Use a booster off the Mini LS

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Videos - Turbocharged A-Series on Dyno & at Wakefield
Mafs waz not my strong subgeckt at skkol

What booster....? They never had one std, did they?

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

Exactly....

I am with you doc in that a street car should have one but the point I am trying to make is that if you want to run without one you can.

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Videos - Turbocharged A-Series on Dyno & at Wakefield
Mafs waz not my strong subgeckt at skkol

OK cool.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

We are pretty spoiled for choice with pads these days, you have to make a conscious effort to find bad ones. Some of them used to feel like timber blocks until they warmed up.

I like the booster mostly for the pedal feel, but also for a little bit of technology under the bonnet.

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SooperDooperMiniCooperExpertEngineering

All garage work involves equal measures of enthusiasm, ingenuity and a fair degree of irresponsibility.

Touche

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Lillee - 1969 Morris Mini K

test data link in my first post... anyway, better to be informed and take the risks then uninformed and inherit the risks.

love the cockpit mounted booster

Besser, can you explain your take on what the study you linked means by pedal 'gain'? It's looking to me like we've both read the same thing and come to different conclusions. In my mind that says more about the quality of the writing than about us!

What I took from it was that on slippery surfaces too much gain (which I took to mean assistance from servo etc) meant an increase in lock ups. The difference was less on dry surface, but still, an intermediate level of gain was still preferable to high gain.

Or have I cocked up the definition of gain as they are using it?

Just as an aside, when I mentioned no facts/data, I was really referring to the statements made about how humans react in an unexpected situation, rather than about the relationship between pedal effort and braking performance.

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http://www.mini-hb.co.nz

So smac on a drum braked car you obviously would prefer the early single leading shoe brakes over the two leading shoe because of the increased risk of lock up from the self energising servo effect of the two leading shoes.

Well that made no sense....with or without the sarcasm.

Anywho, back to the topic...

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http://www.mini-hb.co.nz

smc..yes yes you are right about gain, I totally agree... it's page 7 point 5 "The highest gain (defined as high deceleration/pedal force in g/lb, or as pedal force/deceleration in lbs/g) configuration did not provide optimum performance in any of the surface x speed combinations."
High Foot pressure to line pressure is not optimum = boosted is better then unboosted. Additionally overboosted braking was also not optimal as per page 13 2nd para, so it continued to say mildly boosted system seemed desirable.

Now for time for data on pedal application time:
Page 6 shows percentage pedal pressure for:
"day dream braking" = standard motivation
"Oh Shite I need to stop" = induced motivation

Given the people were the same and they had the same physical capabilities across both tests the only differential was mind set. Pedal pressure was increased for the same people and pound pedal pressure to deceleration correlated until brake lockup. With boosted to unboosted line pressure being the same yet pedal pressure being the variable it is then clear the mental effort to apply pedal pressure is the determinant of deceleration.

Man..that took longer then single leading shoe brakes (unboosted )

On this subject : Vehicle Standards Bulletin 14 (VSB 14) suggests the LS brakes can only be fitted to a Square Front without booster..... is that right?

Oh I understand motivation is related to the brake force used, it's nice when the numbers support what we'd consider 'common sense'. In any situation your brain has to make a decision on how hard to brake. The more highly motivated, the harder you're gonna try and kick the firewall! Yes that decision takes time, but it seems a stretch of the evidence to suggest that a booster decreases the time taken from your eyes seeing the situation, and the required brake force being met.

I have driven a total of one car immediately before and after a booster was fitted, with no other changes made (many more where other changes were made). In that car the brake pedal had to be pushed further to obtain maximum pressure at the pads. SO less effort, but more distance. Which is better? IMHO it's the one you prefer. That comfort, preference and predictability will far outweigh the time taken for you brain/muscles to push a little bit harder. IMHO, cause that's what we have to go on here

As an aside, my car went for what you guys would call a road worthy yesterday. Deceleration numbers on the brake meter in a panic stop situation (part of test) were better than the previous car that had ABS 7 1/2", average pads, no booster.

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http://www.mini-hb.co.nz

I run 7-1/2" discs and EBC greenstuff pads.
With no booster fitted, the annual brake test with a Tapley meter onboard regularly gave ~1.0G deceleration.
I agree you don't need a booster for good stopping, but IMO it's much nicer to drive as a daily in traffic if you have one. Particularly when you are an old fart like moi.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

smac was that a mini with ABS?

Your brakes and your booster are still only a part of a bigger system though. I remember my housemate saying he wouldn't drive a car with drums on the front - but he was very surprised to find that the mini with drums would pull up much faster than his corolla. He could have had the best brakes in the world, but it's still not going to stop well with $60 Chinese tyres vs the mini's yokos.