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anyone like racing with ABS?
I've used this car a few times now in wheel to wheel racing, and when I really start to pick up the pace... and go deep in the braking zone, I have problems judging just how deep to go. I'm running an 04 miata with ABS.
There is no feedback. The pedal doesn't kick back; you don't hear any pre-lock-up squeel; the pedal just gets... well: hard. Kind of like brake fade. It's not at all confidence building. Worst, I can't seem to judge how deep I can take it. Anyone like racing with the miata's ABS? If so, what do you feel for with threashold braking? |
Sounds like you need more time on track.
What pads, fluid, rotors are you using? |
Newb thread. you need to confirm a good bleed, then practice.
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In the wet, yes I love it.
With a proper "motorsports" tuned ABS, yes, I like racing with it because it will be faster. With a shitty OEM ABS system, and upgraded brakes so the ABS gets a confused, that I don't like so much. |
Originally Posted by Efini~FC3S
(Post 987304)
In the wet, yes I love it.
With a proper "motorsports" tuned ABS, yes, I like racing with it because it will be faster. With a shitty OEM ABS system, and upgraded brakes so the ABS gets a confused, that I don't like so much. I mean it stops... I just can't reliably find the edge. In the past I was a racer that really used up the braking zone... now, not so much. Can you explain your "motorsports" tuned ABS? Do you do something like unplug, fine adjust/tune your bias thru prop valves or dual pedals and then plug the abs back in? What braking technique do you use other than just the "plant it hard and pray" technique that I'm currently using? |
IIRC Emilio uses ABS on all his race cars.
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Originally Posted by M.Adamovits
(Post 987369)
IIRC Emilio uses ABS on all his race cars.
At this point I'm not feelin' it... and want to unplug the abs fuse. |
Originally Posted by hustler
(Post 987284)
Newb thread. you need to confirm a good bleed, then practice.
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Originally Posted by midpack
(Post 987407)
This man speaks the truth.
In the formula car, you can feel every little twitch and hear each wheel for feedback. In the MSM, the brakes are just heavy and there's so little feedback. |
If you haven't added a prop valve to the system, you're not going to be faster than a non-ABS car.
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Originally Posted by gtred
(Post 987335)
Willwoods, hawk ht-10's, blues or PF pads. High temp fluid.
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Originally Posted by hustler
(Post 987431)
It's 2013, stop using pads from the 80s.
Sav: I'll take you up on the prop valve. I suppose I'm supposed to dial in more front brake bias until I get reasonably even f/r lock and then plug in the ABS? |
Originally Posted by gtred
(Post 987335)
Can you explain your "motorsports" tuned ABS?
I don't know of any such thing for a miata... |
Originally Posted by gtred
(Post 987432)
Ha! I bet you can't disco...
Sav: I'll take you up on the prop valve. I suppose I'm supposed to dial in more front brake bias until I get reasonably even f/r lock and then plug in the ABS? Motorsport 4-channel ABS like the Bosch M4 system is ~$10k IIRC. Since I'm already adding ABS hubs/rings to Theseus for the Racelogic system, I briefly considered adding an M4 ABS system too, until I saw the price tag. $10k buys an awful lot of flatspotted Hoosiers. |
Ah, finally a plausible explanation how the 01+ EBD works.
FWIW the 99/00 systems have a prop valve and don't use ABS for proportioning. Wouldn't the EBD system cause heavy understeer during trail-braking then? |
NB ABS + prop valve = win
Take some practice to get the most out of and nothing I can write here will help. Just go scare yourself until you get the feel for it. 949 Racing SuperMiata - YouTube |
Originally Posted by gtred
(Post 987432)
Ha! I bet you can't disco...
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Originally Posted by emilio700
(Post 987550)
NB ABS + prop valve = win
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Originally Posted by Savington
(Post 987461)
Factory ABS relies on the ABS to do all the proportioning. The caveat here is that you have to actually engage the ABS to get the proportioning working - it will add rear brake after the ABS engages on the front, but that happens way too early.
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Originally Posted by jasonc sbb
(Post 987646)
do you mean the 99/00 abs and replacing the factory prop valve, or taking an 01+ with ebd and adding in a prop valve?
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Originally Posted by emilio700
(Post 987550)
Just go scare yourself until you get the feel for it.
Driving in the rain is helps too |
The first SCCA race is this weekend, so no time to dial in a new system. Hopefully GP3 will read this and keep out of my way!
The explanation of the new "electric brake distribution/proportioning system" does give me some insight as to what is going on. Apparently, you have to begin to lock the fronts before rears gain more bias... which accounts for the "always hard pedal" feel when deep in the brake zone. That also explains why it merely locks the fronts when the abs fuse is pulled. I will add a prop valve to the fronts after this weekends venue...I'll pull off the #'s and add plates for some street driving test-n-tune. Thanks for the help, education and advise! cj |
Originally Posted by gtred
(Post 989330)
I will add a prop valve to the fronts after this weekends venue
I posted this in your last prop valve thread - read it again.
Originally Posted by Savington
(Post 872863)
It's a little counterintuitive, so you need to forget everything you think you know about how a bias valve works before reading this explanation. :)
The ideal braking pressure applied to the front and rear calipers is a non-linear curve. As you start braking, both axles (front/rear) support approximately the same weight, so both can support the same brake pressure. As the car stops harder and harder, more of the weight shifts to the front of the car, which requires the rear brakes to do less (and require less pressure). If taken to the extreme, you end up with a car standing up on its front tires only, with the rear brakes requiring no pressure at all. The ideal curve is the blue line, and the brake pressure applied to the REAR brakes is the white line. You can see the "knee" point - it's the poiint at which the bias valve begins to restrict the rear line pressure. The area under the ideal curve is where the front tires lock first, and the area above the ideal curve is where the rear tires lock first. https://www.miataturbo.net/attachmen...ine=1335986460 As you turn the knob on the bias valve in, it pushes the knee point further up, and therefore closer and closer to the ideal curve, which optimizes the balance between the front and rear brakes. The stock bias valve does the same thing - the Wilwood valve just allows you to adjust that knee point and get it much closer to the ideal curve. Remember that when you adjust the valve, you don't ever want to go above the ideal - if you're in a hard braking zone and you go over a small bump which reduces rear grip and ends up locking the tires, you'll spin the car. I will typically run a lot of rear bias on smooth tracks with very little trailbraking, and dial the bias back a bit on bumpy tracks with long, sweeping braking zones. On race tires with our 11.75" kit in the front and 10.9" Sport rotors in the rear, I typically suggest starting at 5-6 turns from fully in, and then adding more rear bias to taste. On street tires, you'll want to run more rear bias than that, but exactly how much will depend on your application, pavement, etc. |
Check out EBD discussion on a tech forum where a bunch of pros hang out:
How do EBD algorithms work? - The AUTOSPORT Bulletin Board |
Originally Posted by Savington
(Post 989371)
Wrong, wrong, wrong.
I posted this in your last prop valve thread - read it again. Also, the reference to the EBD thread was also quite informative. Actually, what I didn't get when you explained this to me the first time was about the "replacement of the stock prop valve with the adjustable one". My car doesn't seem to have a prop valve at all. That thing on the firewall that looks like a prop valve is hollow; and is referred to in the parts manual as a "pipe joint". I'll certainly try the prop valve fix that you've recommended. It looks like I'll need a little more supervision than the next. |
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