ABS???

The Oily Bits S2 Specific Topics
1

To ‘celebrate’ the fitting of my Sparco wheel this afternoon, I went out for a 40 minute blat about the Cotswolds :slight_smile: Funny how quickly you get used to power eh!!! (more please! :wink:)

Impressions of the brakes were not stunning however! I could feel the extra weight of the car being slowed down and the brakes deffo got hotter quicker! The car has Pagid RS42 pads… the same as I have always used on every Elise/Exige I have owned…

However, it seems to me the ABS is cutting in WAY to early. There does not seem to be the same level of instant and then constant retardation as I felt in the ‘K’ cars…


Is this because:-

a: the ABS threshold is set too early, ie, WAY too soon before wheel lock up (if so can this be adjusted?), or

b: the extra weight of the car actually is limiting the 2 pots up front? I never had any probs with VERY good retardation with the lighter ‘K’ cars

Is it possible to ‘turn off’ the ABS completly? I would really like to try this to see when I actually get wheel lockup! Never actually locked any wheel on the ‘K’ cars… except when wet!

I really want the stoppers to match the accel! :crazy:

Cheers, Pete. :slight_smile:

2

Just before Jonny tells you where the fuse is… :tired: :smiley:

You have to go AP 4 pot, braided with SRF…It’s a must and my ABS has never ever been an issue. Maybe it is weight :confused:

I have however just got through pads and discs front and rear in just over a year…surface cracks already :cry:

3

R600+ being done tomorrow! I prefer this to SRF!

Braided hoses… it’s a clam off job yes?

Weight… 935 KG is a lot… over 100KG heavier than even my S2 Elise. However, with a 100kg Pax in that car, the weight was the same as my driver only Exige… and I had no issues!

Ok Dude… where is this FUSE! :confused:

4

Cannot believe you have surface cracks in your AP’s already! :smiley:

How many TD’s have you done with them?

Sometimes, I reckon it’s cheaper to just use the standard disks and replace them more often! :wink:

5

I must say I don’t really have a problem with my ABS cutting in too early but I am using RS14’s with stock at the rear.

However I do have a question :smiley:

From my understanding ABS cuts in when it senses wheel lock. Now then, people fit the four pot brakes to increase breaking force over the two pots. So given that the weight of the car is the same and the tyres are the same, if the breaking force applied through the pad to the disk is firmer with the four pots will this not cause the disk/wheel to lock sooner?
If not why not?

Boothy

6

Yes, ABS is designed to stop the wheel locking. On my Boeing 757, we have several brake levels to achieve different deceleration… but the ABS is very clever as it ‘learns’ the rate it can achieve.

The threshold of ABS can begin to cut in early, well before wheel lockup or late, just as the wheel almost locks up. It is ‘safer’ for the lowest common demonator to set this on the early side!

With NO abs, you can feel the wheels starting to lock up and then just feather off a bit…

I have often thought about your ‘question’ too! I think it is because the larger disk allows more ‘torque’ to be applied to the wheel and this enables an better initial bite and also for you to feel the optimum level just before the wheel lock.

Anyway, where is this bloody fuse please!!! :smiley:

7

Interesting you use RS14’s on the front…

Does that give you an initial really good brake ‘bite’ mate?

8

The ABS can be an issue on uneven roads, rears locking and ICE control are common, not sure which fuse it is, but as my ABS light is just on these days I don’t have any and its no issue, even with the APs it is very hard to lock up when the tyres are hot, however when they are cold and it’s damp you need all the help you can get :wink:

9

[quote=pete757]On my Boeing 757, we have several brake levels to achieve different deceleration… but the ABS is very clever as it ‘learns’ the rate it can achieve.

The threshold of ABS can begin to cut in early, well before wheel lockup or late, just as the wheel almost locks up. It is ‘safer’ for the lowest common demonator to set this on the early side!

With NO abs, you can feel the wheels starting to lock up and then just feather off a bit…
[/quote]

How cool is that,
“on my 757”…lol :smiley:

If I was gay I’d don my SC and shag you :smiley: :smiley: :smiley:

Boothy, dunno mate :confused:

10

Don’t know about the fuse but on track days I just unplug the ABS sensor on the offside front wheel and cable tie safely and that deactivates the ABS simples :wink:
Also if the front tyres are old and worn that can cause over sensitive ABS

11

Is that sensor near the wheel speed sensor?

12

If you turn the steering wheel to the right full lock and look in from the front of the car there’s a plug to the right on the caliper, unplug it turn the ignition on if the ABS light stays lit you’ve got the right one :slight_smile:

13

I’m pretty sure the wheel speed sensor is nearside rear so you must be looking at ABS sensor thinking about it :wink:

14

Cheers!

I’ll check it out tomorrow! :tired:

15

Pierre…
You heavy metal jockeys are spoilt … ABS on your Boeing ??
Blimey …on my little Shadow you have to cadence brake with differential heel brakes …On wet grass !!!

Try that one in high heels :smiley: :smiley:


Nice car btw :wink:

16

[quote=jfk][quote=pete757]
You heavy metal jockeys are spoilt … ABS on your Boeing ??
Nice car btw :wink: [/quote]

Yep!!! AND autobrake!

In fact, if you are clever, you can select a brake level, land in the right place and the whole lot will stop just abeam an exit! :smiley:

And if you are really bored, just let it land itself… it even stays on the Runway Centerline too!

Another Tea please Doris! :smiley:

17

[quote=pete757][quote=jfk][quote=pete757]
You heavy metal jockeys are spoilt … ABS on your Boeing ??
Nice car btw :wink: [/quote]

Yep!!! AND autobrake!

In fact, if you are clever, you can select a brake level, land in the right place and the whole lot will stop just abeam an exit! :smiley:

And if you are really bored, just let it land itself… it even stays on the Runway Centerline too!

Another Tea please Doris! :smiley: [/quote]

Hey Pete - we need to swop some flying stories … from a back seat perspective …

So I assume that when we have a nice gentle breaking and then a sudden harder application of reverse thrust and stuff its because the braking level was miscalculated for the exit you need :wink:

18

[quote=AndyD][quote=pete757][quote=jfk][quote=pete757]
You heavy metal jockeys are spoilt … ABS on your Boeing ??
Nice car btw :wink: [/quote]

Yep!!! AND autobrake!

In fact, if you are clever, you can select a brake level, land in the right place and the whole lot will stop just abeam an exit! :smiley:

And if you are really bored, just let it land itself… it even stays on the Runway Centerline too!

Another Tea please Doris! :smiley: [/quote]

Hey Pete - we need to swop some flying stories … from a back seat perspective …

So I assume that when we have a nice gentle breaking and then a sudden harder application of reverse thrust and stuff its because the braking level was miscalculated for the exit you need :wink:

[/quote]

Mate!!! Yep different from a pax point of view!!!

One of the biggest misconceptions is that reverse thrust contributes loads of braking. It does not! The difference in stopping distance without it is only a matter of a couple of hundred feet on a 10,000 runway! Furthermnore, if reverse thrust is used, it should be used straight away as it is more effective… drag is squared as speed inceases… Leaving it till late does nothing other that make lots of noise! (Indeed our standard procedure is to not use it as it saves all that noise and reduces another heat cycle on the engine)

The Autobrake system setting is variable… it is designed to achieve a ‘rate of deceleration’. So with no reverse thrust, the brakes work a bit harder… with reverse thrust they do back off a bit as a small proportion of the deceleration.

A good crew will plan ahead and select the level of autobrake with the knowledge of where the runway turn-off points are. A not so good crew will perhaps suddenly see an exit coming and then manually brake the aircraft… hence the big jerky stops!

However, if you fly with me mate, you wont feel a thing! :wink:

19

[quote=pete757][quote=AndyD][quote=pete757][quote=jfk][quote=pete757]
You heavy metal jockeys are spoilt … ABS on your Boeing ??
Nice car btw :wink: [/quote]

Yep!!! AND autobrake!

In fact, if you are clever, you can select a brake level, land in the right place and the whole lot will stop just abeam an exit! :smiley:

And if you are really bored, just let it land itself… it even stays on the Runway Centerline too!

Another Tea please Doris! :smiley: [/quote]

Hey Pete - we need to swop some flying stories … from a back seat perspective …

So I assume that when we have a nice gentle breaking and then a sudden harder application of reverse thrust and stuff its because the braking level was miscalculated for the exit you need :wink:

[/quote]

Mate!!! Yep different from a pax point of view!!!

One of the biggest misconceptions is that reverse thrust contributes loads of braking. It does not! The difference in stopping distance without it is only a matter of a couple of hundred feet on a 10,000 runway! Furthermnore, if reverse thrust is used, it should be used straight away as it is more effective… drag is squared as speed inceases… Leaving it till late does nothing other that make lots of noise! (Indeed our standard procedure is to not use it as it saves all that noise and reduces another heat cycle on the engine)

The Autobrake system setting is variable… it is designed to achieve a ‘rate of deceleration’. So with no reverse thrust, the brakes work a bit harder… with reverse thrust they do back off a bit as a small proportion of the deceleration.

A good crew will plan ahead and select the level of autobrake with the knowledge of where the runway turn-off points are. A not so good crew will perhaps suddenly see an exit coming and then manually brake the aircraft… hence the big jerky stops!

However, if you fly with me mate, you wont feel a thing! :wink:

[/quote]

Cheers Pete !

Get your self to China Eastern quick :smiley:

Did I read also fy Airbus ? I want to know what makes an A320 shudder and vibrate like crazy when trying to get to cruise speed, so never get there and then wobble around like its gonna nosedive or rollover with the captain saying everyting is fine while you can hear warning sirens going off in the back ground :astonished:

I love China …

20

Sound like a normal flight to me mate! :smiley: