@calmotion posted:Performance question:
Being the car is so light as it is. Would the added value / expense for the Wilwood disk brake/pad be justifiable instead of using a good brake pad / disk brake?
To an extent and with the right tires, but you can also get to a point where you are over-brake'd and just lock up quicker...
@WOLFGANG posted:What no BREMBO?
Actually we've modified both 964 and 986 Brembos to work on a Speedster. Partly for the "cool" factor and partly for quality vented brakes, which were much more scarce back then. You had to learn how to use them and modulate your left foot otherwise it was just too much.
@calmotion posted:Thank you. I have similar 5 x 130 / 16 summer tires hence the question with performance. Would you say a brake bias kit would help more? Is there one available?
During a full emergency stop (with 2 people in the car) from 85 or 90 mph do you get brake fade before coming to a full stop? Under reasonably heavy braking do you have to worry about one end locking up before the other?
No to the first question means you have adequate brakes for a pleasure driven street car. No to the 2nd means the brakes are pretty well balanced.
Beam front end I have had .... Now a full 911 front end. I get it that 911 brakes are vented and are better but unless you have ABS you will get to lock up soon enough to realize there are limitations to the car.
All I know is that if you calculate the surface area of the pads you might be surprised to find that for the rear a Golf caliper with built in parking brake works ! my 2 sheckels
@calmotion posted:Thank you. I have similar 5 x 130 / 16 summer tires hence the question with performance. Would you say a brake bias kit would help more? Is there one available?
Summer tires? Which ones? Treadwear rating? 300 or lower is pretty sticky. Over 300, not so much, you'll lock up and slide much quicker.
As to brake proportioning, the dual master cylinder and caliper sizing usually take care of that. You can't change the ratio on a street car without separate front and rear master cylinders, unless you put in a "proportioning valve" on one or both lines. I put "proportioning valve" in quotes, because all the valve can do is reduce the pressure in whatever line you put it in. Most people install one in the rear line, so in effect they can only bias TOWARD the front brakes.
Having had two beam-equipped Spyders, I'll share my take.
My first car had CSP solid disc front and drum rear. I changed the rear shoes to Type3 which are 10mm wider. The front calipers are single piston, sliding caliper(floating??), cast iron generic European General Motors. The brakes worked great for regular and spirited driving. Until one day they overheated at 85mph going into a corner after a couple miles of VERY intense driving on a Pennsylvania park entrance road. I still don't know how I made the corner. I would flush and bleed with fresh fluid every other year religiously, so moisture wasn't the problem. This car had Bridgestone Pole Positions which I think were above a 300(maybe 400?) treadwear.
The second Spyder has solid discs all around. They are drilled and NON-vented. 4 piston Wilwood with Wilwood performance street/track pads in the front. Generic VW single piston e-brake caliper in the back with stock pads. I have the 20.7mm(I think that is the size) dual circuit MC. These brakes are nothing short of superlative. Your passenger better be wearing the shoulder belts when you pounce on these! They are VERY easy to modulate and keep right at the lockup/max threshold. They do not fade or overheat, ever. Even at the end of a 30 minute lapping session at Lime Rock Park. You brake pretty heavily there at turn 1, tap the brakes lightly at the Lefthander, then don't touch them unless you come up behind a slower car in a no-passing zone. On HPDE days, the only acceptable place to pass is on the main straight unless you get a point-by.
IMHO, for 99% of the folks on here, the EMPI discs are adequate. I really don't think many are out there pushing their cars hard enough to need more braking.
Discs are better in every single way except possible squeal/noise if they don't get enough use.
That’s way too much bother for me. The time to do it was in 2017 when Greg built the car. I was hoping someone made an upgraded bolt in rotors and calipers. That does not exist for wide 5s. I don’t track the car. The current setup is adequate.
Summer tires? Which ones? Treadwear rating? 300 or lower is pretty sticky. Over 300, not so much, you'll lock up and slide much quicker.
I have proxies 7 and 8 x16 
mostly use for backend driving. I was on a downhill /freeway and had sudden stop upfront. The back wheels lock up hence the ask.
thanks everyone.
@calmotion posted:The back wheels lock up hence the ask.
Yep.
@calmotion posted:Summer tires? Which ones? Treadwear rating? 300 or lower is pretty sticky. Over 300, not so much, you'll lock up and slide much quicker.
I have proxies 7 and 8 x16
mostly use for backend driving. I was on a downhill /freeway and had sudden stop upfront. The back wheels lock up hence the ask.
thanks everyone.
In that case, a valve in the rear line to reduce the pressure should work for you.
I can lock all 4 if I want on mine, but the front locks first, which is the way I like it.
@DannyP posted:In that case, a valve in the rear line to reduce the pressure should work for you.
I can lock all 4 if I want on mine, but the front locks first, which is the way I like it.
Me, too. I'd rather understeer than fly off the road backwards! Understeer is way easier to catch and correct, and if you don't catch it you get a panoramic view of whatever you're about to hit.
@JMM (Michael) doesn’t this car have tendency to oversteer having the motor in the back 🥲. I still feel this behavior even though mine has a mid engine configuration.
@calmotion posted:@JMM (Michael) doesn’t this car have tendency to oversteer having the motor in the back 🥲. I still feel this behavior even though mine has a mid engine configuration.
Are you running staggered a wheel/tire combo? Ever played with tire pressure? AFAIK, you SHOULD be able to get it pretty neutral with some adjustments.
Yes. Staggered 7 and 8 and right now I tried low pressure and now testing 32 all around
YES that is the goal to be neutral 👍🤘
What size tires are you running on the rear?
@dlearl476 posted:What size tires are you running on the rear?
they are 205x50x16 and I think it’s 185 upfront.
That’s what I ran. Maybe fiddle a bit more with TP. Also, a trip to a local track day to search out a suspension guru with a set of 4 corner weight balance scales might help.
@dlearl476 thanks. I read about the weight balance all 4 corner / adjust the coil over. I’m not stunning any stablizer bar yet and thought that might help as well. Fun cars for sure.
