Pwr Brakes

[skygazer6033]

You can count on the production cars having power brakes. With 15 inch wheels the brake disks will be very small and therefore need to be boosted in order to be able to stop efficiently without having to use both feet on the brake pedal. May not mean anything but the crash test animations show a brake booster.

 

[ArthurKent]

I have no clue as to why folks think that a 15 inch wheel requires power brakes. The smaller the wheel, the less is the braking force
required, not more. Regardless, the notion that a 1200 pound car needs power brakes is ludicrous. Almost all the braking is
done by the front wheels of any car, and the Elio has the normal two fronts, therefore has pretty much the same sheer braking
power as any other car. The Elio will stop faster than any car you folks have ever driven, and it won't require a lot of leg effort to do so.
Count on that.

 

[skygazer6033]

Has nothing to do with wheel size other than than the fact caliper has to fit inside which means the disk has to be small probably 10 inch or less. Disk brakes are not self energizing so all the brake force you have is by the pedal unless boosted by engine vacuum. That's the reason large motorcycles that weigh 600 to900 lbs. have 2 11 or 12 inch disks on a single front wheel.

 

[wheaters]

I designed and fitted a disc brake system for my car, to replace the twin leading shoe drum brakes originally on the front axle.

On a car you can use a smaller diameter disc than on a motorcycle because your foot can press a brake pedal harder than your hand can squeeze a brake lever. Which is just as well, because car wheels are usually smaller.

The drums were troublesome for a number of reasons. The discs require a harder push but they are very predictable and more efficient. The car weighs a bit less than the Elio.
I used Triumph Spitfire discs mated to alloy calipers originally designed for the Triumph T140 Bonneville motorbike from the mid 1970s. The wheels are 16 inch and the discs are 9 inch.

 

[NSTG8R]

My '73 Porsche 914 weighs around 2000 lbs, has approx. 10" - 11" brake rotors (didn't actually measure them, but I could if somebody doubts it) and 15" wheels, no power brakes or power steering. Handles like it's on rails, and stops on a dime (or 1/10th of a Euro). The Elio doesn't need power brakes or power steering, it would just add weight and cost to the vehicle. Keep it light, keep it simple, keep it inexpensive and keep it on target for a Sept. '15 release.....I'm Kevin Jung, and I approve this message.

 

[skygazer6033]

Perhaps your right but I've never heard of a car with disk brakes that didn't have power boost. We shall see.

 

[wheaters]

Perhaps your right but I've never heard of a car with disk brakes that didn't have power boost. We shall see.

Drivers expect servo assisted brakes because they have become used to a light pedal. That's the only reason to have them. I decided to keep my car simple because it's so small and light and have been rewarded with a system that gives far better feel and control. Which is important when driving on slippery surfaces.

 

[NSTG8R]

Perhaps your right but I've never heard of a car with disk brakes that didn't have power boost. We shall see.

Well, it has been upgraded to use 911 brake parts, but the only difference between the 914 and 911 components is the bore size of the master cylinder and the piston size on the calipers. Rotors are the same size, but carry a 5 lug pattern (cooler wheel choices!) instead of the stock 4 lug. Neither of them (in those model years and prior, or any of the aircooled models that I'm aware of) use a boost of any kind. They're so simple, it's ridiculous, and hopefully Elio follows suit. It mounts directly to bulkhead just forward of the brake pedal, a simple rod actuates it. Blue caps on top go the fluid resevoir mounted directly above it, and the blue caps at the top of the pic feed the calipers. 4 wheel disk brakes. Works perfect, lasts a long time, no boost required.

 

[skygazer6033]

Ok my statement was "I've never heard of a car with disk brakes that didn't have power boost" well now I've heard. I once drove an old Volvo off a used car lot that had a bad booster. Standing on the brake with both feet took about 300 yards to stop from 40 mph. One of the first disk brake cars I ever drove. Not a good experience.

 

[NSTG8R]

Ok my statement was "I've never heard of a car with disk brakes that didn't have power boost" well now I've heard. I once drove an old Volvo off a used car lot that had a bad booster. Standing on the brake with both feet took about 300 yards to stop from 40 mph. One of the first disk brake cars I ever drove. Not a good experience.

I hear ya, I had the booster on my F250 diesel go out (no manifold vacuum on diesels, separate belt driven vacuum pump) coming home during rush hour. Thought I was going to break the seat bolts loose trying to get that beast to stop!