Pulling ABS fuse(s) for the track

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davekmoore
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Re: Pulling ABS fuse(s) for the track

Postby davekmoore » Fri Jan 02, 2015 1:59 pm

beavis wrote:Dave, I have pulled the single fuse under the bonnet to disable ABS ......

....... and a few laps as a passenger in your car at Winton confirmed your brakes work just fine. The big forum says SE/NB8C has a dummy prop valve though, and the bias is controlled by the ABS. I'd hate to pull the fuse and find the brakes are 50/50 front/rear.

Do you always run without ABS on the track?

Not yet installed the speedo sensor by the way. Also aware I still have your guard roller.
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beavis
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Re: Pulling ABS fuse(s) for the track

Postby beavis » Fri Jan 02, 2015 2:05 pm

davekmoore wrote:Do you always run without ABS on the track?

No. I only removed it when it was kicking in at an intrusive level at Calder Park. I didn't notice unusual bias.
The problems have gone away with a hotter spec pad.

davekmoore wrote:Not yet installed the speedo sensor by the way. Also aware I still have your guard roller.

:) I'm glad you are, at the very least, thinking of me.... :oops:
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zossy1
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Re: Pulling ABS fuse(s) for the track

Postby zossy1 » Fri Jan 02, 2015 3:43 pm

This is the second thread like this in a few months. I find it fascinating.

My race car is one of the few cars running mx5 cup at the moment that does NOT have ABS. All else being equal, I suffer at certain points on the track but at others, it doesn't make much difference. All the front runners are running Carbotech or Hawk pads with either NB8B brakes or better.

Several cars on the grid have paid $$$$ to have ABS fitted. I would like to fit it to the blue rocket as I think it would gain me a couple of tenths at WP in being able to brake deeper into some of the corners with preceding kinks without locking the inside front, and possibly also allow trail braking at one or two other spots without locking the inside wheel. It would also be magic in the wet and would save me money in flat spotted tyres (I destroyed 4 tyres last year with flat spots and damaged one or two others).

The MX5 ABS (at least that commonly found in NB8Bs) is a 3 channel system monitoring the fronts individually, and the rears as one combined unit. The ABS pump functions as a prop valve that, I understand, monitors braking and adjusts the bias in accordance (I would guess) with which wheels are locking first and adjusting the bias accordingly (with, I would suggest, a natural road-safe tendency towards front bias). I would imagine the bias adjusting servo would stop working if the fuse was removed, freezing bias at the level it was at before the fuse was pulled. Most of this is a guess though, but from my observations, the unit seems to work well under racing conditions. Brake problems in ABS cars tend to more often be a function of brake fluid quality, pad material and rotor quality rather than the ABS system performing poorly.

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Hellmun
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Re: Pulling ABS fuse(s) for the track

Postby Hellmun » Fri Jan 02, 2015 7:25 pm

I've pulled the fuse before and dríven on street tyres and found the car was crazy front biased. I've been meaning to try it with R-specs to see what it's like with grip at the front. I wish there was a display or output to use to see on the datalogger to tell when ABS engaged. On the road you can feel the pedal pulsing..but on the track even purposefully stabbing the brakes doesn't pulse my brake pedal at all. Mx5 ABS is just very unintrusive on track... though I understand how the ABS could cause a big increase in wear. Just bear in mind both the pads and rotors are thinner compared to sport brakes. So you'll see a faster wear rate on consumables with the wilwood kits (at least with dynalites and the 22mm rotors).

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Re: Pulling ABS fuse(s) for the track

Postby greenltd » Sun Jan 04, 2015 4:41 pm

Dave like Bob said, i pull the abs fuse under the bonnet for motorkhanas. It disables the abs. Perhaps this leaves the airbags functioning unless the under dash fuse is pulled

Quick thread hijack - Beavis, i now own Chrystal so its me you have seen at Mulgrave. Do you have a green na and toot at me recently ?

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Re: Pulling ABS fuse(s) for the track

Postby Boyracer » Mon Jan 05, 2015 7:54 am

I would get rid of the Willwoods and keep the ABS.
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Re: Pulling ABS fuse(s) for the track

Postby beavis » Mon Jan 05, 2015 8:09 am

greenltd wrote:Quick thread hijack - Beavis, i now own Chrystal so its me you have seen at Mulgrave. Do you have a green na and toot at me recently ?

I bought the NB shocks off you.... was in the Calais, not me in the NA.
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