Electric AC Cobra (looking to reduce high energy consumption - 489 Wh/mi)

[mizlplix]

Greetings. I have a 1930 Model A Ford speedster EV, which is about as "Brick" as it gets, but I still get 256WH/Mile.

If you are getting that horrible of a WH/Mile, I would look else where than Aero, you have something else going on....

The last Cobra I drove would do 210 MPH with the windshield removed and a bored/stroked 412Cu. In. small block engine.

Miz

[RE_Farmer]

Wayne,

Here's a radical idea; if you just want a fun car (i.e. not driven in nasty weather), you could swap out your "bill board" windshield for a couple "Brooklands Type" racing screens:

MG, Triumph, Austin Healey, Sunbeam Tiger iCatalog - Victoria British, Ltd.

[ev99saturn]

Miz, I keep looking for other reasons for the poor wh/mi, although I'm comfortable that aero and over-the-top-terrible rolling resistance drag radials are certainly contributors.

The car is a new build with very few miles so far, and I'm wondering how long it takes for the brake pads to break-in.... i.e. might they be dragging more than they will after, say, a thousand miles or more?

With brakes in mind, I did a test with the car on jack stands. I brought the motor up to 2,000 RPM then timed the spin-down to stop. After 5 times to average the tests, I removed the rear calipers and re-ran the spin-down test.

It took about 10 seconds with the brakes removed, versus about 7-8 seconds with the brakes installed. This seems like a marginal difference, but could still be significant.

The other question it raises is: is a 10 second spin-down from 2,000 motor rpm reasonable? i.e. should it take longer, suggesting resistance somewhere in the drivetrain?

Your 1930 Model A sounds like an awesome EV build! It's lower wh/mi gives me hope that I can get the Cobra into reasonable territory!!

Wayne

Originally Posted by mizlplix

Greetings. I have a 1930 Model A Ford speedster EV, which is about as "Brick" as it gets, but I still get 256WH/Mile.

If you are getting that horrible of a WH/Mile, I would look else where than Aero, you have something else going on....

The last Cobra I drove would do 210 MPH with the windshield removed and a bored/stroked 412Cu. In. small block engine.

Miz

[ev99saturn]

Well, with no roof on the car, I don't plan to drive it in nasty weather! It's strictly a fair weather car.

Factory Five Racing, the kit manufacturer, also offers the 'challenge' car, which has a tiny windshield like in the catalog page below. Given what I have learned in recent weeks about the aero of this car, I'm not surprised that Shelby made the windshield change for that reason.

I have considered removing the windshield just to run a few wh/mi tests. If/when I do, it will get posted to the fuel log on this site.

At the moment, it is off the road again as I am preparing to double the battery voltage, bringing it up to 240V.

Wayne

Originally Posted by RE_Farmer

Wayne,

Here's a radical idea; if you just want a fun car (i.e. not driven in nasty weather), you could swap out your "bill board" windshield for a couple "Brooklands Type" racing screens:

MG, Triumph, Austin Healey, Sunbeam Tiger iCatalog - Victoria British, Ltd.

[Ryland]

Originally Posted by ev99saturn

With brakes in mind, I did a test with the car on jack stands. I brought the motor up to 2,000 RPM then timed the spin-down to stop. After 5 times to average the tests, I removed the rear calipers and re-ran the spin-down test.

It took about 10 seconds with the brakes removed, versus about 7-8 seconds with the brakes installed. This seems like a marginal difference, but could still be significant.

The drums are going to add weight and act like a fly wheel to a point, so if there is no drag then the drums should help it spin longer.