power assist brakes for a 1303?

[davygrvy]

Has anyone ever added a power booster like this to the front circuit?

http://www.mpbrakes.com/products/pro...product_id=221

I'm contemplating mounting one in the bonnet. Run a vacuum line down the tunnel to the manifold..

Front discs are in (toplineparts kit). The metering and adjustable prop valve will get added next week to prevent the current nose dive it has for better weight transfer for high speed panic stopping. Type3 rear drum conversion happening next week as well.

[Axl]

I'm looking at that and just trying to figure out if it will fit in the rather small spot for the master on the Beetle .

I have been kicking around the idea of power brakes on a Beetle , with the fact that if I build up a 1303 like I want to , its going to have a 300HP+ Scooby engine . Stopping at higher speeds is a definate must!! After being a mechanic for GM for the last 5.5 years , I think I have come up with an idea to not only give me power brakes , but also power steering as well . And that would be with a Hydroboost system . It all works off of assist being provided by hydraulic fluid being pumped to the power steering and the hydroboost master cylinder from a single power steering pump . The nice thing about these systems is that the booster is a lot smaller than a vacuum unit . I haven't worked out all the details , yet , but let me know what you think.

[Steve C]

Hi

I dont think they are needed.

Look at all the Porsche and other race cars that don't have power assistance, its all about correct hydraulic system sizing, not putting a booster on, a booster wont fix poor brake choice.

If you feel that you must go down this path, you can get remote boosters, # VH44 is our local part number for one

Steve

[Axl]

Originally Posted by Steve C

Hi

I dont think they are needed.

Look at all the Porsche and other race cars that don't have power assistance, its all about correct hydraulic system sizing, not putting a booster on, a booster wont fix poor brake choice.

If you feel that you must go down this path, you can get remote boosters, # VH44 is our local part number for one

Steve

Not sold on that train of thought . If thats all there was to it , then power assist wouldn't be standard equipment on almost every single vehicle available today . In some cases , you can get away with it , but when weight and/or speed gets too high , then the size of the pistons in the system would be just too large to be practical . I worked with this guy who had a supercharged V8 30's Ford pick-up , with drum brakes all around . He could go fast in it , but as he told me , it takes about 5 blocks to slow down . I like going very fast , but I also like the idea of being able to stop on a dime and give change .

[Steve C]

Hi

OK if you think you need them go ahead, but look at every modified brake setup on this site, nobody is using a booster.

Steve

[evilC]

Originally Posted by Axl

Not sold on that train of thought . If thats all there was to it , then power assist wouldn't be standard equipment on almost every single vehicle available today . In some cases , you can get away with it , but when weight and/or speed gets too high , then the size of the pistons in the system would be just too large to be practical . I worked with this guy who had a supercharged V8 30's Ford pick-up , with drum brakes all around . He could go fast in it , but as he told me , it takes about 5 blocks to slow down . I like going very fast , but I also like the idea of being able to stop on a dime and give change .

I go along with Steve on this one. On a vehicle as light as a beetle there is no need to power assist the brakes or the standard steering. If you are contemplating 300bhp in a vehicle that weighs ~850kg then the last thing you need is a system than deadens the feel of the vehicle. Max control is whats its all about. Having worked for GM you will of course be aware that they steadfastly refused to power the brakes on their fastest Corvette even when it was capable of more than 170mph. They did it to maintain feel and control - it couldn't be for cost reasons

As regards power steering, again there is no reason to do so in standard trim unless of course you will add a huge amount of caster (>10deg.) or seriously quick steering (1 1/2 turns lock to lock)(that could be beneficial).

Power steering and power brakes are there to ease the control requirements for the wide range of drivers from the geriatric to the infirm but I assume that most contributors to this forum are fit and healthy?? Also, modern cars are setup with brake, steering and suspension geometries that make it almost impossible to steer and brake without those powered systems. Try driving a modern car on (an unoccupied) down hill curvey road with the engine switched off

[Humble]

The main reason newer cars have power brakes is ease of drivability. So even grandma can push the brake pedal down and stop safely. If you remove the vacuum assist to one of those systems (engine off) and try to hit the brakes it's suddenly very difficult to stop the car because the pedal effort went through the roof. The reason for that is most power brake systems have a very low pedal to master cylinder push rod ratio, like 2:1 or even 1:1. On cars without power brakes mechanical leverage is used to reduce pedal pressure but maintain easy braking. Cars with manual brakes use a pedal ratio as high as 7:1 and in the beetles I believe it's about 6:1. So 100lbs of pedal pressure in a car with power brakes is about 200lbs of force at best without vacuum assist and poor grandma will break her leg before she stops the car. With manual brakes 100lbs of pedal pressure is good for 700lbs of pressure at the master cylinder and even grandma can hit the binders hard in a properly setup manual system.

Power brakes in a beetle isn't worth the extra hassle and the money would be better spent on a manual setup. However, there are mechanical brake boosters that reduce the pedal force a bit which could be a better and cheaper option.

[Axl]

Another reason I was thinking of adding the power assists is , its just damn cool to say my car has assists , and nobody elses does . Its just one of those things to kind of set your car apart from the rest . It seems most of the stuff I have been thinking of has been done to death , and it is getting harder and harder to be original . I hope you can understand my thinking on that .

[Humble]

Yeah, I feel ya there. When there's 23 million copies of the car you have how do you make yours stand out? Any more you don't need fancy gimmicks or electro-wizardry, simple and clean will take you farther than you know. That's why I dig the german look and went that route on my car.

[evilC]

When I started mine I was unaware of 'Germanlook', 'Cal-Look', Rat-Look', whatever. All I know is that 'Germanlook' matches my philosophy about cars the best. Its about performance and engineering, not gimmicks. Its about adapting/modifying and exploring engineering possibilities to make the cars and vans better. Despite the title, for me its the engineering that sparks my interest but if it looks good aswell then so much the better. You will see on this site that contributors explore the potential of their mods on the track, not in the bar and thats what makes it authentic.

[Steve C]

Originally Posted by evilC

You will see on this site that contributors explore the potential of their mods on the track, not in the bar and thats what makes it authentic.

I'll drink to that, this is absolutely my favourite VW site, it also fits with what I feel is the ultimate goal of modifying a VW, to make it them go, stop & handle.

Steve

[Wally]

Originally Posted by evilC

When I started mine I was unaware of 'Germanlook', 'Cal-Look', Rat-Look', whatever. All I know is that 'Germanlook' matches my philosophy about cars the best. Its about performance and engineering, not gimmicks. Its about adapting/modifying and exploring engineering possibilities to make the cars and vans better. Despite the title, for me its the engineering that sparks my interest but if it looks good aswell then so much the better.

Cheers to that mate!