Write-up: Budget 4-piston calipers for 944 NA
#16
But on the n/a you have smaller diameter and thinner rotors , so with the volvo caliper even if you have a similar piston area to the 951 you still don't get the same braking capacity and definitelly not the same heat dissipation because of rotor thickness and steel volvo caliper instead of aluminum.
#17
Do they center on the rotor? That is, when they are mounted, does the rotor sit exactly in the middle of the piston faces on either side?
Also would like to know the weight of these, they look heavy.
Thanks for the write-up
Also would like to know the weight of these, they look heavy.
Thanks for the write-up
#18
They're actually lighter than stock, believe it or not. I don't have a scale, but I'd guess a pound or two.
#19
been bored for a while at work so ive been doing reading about brake systems...
found some interesting info re: piston sizing.
Stock 944NA: 1x 54mm (floating style)..........= 4580 sq.mm piston area...we'll call this 100%
Stock 86 951: 2x 38mm + 2x 36mm (fixed)...= 4302 sq.mm piston area.......................93.9%
Stock 87 951: 2x 40mm + 2x 36mm (fixed)...= 4547 sq.mm piston area.......................99.3%
1992 VOLVO: 240 4x 38mm (fixed) ...............= 4534 sq.mm piston area.......................98.9%
so the stock 944NA calipers actually have the MOST piston area of all these options. (even though it is a single piston, the floating design effectively doubles piston area)
however the fixed type calipers (951 and Volvo) tend to have advantages in:
1) heat dissipation (due to material, mass, and general caliper design)
2) more even pad+rotor contact = more efficient braking and better pad wear
3) weight (if you've ever held a 944NA caliper and a 951 caliper at the same time, WOW)
Since the 944 NA and 951 have the same brake master cylinder, the caliper piston areas must have been kept similar to achieve similar pedal feel. What is nice is that we can see the Volvo calipers are almost identical in piston area to the later 951, but actually a little bit more than the 1986 951 brakes.
found some interesting info re: piston sizing.
Stock 944NA: 1x 54mm (floating style)..........= 4580 sq.mm piston area...we'll call this 100%
Stock 86 951: 2x 38mm + 2x 36mm (fixed)...= 4302 sq.mm piston area.......................93.9%
Stock 87 951: 2x 40mm + 2x 36mm (fixed)...= 4547 sq.mm piston area.......................99.3%
1992 VOLVO: 240 4x 38mm (fixed) ...............= 4534 sq.mm piston area.......................98.9%
so the stock 944NA calipers actually have the MOST piston area of all these options. (even though it is a single piston, the floating design effectively doubles piston area)
however the fixed type calipers (951 and Volvo) tend to have advantages in:
1) heat dissipation (due to material, mass, and general caliper design)
2) more even pad+rotor contact = more efficient braking and better pad wear
3) weight (if you've ever held a 944NA caliper and a 951 caliper at the same time, WOW)
Since the 944 NA and 951 have the same brake master cylinder, the caliper piston areas must have been kept similar to achieve similar pedal feel. What is nice is that we can see the Volvo calipers are almost identical in piston area to the later 951, but actually a little bit more than the 1986 951 brakes.
#20
A Pound or two ??? ...And the rest
The Stock Iron's are 11 Lbs each!
I replaced all of these with Aluminium Wilwoods
Front 6 piston DynaPro @ 6lbs each
Rear 4 piston Dynalite @ 4.5Lbs each
Caliper Piston Area: (Increase) Inches Square
Front 14.186 to 15.587
Rear 9.621 to 11.879
Clamping Force: (Increase) PSI
Front 1460 to 1608
Rear 1034 to 1090
Contact patch : (Increase) Lb's
Front 1310 to 1438
Rear 990 to 1043
What does this all mean ?, in a car Less 500Lbs+ Vehicle weight, it' stops
very very easily and effortless.
Last Friday I did 40 laps continuous of a twisty Race Circuit, each lap had 3 sections of 100mph down to 25mph that's a total of 120 stops and all 4 calipers had the softest compound available for great bite and I knew due to their power and the low vehicle weight they would not need to cope with too much heat and require a harder temp compound.
They were as you'd expect getting quite Hot! but never faded or do I now need
to replace them soon!
R
#21
Dude no offense but you keep coming into threads on here and posting information about your build and how great it is, rarely offering anything useful to the topic at hand. Thanks for the info about the stock caliper weight though. We all get that your car is very well set up, you don't need to rub it in
#22
Dude no offense but you keep coming into threads on here and posting information about your build and how great it is, rarely offering anything useful to the topic at hand. Thanks for the info about the stock caliper weight though. We all get that your car is very well set up, you don't need to rub it in
There's no rubbing in required just free of charge advice and opinions attempting to "offer something useful to the topic"
R
#23
but not as much in a stock-weight car (though still a consideration)...
your wilwoods also cost 5x what the Volvo solution does...
#24
I have been weighing all the parts I remove or swap out on my car. The stock 944 NA calipers, loaded with pads, weighed 12 pounds even. The Volvo 240 calipers, loaded with new pads, weighed 10 pounds, 1 ounce.
(weights are per caliper)
(weights are per caliper)
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curtisr (01-27-2021)
#29
Decided to replace my rotors today, after reading that fixed calipers (like these) and Redstuff pads are more sensitive to disc warping. Mine were ok but almost at the wear limit, and ever so slightly warped. Not really enough to worry about in real life, but it was there.
Anyone want those slotted NA front rotors for almost nothing? Just ordered new ones, along with new wheel bearings and all new hardware since I'm in there.
Anyone want those slotted NA front rotors for almost nothing? Just ordered new ones, along with new wheel bearings and all new hardware since I'm in there.
#30
Great thread, thanks for the discovery, I've been thinking about the brakes on my NA lately so this is great timing for me.
I can't wait to get some Volvo hotness on my car. VW guys can have fun with Porsche parts, but once they see my Volvo stuff they'll be jealous.
But the actual performance increase will be marginal, correct? The rotor is still the same, the piston area is about the same, and the calipers are still iron. I'd do it just for the 2lb unsprung weight reduction and the cool-factor, though.
I can't wait to get some Volvo hotness on my car. VW guys can have fun with Porsche parts, but once they see my Volvo stuff they'll be jealous.
But the actual performance increase will be marginal, correct? The rotor is still the same, the piston area is about the same, and the calipers are still iron. I'd do it just for the 2lb unsprung weight reduction and the cool-factor, though.