fst951

Yes it does appear to be a silicone ester formula.

You may want to cease using this ASAP if you are running an ABS unit as well.

Just a thought. Nice boiling points, however.

Sab

BB,
that is one great looking airfilter. Do you have any more infor or pics?
I am pretty sure Cameron won't mind the highjack.
regards,

Mark

IIRC - the GT brakes are actually an upgrade from the S4. The GT's have 2 different size caliper pistons, with the leading edge piston slightly larger then the other. I doubt that you will see much difference at all from the GT's to the Big Reds...Save the BIG$$$ and just paint your current calipers red. IIRC (Again) - the outer dimensions are the same.

Cameron

No issue on the air intake hijack.

Re the SFR, can someone enlighten me on the ABS compatibility issue?

Dennis,

IIRC, you have set your car up for the track. What weight are you running?

Tim,

If I make the decision to go, I will let you know to see if you were able to source some already.

Thanks everyone

Rehan

fst951, Castrol SRF is not a silicon based fluid. It's a DOT 4 fluid and supposed to be one of the best brake fluids on the market. Just look at the wet boiling point, 270C.

Read more about brake fluids on http://www.stoptech.com/whitepapers/brakefluid1a.htm

worf928

I have used a similar set up - stock calipers, 33 BAR regulator, Hawk SP+ pads, ATF Blue, and non-holed rotors - on my '91. The only time I had issues with fade was when the pads got worn down to ~35% of original thickness.

TeufelHei

I'll probably need two sets anyhow. I figure I'll need a spare set just in case the money for the track car runs dry from suspension upgrades and other nonsuch.

Dennis K

I used to have a stock '90 GT which I ran with the stock brakes, then switched to Big Reds. That was 3505 lb. according to Porsche but probably more. The current track car is about 3250 lb full of fuel.

The cheapest I've seen Castrol SRF is $57/liter at daliracing.com. The advantage is that its wet boiling point is so high that you could theoretically save money because you wouldn't have to change your brake fluid as often. SRF's wet boiling point is still lower than most good fluids' dry boiling point so most people use Superblue or Motul and change more often.

See this fluid boiling point chart on this page.

I use Motul instead of Superblue because it's quite readily available at most motorcycle shops that are open late or on weekends. ATE Superblue is sort of a specialty item that only higher end auto shops or racing supply places have.

John Veninger

Incorrect. The GT calipers are the same as the S4 for the same year. There was a change in piston size, I think in 88. There was also a dust seal change in 89, but the 86.5-91 use the same pads.

fst951

Man, Rehan maybe the English to Swedish translator is kaput, but I read the link you sent and it sure looks to support what I said.

You would think that Castrol, who makes the stuff would print the correct info....

Castrol SRF Racing Brake Fluid
Castrol SRF Racing Brake Fluid is an ultra high performance product formulated specifically to satisfy the ever increasing stresses placed upon the braking systems used in international motorsport. The exceptional performance of Castrol SRF is due to a novel silicon ester technology pioneered by Castrol and unique to the extent that it has been granted patent-protection in numerous....

Sure looks like it is silicone based to me....

Check it out

http://www.castrol.com/castrol/produ...tentId=7001576

Good luck.

John Veninger

There is no compatability issue using SFR. It is NOT a DOT5 Silicone fluid.
It is much different formulation and can mix with dot 3 or dot 4 fluid.

Rehan

fst951, what I did mean is that the SRF fluid is NOT a Dot 5 fluid. If you just say silicon based most people will think that it's a Dot 5 fluid.

Jim M.

I converted my 89 GT to big red's, with stock pads, I noticed a difference. I also added a 55 Bar bias valve later. The 55 Bar val also made a big difference. On my 93 GTS I've just added the 55 Bar bias valve and also saw a difference. My son has a 350HP 951 (highly modified) with the big reds on the front. On the track it made a huge difference, both in brake performance and confidence.

I recommend the swap over!

Jim Mayzurk
93 GTS

fst951

Hi guys.

The chemistry is what I was arguing. It is silicone based.

I understand it isn't DOT 5, but if you go on to read the description, it does state that it may leave a less firm pedal because of its compressibility. This seems to be exactly what the customer is complaining about. I also called castrol on the phone and asked about the compatibiliy with ABS pumps. They didn't know how to anser the question of whether it was safe to use or not.

I might just change to Motul 600 and see how you like the pedal then.

Good luck.

Cameron

I appreciate all of the feedback and opinions, as well as the research on the SRF.

I have been running it for a year now and the pedal is nice and firm. This car is an agressively driven DD with track use of several DE's per year. I wouldn't want to change away from something that is working for me until I understand fully if there is an issue.

Anyone else here use SRF with the Bosch ABS? Any problems to report? I have envoked the ABS only a couple of times, and it did its thing. ie didn't let me lock 'em up. If there was a problem, what symptoms would I observe?

Thanks!