What is the story with brake boosters? I see people remove them and put in a different master cylinder. Were they needed on a car as light as an Europa?
I can understand why you're asking that one, it must be one of the most commonly talked about brake mods to our cars (and the period Elans as well). And it gets more confusing if you read up and find that for the dual circuit cars boosters were fitted as standard but for single circuit cars they were originally an optional extra. So Lotus obviously didn't think they were essential - but more later on that optional choice. It's even more confusing when you look at the 90's Elise S1, fractionally heavier yet came without servo assistance but has short pedal travel, low pedal pressure and brakes like nothing else.
So do you need one (or two ! ) servo/booster for good brakes ? Nope, but there are obvious plus and minus boxes and you'll need to decide if those boxes are important to you.
Probably the most notable are pedal pressure and travel. Let's talk about travel and an extra 1/2" or 3/4" of travel might not sound much but the first time you experience that extra distance you'll be thinking you aren't going to stop. But if you swap the m/cyl from say 1" to 0.7" then to displace the fluid needed you're going to get more travel. You can reduce this by re-drilling the actuating rod pivot on the brake pedal & trading pedal pressure for reduced travel, but that's a very limited option due to the space we have to play with. Conclusion - if you stay with standard disc/drums/pads and want the same pedal pressure as a boosted car, you'll need a smaller m/cyl & get more pedal travel.
Pedal pressure; the servo/booster wasn't a particularly high ratio (1.9:1, 2:1 ?) but clearly it made a difference to the braking effort so if you take it off and do nothing else, you'll be pressing harder. And as with extended travel, you might think the brakes are suddenly lousy. Again there are ways to get around this and the simplest is fitting higher friction pad materials, EBC Greenstuff, Mintex, etc. Fitting larger discs or different calipers will also get you back to the lighter pedal of an assisted car, but that's obviously a more complex option.
My personal take is that you can run any brake system, single/dual circuit, assisted or non-assisted and you'll be fine. But the trick is to ensure your choice is balanced and designed to run as such so you'll probably end up making more than one alteration if you want to achieve the braking feel of the previous design.
Brian
