Winmax W6.5's and W5's

[Magpie]

Changed out the Winmax W5's yesterday, was told by Plus that the fronts were low, they were not wrong.

The W5's have done about 4 track sessions (1 x MR Tuning track day, SDT at Morgan Park, Cootha Classic and Jap Nats).

The pads were 15mm thick on install and the rotors were FR 21.92mm and FL 21.78 (DBA T3's)

When the pads were removed they were all about 9.2mm and the discs were FR 21.65 and FL 21.60.

I'm happy with the way the DBA T3's are wearing. Now to see how the W6.5's wear.

The final few stops when bedding the W6.5's in almost through me through the windscreen. Heaps of initial bite and a very progressive feel once they are up to temp, cold they are a little better than the W5's and when hot more bite than the W5's however progressive feel is about the same.

Will be testing them on the track soon so will give some more feedback then and possibly pull the pads out and measure them.

Bed in runs
Bed In by Eipeip, on Flickr

[Magpie]

Replaced the W6.5's on the weekend. They were very well used... I have installed another set of rotors on the front whilst I get the T3's machined.

The pads/rotors did WTAC 2015, 3 x half day general practices at QR (national), 2 x SDT days at Morgan Park (1 was almost 80 laps), Noosa Hill Climb, Jap Nats 2016, 4 x QR Street Sprints and 2 MX5 track days (from memory)

in mm's
FR 21.45 FL 21.10
RR 9.35 RL 9.6

Therefore the impact on the rotors using the W6.5's is:
FR -0.47 FL -0.50

The rears are still running on W3's (second set),however the plan is to go to W6.5's on the rear as well. More than happy with these pads, they need a gentle application initially and when they start to bite then you can build up the brake pressure.

[Trackphotos]

After Mt cotton yesterday, I can say that the W5s stone cold are less than ideal for downhill braking into hairpins you say the 6.5s are better both cold and hot, I might have to give them a go after these ones are done.

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[The American]

I've been very happy with the W3's in the short events I've been doing. They are rated for 0-600c vs the 6.5s 50-800c.

Mark have you recorded the top temps your brakes are reaching on track?

[Magpie]

Will be doing some rotor temps again this and next weekend. The temps will be done using thermal paint but will give a good range. I still have the temp strips on the calipers again I will record these.

Trackphotos the W6.5's do work from a lower temp. One day I will hand the keys over and you can test the W6.5's out.

[Magpie]

Something did not sound right with my figures so I re did them. The values are still about the same however better to give accurate facts.

T3 current thickness
FL 21.14
FR 21.15

When W6.5's installed
FL 21.60
FR 21.65

Hence wear is
FL 0.46
FR 0.50

For the W6.5 pads themselves
15.0 thick when installed, when removed FL 6.5 and FR 6.3. Due to uneven wear on the pads I took the combined thickness and divided by 2.

Therefore 1mm of rotor wear equates to about 17.7mm of pad wear. However you would not want to take the pads down to below about 7mm so 14.5:1 pad to rotor wear ratio would seem about right. Hence you could expect to chew through a set of T3's every 4 sets of W6.5's.

Now it is a case of seeing if it is worth using T3's or OEM or EBC rotors. Also may need to buy a set of calipers specifically designed to measure rotors instead of the micrometer I currently use.

[Trackphotos]

I think I may have found the limit for oem-replacement rotors, mine are covered in little cracks since I put the W5s in. Don't think it's anything to be concerned about, but certainly suggests the extra heat is affecting them in a way the A1RMs didn't.

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[Magpie]

Can you feel the cracks? mine have small cracks but they are confined to the layer of pad material and not in the actual disc.

I did wear my pads down too far, to the point that the backing plate of the pad has an impression of the brake piston. The national at QR is very harsh on brakes.

[Trackphotos]

No, can't feel them. It's just the usual crazing that comes with high enough temperatures, from what I've read it can happen to any brand of rotor with any type of pads, as long as they get hot enough. These rotors were new with this set of pads, so lots of life yet.

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[Magpie]

Put some temp paint on the front rotors when I installed a new set of W6.5's on a set of EBC slotted rotors. On a side not another MX5 at the track was using the W5/W3 combo (Francois Siebrits) and from the conversation very happy with them. We did discuss about going W5's or W6.5's the whole way around the car since his car is not road registered. Francois felt that the rear was not doing enough, so a brake basis was discussed as well.

They got a good work out at QR Street Sprints Round 4 as did a PB as well as quite a few 62 sec laps. The cracks on the rotors are just cracks in the pad layer and not the rotor themselves.

The paint changes colour after being subjected to at least 10 mins of the required amount of heat

Green goes to white at 458°c
Orange goes to yellow at 550°c
Red goes to white at 630°c

The highest temp a paint can be subjected to without a colour change is
Green 180, Orange 475, Red 425

FL - between 458 and 475°c The orange paint never changed colour.
DSCN3260 by Eipeip, on Flickr

FR - between 458 and 475°c The orange paint never changed colour.
DSCN3250 by Eipeip, on Flickr

Plot going through the dipper, (green/blue/orange fastest lap). This round I concentrated again on T1/T2 but also getting on the brakes and building up pressure faster so I could trail brake more. It worked in general when looking at the rest of the plots.
Dipper_Rnd_4 by Eipeip, on Flickr