951 MO30 brake upgrade - any suggestions?

[daltonr]

Hi guys

My venerable but very quick 1989 Porsche 944 Turbo 250SE upgrade continues. Next on the agenda are the brakes ... and I'd be really interested in your views...

Situation:
The car is driven sympathetically but very hard and I do a few track days per year. Last of the late brakers + turbo motor (less engine braking) + standard use of heal/toe (less engine braking) + v spirited driving = v heavy brake use. Regardless of pad I still get some fade, and ultimately judder from over-heated and warped discs.

Current set-up:
MO30 4 piston callipers and I've previously up-rated discs with genuine 968 MO30 Club Sport cross-drilled discs and have run these for many years. Over the past 12 years I've run the following pads on it:
- Porsche pads which lacked a little bite and faded under extreme (i.e. standard) use
- Porterfields which were faultless aside from the squeal which I just couldn't live with
- EBC green stuff which performed much as the Porsche pads (but without the brake dust)
- EBC red stuff which were adequate to start with but went off quickly so not much better than green stuff I'd say

Upgrade options:
[1] Stick with 968 CS discs + upgrade pads. Performance Friction or Pagid Blue RS421 have been recommended - can anyone recommend them or others?
[2] As [1] but upgrade front callipers/discs to 928GTS/993 turbo set-up which will give a slightly larger swept area of disc and a bigger pad - have any of you 944T chaps had any joy with this upgrade? Did you need to adjust the brake bias setup?
[3] A more bespoke setup: custom made hubs built to accept Alcon (or other) floating discs + different pads and possibly callipers

Any thoughts would be welcome. They definitely improved the bite, but as an aside I've wondered for a long time whether the cross-drilled discs are causing increased heat build-up and so fade and disc overheating. Any thoughts on this too would be fab.

daltonr

[daltonr]

Hi guys, thanks for all the suggestions. I'm currently using Castrol SRF and have aeroquip'ed the brake lines some time ago - so those two areas are sorted (although the brake fluid is probably due for a change soon).

Improved brake cooling seems to be the next step which I will get sorted. I don't really want to change the front fogs or appearance of the front PU though - is this a given or is there another way?

I'll get set up with either PF97s or Pagid Orange (I think the ones I want are "RS 4-4"?) at the same time. Do any of you have experience of how they compare to each other I wonder?

I think I'll also go for some Sebro front discs. I will then re-assess whether I need to go with a more serious calliper/disk upgrade.

Edited by daltonr on Friday 5th February 16:07

[daltonr]

plenty said:

Have you tried solid discs? Quite a few folks have reported better performance compared with the drilled versions which reportedly do suffer more from overheating and sometimes heat-induced cracking.

I did indeed, albeit about 10 years ago. I'm sure you're right re solid discs re heat but I was never really happy with them, particularly with the initial bite. That said, at the time I was running standard brake flexys, standard fluid and standard pads. I spent time time with a 993 C2 and decided that I wanted to replicate the bite and confidence I'd experienced in that. So started 10 years of on and off mods to much of the car!

[daltonr]

chfs911 said:

I went for 993TT discs with M030 spindles, custom 45mm top hats and Big Reds 993TT. Swapped to 928 bias valve and it works great on 968.

http://www.968cs.de/

Might be of use? upgraded my 968 to 993TT brakes.

Edited by chfs911 on Friday 29th January 21:01

Great stuff. Nice drifting - like me you clearly believe that a car is handling best when its going sideways!

Do you think the 928 bias valve be a worthy upgrade in its own right for the standard callipers, or just if I want to go up to a bigger calliper/disk/pad at the front?

[daltonr]

Riverside said:

If your brakes are overheating try to improve the cooling before you throw money at it.

I have standard medium blacks, disks & pads & they used to eventually overheat on trackdays.

I changed the fluid from dot 5.1 to Racing Blue and added 944t cooling ducts (earlier turbos had them, our later ones don't), no more overheating, minimal cost.

I'm sure you're right. Wasn't aware of early 944Ts having cooling ducts - where do they vent from?

[daltonr]

diver944 said:

If your car makes standard to 300bhp then the standard brakes should be more than adequate if everything is working as it should and you have good, fresh fluid - ATE Blue is a good, cheap upgrade with a high boiling point. As Malcolm said, a simple 3" duct from the front bumper to the back of the disk also works wonders in cooling

I ran standard brakes for many years on full race slicks and had no problems when I was around the 300bhp mark. Eventually I tried PF97 pads and they were even better, good cold grip and fantastic when hot.

I now have the 928GTS Big Blacks becase I am pushing 400bhp, but I think they are overkill for less than 300bhp

312bhp after a few upgrades over the years - but I'm aiming for 360-375 this year and for once I want to be prepared! I think I'll hold off on the big blacks until I try cooling and pads as suggested.

[daltonr]

edh said:

PFC 97 pads are the solution - plus some brake cooling. 968 brake ducts work very well - if you have the later (968) lower arms. You might also look to run some ducting from the front PU into the centre of the disks.

The PFC pads are very impressive on the track - you can brake very late and very hard with them. They are one of the products that users become evangelical about - they are really that good! I never had any fade at all (300bhp 944 turbo, std weight, trackday tyres). Try a set before you do anything else - it's much cheaper than changing to big blacks etc.. Provided you use a decent high temp grease when fitting, they won't squeal either.

One other thing - when I changed my last set of discs (Sebro from Bert @ berlyn), the surface was still very clean, with no hairline cracks. This suggests to me that cooling was doing agreat job.

- there is a downside of course

They create very corrosive dust that sticks to your paintwork and eats into your wheels - very difficult to remove. I used clay bar every so often.

They also wear discs at a pretty fast rate - although wear on the pads is very good. Considering the discs are cheaper than the pads that may not be too much of an issue.

before I sold my car I changed back to EBC greens - only for road use, but it felt like I didn't have any brakes at all

Edited by edh on Tuesday 2nd February 12:05

Thanks for that. Some questions...

Do the 968 brake ducts replace the front bumper fog lights or do they fit somewhere else?

Sebro discs look interesting - fraction of the price of OE! http://www.eurocarparts.com/ecp/c/Porsche_944_2.5_... As a matter of interest, which pattern have you gone for the full cross-drilled or the single lines of holes? [Edit: Actually on closer inspection it looks like the minimal cross-drilled ones are for the rears only]

Do you find the PF07 brake dust worse than standard Porsche pads? I think this is the only real advantage of EBC - no dust!

Edited by daltonr on Friday 5th February 16:08