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Sorry to go off topic from this thread. I recently found out first hand that 7.1 GT3 and 7.2 GT3 front uprights aren't a bolt-on swap. Sure the geometry are different, but what make them not a bolt-on swap is type of wheel speed sensor. Haven't done this particular swap myself previously, I assumed they were interchange looking at PET, which shows both generations of car share the same sensor(item #3 in image below).
According to PET, 997 GT3 from 2007-2011 use the same sensor. This is incorrect.
The image below shows the 2 types of sensor.
Left of image is the sensor for 7.1 GT3 (aka 996-style sensor) its shorter, wider diameter sensor that uses the a toothed wheel as trigger.
Right of image is the sensor of 7.2 GT3, Carrera, C2S. C4, C4S, Turbo, GT2, Boxster, and Cayman, it longer, narrower sensor that uses a multi-pole magnetic ring inside the wheel bearing to trigger.
Both types of sensors have two-wires, but the signals are different!
At one point in time I thought the two types of sensor signals were interchangeable by hearsay from a few people who are in the trade. Unfortunate found out first hand that it is not true.
To make this work, I did precise measurements to determine the sensor position offset and depth, then drill the hole, milled the surface, and welded on a boss for the different sensor. That was Not Fun.
Here's the second sensor hole. Again Not Fun at all. If you're considering the swap, I suggest Don't Do it. Unless you have a Machinist and Welder at your disposal.
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PCA National Instructor
TPC Racing stats:
2023 Porsche Sprint Challenge 992 Cup Am Champion
2023 Porsche Sprint Challenge GT4 Pro-Am Team Champion
2022 Porsche Sprint Challenge 992 Cup & 991 Cup Champion
2020 IMSA GT3 Cup Challenge 2nd Championship
2018 IMSA GT3 Cup Challenge 2nd Championship
2016 IMSA GT3 Cup Challenge Champion
2013 IMSA GT3 Cup Challenge Champion
2006 Rolex-24 @ Daytona GT Champion
2004 Grand-Am SGS Class Champion
Sorry to go off topic from this thread. I recently found out first hand that 7.1 GT3 and 7.2 GT3 front uprights aren't a bolt-on swap. Sure the geometry are different, but what make them not a bolt-on swap is type of wheel speed sensor. Haven't done this particular swap myself previously, I assumed they were interchange looking at PET, which shows both generations of car share the same sensor(item #3 in image below).
According to PET, 997 GT3 from 2007-2011 use the same sensor. This is incorrect.
The image below shows the 2 types of sensor.
Left of image is the sensor for 7.1 GT3 (aka 996-style sensor) its shorter, wider diameter sensor that uses the a toothed wheel as trigger.
Right of image is the sensor of 7.2 GT3, Carrera, C2S. C4, C4S, Turbo, GT2, Boxster, and Cayman, it longer, narrower sensor that uses a multi-pole magnetic ring inside the wheel bearing to trigger.
Both types of sensors have two-wires, but the signals are different!
At one point in time I thought the two types of sensor signals were interchangeable by hearsay from a few people who are in the trade. Unfortunate found out first hand that it is not true.
To make this work, I did precise measurements to determine the sensor position offset and depth, then drill the hole, milled the surface, and welded on a boss for the different sensor. That was Not Fun.
Here's the second sensor hole. Again Not Fun at all. If you're considering the swap, I suggest Don't Do it. Unless you have a Machinist and Welder at your disposal.
So im assuming a .1 gt3 knuckle is direct bolt on as i have a .1 tt
7.1GT3 upright is the only one that will be a direct bolt on to a 7.1TT.
7.1Cup will also bolt on but the roll centers are too high relative to the rear TT rear roll centers which are much lower on the OEM TT parts. You would need to swap out the rear wheel carriers to the Motorsport carriers which would also require new subframes and crossmember. Even then, it would be impossible to run the TT at Cup height which is what you would need to do to optimize the suspension geometry.
7.1GT3 upright is the only one that will be a direct bolt on to a 7.1TT.
7.1Cup will also bolt on but the roll centers are too high relative to the rear TT rear roll centers which are much lower on the OEM TT parts. You would need to swap out the rear wheel carriers to the Motorsport carriers which would also require new subframes and crossmember. Even then, it would be impossible to run the TT at Cup height which is what you would need to do to optimize the suspension geometry.
sweet, the cup car sensors are direct fit aswell?
im converting the car to rwd if that changes anything. Was planning on cup rear subframes/solid bushes anyways so thats good to hear!
ty for the infor!
sweet, the cup car sensors are direct fit aswell?
im converting the car to rwd if that changes anything. Was planning on cup rear subframes/solid bushes anyways so thats good to hear!
ty for the infor!
Cup wheel speed sensors are the same as those used on all GT/TT cars 01-07.
In conclusion, since PET can be infrequently incorrect, to avoid machining and welding, check to see which type of sensor is on the car first. This image below should help.
Early type(part # 996 606 406 00) is on Left side of image. Later type(part # 997 606 407 01) is on Right side of image.
I forget when the transition happened, but the GT3 went from using a 42 tooth (i think it is 42 teeth) wheel to a wheel bearing with a mag stripe that has the timing marks as part of the mag stripe. This required a different sensor, BUT I think the output signal is either the same or very similar.
I forget when the transition happened, but the GT3 went from using a 42 tooth (i think it is 42 teeth) wheel to a wheel bearing with a mag stripe that has the timing marks as part of the mag stripe. This required a different sensor, BUT I think the output signal is either the same or very similar.
It's 48 teeth. Transition happened in MY 2010. Output signal is different.
Thanks for the correct tooth count. For the Geek: both are square waves, levels may be different - nothing a simple amp can't fix... I know at least 1 person who did this...
Thanks for the correct tooth count. For the Geek: both are square waves, levels may be different - nothing a simple amp can't fix... I know at least 1 person who did this...
Ray
Anything can be done with enough effort. I guess the overriding question is why anyone would choose to spend the time and energy to hack the ABS system when you can simply install the correct wheel carriers and thus avoid any pitfalls....
Interesting questions: Best answer is 'because one can' - this hacking is actually fairly easy: Both signals are pulses / square waves, I suspect the frequencies (number of teeth on the wheel and number of magnetic lines) are the same, biggest difference is just a level change - I suspect, could be wrong, but not that likely...
Not sure what 'pitfalls' you refer to, but the electronics would likely be not that involved, easy enough to make them robust... Everything else is OEM.
02-16-2020, 11:28 PM
- this hacking is actually fairly easy: Both signals are pulses / square waves, I suspect the frequencies (number of teeth on the wheel and number of magnetic lines) are the same, biggest difference is just a level change - I suspect, could be wrong, but not that likely...