Subject: [Tigers] Stopping Distance

From: "Robert D. Hogan" <[email-masked]>
Date: Wed, 19 Jun 2013 22:42:47 -0400

In the process of scanning some Classic Motorsports articles on a Tiger
restoration, I noticed the author referring to the improved stopping
distance of the project Tiger as 150 feet from 60 to 0 mph after
installation of the Wilwood Engineering brake kit.  Even the 124 foot 60-0
stopping distance of a heavier Nissan Sentra in a Motor trend test, as the
worst in its class, performs better than the quoted Tiger result.

I have yet to research the details or what tires, temperatures, surface
conditions or measurement accuracies were involved in the article's number.
Could anyone shed some light on whether Tiger stopping distance data exists
elsewhere in the plethora of recorded Tiger documents?  The importance is
that a $1200+ Wilwood front brake kit addition hardly seems worthwhile if
the stopping performance isn't more remarkably improved than hauling a 2560
Lb. SunbeamTiger down from 60 mph in under 120 feet much less 150.

Rob

..1560
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From: [email-masked]
Date: Wed, 19 Jun 2013 22:53:58 -0400 (EDT)

I think you hit on the key: tires. Whether oem front caliper/rotor or  
aftermarket, generating enough clamping force to exceed mechanical grip is not a 
 problem. I would guess the kit used included a proportioning valve, to 
allow  better balance, and perhaps had better modulation which is where any 
improvement  in stopping distance likely was found.

In a message dated 6/19/2013 7:43:02 P.M. Pacific Daylight Time,  
[email-masked] writes:

Rob

..1560

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From: "Robert D. Hogan" <[email-masked]>
Date: Wed, 19 Jun 2013 23:17:27 -0400

In a later article (#12 of the Flying Tiger by Tim Suddard) on Strengthening
and Upgrading Our sunbeam Tiger's Chassis, the author refers to using
195/55R15 Dunlop Direzza Sport Z1 Star Spec tires.  Whether those were the
same tires quoted as stopping in 160 feet (nee the 150 of expected
improvements with biasing) is to be determined. These tires would seemingly
not be accountable for such poor stopping performance unless I error in the
assumption of a compound not within the extreme of highest mileage and low
adhesion.

Rob   

From: [email-masked] [mailto:[email-masked]] 
Sent: Wednesday, June 19, 2013 10:54 PM
To: [email-masked]; [email-masked]
Subject: Re: [Tigers] Stopping Distance

I think you hit on the key: tires. Whether oem front caliper/rotor or
aftermarket, generating enough clamping force to exceed mechanical grip is
not a problem. I would guess the kit used included a proportioning valve, to
allow better balance, and perhaps had better modulation which is where any
improvement in stopping distance likely was found.

Rob

..1560

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From: [email-masked]
Date: Wed, 19 Jun 2013 23:51:29 -0400 (EDT)

Not a tire issue, then, as the Z1 Star Spec was right at the top of  ultra
high performance street tire category (since replaced with the Z2, which  is
even better).

The next thing I think about is suspension geometry, wheel rates and
anti-dive...I forget what Tim did with that car, did it also have a torque
arm?
;-)

In a message dated 6/19/2013 8:17:07 P.M. Pacific Daylight Time,
[email-masked] writes:

In  a later article (#12 of the Flying Tiger by Tim Suddard) on
Strengthening and  Upgrading Our sunbeam Tigerbs Chassis, the author refers
to using
195/55R15  Dunlop Direzza Sport Z1 Star Spec tires.  Whether those were the
same  tires quoted as stopping in 160 feet (nee the 150 of expected
improvements  with biasing) is to be determined. These tires would seemingly
not be
accountable for such poor stopping performance unless I error in the
assumption of a compound not within the extreme of highest mileage and low
adhesion.
Rob

I  think you hit on the key: tires. Whether oem front caliper/rotor or
aftermarket, generating enough clamping force to exceed mechanical grip is not
a problem. I would guess the kit used included a proportioning valve, to
allow  better balance, and perhaps had better modulation which is where any
improvement in stopping distance likely was found.

In a  message dated 6/19/2013 7:43:02 P.M. Pacific Daylight Time,
[email-masked] (mailto:[email-masked])   writes:

Rob

..1560

[email-masked] (mailto:[email-masked])

[email-masked]

---

From: "Robert D. Hogan" <[email-masked]>
Date: Thu, 20 Jun 2013 00:26:39 -0400

I have not read that a torque arm or traction master kit was used on the rear
suspension.  Paragraphs following the braking performance indicate higher rate
front springs and Dalebs Restorations thicker rear springs were later
elected to improve on track performance.

In doing a cursory internet search, the complexity of the braking performance
questions are revealed regarding decision lag time, braking g levels and other
variables in quoted performance.  Certainly the Car & Driver, Road & Track and
Motor Trend magazinesb tested braking performance figures must have a
standard for correlation.  One internet blog description provided the
following data:

Some 60-0 braking times in a past issue of Road & Track (April 2013). If you
are thinking of some particular cars I could look them up for you if they're
in there.

Here are a few popular models:

Subaru Impreza WRX STi Limited 119'

Volkswagen Golf R 130'

Toyota Prius C 128'

Subaru BRZ Premium 128'

Mitsubishi Lancer EVO GSR 123'

Mini Cooper S 119'

Mazda 3i Touring 135'

Kia Optima Turbo 135'

Ferrari 458 Italia 106'

Corvette ZR1 105'

BMW 328i Sedan 123'

Chrysler 300S 129'

June 2013 Motor Trend:

Dodge Viper 94'

Ibve directed my question of comparable results directly to Wilwood
Engineering:

Does Wilwood have any comparable stopping distance information of a Sunbeam
Tiger OEM stock Disc/Drum brake system performance and the Wilwood brake kit
performance?

A Classic Motorsports article on a Sunbeam Tiger referred to the improved
stopping distance of the project Tiger as 160 feet from 60 to 0 mph after
installation of the Wilwood Engineering brake kit.  The 160 foot stopping
distance would seem to be an abysmal number in comparison to most compact
sedans' current 115 to 125 foot stopping distances.

From: [email-masked] [mailto:[email-masked]]
Sent: Wednesday, June 19, 2013 11:51 PM
To: [email-masked]; [email-masked]
Subject: Re: [Tigers] Stopping Distance

Not a tire issue, then, as the Z1 Star Spec was right at the top of ultra high
performance street tire category (since replaced with the Z2, which is even
better).

arm? ;-)

and Upgrading Our sunbeam Tigerbs Chassis, the author refers to using

Rob

I think you hit on the key: tires. Whether oem front caliper/rotor or
aftermarket, generating enough clamping force to exceed mechanical grip is not
a problem. I would guess the kit used included a proportioning valve, to allow
better balance, and perhaps had better modulation which is where any
improvement in stopping distance likely was found.

Rob

..1560

[email-masked]

[email-masked]

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From: "Robert D. Hogan" <[email-masked]>
Date: Thu, 20 Jun 2013 00:47:35 -0400

Regardless of anti-lock or not, the point is what was the stopping distance
of a Tiger's stock braking system and how much was that stopping distance
reduced by adding a $1200+ Wilwood front braking kit?

Secondarily, how does the Wilwood equipped Tiger compare in stopping
performance to more modern vehicles if the same measurement criteria are
applied?

-----Original Message-----

From: [email-masked] [mailto:[email-masked]] 

Sent: Thursday, June 20, 2013 12:29 AM

To: Robert D. Hogan; [email-masked]; [email-masked]

Maybe I missed it.  But these cars all have anti lock brakes. 
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From: [email-masked]
Date: Thu, 20 Jun 2013 00:54:09 -0400 (EDT)

ABS. all other things being equal, doesn't equate to shorter braking  
distances...supposing the driver can maintain threshold braking without  
incurring lock up in a non-ABS car. 

In a message dated 6/19/2013 9:47:21 P.M. Pacific Daylight Time,  
[email-masked] writes:

-----Original  Message-----

[email-masked]

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From: Jay Laifman <[email-masked]>
Date: Wed, 19 Jun 2013 22:01:58 -0700

Yeah, but how many people can really maintain threshold braking without ABS?
I'm sure we all want to believe we can - and I'm sure some of us can.  But,
it's also like the new dual clutch manual transmissions that are shifted
electronically.  There was a long time that I knew that people who knew how
and when to shift, would be faster and more fuel efficient than someone in one
of the automatics and even some of the electronic manuals.  So a sports car
driver would of course properly want a stick.  Even if there was no way to
prove if I had that capability - as much as I want to believe it - I don't
know for sure.  But, now with these dual clutch manuals, as far as I
understand it, there really is no question that the non-manual clutch beats
even the best manual clutch driver.  So, someone who really wants a "real"
performance car, with the best performance, will have to pick a non-manual
dual clutch transmission.

So back to ABS.  In theory, we are all able to threshold brake and we can all
brake in top form to calculate ultimate stopping distances for our cars.  And
I'm sure plenty will say that I can only speak for myself.  But, I'm thinking
that's only a theory that hasn't really be proven.

On Jun 19, 2013, at 9:54 PM, [email-masked] wrote:

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From: [email-masked]
Date: Thu, 20 Jun 2013 00:10:38 -0500 (CDT)

Mike makes good points. My experience is also that the stock front calipers and rotors have enough clamping force to lock up the front wheels, even without the booster when using typical street tires. More tire patch would make the car stop shorter.  Braking distance varies with the choice of friction material. BTW, our tests showed that modern high performance pads can really help the Tiger's stopping distance.

With modern pads, our race tiger's stopping power with stock brakes is not a problem. The problem is heat build up.  After awhile the heat does crazy things (pad fade, pad transfer or boiling fluid.) This occurs even with a lot of cooling air. Vented rotors are simply less susceptable to these heat problems. If you are racing in a class that allows vented rotors or doing a long mountain drive, vented rotors are a good choice. (For years Tigers have used Nissan vented rotors.) Now we have another choice with the Wildwood kit.

Over a decade ago we did some brake testing of stock Tiger brakes on a closed course usually used by a local police department. The police used the heck out of it, so much so the asphalt was breaking down. The surface had a lot of loose pebbles from the aggregate. In fact, wide racing slicks actually performed worse than narrower street tires because of the ball bearing effect of this gravel. This showed me I need to consider the surface when comparing brake tests. To be honest, I have not idea if R&T tests on new pavement, old (less grippy) pavement, asphalt or concrete. 

I guess the best idea is to do a before and after testing on the  same surface.

bt

[email-masked]

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From: [email-masked]
Date: Thu, 20 Jun 2013 11:40:30 -0400 (EDT)

I agree, heat build and dissipation are where a kit like Wilwood's  adds 
value. 

In a message dated 6/19/2013 10:11:04 P.M. Pacific Daylight Time,  
[email-masked] writes:

Mike  makes good points. My experience is also that the stock front 
calipers and  rotors have enough clamping force to lock up the front wheels, even 
without  the booster when using typical street tires. More tire patch would 
make the  car stop shorter.  Braking distance varies with the choice of 
friction  material. BTW, our tests showed that modern high performance pads can 
really  help the Tiger's stopping distance.

With modern pads, our race tiger's  stopping power with stock brakes is not 
a problem. The problem is heat build  up.  After awhile the heat does crazy 
things (pad fade, pad transfer or  boiling fluid.) This occurs even with a 
lot of cooling air. Vented rotors are  simply less susceptable to these heat 
problems. If you are racing in a class  that allows vented rotors or doing 
a long mountain drive, vented rotors are a  good choice. (For years Tigers 
have used Nissan vented rotors.) Now we have  another choice with the 
Wildwood kit.

Over a decade ago we did some  brake testing of stock Tiger brakes on a 
closed course usually used by a local  police department. The police used the 
heck out of it, so much so the asphalt  was breaking down. The surface had a 
lot of loose pebbles from the aggregate.  In fact, wide racing slicks 
actually performed worse than narrower street  tires because of the ball bearing 
effect of this gravel. This showed me I need  to consider the surface when 
comparing brake tests. To be honest, I have not  idea if R&T tests on new 
pavement, old (less grippy) pavement, asphalt or  concrete. 

I guess the best idea is to do a before and after testing on  the  same  
surface.

bt

[email-masked]

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