RE: Brembos, big reds, etc. (The truth and long)

[Todd Phenneger <phen9461@uidaho.edu>]

On Thu, 13 May 1999, Michael G. Wachholz wrote:

> I have been quietly monitoring all the discussion regarding brake upgrades
> and I feel it is time to provide some facts that seem to be lacking.

	Great.

> First, let me clear the confusion regarding sizes of calipers. There is only
<SNIP>
	Great.  THanks for the info.  So the S4 brakes are what some
people improperly call BR's.  I assume this is what came on the RS-2 as
well as it had 968 Club Sport calipers.  And I guess the Black ones my
friend has are the smaller ones that came on the Early 944t's etc.
	Thanks


> Also important is the piston combination in the Porsche caliper is
> unavailable in any other caliper from Brembo. Literally everything regarding
> the Porsche caliper is unique to Porsche and Brembo's contract with Porsche
> prohibits them from selling any parts etc. for the Porsche calipers. Steve's
> "Ultimate Garage" page states the bolts are larger in the Porsche calipers
> however I have been unable to verify this. (And believe me, I have been
> trying.)

	Yep, thats worth noting.  And many calipers (Wilwood comes to
mine) dont have dust boots so have to be re-built every year.  Porsche's
don't.  But neither do the Boxter units.  Do you have specs on the Boxter
Brakes and how they compare.  I suspect they are pretty similar to the
smaller Calipers that came on the early 944t's.  

> The rear calipers were, depending on the vehicle, available in red and use a
> pad size of 3.48" x 2.58" with a new pad depth of 18 mm. This pad has a
> total swept area of 8.98 inches. Note this caliper with a different piston
> combination was used as the stock front caliper on the 86-88 944 turbo, 944
> S2, 968 and various 928 models.

	Yea, I suspect these are similar to the Boxter calipers from the
dimensions I have heard.  ANd these calipers are WAY better than any stock
AUdi Caliper.

> The BR caliper requires 17 inch wheels, the S4 caliper will fit easily under
> 16" wheels (depending on offset) and the smallest 4 piston caliper should
> fit under 15" wheels (have not tried this yet.)

	Yes, I believe it will.  We are putting these on my friends 5ktq
but as usual it takes modifications.  John's Boxter Setup seems like a
simple solution.

> The biggest advantage to larger diameter rotors is by moving the clamping
> point of the caliper further away from the center, one gets an increase in
> brake leverage. Another advantage is more mass to deal with greater thermal
> loads. The downside to this is larger rotating unsprung mass which
> ultimately affects both acceleration and turn-in.

	I'm in full agreement here.

> I have experience with all three sizes of calipers using them in different
> combinations front/rear and with different rear pressure regulators,
> different pads, etc. on a 93 968. The car is a daily driver and has been
> tracked heavily at tracks around the country. I also race a 125 shifter
> kart. I started researching braking systems recently when after speaking
> with a number of so-called experts in brake systems including Brembo, Alcon,
> CoolTech, and others, I was unable to get reasonable, thought out answers to
> what I felt were basic questions. My conclusion is most of the folks out
> there, including Brembo, Alcon, CoolTech, etc. do not design these upgrades
> as a total system solution. (I know I will get flames on that!) There is
> much more to this than bolting on larger calipers and rotors. I haven't
> addressed here the additional issues of master cylinder size and booster
> size which not only are critical components in regards to pedal feel and
> stopping power but have numerous variable related to each of them also.

	Yes, but even with stock MC you will see much better braking from
going with Big Reds or similar up front.  To be perfect though you need an
adjustable prop. valve and maybe a bigger piston or larger resivoir.  I
know the Round Resivoir and MC from the later 200's is better than the
5ktq unit though and we upgraded this on my friends car.  It feels great
now.
	Anyhow, thanks for all the info.
L8R
	Todd