tkacki

Hi,

Just plan to upgrade my '86 924S brakes to four piston brakes. I can buy a set of S2 capilers, fair price.

Questions:
1. Are S2 capilers (Brembo) compatible with 15" rims ?
2. Shoul I change brake disks or they are same as in S2 ?
3. Possible line/hose issues ?
4. Other issues / problems ?

Thanks
TK

TheRealLefty

I'll bite Issues, unfortunately, are numerous. Basically, you would be upgrading an NA to a 951 spec as far as spindles, hubs and rotors. Will not work with 15's. Little rusty in 924S info, but I think your underpinnings are somewhat "hybridized" with front steel arms and rear aluminum ones, early offsets????? If so, what you're talking about is creating an 86 Turbo hub/spindle/rotor/caliper upgrade, I think.

tkacki

Correct. Front steel, rear alu. Early offset.

I was hoping it would involve caliper change with minor line / hose issues and upgrade to 16".
So... bad news for me. I can buy a complete set of rotors with calipers. Hubs seems to be a real problem.

Techno Duck

I am pretty sure the 924S uses late offset wheels.

tifosiman

Correct.

I am inclined to agree, *but* the early 951 cars came with 15" early offset phonedials and they cleared the 951 caliper (one would assume). The early offset 15" phones (not certain about the late) also have a 951 part#, so there may be some logic to that, although I have never taken a look at the clearance of an early 15" phone on 951 calipers. I know that 15" cookies and Fuchs will not clear them.

IF the 15" early phones clear, it is quite possible that late 15" phones may clear as well.

Please note that I have never tried the above theory myself.

As far as brake upgrades go Tkacki, there is a ton of info here on this forum if you do a quick search. Basically, you will need 86 951 calipers, hubs, rotors, spindles, struts and new brake lines to do the conversion on the front. For the rear you will need 86 951 calipers, spacers, bolts, and rotors.

tkacki

Thanks for responses. It was very informative.
I searched the forum. Lots of info on upgrade to turbo brakes. I was not quiet sure if S2 N/A uses same brakes as 951. From Your responses, I assume it does.

tifosiman

You are correct, standard S2 calipers are the same as standard 951 calipers.

tkacki

This is what I can buy. Set of four calipers and four rotors. 300$. Owner claims it's a S2 set.

tifosiman

Those appear to be standard S2/951 calipers (albeit a bit second-hand, they could use a re-furbish possibly).

If the rotors that come with them are from an S2, you won't be able to use them on your car due to the hub offset differences. If that is the case, you would be better off asking him to keep the rotors and deducting some amount from the price.

tkacki

Tahnks for the info. Ok. My last question: How big diference in performance I will experience after upgrade ? Is this upgrade cost effective ?

tod84944

I can help you out on the front. I have a set of 86 951 front spindles and a good set of used rotors. Tifo, are you sure on the 15" PD on the 86 951??? The 2 I parted out had 16" PD's, and the one that I help out on (seems like every Sat morn), also has 16's.
Tkacki, I have a 89 S2 that I just put back on the road, I will take an late offset PD, and see if it will clear the brakes. I don't think it will, the 16" d-90's have just slight clearance.

tifosiman

The *Very Early* 951's had them. None had them by the time the 86 model year hit the states. But there are some early 85 ROW models running around with them.

tod84944

One more thing, like I said, I have the spindles and rotors, but you will have to source a set of hubs. You can look on e-bay, they pop up on there. Best thing you will need is to find the parts off of a 86, so it will be a direct bolt on operation. You can get everything used, and it will be a lot less on the wallett. Come to think of it, I might have a set of the rear arms that the calipers will bolt direct up to. You would still have to find a set of rear rotors though.

tifosiman

There are at least 2 sets of the hubs he needs on Ebay right now.

Legoland951

The 924S or 944 n/a brakes are more than adequate for most people. I knew a guy who ran a 3.0L 968 engine in his race car but kept his n/a brakes while having absolutely no problems. Also, John Anderson used n/a brakes on his 3.1L race car and also had good results. I have smoked (actually see smoke coming around the fenders and quarter panels) my n/a brakes at the track and never had warpage problem or any significant fade. My opinion is that 99.9 percent of people will never get to the limit of the 944 n/a brakes unless you are running a full weight modified 944 turbo on the track. The 4 piston calipers are more for looks especially on an n/a.