likely to be relatively small and light. The advantage of the batteries is you could roast the tires for longer before you ran out of juice (assuming full charge).

[ClayPerrine]

It seemed to be very efficent on the Town car. I only got to see the car run one time. He said that with the factory 26 gallon tank, he could get from Texas to NY city on one tank of gas. But it said it sucked only being able to do 20 mph and having to stop for 1 hour every 20 miles when driving in the mountains. He figured that the engine/pump, and the accumulator needed to be bigger to be able to run in the mountains.

He actually built this from spares from his forklift repair business, so the parts were not optimized for the car. It had a flat out top speed of 68 mph (max speed of the motors), and no regenerative braking. I figure with the better aerodynamics of a 914, plus better matched hydraulic motors, a bigger or multiple accumulators, and regenerative braking, I could get 140mph and 100 MPG with tire boiling accelleration from 17 hp.


Am I crazy?

[914forme]

Yes Clay we know you are crazy, but your Idea is very doable. But why a gas engine???? Take a small diesel run it on Bio at a constant speed, push the pumps. You can get small diesel as the day is long, fuel efficient and can clatter away way back and still be air-cooled.

I can't remember the exact torque and hp difference but hydraulics will make more with less than a gasoline engine.

Combine the diesel file and a pump, regenerative braking is an interesting idea, but I see one problem as your valve slips to reverse the flow you will lock the wheels very bad, but you stop fast! So you will need a way to let the valve bleed off the pressure before you kick into regenerative braking. Fluids don't compress like air does, so you got to watch your pressures.

Small U-build car form the 80s. Centurion achieves 128-mpg fuel economy on its diesel engine. It appeared in Mechanix Illustrated magazine and in the movie Total Recall. Plans include 13 large drawings and a photo-illustrated book.

According to Sports car graphics - the 914 has a drag of 225 lb., with tire drag and areo drag combined. Can't find the .cd number right now but it is lower than most would think with the top on, and windows up, and head lights down, low .3? is very doable.

Take care, Stephen

[sgomes]

About 180 wh/mile if everything is just right, so that's 10,800 W which is also about 14.5 HP.

Very close to my measurments!!!!

Currently my car @65mph: 116V @ 100 amps = 15.5hp

I still have some poor tires and really bad alignment.

[type11969]

Dunno if you guys read about the Ford Tonka Truck with the hydraulic launch assist:

http://www.pickuptruck.com/html/autoshows/...ford/tonka.html

Same idea, but to a much much lesser degree.

[redshift]

I am interested in removing a sick whore from a commode. Clay, where did you see that?

Jake knows exactly how much power is going where/when.. he's dynoed all that info.. ask Jake. We had a discussion last year about loads on the engine.


M

[type11969]

Damn, that guy got a 914 hat too?

[ClayPerrine]

The reason for gas is that any engine run at a steady state will produce more fuel effeciency than an engine that is rapidly accellerated and decelerated, the car is already setup for gasoline (including vapor emissions control) and it's the most readily available fuel. Plus, with a little briggs and stratton engine, you can run it on just about any gasoline you can find, including drip gas without affecting it. I am sure that bio-diesel would improve the economy of the car, but I figure that this could be done one step at a time.

If it only takes 15 HP to run the car at speed, then I need about a 20 horse motor to be able to keep the car moving, and still refill the accumulators.


FYI, this is a future project, not something I am going to start tomorrow. Just a thought.

Thanks everyone.