Thats scary, let us know what you come up with, I would like to avoid this issue if possible.

 

Thanks for the pics rob. That's a very slick set up you have there. Maybe that's an option for the OP? And yes RKT definatly knows what they are doing. If i decide to a cage they're the one I'm going to!

 

At 130 MPH, stock-sized tires are rotating 28 times per second. This may be too fast for the wheel-speed sensors to provide accurate information and if one wheel starts dropping counts first, the system will interpret this as one wheel sliding.

I searched around and couldn't find any published maximum wheel rates or frequencies for Mitsu ABS, but did see that some Ford systems top out at 20 Hz. That's around 100 MPH to you.

Upshot: this may be unfixable.

edit: Oops. The wheel has, of course, many sending points, as opposed to only one. So even after correcting for Nyquist, 28 rotations per second is already waaaaay above 28 Hz. Ignore me.

 

If everyone was having this problem I'd believe that .... but so far its just me.

 

I had a talk with the Grand Am factory Subaru team owner who cautioned me about using ABS. He said the pedal will go hard and you nwill have no brakes. I told him I never experienced it in my Evo. I once owned a 1990 Gp N factory BMW M3 race car that had the BMW Motorsport ABS pump which was designed for racing. Must be something to do with federal regulations. I think we need a auto industry engineer to explain why they build a brake system that will refuse to operate in certain high speed applications and what is different in the racing ABS units. I saw that BMW North America now offers racing ABS units for current models. I have the Ralliart catalog's from Evo 5-9 and they did not offer a racing ABS pump. Just talking with Charlie and he says Corvette owners are retrofitting the BMW Motorsport E 46 ABS 4 line system. I wonder after seeing Bosch on my old Evo master cylinder whether Mitsubishi has Bosch build their ABS system. Street ABS are designed for panic stops at 35mph not 135mph.

 

the reason is , the street ABS system's are more designed to prevent accidents or scary moments at slippery condition's. And has nothing to do with racing, like high level of braking continuously.
Also the pump etc is just more parts there waiting to fail.
There is no need to reinvent the car in racing, you just need to made it more easy to fix and more reliable. That is why i am the fan of the pedal box. Nothing there to go wrong really, light simple easy fix.
And you will never have anything between your pads and your feet to change any feedback.
Once you get used to it , i do believe you will never look into redesign or "upgrade " you ABS system with other pumps etc. Even if the racing abs systems.
you guys are great drivers , so i do not think you will have ever any issue to find the threshold in braking. The pedal box will never let you down, and NOTHING has a same feel or feed back as a simple brake system. Good example go-karts.

 

Mitsu claims that the Sport version of ABS, as on the Evo X, is intended for high-speed use (but they didn't say "racing"). But this doesn't help the thread-starter, of course. I searched for any details on the speed sensors or pump that could explain why S-ABS could be used at higher speeds than previous ABS systems, but all I could find was information on how the accelerometers (including yaw sensors) are used in S-ABS.

 

OP, Why not just remove the ABS system?

 

It's a good system. I found it to work well and never experienced the fail condition. Topping out 4th gear entering the toe of the "boot" at Watkins Glen it would engage every lap when I tried to late brake and helped make my apex. I have a switch to turn it off when it rains and the grass is wet.

 

Does the ABS on Evos prior to the X monitor the brake-line pressures to each wheel?

 

i thinks so. But the ecu didnt read the speed from them before.The X has a much more integrated ABS to the awd system then the older evos.

 

From what I understand, I agree with your second comment that the ABS is more connected to the AWD system in the X, given that the AWD system's ECU now uses the ABS for some of the yaw control (i.e., the part that is turned off when you hold the ASC button for three seconds). But I don't understand your first comment. How can the basic ABS system work (on any car) without wheel-speed sensors? My understanding of the plain ABS system (i.e., non-sport system) on Evos is that it is a relatively straight-forward four-channel system.

 

I'm on the fence with ABS. Personally braking to 10 with R/A6's I've only came into ABS on a handful of occasions and that was when the track was indeed slick. I've locked up certain tires before on ANY braking pressure as well but that was due to the wheel speed sensor failing, which is now wrapped with heat wrap and fixed that problem. Technically, with enough track experience like most of you here you're able to drive around it. But I also agree not having it and getting a true pedal box is also the way to go. Personally I don't have the coin or shop skill to do that though.

Bosch does indeed make a Motorsports ABS system for the Evo's, but they're 4 figures cost wise.

 

one of the huge advantage of the pedal box, you are the one who make the pressure on the pads with you own power , there for you have 100% control on the pressure and the braking force.
Mean while the booster and so will take away that very important factor. And takes away a brake feel from you r foot. As easier to push the pedal in , you will be further away from the brake force feed back and the tire grip feedback on the road/surface.

 

Sounds very familiar to what led to my incident in 2008.

Braking down from near 140mph, I just had nothing. I had come to the conclusion that I simply lost vaccuum assist as you can see some marks on the track and I have video to show my speed decreasing to around 100mph before I left the track surface. Moving too fast from gas to brake?

This is why I haven't tried to learn to LFB...