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Disabling ABS for extreme tracking/trialing?

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Old 01-14-2019, 02:05 PM
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Sword_of_the_Spirit
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Default Disabling ABS for extreme tracking/trialing?

Hello,
Anyone here disable the ABS functionality instead of going straight to the Cup ABS ECU for trialing/tracking? I grew up karting and there isn’t a problem with modulation, I just don’t want to functionally deal with potential ICE mode at Laguna without breaking the bank for Cup/GT2 piece. $4500 over at Freisinger......

Thanks
Old 01-14-2019, 03:42 PM
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Paddy
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After years of tracking my 993 with the stock calipers then full RS front & rear with aggressive PFC pads I never experienced ICE mode and honestly only really got into the ABS once. Not sure it's really needed.
Old 01-14-2019, 04:22 PM
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Thanks Patrick. I’ve gone into ABS (not pedal, but steering feel) before at Buttonwillow. Never any of the bigger tracks I’ve been RA, Mid. With my setup of tire % difference being near equal, LSD, plus proper RS brakes, I’ve never experienced Ice Mode. It’s more common in the GT3 and later variants due to increased complexity. I just hate bumpy turn 7 and don’t want that “what if”.
Old 01-14-2019, 04:42 PM
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pp000830
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Would pulling the ABS Relay(s) in the frunk on the passenger side fender wall disable the system?

Last edited by pp000830; 01-14-2019 at 05:31 PM.
Old 01-15-2019, 01:13 PM
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centerpunch
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I had an '87 Turbo Cup factory race car that I bought new that had an ABS switch from the factory. When I bought the car from Holbert (then Porsche Motorsport North America), they told me most racers turned the ABS off in the dry, but almost everyone used it when it was wet.

Post 713 in this thread one guy shows where the switch was connected, probably a similar circuit in the 993. When I turned the switch off in my car, the ABS warning light lit up.

https://rennlist.com/forums/924-931-...l#post15192316
Old 01-15-2019, 01:31 PM
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Mark in Baltimore
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Tracked/raced my car for about ten years and, like Paddy, never had an issue with ABS, never got into it and never experienced the ice mode that the newer cars can experience. Not worth disabling, IMO.
Old 01-15-2019, 05:46 PM
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Nader Fotouhi
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The only reason you experience ice mode in a 993 would be a large discrepancy between front to rear rolling diameter, and there is no need to use such a mismatched tires.

Originally Posted by centerpunch
I had an '87 Turbo Cup factory race car that I bought new that had an ABS switch from the factory. When I bought the car from Holbert (then Porsche Motorsport North America), they told me most racers turned the ABS off in the dry, but almost everyone used it when it was wet.

Post 713 in this thread one guy shows where the switch was connected, probably a similar circuit in the 993. When I turned the switch off in my car, the ABS warning light lit up.

https://rennlist.com/forums/924-931-...l#post15192316
Interesting. I had a 91 994S2 and would experience ABS being disabled when hitting rumble strips on a few particular corners. The brake bias was such that if you touched the brake pedal, the rear would lock up. I use to turn the key on and off to restart the car and reset the ABS coming out of those corner until I got wise and installed a cut off switch to reset the ABS. Needless to say, my lap times did not suffer as much.
Old 01-15-2019, 06:15 PM
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TheOtherEric
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Between me and acquaintances, we tracked 993s for hundreds of track days and nobody ever complained about the factory ABS. This “icing” whatever that is, is a non-issue for us. Personally I run TT fronts and RS rears.
Old 01-16-2019, 02:11 AM
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Thank you guys. It really means a lot.
I’d agree that it seems those with a larger discrepancy between tire circumferences have the problem (later cars), but I’ve experienced ABS, just not “Ice Mode”. It’s the “ripples” in the pavement or rumbles it hit. For me at my recent outings, it’s the sweeping left turn 1 CW at Button. Maybe I’m an anomaly.... But I’ve run tracks that you guys have as well with especially the Midwest ones like Mid, RA, and Autobahn. With that said, for those that have disabled in variants of this vintage, have the fronts locked almost immediately as a result as I have heard on my recent forum searches?
Honestly, besides a system brake setup with bias controller, my only option maybe the Cup controller. I hope not as both aren’t light on the cc.
Old 01-16-2019, 10:01 AM
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Bill Verburg
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Originally Posted by Paddy
After years of tracking my 993 with the stock calipers then full RS front & rear with aggressive PFC pads I never experienced ICE mode and honestly only really got into the ABS once. Not sure it's really needed.
+1
Old 01-17-2019, 10:12 AM
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MB965
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Originally Posted by Bill Verburg
+1
Agree, not a problem on track.
ICE mode not possible with the 993 ABS system.
Old 01-17-2019, 03:49 PM
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mhm993
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TT and RS calipers
25,000+ track miles. No ice.
Old 01-17-2019, 05:55 PM
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FWIW, The 964 Cup had a high pressure defeat switch attached to the hydraulic line so when the brake pedal was pushed *really* hard the ABS turned off to avoid ice mode when car was spinning out of control (ABS apparently confused easily) as well as an ABS off switch in dash for turning off for driver preference to not use ABS. 964 a 3 channel ABS systems for race and street.

I think 964's early generation ABS had this issue with "ice" and 993 doesn't have it in either the 3 or 4 channel variety and Cup drivers liked 993 system to extent neither switch was necessary.
Old 01-17-2019, 10:12 PM
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Fair enough. Thanks guys for the help with the “what if” scenario.

Interesting that it’s possible with prior gen and 996gt variants. I’ve never experienced it and am deliberate with my applications, so it what it is.
Old 01-18-2019, 01:38 AM
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You have any definitive info MB965?


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