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westcoast911 westcoast911 is offline
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Join Date: Feb 2012
Location: Vancouver B.C
Posts: 300
Quote:
Originally Posted by Bill Verburg View Post
I've looked at 3 different GTP setups not counting the GTP/L which was pretty nice

Most likely what you have is the Kit w/ F40 front calipers, and Lotus rear calipers on 993tt 322mm rotors f/r w/ a 930 m/c

I have feedback from multiple owners, all of it along the lines of what the OP has reported, some have led to serious accidents

torque bias for the F40/Lotus GTP kit is very much front 2.03, for referencea ll 911 before Porsche started messing w/ bias in '84 were 1.491

You should never use a p/v on the front

and w/ your current setup be sure to remove the stock one on the rear circuit

there are 2 things that you can do to alleviate the issue
1) lower the front bias w/ a caliper w/ smaller pistons, a 993RS/tt front(aka Big Red) bolts on w/the correct adapter and lowers torque bias to 1.856
2) raise rear bias, a 993 rear caliper can be adapted w/ a little work, a 965 rear can be adapted w/ a little less work, either of these will lower the bias w/ 993RS/tt front to 1.520. A 993RS rear can also be adapted and is far more difficult to do but that will lower the bias to 1.426

I don't understand why RaceTech sold that kit, the previous version was Big Red(993tt/RS) all around and was fantastic as long as you got the 993RS rear calipers, form what I understand some came w/ 993 tt rears which would be as bad as the GTP kit
I'm going to make a second call to race tech on Monday and see what they have to say.
Bill, from a performance perspective, would I be better served re installing the OEM Carrera brakes? Are there some simple mods that could make the stock pieces more effective? They did come with the car as well.
Old 01-26-2014, 07:41 AM
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