Elan BBK comparison, kits lack important specs

[HJ2]

Just kidding (again) Dave, here is the same Nanny i wish you:
I am sorry, but she lacks important BBK specs (to keep things on-topic)

[GeoffSmith]

Dapinky Fine, the Forum nanny

Shush you. You and your none-popularist voting nation.

have you got a smiley thing for that?

[dapinky]

Henk-Jan.....

.... I know what the intention was - (and even it hadn't been that, I would have accepted it from you, as you have been here long enough, and contributed enough, to make such comments )

Anyway, this post seems to have gone a little ...

....maybe I should leave it here for a few more days (just for the entertainment value), and then it is probably best consigned to the 'cyber-bin'.....

......early next Thursday is as good a day as any to 'toast' it.

(I don't believe that the information on the forum would suffer from the removal of the entire thread, and I will then also look at a certain other 2 threads to see if they would benefit from some 'pruning' of posts - I won't delete them in their entirety as there is some good information on them, and they were started as genuine enquiries, and as such, should remain)

[lotusflasherman]

Well at least I'm learning something now .. much better topic, when off topic

No idea who "Nanny" was but Google Image search has found her... Was it on Sky in UK?

[rip]

Henk-Jan.....

.... I know what the intention was - (and even it hadn't been that, I would have accepted it from you, as you have been here long enough, and contributed enough, to make such comments )

Insults to strangers can become banter between friends.
Joining a forum & immediately arguing with people is likely to rub them up the wrong way.
...especially when those you are arguing with are actually talking from experience.

[Dave Eds]

Insults to strangers can become banter between friends.

TWAT.

[Rambo]

Insults to strangers can become banter between friends.

TWAT.

Ha ha. Very clever Dave

[rip]

Insults to strangers can become banter between friends.

TWAT.

Ha ha. Very clever Dave

I know you 2 well enough to laugh instead of get upset.

[TrevorB]

I have regularly read various technical explanations on this Forum it is only now that I appreciate the expression 'ignorance is bliss'


Trevor

[isuzuowner]

You say that a Prop Valve is a 'band aid' but then state that you use different .cf pads to adjust bias - wow!...... at least a prop valve will retain a far more calculable operation over a range of conditions, whilst different pads will work differently even as they are being used....

That's why they make pads in different brake coefficients.
That's why people who want to adjust their braking balance commonly change pads to a different cf on one end or the other.
Having the same pad coefficient for the front and back ignores the fact that the front brakes typically operate 200-300 degrees higher than the rear brakes anyway, shifting the cf accordingly.

[isuzuowner]

:roll: If he doesn't respect the cars we drive or the people that drive them, then there's not really a place for him on our forum.

The statement "A bias valve on a production car is typically a sign of someone in the engineering department not picking the right parts, discovering the error too late, and scrambling to fix that problem too close to the production date." is written by somebody who either doesn't understand the basics of engineering, or is an internet troll... Your choice, matey.

Bit fed up with 'Isuzu good, Lotus bad' mentality, particularly when expressed with such ignorance about weight transfer and brake balance, but it's been in every post he's made...

So are these ...BRAKE-PROPORTIONING-VALVE-Isuzu

You really want to use an eBay used auto part listing for your documentation of your point?
Because if you ran a internet search for "isuzu trooper brake proportioning valve", that is the single entry that the search would return.
And there is a reason.
Because the item pictured is PN 8970222810, and is called a "Brake Metering Valve".

I contacted the seller and asked:
I am looking for something called a brake metering valve, PN 8970222810, for an 94 Trooper without ABS. It looks identical to what you have pictured. Is it possible you have this item named incorrectly?

The seller responded:
Yes it's possible, different makes call them separate things...proportion and metering is used interchangeably

Sincerely,

eBay Team
Heritage Used Car and Truck Parts, LLC
2700 Newman Rd
Mobile, AL 36695

The problem is that a "brake proportioning valve" is not in fact the same thing as a "brake metering valve".
Metering Valve
For your disc / drum brake system, a metering valve is essential for proper balance. A metering valve will control fluid flow from the master cylinder causing the rear drum brakes to engage just before the front disc brakes. This allows the car to settle evenly under braking instead of nose diving.
That description is similar to the residual pressure valve, and is an important distinction from a proportioning valve, in that a brake metering valve does not clip off or reduce the maximum hydraulic pressure.

So, no, it is not the same thing, and the terms can not be used interchangeably.

The gentleman from Heritage Used Parts most likely does not particularly care about the distinction, and based on his comment, he is calling every feature in the brake system between the master cylinder and the caliper a "proportioning valve". And he has 45,000 listings, so if he misses out on sales because he has items listed with incorrect names, he really isn't going to notice.

The same does not hold true of internet troll flickerman.

It is hard to tell which is greater, flickerman. The level of your ignorance. Or your desire to show off your ignorance.
If your electrical engineering work ever involved providing electric service to homes and businesses, let us hope they all kept plenty of candles on hand.

[Rambo]

I have been following this thread carefully but have I missed something here ? Who is the flickerman to whom you refer ?

[alan e]

:roll: If he doesn't respect the cars we drive or the people that drive them, then there's not really a place for him on our forum.

Come on Mr Pink where are you

[HJ2]

The level of your ignorance. Or your desire to show off your ignorance.

You are now talking about your own set of soft skills and somehow mismatched isuzuowner with flickerman (whoever that is), right?
It is better to substitute 'your' with 'my' in this context. my2cents

[dapinky]

Come on Mr Pick where are you

Do you mean me???

You say that a Prop Valve is a 'band aid' but then state that you use different .cf pads to adjust bias - wow!...... at least a prop valve will retain a far more calculable operation over a range of conditions, whilst different pads will work differently even as they are being used....

That's why they make pads in different brake coefficients.
That's why people who want to adjust their braking balance commonly change pads to a different cf on one end or the other.
Having the same pad coefficient for the front and back ignores the fact that the front brakes typically operate 200-300 degrees higher than the rear brakes anyway, shifting the cf accordingly.

Bollox.

They make pads in different coefficients for different applications - not so a weekend warrior can swap the amount of braking on each end... for an amateur to do so is asking for trouble, as ALL pads work in different ways and certainly different compounds will behave differently at different temperatures and rates of heating. Without understanding the full picture (which is more than just the published .cf), I would even go so far as to use the word 'stupidity' to describe such actions....

Please accept this post as a FINAL WARNING - not for what you say against me, but for the way in which you make an attack against 'flickerman' and call his professionalism into account in his field of expertise.

This forum could well benefit from your knowledge of the Isuzu marque, but I am not prepared to allow you to continue in the vein that you have so far conducted yourself, especially in your tone to other members. I will have no hesitation in banning you permanently from this forum without further warning.

[Simon_P]

The level of your ignorance. Or your desire to show off your ignorance.

You are now talking about your own set of soft skills and somehow mismatched isuzuowner with flickerman (whoever that is), right?
It is better to substitute 'your' with 'my' in this context. my2cents

Well said H2O

Imcluelessowner whataloadofbollocks you spout.

[GeoffSmith]

Permanent ban. Goodbye and thanks for all the fish.

[lotusflasherman]

Probably means me ...

Seems like there is a lack of understanding about longitudinal weight transfer and why Brake Proportioning Valves have a role to play.

I know a lot of members know "A bias valve on a production car is typically a sign of someone in the engineering department not picking the right parts, discovering the error too late, and scrambling to fix that problem too close to the production date. " is just total bullshit but thought I'd post the reasons why for those who don't. BPV's are perhaps a more sophisticated engineering solution than the modern philosophy of big brakes, that brain-dead drivers can easily lock, and ABS to stop them making fools of themselves.

Having been involved in motor racing through the '70's, I have a shelf full of technical books about car design and setup and a few of the more readable, and entertaining, are by Carroll Smith, driver, engineer, and team manager who oversaw the preparation on the Ford GT40's that won the 1966 and 1967 24 Hours of Le Mans. (I do like to know the provenance of my information. ) Paid good money for those books in the 70's but found you lucky people can download this one free! Caroll Smith - Tune to Win pdf. Chapter 3 deals with load transfer, Page 32 with longitudinal weight transfer. Front/Rear Brake bias is on P112.

For retardation the amount of transfer forward is related to the braking force applied (very variable) and other constants of where the CofG is related to the wheelbase, the wheelbase itself and a few other things like suspension spring rates and geometry- anti-dive, anti-lift, anti-squat etc. What speed the vehicle is travelling at is also a factor ... this is due to kinetic energy being proportional to the square of the speed so the brakes have quite a variable challenge. Taking the same amount of energy into the brakes from a car doing 100mph creates less retardation than from 50 mph so longitudinal load transfer is less at higher speed.

Banged a few numbers into an Excel Spreadsheet and using the weight of an S2 as 1230kg (from the MOT Test chart for braking calculations) I find that at:
120mph it has 58.99kWh of kinetic energy; 100mph is 34.13kWh; 80mph is 17.48kWh; 60mph is 7.37kWh; 40mph is 2.18kwh; 20mph is 0.27kWh. So to reduce speed as quickly as possible by 20mph the brakes need to absorb quite differing amounts of energy, 20mph to rest is obviously just 0.27kWh but to save you finding a calculator ... 120 to 100 is 24.85kWh; 100 to 80 is 16.66kWh;, 80 to 60 is 10.12kWh; 60 to 40 is 5.19kWh. So a braking system that suits track days may be very different to one that suits the high street. The challenge is to find the best compromise.

[In one of his books Smith comments that he once calculated the kinetic energy absorbed by the braking system of one of his cars during 24hrs at Le Mans was more than the electricity energy used in a whole year by the town he lived in. Probably indicates that 24 hr racing has some very boring periods. ]

Race cars with separate master cylinders for front and rear brake systems have a balance bar between them. Whilst the designer had made some decisions about braking forces at front and rear by choosing disc sizes, caliper piston sizes, master cylinder bore and other relatively fixed dimensions. Pads could easily be changed and the balance between front and rear braking was changed by altering the position of the pedal rod attachment to the balance bar. In the middle it was 50/50 but moved towards a master cylinder increased the bias to that and reduced it to the other. Clever designers provided a screw adjustment so the driver could alter it from the cockpit as reducing fuel load changed the CofG or rain affected speed and available adhesion. The general principle was have a bias to the front locking and reduce it slowly but never lock the rear. Locked front causes the car to plough on in a straight line until the driver recovered rolling adhesion by lifting off the brake and could then turn it to a late apex, with a bit of luck. Locked rear causes rear end instability and the car can slew sideways, that can be severe and approaching a corner it may point you at the corner entry already oversteering, or go the other way and aim you off track and there's no chance of getting round, or induce a quick spin to see who was behind.... Not something to ever do on the public highway!

Road cars do not have separate front and rear systems but dual braking systems connected diagonally so the loss of one circuit maintains stability for stopping on one front and the diagonally opposite rear brake, so a mechanical balance system is not possible. Proportioning valves are the hydraulic equivalent of the mechanical balance bar with the added advantage that they can have a non-linear characteristic, related to hydraulic pressure, that more closely matches the varying needs mentioned above. Never perfect for all conditions and speed but an engineering compromise. Production Saloon Car Racing Regulations often precluded going to front & rear systems if the car was originally diagonally connected so cockpit adjustable BPV's were fitted to control the bias, if allowed. Modern production cars use a different design philosophy of big brakes and ABS but many also use BPV's to get the best out of the system until ABS kicks in.

The early M100's had an arrangement of a 70 bar pressure limiting valve and 3/15 proportioning valves - linear to 15bar then ramping at 0.3 rear to 1.0 for front. Later cars just had 2/15 proportioning valves, so 1 to 1 to 15bar then 0.2 rear to 1.0 front. (I believe bleeding the early version was troublesome.) Without ABS specified, Roger Becker and his team produced a car that performed very well with a benign but adequate brake system, if properly maintained. I did 160,000 miles in 2 SE's to Mr Becker's specification.

There is a lot of interest in increasing the braking capability with big brake conversion kits as the OE setup is less capable than 'Big brakes & ABS' that may be on the car in front. Worth considering the increase in unsprung weight of some of these conversions and the detrimental effect on ride and handling that can occur but if you only drive on straight roads brakes might be more important than cornering.

My third SE has an Everest Chip, 17"x7J wheels with Toyo Proxes and Hispec calipers front and rear with bespoke 294mm front discs and 264mm rear. Now far from benign, the brakes are much better but it's very twitchy when used hard. High speed braking is improved but medium/low speed rear lock up is now quite possible because the increased front brake force and tyre contact is creating more longitudinal transfer and unloading the rear wheels more than before. Front wheel drive cars don't tend to lock front wheels, as to do so stalls the engine, but rears can be virtually off the ground and lock easily. Very important to obey the First Commandment of high speed driving front wheel drive cars - "get all your wheels pointing dead straight before you stand on the brakes" ...

[Simon_P]

Permanent ban. Goodbye and thanks for all the fish.

Saved me asking where the ignore button is - Have we got one?

[Rambo]

Permanent ban. Goodbye and thanks for all the fish.

Geoff - we call it pish in Scotland