Can a light salooncar do without power-brakes?

[Frank N. O.]

I know a fwd car at about 1050 kg can easily do without power-steering because I've tried one (1992 Ford Orion 1.8 Zetec 16V with 3.75 turns lock to lock and 175/70-13 tires) but can you do without power-brakes at that weight? As far as I know the McLaren F1 has manual hydralic brakes and it isn't lighter than this. The idea is for my Turbo-Electric hybrid car, not as much to make the car use even less fuel but also to make sure the feel of operation and precision is kept from a normal car. I've read that electric power-steering is often very bad in terms of driver-feel and I'm not impressed by the conventional power-steering on the 2001 Peugeot 206 I've been driving the last 3 years so I am very interesting in finding a design that puts the driver back in the information loop.

Any ideas? I wouldn't think that electric servo brakes would be too nice in feel but I haven't tried a car with such brakes to my knowledge.

Frank

[Commander]

Well, I can tell you that my 1972 Chevy Nova had 4 wheel drum brakes, non power assisted. Braking from high speeds was a bit frightening at times, but otherwise they worked just fine. The Nova was a heavy car too.

[chris]

Mclaren F1 can do without those, but the steering is said to be quite heavy at times, and the brakes also need a bit of strength to operate.

But look at a Lamborghini Countach to see what happens when its done the wrong way. Incredibly heavy steering results, and the other major controls are also very heavy.

McF1 does also have desirable attributes, such as all of its weight being between the front and rear axles and not overhanging them, that helps steering responsiveness. And if it does get to a point when you are going fast through a corner and can't turn it any more with the steering, you can adjust the cornering line with the throttle if you are very brave.

Electric power assist can be bad, but it can also be good as well, depending on who is offering it.

[Frank N. O.]

Well the basic layout of the car-concept would have the batteries put centrally between the driver and the rear axle-line and just have the gasturbine electricity generator up front and maybe also the electric engine. It would use conventional drive-shafts and have either fwd or awd, in both cases with advanced lsd's, like perhaps the Haldex clutch or Quaife ATB.

Frank

[chris]

What about something like the Ferrari E-Diff? That would be a more ideal solution.

I also think the way that the steering loads up in an F1 is a good thing, because it in some ways prevents you from making sudden steering inputs which may unsettle the car.

[Frank N. O.]

Ferrari E-Diff? Never heard of it. But make no mistake, this is a car intended for personal transport in calm legal speeds, not a McLaren F1 mk2 for Le Mans 2005.

I just want a simple, effective system for the car since the advanced driver-cushioning design of the 206 has now left me cold about driving and when it's cold like now, I rarely drive at all since I can't feel the wheels thrue the steering-wheel and the brakes are very soft an unprecise and without a engine's constant vacuum I'm concerned if a servo can give constant predictable brake-feel.

Frank

[chris]

The E-Diff is like a LSD on steroids, with a computer overseeing the workings of it. It's found on the Ferrari F430. I don't know if it is used on the F1 cars, but it might be. It also has some degree of driver-controlled adjustment to the way it works.

Honda also had a somewhat similar system called ATTS (active torque transfer system). It was used on a version of the old (and no longer made) Honda Prelude VTi-R coupé (otherwise known in Japanese car-maker speak as a "specialty model"). It was a front-driver with a 147kW 2.2L inline-4. It could get all of its power to the road quite effectively thanks to the tricky ATTS system.

The controversial torque transfer system used at the German GP on the BAR-005 T-car was largely based on the Prelude's ATTS system.