MkII big brake conversion parts

[fosley]

I know these for a fact:
- '92 and '93 NA brake calipers, pads and rotors are interchangeable
- '93 turbo rears use the same pad shape, but possibly a little thicker
- '93 turbo rears have a larger diameter, thicker rotor that won't fit in the NA calipers without an adapter to move the caliper out and thinner pads (the pads are like 2 mm too thick)
- '93 turbo fronts are a two-piston design with larger diameter, thicker rotors
- '92 NA 14" wheels won't clear
- My 16" aftermarket wheels clear fine, but the valve stem sticks straight down and rubs the calipers; before actually driving the car, I'll need to get elbowed valve stems; to run 15's, the stem would probably need to be offset to the outside so it completely clears the caliper

I've been told by enough people that I think these are true:
- Early turbo rears are identical to NA rears (therefore, anything true about late turbo rears vs. NA rears is true about late turbo rears vs early turbo rears)
- Early turbo front rotors are the same as NA front rotors, but the calipers are a two-piston design unlike the NA's one-piston design (therefore, anything true about late turbo front rotors vs. NA front rotors holds true here)
- Late turbo fronts have larger diameter, thicker rotors than early turbo fronts
- Late turbo calipers are all bigger and more massive--this makes them heavier (I think I measured about 6-7 lbs per corner for drained caliper + rotor, but don't quote me on that) but more resistant to brake fade

I paid $600 for a '93 turbo conversion, but did not get the master cylinder, proportioning valve or brake booster. I bought mine used from a board member at the forum-that-shall-not-be-named-lest-it-get-edited-out-and-make-me-look-like-a-tard. I also just bent my N/A dust shields a little and they clear fine.

Gairloch: There is a very significant mass difference between the stock rotors from NA to late turbo. I'm fairly sure the early turbo rotors are the same as the late turbo rotors, which means the calipers aren't the only major point of improved heat soak.

Like you said, the biggest advantage is heat soak, however, there should be a significant increase in braking torque for really wide, sticky tires. I haven't driven mine yet, so I don't know.

From other discussions, it seems like the best bet would be upgrading an NA to early turbo fronts, master cylinder and proportioning valve, or to go all-out and get a Wilwood upgrade or something to get late turbo braking in a lighter package. In either case, you should get Dot 4 or convert to Dot 5 fluid (higher boiling point, so heat soak isn't as big of a deal), steel-braided lines (more efficient pedal pressure to wheel torque conversion), and a good set of pads (stock brakes + good pads > late turbo brakes + crap pads). Only if you are experiencing heat soak will the late turbo brakes benefit you (and you might even lose speed because of the 30-ish lbs of extra unsprung weight).

[kawasakizx636]

Gairloch, i see that u say that u wouldn't recomend upgrading to 93 turbo brakes, but i need new brakes either way, so i mine as well upgrade to the 93's.
te51levin, my vin number is JT2SW22J3********

thanks

[eckoman_pdx]

Besides the fact the car is a 91 turbo, the reason I was curious about the 91Turbo brakes vs 93 Turbos is because I was actually considering Wilwood, Precsion or Rotora.

I have Wilwood 4 Pot calpiers, pads, 12.2" 2 piece rotors, and wilwood SS lines on my other car's front (not a toyota), and in the rear is a drum-disc conversion w/ 11.1" big brake rotor upgrade with hawk pads and earls lines, then an up bigger MC and the proper Prop valve, and a bigger Brake Booster, all running Motul RBF 600 DOT4 racing brake fuild. The car stops like a champ.

I know a set-up like that would cost a grip on an MR2, but I was conisdering looking into it. Then I kept reading about 93 turbo brake swaps, so I thought I'd look into it, see the differences between 91 and 93, to see if that is an option or worth it instead of going the wilwood/precsion/rotora route.

[Gairloch]

Originally Posted by kawasakizx636

Gairloch, i see that u say that u wouldn't recomend upgrading to 93 turbo brakes, but i need new brakes either way, so i mine as well upgrade to the 93's.
te51levin, my vin number is JT2SW22J3********

thanks

That makes sense. Just remember that if you are using 14" stock wheels they won't fit over '93 turbo calipers.

Originally Posted by eckoman_pdx

Besides the fact the car is a 91 turbo, the reason I was curious about the 91Turbo brakes vs 93 Turbos is because I was actually considering Wilwood, Precsion or Rotora.

I have Wilwood 4 Pot calpiers, pads, 12.2" 2 piece rotors, and wilwood SS lines on my other car's front (not a toyota), and in the rear is a drum-disc conversion w/ 11.1" big brake rotor upgrade with hawk pads and earls lines, then an up bigger MC and the proper Prop valve, and a bigger Brake Booster, all running Motul RBF 600 DOT4 racing brake fuild. The car stops like a champ.

I know a set-up like that would cost a grip on an MR2, but I was conisdering looking into it. Then I kept reading about 93 turbo brake swaps, so I thought I'd look into it, see the differences between 91 and 93, to see if that is an option or worth it instead of going the wilwood/precsion/rotora route.

I hear what you're saying. I can tell you from experience on a race track though that the turbo calipers are more than capable enough when you use a high quality brake pad. I've thrashed on NA, '91 turbo and '93 turbo brakes and have the '91 turbo brake system in my car currently. I use Carbotech XP-8 brake pads on the track.

Of course, the tires you're using make more difference to your stopping distance than what you have for brakes in any case. Even the NA brakes are more than capable of locking up the wheels with even a sticky street tire.

[fosley]

Ok, so I was finally able to look up some part numbers and find out a few things. First, "93+" for purpose of brakes means it was built after Jan '92 and "92-" is built before Jan '92. I'm not sure whether cars built during Jan '92 are considered '92 or '93.

The actual pistons on the '92- and '93+ turbo fronts are identical, so the '93 caliper shouldn't give you any extra clamping force (afaik). However, the pads are different, so may have more surface area or something (not sure what the difference is, just that they are different part numbers). And again, the calipers are more massive on the '93+.

The front rotors, rear rotors, rear pads and rear calipers are the same on all NA's and '92- turbos. There is a second part number for each part for '93+ turbos.

Brake master cylinders get complex, because the ABS and sunroof options makes a difference (the sunroof stores in the frunk, so the booster gets moved out of the way or something). There are 10 MC's; each of the following for ABS, then again for non-ABS: '92- NA w/o sunroof, '92- turbo + '92- NA w/ sunroof, '93+ NA, '93+ turbo to Nov '93, '93+ turbo after Nov '93

Five different brake boosters: '92- NA, '93+ NA, '92- turbo, '93+ turbo w/o ABS, '93+ turbo w/ ABS.

Note: there are certain '93+ turbo parts that have 2 part numbers. However, the earlier parts are superceded by the later parts; if you buy from Toyota, you'll get the later part, even if you're getting it for the earlier manufacture date, but if you buy it from a used car, you may get the earlier (presumably inferior) part. The parts affected (I probably missed some) in the Aug '92 cutoff: rear rotor, front rotor, parking brake cable support bracket*. In the Apr '93 cutoff: rear pad. (* The e-brake bracket actually affects all years, turbo or non.)

[te51levin]

Originally Posted by kawasakizx636

te51levin, my vin number is JT2SW22J3********

thanks

Bummer. Since it's a Canadian market car, the EPC doesn't show me what options it was delivered with. I don't know whether it has ABS or not.

[kawasakizx636]

ah ******, wish i wasn't a newb lol, i'll slowly figure everything out. i'm gonna own a mr2 for life lol, well untill i upgrade to a ferrari lol
thanks for all your help though, and i'll probably be getting these parts thru u in a month or so.

[benc903]

can still get parts?

[te51levin]

Of course! Prices do rise over the years, but we should not have a problem getting whatever you need. Most prices within this thread will be within 10-12%.

[mecm]

Im trying to upgrade my brakes from 93 N/A to a 93+ turbo wonder if you can help me in what i need

[te51levin]

Originally Posted by mecm

Im trying to upgrade my brakes from 93 N/A to a 93+ turbo wonder if you can help me in what i need

It's all laid out in the very first post in this thread. Prices quoted are over two years old, so they will be higher by probably 10% or so.