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brake requirements with engine upgrade/ boosting drum brakes


maxted

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Just wondering if anyone has some knowledge on this, Im swapping a mx5 b6ze (115hp) into my mazda b1500 ute that originally had a UA engine (59hp) ( the same chassis although did come out with a VB engine (100hp) and i believe it still had drum brakes front and rear).

 

with the increase in power is there someway the Cert guy measures the braking efficiency? 

I'm leaning towards retaining the drums so i can keep the standard wheels ect, and i have put all new cylinders and shoes all round (all 8 of the cylinders $$$$) and they seem to work well, So i was thinking wether boosting the drums would help? I have been looking into putting a vh44 pbr inline remote booster as there is no room for a booster on the firewall ( especially once the mx5 intake is there).

 

any help much appreciated

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i think the next shape 1977-82 came out with drums all round and solid discs/ drum rear. so i could possibly track down some solid front discs.

 

then the following UN shape has vented discs that can be adapted with different balljoints to fit but i have heard that it messes up the geometry of the front suspension. (i have these brakes and hubs ect)

 

its not going to be a performance vehicle, just going with b6ze to get efi and reliability for daily driving, so if i can retain the drums and just boost them to get through cert I'm more inclined to do that

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cert brake check for something with more than 50% increase in power over factory, is 5 stops from 100kph- 0kph, under 4.4 seconds, in a total of 3min max.

 

Fade is the main problem with drums in this test- the heat build up causes them to lose efficiency. A booster wont really help with this- as the booster just decreases the force you have to use on the pedal.

 

I have had a few customers who have managed to get things with 4 wheel drums to pass a cert brake test by fitting hi temp linings to the shoes.

 

If i was you id try the brake test yourself, and see what happens, it might be fine as it is

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Last time I got a cert way back it was 3 hard stops from 100km with a portable deaccellerometer thingy sitting on the floor

Same as they used to use for truck cof before the days of brake rollers

Ask your friendly local cert guy

Boosted at least has to be good

What PCD/size are your wheels?

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Thanks Cletus! thats exactly what i needed to know, that was my thoughts as the booster just makes it easier to apply more force.

 

Do you know how they work out the power increase? as this model ute did come out with a 100hp engine so 15 more hp wouldn't break the 50% increase, or is it pretty strict to what the ute had in it regardless i.e. the 59hp UA

 

Steve- Yeah I was going to get in touch with Barry Dowler soon when i have got it mounted in there, its the normal 6 stud pcd and 14" rim, but i definitely want to keep the standard wheels as they have a odd way to clip hubcaps on and I'm definitely going to use those hubcaps

 

Maxpower- now that is some out of the box thinking i like that haha, but i want to be 100% legal tegal as I'm wanting to use it everyday and insurance and actually being safe so my wife can drive it blah blah blah

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Do you know how they work out the power increase? as this model ute did come out with a 100hp engine so 15 more hp wouldn't break the 50% increase, or is it pretty strict to what the ute had in it regardless i.e. the 59hp UA

 

its based on the engine fitted in that particular vehicle, because there may be diffences in the brake system for the same model with a more powerful engine

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aha yeah that does make sense, if I can prove that this model only had the same brake set-up with all the engine combinations until the next generation would the certification man take that into account? like various workshop manuals i have show only drum on the front right up to 77' and that they came out with the VC 1800.

 

I've just grabbed my old boys nz hobby car manual to have a squizz through and see what it states in there 

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Why would you even want to cheat a brake test? Clearly you've never experienced severe brake fade. I can tell you that heading down a hill onto a corner with both feet on the picks and the car ain't slowing, you have very little time to weigh up the pros and cons of "alternative" braking methods..

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