I`m gonna do a brake test any ideas?

[daZvert]

Just for research purposes, I`m going to attempt a brake test from stock to uprated, only on my vert but it should shed some light on how much better/worse the upgraded set up should be....so at the moment I have good stock brakes on all 4 corners and next week I will have evo8 Brembos with grooved and drilled disc`s on the front and grooved/drilled discs and red stuff pads on the rear stock calipers..Oh, and all new braded hoses too

So my test will involve braking hard from 30 and 50 mph and see how long in seconds it takes to stop and the distance travelled, I would like to do some sort of brake fade test aswell, not sure how to do an accurate test on this without doing a track day, any ideas on more tests i could do whilst im playing?

 

Daz

Edited May 15, 2011 by daZvert

[AlanZ]

Try braking from 70/80mph to 20/30mph...

 

This is the braking distance to remove any pad build up on the disc.

 

 

Alz.

[AlanZ]

Also, I have the same set ready to go on my 300 Daz.......

 

I will be watching ur thread with eager eyes to see if the results are good matey.

 

Alz.

[daZvert]

Also, I have the same set ready to go on my 300 Daz.......

 

I will be watching ur thread with eager eyes to see if the results are good matey.

 

Alz.

 

bloody hell ,have you not fitted them yet?:laugh: I thought you fitted yours ages ago.

But deffo going to do the test, will be very interesting

[daZvert]

Try braking from 70/80mph to 20/30mph...

 

This is the braking distance to remove any pad build up on the disc.

 

 

Alz.

 

yeh,I thought about going 70/80, probably have to do that at night/early morning

how long do ya reckon it takes to bed the brakes in properly?

[jonce]

Hi bud, hows things with mine LOL

[AlanZ]

That is a very tough question matey, many different views out there....

 

Best person to ask, in my opinion, is "jimmer"....

 

Alz.

[AlanZ]

bloody hell ,have you not fitted them yet?:laugh: I thought you fitted yours ages ago.

But deffo going to do the test, will be very interesting

 

I know..... I know....

 

Just been busy at work, and chroming/polishing.... :whistling:

 

Alz.

[Car.Mad]

My zed flew through the mot brake test. 2 pads were jamed at a funny angle and there was so much air in my lines the pedal went all the way to the floor and there still better than stock :lol::lol:

[daZvert]

Hi bud, hows things with mine LOL

 

done, I think? will ring him 2morra bud!! just waiting for your addy to post back them back out to you, I sent a pm asking for it, I just assumed you were still in Germany and not bothered

 

Daz :cool3:

[leo-r32gts]

A friend of mine did an unexpected brake test from 170 mph (so he tells me) in his M3, only cost him about 750 quid to put it right afterwards. two warped discs and crispy pads!

 

I noticed with the standard brakes that after 3-4 hard stops from 50-70 mph they are cooked and braking efficiency massively reduced. Wasn't braking hard enough to trigger the ABS, but pretty much 95% of maximum I would guess.

 

I think trying to time the 50-30 test will be too quick and the accuracy only as good as the person operating the stopwatch. If you try it in a regular car you will see that actually, you can do this very quickly if you try - probably just over a second, depending how sensitive your foot is.

 

I would say you need to do 70 to a complete stop to give any really meaningful results, but this is unkind to your discs and not really good driving etiquette either. That said, if you go out early on a sat or sun, you should be able to do it somewhere quiet without risking an accident. Thing is though, you have to slam the anchors on as hard as you can without triggering the ABS, which is easier said than done. When you really need the brakes its surprising how strong they are - I doubt anyone uses 100% of their ability without taking it on a track. Why would you, you'd have to be anutter to drive like that.

 

think you need to find an airfield bud.. then set a pair of cones out as a reference point. I would be surprised if you were able to improve efficiency by 25%, which would be a just reward for such an improvement in equipment.

 

Best of luck anyway - will wait for the results eagerly!

[Sherrgar]

a test really needs repeatabilty. can you ensure you push the pedal down with the same force each time? In Germany you are expected to be able to contort the pedal!! At this pressure you will be close to breaking the seat. gulp.

I'd suggest when you do this test on a closed circuit, that is shared with other test pilots & has road markings and traffic and speed limits and looks just like a normal road... choose a start speed (eg 70) but measure the test from 10 mph less ( so thats 60)down to a min of 15 mph. A stop watch is not ok/a laptop consult is accurate and can be recorded. failing that, film the speedo with a video camera.

hope that gives you an idea.

[daZvert]

Thanks for the ideas lads, some interesting thoughts going on, and thats why i started this thread as I knew it wasnt just a matter of slamming the foot hard down.

Another thought i had was to take it to an mot station and complete a few tests there? would there machines be able to register some results?

[Yowser]

Great idea.

 

Do it from 60-0mph ? - Its the highway code test figure (for comparing) and its what a lot of modern vehicle brake tests are done from (again for comparing).

 

You will want the road and enviroment conditions to be the same, and your tyre temps. With no other suspension or weight changes made to the car inbetween.

 

Repeat at least 3 times for consistency, allowing a good few mins of gentle driving for cooling inbetween. Release the brake pedal as soon as your stopped, avoid holding the brakes on for anypoint after.

 

For brake fade testing - do the same test over and over without cooling breaks until you experence either a soft mushy pedal, or a hard pedal but poor braking.

Edited May 15, 2011 by Yowser

[Paul C]

LOL! I actually just carried out a before & after test the other day when I upgraded to my brembos!

 

Before:

 

 

After:

 

 

brakes were cold at both tests & not bedded in for the after results but gives you some idea of braking force increase! :)

[Yowser]

Braking force is actually irrelevent of stopping distance though, providing the brakes can lock the wheels (which the stocks can at the speeds were talking anyway).

 

A vehicles minimum stopping distance is dependent on the coefficient of friction between tyre and road.

 

A vehicles maximum braking is done at the point just the tyres lose traction(wheels lock). The ABS's job is to keep the tyres traction with the road at this point.

 

What I would expect the results of this test to be is that the recorded braking before and after for the single stops is about the same. But the brake distance over repeated tests will be greatly reduced as heat dissapation is improved, reducing brake fade.

Edited May 15, 2011 by Yowser

[Steams]

Can I have your Z31 if your test fails?

[leo-r32gts]

LOL! I actually just carried out a before & after test the other day when I upgraded to my brembos!

 

Before:

 

 

After:

 

 

brakes were cold at both tests & not bedded in for the after results but gives you some idea of braking force increase! :)

 

Apparently your car weighs 1740kgs. I hope that isn't true - if my car weighs that much I'm selling it.. Thought they were supposed to be 1560kgs or thereabouts? :offtopic:

 

 

Braking force is actually irrelevent of stopping distance though, providing the brakes can lock the wheels (which the stocks can at the speeds were talking anyway).

 

A vehicles minimum stopping distance is dependent on the coefficient of friction between tyre and road.

 

A vehicles maximum braking is done at the point just the tyres lose traction(wheels lock). The ABS's job is to keep the tyres traction with the road at this point.

 

What I would expect the results of this test to be is that the recorded braking before and after for the single stops is about the same. But the brake distance over repeated tests will be greatly reduced as heat dissapation is improved, reducing brake fade.

 

Myth seperated from fiction yet again. Yowser, you are rapidly becoming a fountain of knowledge! Basically, unless you increase tyre size, you can pretty much achieve the same stopping distance with any size of disc capable of locking the wheels? Meaning that actual stopping performance on a one off basis won't be significantly improved (in normal driving conditions), no matter how big your discs are?

[Paul C]

Braking force is actually irrelevent of stopping distance though, providing the brakes can lock the wheels (which the stocks can at the speeds were talking anyway).

 

A vehicles minimum stopping distance is dependent on the coefficient of friction between tyre and road.

 

A vehicles maximum braking is done at the point just the tyres lose traction(wheels lock). The ABS's job is to keep the tyres traction with the road at this point.

 

What I would expect the results of this test to be is that the recorded braking before and after for the single stops is about the same. But the brake distance over repeated tests will be greatly reduced as heat dissapation is improved, reducing brake fade.

 

Well, yes and no. It is true that friction between the tyre & the road has a great impact on braking but a braking system that can give greater braking effort will of course absorb the energy quicker allowing the vehicle to stop quicker. There will be a period of time where the energy needs to be absorbed way before the wheel will lock up given good tyres & road surface.

[Yowser]

Well, yes and no. It is true that friction between the tyre & the road has a great impact on braking but a braking system that can give greater braking effort will of course absorb the energy quicker allowing the vehicle to stop quicker. There will be a period of time where the energy needs to be absorbed way before the wheel will lock up given good tyres & road surface.

Yes, with full pedal force applied to a larger brake system will result in reaching the point of locking the wheels quicker than a smaller setup.

 

But were talking hundreths of a second difference. Both will lock the wheels at 60mph as soon as you slam them on, at which point the ABS takes over.

 

Its actually well proven in many tests that Big brake kits do not improve minimum stopping distances at legal speeds.

 

In fact typically the distance is increased ! Why? Becuase many aftermarket brake kits do not retain the same Front/Rear brake bias ratio with the Brake master cylinder......and/or.....the stock ABS system can not cope with the increased braking forces generated and struggles to keep the vehicle tyres at the optimum point of traction.

 

For a road car, the real benefits are noted in pedal feel - A higher clamping force per pedal pressure, which means the car bites and brakes harder with smaller touches of the brake pedal. The real benefits for track use are improved heat dissapation.

[Paul C]

LOL! Well in all my experience I cant agree with that!

 

Mercedes fit sport pack brakes as an option to most of their range - braking is much improved!

 

There would be absolutely no need for manufacturers to fit increased sized brakes - the AMG range have huge brakes compared to the base models & a massive increase in braking performance!!

 

ABS is looking for wheel lock up based on the wheel speed sensor.

 

I am not really sure where you are coming from on this one!

[Yowser]

LOL! Well in all my experience I cant agree with that!

 

Mercedes fit sport pack brakes as an option to most of their range - braking is much improved!

 

There would be absolutely no need for manufacturers to fit increased sized brakes - the AMG range have huge brakes compared to the base models & a massive increase in braking performance!!

 

ABS is looking for wheel lock up based on the wheel speed sensor.

 

I am not really sure where you are coming from on this one!

 

Braking performance will certainly be improved - forces generated are much greater - the car brakes harder with less brake pedal effort.

 

But have you actually compared minimum stopping distance ? - Providing these sport packs/AMG Range options dont include Suspension and wheel size changes...which Im sure they do, and would affect stopping distance.

 

Im sure the reason for manufacturers fitting bigger brakes is because its expected that the sports models are going to be driven a lot harder than regular models and perhaps at higher speeds. There are lots of benefits to bigger brakes but Im only talking about min stopping distance at road legal speeds here. The other reason I bet is - marketing. Customers expect big flashy brakes if they are buying a more expensive sports model.

 

As for ABS - ABS systems takes snapshot wheel speed sensor measurements in milliseconds of all wheels, and control what to do with this information with a set algorythm. The larger braking forces generated confuse the system which shuts of line pressure for set time periods based on the stock pressure-torque characteristics. The result is that its no longer capable of holding the tyre consistently at its peak traction.

 

Although this is in regards to much larger systems than the GTR setup, which appears to be a decent match for the stock Brake master cylinder and abs.

Edited May 15, 2011 by Yowser

[Sherrgar]

stop arguing you both know the conclusion= larger brakes are for the large numbers (speed and application qty) to bring you from the realm where stock brakes cannnot be effective.

 

but then there's intial higher cost Vs less wear arguement. and space available. and bragging rites down the Meet. and we havn't even began on various mat'ls properties yet which totally opens the game....hehehe

[Guest Chris Bower]

I tried a brake test of my own once - didnt go to well! lol, when i had my rover tomcat turbo, m8 said hows the brakes?, slammed on abs packed up!, o/s disc shatterd, car spun! scary experiance, had to have new driveshaft and everything!, never again stupid rover shite!

[Steams]

I tried a brake test of my own once - didnt go to well! lol, when i had my rover tomcat turbo, m8 said hows the brakes?, slammed on abs packed up!, o/s disc shatterd, car spun! scary experiance, had to have new driveshaft and everything!, never again stupid rover shite!

 

awesome :lol: