S2 brakes on early offset car?

[murrayg]

Hi all,

Can I put S2 brakes on my 85 944 and retain my early offset?

Thanks!

Gord.

[9FF]

Sure but I have to ask why? The na brakes are very good and more than enough stopping power if serviced correctly.

To convert fronts you will need:
1. 86 turbo spindles and hubs
2. S2/Turbo brake discs and calipers
3. S2/Turbo flexible brake lines.
4. S2/Turbo proportioning/bias valve
5. S2/Turbo struts

[Timmay!]

+1. Spend your $ elsewhere.
If you want quicker stopping, reduce weight. Way cheaper.

[murrayg]

Why? Good question. I'm looking at buying a junk 89 S2 and installing the 3.0 engine in the 85 944 (early). The brakes are at no cost since there on the junker. I'm all about saving weight, and I'm debating if this is worth the effort / increased weight. I also want to keep my early offset wheels. To put all the suspension, control arms, brakes and wheels would result in "S2" comparable weight, which is not what I want.

comments??

Gord.

[Porsche-O-Phile]

If you can lock up all four wheels, you have enough braking power.

FYI - only test this with old tires since you'll flat-spot them.

N/A brakes are fine. I am upgrading to big blacks on my track car, but that's more to help with heat saturation/fading after several laps rather than overall braking power. For that, the stock brakes are just fine.

[9FF]

...I also want to keep my early offset wheels....

I don't think you have thought this through. If you have stock early wheels they will not work with S2 brakes. You need the 86 Turbo 16in wheels to get clearance on the calipers and maintain early offset.

If you are fitting an S2 engine into the early car it would definitely be worthwhile upgrading the brakes to match the extra power, but your choices are limited to the 86 Turbo suspension/brakes as that is the only year bigger brakes were user on an early offset.

[murrayg]

P-O-P, I agree with you. Perhaps I should have been more clear on the intended mission of the car. It will see several track days a year here - Atlantic Motorsport Park Official Website
While I agree that if you can lock up the tires, you have enough braking power, the issue with the NA brakes is heat dissipation / fading. Corner 9 at AMP is the killer on NA brakes, and why I'm considering the S2 brakes. Add to that more HP (the 3.0l motor), I feel the NA brakes will be inadequate.
I really do appreciate the feedback and discussion, its very valiable. However, my question was a technical one, Can I do it and keep the early offset? Wheels are 17"X7 & 17X9 turbo twists (ET23 &ET15)

Gord.

[9FF]

P-O-P, I agree with you. Perhaps I should have been more clear on the intended mission of the car. It will see several track days a year here - Atlantic Motorsport Park Official Website

While I agree that if you can lock up the tires, you have enough braking power, the issue with the NA brakes is heat dissipation / fading. Corner 9 at AMP is the killer on NA brakes, and why I'm considering the S2 brakes. Add to that more HP (the 3.0l motor), I feel the NA brakes will be inadequate.

I really do appreciate the feedback and discussion, its very valiable. However, my question was a technical one, Can I do it and keep the early offset? Wheels are 17"X7 & 17X9 turbo twists (ET23 &ET15)



Gord.

Ok, now that all the facts are revealed there is a good solution.

You can swap the S2 brake discs, calipers and spindles and those 17in wheels will clear nicely. You will need struts from any turbo or S2 as the spindle attachment is different. As you are keeping the early offset A-arms (it is only these that determine the offset), you will also need camber plates fitted to dial the camber back.

As you are tracking I assume you will be changing the struts and fitting camber plates anyway so that shouldn't be an extra expense.

[smokin_944]

Porsche-O-Phile and murrayg are correct. While the N/A brakes may be ok on the track with a 2.5 engine, the brake fade is B-R-U-T-A-L after hard driving... With a 3 liter engine they will be damn near useless if you drive hard for any length of time. If the stock brakes were in fact that good you would find them on the turbos and S2s. Not likely now is it? Just sayin...

[murrayg]

Thanks 9FF (L.C.?). The key here is:" the early offset A-arms (it is only these that determine the offset)".

Gord.

[Cocacolakidd]

'87 and up offset spindles are different also and will not blend in with the early offset suspension...'86 turbo Spindles needed in this case. S2 hubs, Calipers, and rotors will fit with the 17" rims. For a better fit use '86 Turbo Struts and top tower mounts on the conversion (Even '86 Turbo Struts cut, and installed with new inserts).

Brembo '87 and up 4 pot calipers are better than the '86 as the pistons are larger at 40mm, etc.

Agreed that the NA brakes are excellent for normal use, but for hard charging racing the upgrade to the 4 pot calipers and bigger disks are needed or over heat brake fade will come on quickly.

[9FF]

'87 and up offset spindles are different also and will not blend in with the early offset suspension...

Just to clarify, you can fit 87+ S2 spindles with early offset as long as you change the struts to S2/turbo struts and fit camber plates.

[Cocacolakidd]

YES - as long as the spindles are '86 Turbo. The '86 Turbo spindles will mount the later Calipers (Turbo and S2 Brembos), and fit the early offset. With those the total up-grade will go together.

If you are doing allot of heavy duty racing look into having the "A" arms strengthened/boxed as they are a little week for heavy duty stuff - In fact there was a fellow on the used parts forum who was selling a pair of "A"arms that were up-graded boxed. They looked pretty good for the $40.00 pr., but were not selling.

[9FF]

Cocacolakidd, I wasn't asking a question, you don't need the 86 spindles, 87+ (ie: what he has) will do fine.

[Timmay!]

Fiment questions aside....
We race the livin' @#$%% out of our 944's and 924S's with stock brakes. Maybe you should run a higher temp fluid like Ate Super Blue and rig some brake ducting. Remove your splash guards (those sheet metal discs on the inside of the rotors that everybody mistakenly refers to as "dust shields) , at least during the nice weather months.
That should serve you fine until you swap the 3.0 liter over. It will also keep your S2 a roller till you do the swap.

[Cocacolakidd]

Cocacolakidd, I wasn't asking a question, you don't need the 86 spindles, 87+ (ie: what he has) will do fine.

I have never been able to use the '87 and up Spindles because their off set is different by 12mm from the '86 Turbo Spindles. Plus the alignment holes for mounting the struts is at a different angle from '86 to '87 plus.

I have done 20 + of these up-graded brakes to turbo and S2 Type, and just never found those '87 up spindles to fit well and align up on the early cars.

[9FF]

** * *Quote*

** * * *

Cocacolakidd, I wasn't asking a question, you don't need the 86 spindles, 87+ (ie: what he has) will do fine.

I have never been able to use the '87 and up Spindles because their off set is different by 12mm from the '86 Turbo Spindles. Plus the alignment holes for mounting the struts is at a different angle from '86 to '87 plus.



I have done 20 + of these up-graded brakes to turbo and S2 Type, and just never found those '87 up spindles to fit well *and align up on the early cars.

I hear you, yes the 86 turbo spindles are a straight swap for the conversion. I have used the 87+ also and yes the camber angle is different and that affects the camber when you fit them to early offset. I dialed mine back to stock with camber plates. I was keen to use the 87+ hubs and spindles in my conversion because they are both much stronger, so I worked with the later spindles.

Basically, if you are not going to be running lots of camber the 87+ spindles with camber plates are the better choice and come with better hubs and spindles. Otherwise get the 86T spindles and that won't mess with your camber. Either way you will need S2/Turbo struts.

[murrayg]

This is all great stuff guy's, it seems the front is fairly clear. What about the rear?

[fennacf]

If you have an early 85 you'll lose your speedometer with the conversion. You can use a late model 944 transmission and early 911 electronic speedometer in the older 944 instrumentation clusters.

I had to convert to the electronic speedo when converting to brembos.

I have an 84 chassis with an 88 transaxle and an 84 911 speedometer wired to the sensor in the transaxle.

Here are some of the details if you decide to go electric (I also have PowerPoint schematics that I can provide):

The speed sensor used by the 944 is a Hall Effect Sensor with differential amplifier so it needs a power source where the 911 does not. Here are a few details for the wiring.

Wiring connections are as follows:

Connected Pins "A" & "+" from the speedo and lead "H+" from the sensor to 12V ON/ACC power. Connected pin 31b from the speedo to "HG2" from the sensor. Connected pin "-" from the speedo and Pin "3" from the sensor both to ground.

Sensor differences:

From the schematics is appears that both sensors are impulse sensors but the 911 uses a magnetic type sensor while the 85.5+ 944's use a Hall Effect Sensor. Both produce a sinusoidal output and for this application were interchangeable.

[Cocacolakidd]

For the rear brake up-grade use Turbo/S2 Brembo Calipers and Turbo/S2 Rotors - Direct fit. Some have different mounts for rear shocks - use what you have there also.