have a word with the freak he does full kits for the mx5

 

whos the freak?

 

http://www.freakyparts.co.uk/

Pretty sure an NA weights about 940kg so the ones in your link may not be able to cope

 

The feel of your brakes will suffer. Pedal feels so much softer.

 

You need Wilwood dynalite calipers.
Not true about the pedal. If the piston is matched correctly no need for the pedal to feel soft.

 

OK well my kit from Freaky Parts gave me the worst pedal feel of any car I've ever driven.

 

Mine doesn't if the pedal feels exactly the same as my wife's mk2

But it stops a hell of a lot quicker

 

Not true about the pedal. If the piston is matched correctly no need for the pedal to feel soft.

OK well my kit from Freaky Parts gave me the worst pedal feel of any car I've ever driven.

Interesting...

Would love to know what factors would cause this? I was under the impression a caliper change wouldn't make any difference to pedal feel and it would be the rest of the system such as brake lines, and servo/master cylinder etc..?

I'd always thought kits like those from Freaky Parts would be the way to go for a MK1 brake upgrade.. :mellow:

 

The problem is that the pistons require more fluid to push them the same distance as the standard ones, so I have to push the pedal further. It makes it feel soft, to the point where I can make the pedal bottom out very easily. Modulation on track feels horrible, I have to make large pedal movements for very small brake changes rather than the slight pressure changes of the standard system. I've had to buy a Wilwood master cylinder in order to try and fix this, at around £200 from America. Fingers crossed this will take me back to where we were before in terms of pedal feel.

All in all, the biggest regret I've had in building my track car was buying this kit.

 

When you order calipers you get options of piston size to try to best match that of the oe size. The reason for poor pedal is that people dont know what they are doing and order the wrong sizes.
There are other reasons but thats the main one.

 

I had no choices, I bought an MX5 kit.

 

Team awesome - that to me sounds like poor piston matching. I would have sent the kit back not paid for more parts to sort it.

 

I wish I had, but we're a little late for that now so have to just get it working.

Still can't recommend anyone buys the kit.

 

The calipers flex quite a lot too.

 

Pretty poor showing by FreakyParts for selling a ill-matched kit. Did you go back to them and ask them about it? Did they own up?

It's not like it's hard to match piston sizes. Total piston cross section should be within 20% of OE if you want a similar pedal feel. The only remedy will otherwise be a master cylinder with a bigger cross section.

 

I have the freaky parts kit and I'm very impressed with the power and feel of the brakes.

 

Pretty poor showing by FreakyParts for selling a ill-matched kit. Did you go back to them and ask them about it? Did they own up?

It's not like it's hard to match piston sizes. Total piston cross section should be within 20% of OE if you want a similar pedal feel. The only remedy will otherwise be a master cylinder with a bigger cross section.

I went back with the other issues I had, some were sorted and others I sorted myself (the brackets required grinding to accept the calipers).

At the time I didn't know about the piston sizes, still don't know which I have. I thought it was air in the calipers but they are very much air free, and then I assumed it was the flex in the caliper. By the time I figured out the likely cause, it was a few months after the kit was bought and a bit late to go back.

It's a shame because it's not as good on track as it was before I bought them, the brakes don't feel as good.

 

Hmmm...something doesn't quite add up since there are other who apparently have the same kit that seems to work fine. Not meaning to condescending but how do you know there's no air in the system? Even repeated bleeding sometimes is no garantee that all air is out. Just seems odd that some people are happy with the kit.

 

It's been bled about 1000 times. The pedal is soft, but stable if you get what I mean. I think mine was an early kit.

 

had a set of these on a seicento turbo i had and my god there was some stopping power in them would stop on a euro coin could fault them 1 bit

 

ok threads run OT a bit,

what i would like to know is why the kit i linked to would be insufficient for a std road going 5, is it pad size?

also dose any 1 know what the standard piston size is so i can work out the required piston sizing for some wilwood calipers

 

The calipers in the link are not large enough to provide power enough for the mx5. Those calipers are more suited to Caterhams etc.
If you can hold on til tomorrow I will try to dig out what piston size I got on mine.

 

that would be excellent,

also i discovered that standard pistons for a 170mm disk are 54 mm dia, so pie x 54mm = 169.646mm of piston area per calliper. if i wanted to keep the same pedal feel im assuming i would need a calliper with the same total piston area as the standard calliper,the smallest piston available for the dynalight is 35mm which has an area of 109mm x 4= 436mm of total area per caliper that im assuming would give a "softer" pedal unless i fitted a larger dia master cylinder. am i right in thinking this

cheers

tom

 

Pretty poor showing by FreakyParts for selling a ill-matched kit. Did you go back to them and ask them about it? Did they own up?

It's not like it's hard to match piston sizes. Total piston cross section should be within 20% of OE if you want a similar pedal feel. The only remedy will otherwise be a master cylinder with a bigger cross section.

I went back with the other issues I had, some were sorted and others I sorted myself (the brackets required grinding to accept the calipers).
At the time I didn't know about the piston sizes, still don't know which I have. I thought it was air in the calipers but they are very much air free, and then I assumed it was the flex in the caliper. By the time I figured out the likely cause, it was a few months after the kit was bought and a bit late to go back.
It's a shame because it's not as good on track as it was before I bought them, the brakes don't feel as good.

Interesting. Exactly my findings when fitting Wilwoods to cars (not MX5s).

Massively disappointed and wished I'd kept the standard brakes. Shit pedal and flexing calipers. Avoid.

 

Ryder666:

For a sliding caliper you need to double the calculated area for comparison to a fixed caliper with opposing pistons (as a sliding caliper effectively uses the piston area and the bore area to provide clamping force)

So the effective piston area for a 54mm piston in a sliding caliper is (pi * r * r ) 3.14*27*27*2(pistons)= 4578.12 Sq mm

Dybalight with a 35mm piston gives 3.14*17.5*17.5*4(pistons) =3846.5 Sq mm

So the effective piston area of the Dynalights is a 20% reduction on the effective piston area of the standard caliper.

That means pedal effort would be increased by 20% for the same clamping force, but the pedal gravel would reduce 20%.

I don't know what the effective piston area of the Freaky parts kit is, so can't tell you the maths on that one, but I do know that every other car I get in after driving my Eunos feels like it has rubbish brakes with a long, soft pedal.

One of the potential drawbacks of the need for increased pedal pressure is that the increased force acts on the pedal, arm, linkage and master cylinder as well as meaning an increase in line pressure for a given caliper clamping force.

If you have a car which is already prone to flex in the pedal end of the braking system (for example - a master cylinder mounted on a flexible bulkhead) then this would just create the impression of weakness/flex in the system. Some might feel that as brake caliper flex (which it may, or may not be) unless the master cylinder is suitably braced to prevent that flex. Equally, old and flexible brake hoses will expand more with the higher line pressures, giving even more flex in the system and reducing pedal feel.

The thing with changing any part of a mechanical system is that you need to consider the effects on other parts of the system, especially if you don't get the results you were expecting or hoping for.

I have a master cylinder stopper built into my S-Special strut brace, braided hoses, New fluid and the freaky parts kit which I fitted carefully to ensure it was all fitted flat and square with clean mounting faces and torqued up securely to make sure there was no extra flex added at fitment.