KSira

So, my new engine should be ready in a month or so, with some added power. Since my car is a pure track day car, that also means upgrading the brakes. Is the Big Red kit with cooling sufficient for a high hp car, or is there any other options out there? I now of the GT3 upgrade, but with parts for converting to late offset this will be very expensive.

Edit: Is it possible to only use the 87 hub/spindle in front, keep the rest as stock 86 Turbo, and use the GT3 brake adapters?

Dougs951S

If it were my car, I would save your cash on the GT3 brakes and convert to late offset N/A hubs and spindles. They are stronger and will allow you to keep your early offset and wheels, and use steel arms and their cheap balljoints. You will lose negative camber, but will still have enough for the street. If you track your car ( I assume you do if you want big brakes ) you can either get camber plates to get your negative camber back, or slightly modify the camber bolt and ridge it rides against on the spindle using a grinder. Depending how weight conscious you are, I would either get a set of 330mm cayenne rotors and use those with the Lexus LS430 front calipers, or use the slightly lighter 322mm 993TT rotor. Both of those will need to have holes drilled in them to fit the centering set screws. When you use the lexus calipers, you ditch the stock 951 rear calipers and flip your fronts over to the rear position. Use an 86 proportioning valve, bleed, and you're done for ~1/4 the cost of GT3 brakes.

pormgb

Just done this conversion, I went with Lindsey's Big Reds and 330mm 996TT Rotors. I also upgraded to late offset spindles + hubs and a Wilwood proportioning valve, I already had late offset struts.

Mine was a bit tricky, I have a nice set of SFR early offset tubular A arms that I didn't want to ditch, with these A arms and Ingals camber bolts I was able to dial in enough negative camber without using camber plates.

One thing I researched and did not do was to move the front calipers to the rear. With larger front brakes, very little pressure/bias (need for proportioning valve) is needed on the rear, so moving larger front calipers to the rear can cause the rear to lock, Lindsey has a good write up on brake biasing.

odb812

What type and size front tire do you use? What brake pads? How hot were your brakes getting before engine upgrades? What cooling do you have in place? How much does your car weigh? What about the brake system do you believe needs to be upgraded?

I'm a slower driver and I have an '89 with the big brakes, so I'm not a good comparison, but I've seen some of the faster drivers in gutted cars on Hoosiers with much higher hp than stock do alright with the smaller factory calipers and some ducting.

Carrera51

If you are going to track the car, I would start with good track pads and good racing brake fluid, and get some cooling ducts directing air to the brakes and see how they perform. I think you will be surprised.

KSira

Thank you for the info. Do you know if it is possible to use late offset spindles + hubs with early offset struts and A arms?

KSira

I ran with PFC racing pads, 968 cooling, and SRF brake fluid with the stock engine, and had no heat problems. Now with well over twice the HP, I will add cooling ducts and brake cooling plates, but I am worried that this will not be sufficient.

pormgb

You will need late offset struts for late offset spindles, late offset spindles have a thicker mount that won't fit into early offset struts.

Regarding A arms, if you use camber plates you could probably dial in sufficient negative camber, I don't think its possible without camber plates.

Without camber plates and camber fully adjustment for negative camber, you will be seeing positive camber. I was able to over come this by slightly adjusting the SFR A arms heim joint, I think there is about a 1" difference between early and late A arms.

ninefiveone

Here are the tried and tested facts:

- you can use late offset spindles and hubs on early offset control arms, tie rods, etc. no need for late offset struts or any of that nonsense. You do need camber plates or a grinder if you want camber amounts appropriate for track usage.
- putting front calipers on the rear makes no sense. Just change the proportioning valve. 5/33 is typical. I've seen people try the 5/45 and they always find that's too much. Bottom line, there is more than enough caliper and rotor back there.
- I find that better pads and cooling works up to about 325 rwhp on track. A lot of it is about driving style. More experienced drivers tend to have more skill in managing the brakes. Less experienced drivers overuse the brakes and tend to see higher temps and fade.

I've been running big reds on late offset hubs and spindles on steel a-arms on my '86 turbo for years. On track. I have camber plates. I'm running coilovers now but the late spindles fit fine on my stock struts before I switched.

KSira

Very useful info. Very much appreciated. Thanks!

EDIT: Hoping to see 500whp. Guess Big Blacks is the only solution then. Wanted GT3, just can't justify the cost.

JustinL

Is your rotor on the wrong side of the car?


I have big reds on my K27 powered 951S and it is plenty for the track with SRF fluid and decent track pads. The stock M030 brakes with good pads and fluid were also plenty, but I got a great deal on the big reds so I couldn't pass it up.

pormgb

Wow, good catch!!

Are the holes going the wrong way? Does it really matter?

JustinL

I'm sure it would be fine because that's so much more brake than the car needs, but the vanes in the rotor are designed to spit air out radially after sucking it in from the hub area of the rotor. Running it backwards will impede the cooling, but by how much I have no idea.

JustinL

Also, forgot to mention that the holes don't always represent the direction of the vanes. On 996TT rotors I think they do, but it's not always the case.

pormgb

Yep, found the same information, 993TT rotor vanes point in the same direction as the holes.

I just flipped them, thanks for you observation!!