DER951

That stoptech link looks like a lot of good info, but I haven't had time to read it yet.

On the issue of bigger brakes requiring bigger wheels, the 951 turbo S/S4 calipers are the largest that will fit with 16 inch wheels (and 993 calipers are reportedly interchangable with them, and have better piston seals). Numerous threads have stated that brakes bigger than these are more for bling than needed stopping power, even for a full-on track car.

It's also been stated many times that reducing weight has the same effect as increasing horsepower. It also improves the performance of an existing brake system (and bigger brakes/wheels add weight).

Oddjob

Sam,

Disregarding the hub failures (thats a separate issue):

Do you agree or disagree that the late offset non-M030 knuckles and the M030 knuckles have the same spindle post diameter and use the same bearings? Having both types of spindles, I just dont see anything that physically indicates the M030 would be any stronger.

One thought, the number of M030 equipped cars is much fewer than the number of non-M030 cars. So in any given area/region, if there is 1 M030 spindle failure out of 10 M030 cars per 10000 track miles driven, and 5 non-M030 failures out of 50 non-M030 cars... failure rate is the same, but sounds like its five times more likely.

But regardless, any 87 and later spindle failure is quite uncommon (the pre 87 early offset spindles are known to break). If you throw out the late offset spindle failures that were caused by either an accident/impact or by a burned out or improperly packed/tightened wheel bearing (causing a lot of excess heat transferring to the spindle), the very few examples of late offset failures are so seldom that Im not sure any conclusion can be made.

Where (tracks/areas) and how many spindle post failures are you seeing? Where on the spindle are the failures occurring? Fatigue, stress?

I appreciate any info, because up to this point, I have never been concerned about an '87+ spindle.

Jim

TurboTommy

I'm also interested in this topic.
I'm considering swapping out my "S" brakes for big reds. I'm assuming that the rear "big reds" is a bigger package (rotors and calibers) than the standard rear brakes.
So, would the total stopping power of the big reds be significantly better than the M030 brakes.
Can anyone with experience with this comparison confirm this?

333pg333

I think this is a good point. The weight issue and the cost issue will see me keep my M030's. Thus far they have kept me on the track when I thought for sure I was paying a visit to the sand-pit. The 'Stop-tech' link is full of good info and it would be interesting for some of those more knowlegable than me to read and comment on this.

Tom Pultz

Not sure this has been clearly stated... but if you run M030 spindles you must run M030 hubs as well to maintain the correct relationship between rotor offset and caliper.

DAR951

One thing not yet mentioned, that you will need to consider is offset.

While you can directly bolt-up any of the late-offset spindles you're considering to your early off-set control arms, doing so will reduce the maximum negative camber you can achieve.

Some of it can be "reclaimed" with camber plates, but unless you also "upgrade" to the longer arms (and then all that comes with that... bigger offset wheels, etc. etc.) you'll be limited to around 2 degrees (+/-) negative camber, if you run the stock bolts (with stock style camber adjusting struts) at full negative WITH plates also at full negative.

Made this change over the winter to my '86 race car... Not difficult, but lots of little stuff to do/consider to get it right and still allow for a reasonable range of adjustability to dial-in a setup.

JET951

so why cant you get much neg camber out of it? if i leave my control arms and tie rods and bolt up a set of 87 or 88 non m030 why would that change the camber??

JET951

i will tell you my set up at the moment.

968 front clubsport struts and tri rate springs, with 86 control arms, m030 sway bar, but the 86 brakes.

Oddjob

I would not mix and match the pre and post 87 parts. You should go with the complete late offset conversion. Which includes the control arms, tie rods, knuckles, hubs (and whatever upgraded calipers/rotors).

If you use the early offset control arms and tie rods, with the late offset knuckles and hubs I think your going to run into problems getting the full car alignment to work, not just camber specifically - but getting the camber you want with the toe and caster and the correct track width to match/work with the rear. You would be changing the suspension geometry to something the factory never designed/tested. Would the car drive down the street straight - sure, but on the track it could end up with some different turn-in characteristics and some unusual tire wear.

Also, Im not sure what wheel offset you would end up needing. A late offset wheel will not work with the early control arm length, but I would be doubtful that an early offset wheel would work with the late offset knuckles.

If youre thinking about doing that, you might as well just get caliper adapters for the 86 spindles and mount big brakes on the existing setup (but I believe some of the brake kits would require custom 2-piece rotors for the hat height to fit the early hubs).

This is speculation on my part, since I have never tried to upgrade an 86. But I have seen several that have been upgraded, and they either did the full offset upgrade or just adapted larger brakes to their existing hubs. If you want to try, knock your socks off, and let us know how it works.


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DAR951

The strut mounting holes in the late offset spindles are located differently in relation to each other to allow for a slightly different (sharper) angle of the strut, as dictated by the longer control arm... Keep that angle, but don't add the longer arm and now you have the hub standing up straighter (less camber).

JET951

ok i can see how that would be different. so i guess one of those kits from SFR or lindsey would be a good way to go. i want to keep my offset because i like the dish, 23mm. but i dont want the big reds,blacks because of the extra weight of the rotor. truth be told i am doing fine at the moment with the smaller calipers with race pads and fluid on the track, but a power increase is in the works and this is why i am worried about stopping.

DAR951

This (not upgrading the arms) isn't really a big deal. The angle changes aren't that large. All things being equal, yes, do it all... But all things are rarely equal...

In my case, I already had early offset Fabcar arms and several sets of early offset wheels... I wasn't willing to take the money hit or the hassle of selling-off/swapping-out all those parts.

1) Alignment isn't an issue beyond the reduced range of available negative camber I already noted.. If it tracked OK before, it can be realigned to track OK after.

2) Early offset wheels, fit just fine on late offset spindles/hubs. Other than bearing size and clearance to the tie rod end, the only difference is the alignment of the strut mounting holes (that reduced camber range thing);

3) If you want to keep your '86 spindles and go with big brakes, all that's needed to fit the S-4/993 calipers is an adapter and a machine shop to turn down (slightly) the OD of the '86 hub to fit the ID of the stock Turbo-S rotors. This setup will let you run/keep running 16" wheels. Bigger calipers (big blacks or reds) will require at least 17's and IMHO are a waste... with good/the right pads, the factory Turbo-S brake setup (S-4 calipers) kills.

4) In a shameless plug... If you want to go the route of 3), I have a complete set of '86 spindles, hubs (machined for stock Turbo-S rotors with an almost zero mileage set of bearings), adapters, and cooling ducts available.

cobalt

I have the big reds on my 94 and the big blacks on the GTS. Same caliper different color. You will see no improvement in stopping power by just switching to these brakes.

Braking is really a function of tire grip more than how big the brakes are. Setting your sights on improving tire quality and larger contact patch or lightening the car will improve braking more than increasing brake size. All the brakes do is stop the tire from rolling. If it is not gripping the biggest brakes in the world will not stop the car.

The advantage of the big brakes are heat disipation. The larger rotor will disipate heat faster and prevent your brakes from fadeing or fluid from boiling. You will probably find that the S4 brakes with good pads are more than adequate, use a smaller rotor which weighs less and allows you keep the 16" wheels which cost and weigh less and use less expensive tires of the same quality.

I do admit the big brakes look great but if they were not stock on my other cars I would not spend the extra money on them unless I used the car for nothing but track use.

JET951

DAR951, how did you bolt the s4 rotor up to the 86 hub? you said you turn down (slightly) the OD of the '86 hub to fit the ID of the stock Turbo-S rotors. but dont the 86 rotors bolt on the inside of the hub? where as the s brake rotor slips over the top of the hub?

DAR951

You can install S-4 calipers and Turbos-S stock rotors on the '86 hubs and spindles (the setup I used to run) by:

1) Using an adapter to allow the S-4, radial mount, caliper to bolt-up to the axial mount '86 spindle;

2) The adapter also spaces the caliper out, to position it for the use of the stock Turbo-S rotor as a replacement of the stock non-S rotor (which you correctly note, bolts to the inside of the hub);

3) For the Turbo-S rotor to sit on the outside of the '86 hub, the OD of the hub must be turned down slightly (a few thousandths or so).

While there may be some debate (I've never heard of or seen any hard data, only opinion) on whether the '86 hub/spindle combination is strong enough to handle this upgrade, my car came with it installed by the PO and had been running it without a problem for a number of years prior to my racing it this way for 3 seasons, before swapping it out for the M030 spindles and Racers Edge Billet hubs.

As mentioned, I have for sale, the complete set of '86 hubs, adapters, spindles, and cooling ducts, machined as necessary to bolt-up a pair of S-4 calipers and Turbo-S rotors.

Also, if you do go the M030 route and need a set of Hubs, I've got a pair of them available too... (sorry, no M030 spindles).

Hope that helps some.