The Roadster NA Journey Begins

[Magpie]

The brakes are NB8B with winmax W5's on the front and W3's on the rear.

Agree that the car is only starting to be dríven to its possible potential and it should be able to do at least 1:50 at EC. Did almost 14 laps straight at QR and whilst getting a PB no brake fade and no miss!

The COP's were changed to VDO branded ones, no OEM available on a few hours notice. The ones I purchased were the wrong part number!

Yes at EC the brakes are pushed, but it would be simpler to look at cooling as opposed to different calipers/rotors. It is a heat management issue so getting more air maybe sufficient. Plan is to put brake bias in and get more out of the rears and possibly use W5's as well. If the rear does more work the heat can be spread between the front rear.

The car was setup for more understeer at EC, however today at QR the understeer was a lot more pronounced than at EC. Alignment was great and the tyres got up to temp really well.

Personally what I learnt at EC was put into practice at QR today and paid dividends. I reckon times will drop with more seat time and some minor tweaks to the bump/rebound settings.

[plohl]

What tyres were you running today?

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[MattR]

Mark,
I think getting more air to the brakes will only mask the problem. With your car I would be starting to look for upgrades. Have a look what Brian Ferribee and Henri VanRoden are running on their na 2b cars for an idea.

The potential of your car will easily cook nb brakes as they won't cope with the heat. For 5 lap sprints and time attack you may get away with it, but just keep in mind that you may need to upgrade.

[Magpie]

plohl still the FZ201's. 26 cold front rear 27 cold.

Have a set of DZ03's and AD08's to test as well.

MattR I agree that an upgrade maybe needed. I'm working with MT Tuning to come up with possible solutions and the view is to go cooling first and then see. Plus cooling is the cheapest as all I need to do is double the diameter of the current setup.

No more mods only tweaks to the existing setup. Once the brakes are sorted out then it will be a more substantial mount for the wing in between the rear bushes will be replaced.

[Dan]

The brakes are NB8B with winmax W5's on the front and W3's on the rear.

You could go up in compound too.

I just had a look here (http://www.brakesdirect.com.au/winmax) and the W5 you are using on the front looks like it has a temp range of 100-750C and the W7 which is the higher model has a temp range of 100-850C.

Then looking over at Carbotech, I run the XP12's which I am very happy with and they have a temperature range of 121-1010C with the XP20 going to 135-1093C (http://www.ctbrakes.com/brake-compounds2.asp).

I also think you guys have the option of the Raybestos pads on the earlier MX5's, I run the Raybestos ST-43 pads on my Evo 10 which is much heavier than your car and has a bit more power (300kw at the wheels) and I never see any fade since I fitted them but that car has much bigger rotors and calipers as well as air guides to help with cooling.

Well i assume longer on the brakes but not as aggressively.


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Regardless of the intensity of braking the car still has a lot of braking to do because of the car’s power which is compounded again if he’s carrying less speed into the corners which causes him to brake more than optimal as it was his first time at this track (which just happens to be one that is pretty demanding on brakes). Braking later isn’t going to fix things, it will make it worse.

Also I bet he’s got more time to be found in the corner as braking later isn’t usually where big amounts of time are found (hundredths & tenths) whereas carrying more speed through the corner by taking a good line and getting on the throttle earlier is where the time is (halves and seconds), the reason being that the benefit of carrying speed out of the corner benefits you all the way down the straight after the corner which is usually hundreds of meters whereas braking earlier only affects you in the small area that you braked earlier than optimal.

I think if he got out there again today the problems would start to go away (maybe not eliminated though) as braking would be reduced.

[Dweezle]

Thanks Dan for the explanation.
Also sorry if i have hijacked this thread.


Just seemed strange to my simple mind that my stock little 1.6 brakes appeared to be a non issue doing 1.56s on my first and only time on the GP Circuit.
The length between the braking points seemed to make that a non issue.
That was only on short 5 lap sessions though.

This could be making all the difference!!

Perhaps if i did a longer stint it, heat would build up to become a issue.

Magpie, do you have any vids from SMP??
Would love to see your laps




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[Magpie]

Dan you views are very correct, I need to carry more speed through the corners and today at QR I have managed that, turning in a lot later and whilst my apex speed is less I can get the power to the ground earlier. I reckon I have a lot of time to improve on at EC, just need more seat time.

Thread not hijacked, all good. I will post some videos soon.

This is what was trying to be explained to me on Monday, brake later, turn in later, sacrifice apex speed for better track position and getting on the gas earlier. To use another's persons words "you spend more time in turn 2 than in turn 1 so this is where you can make the time up when you have less horsepower".

Thought about W7's however as a street pad it would be an overkill...

I was going to post this in the data logging thread. Turn 2 at Eastern Creek
Green - one of my first attempts.
Red - Oztrackdays VBO file of a 1:41 lap
Blue - my line after advice. The small advice gave 1.3 secs alone on turn 2. I could have tightened up a bit more on the exit and moved to the inside to setup for the next corner.

Putting into context Oztrackdays was doing 229 at turn in on turn 1, for me 192. Apex speed 170 vs 159. Turn 1 approx. 10.5 secs (brake point to brake point), Turn 2 20 secs (brake point to brake point turn 4) approx. the same distance. Much better to work on turn 2/3 than worry about turn 1.

The Red and Blue are 2 different lines.

Turn 2 by Eipeip, on Flickr

Just because, going through Turn 1. Very little roll.
IMG_1400 by Eipeip, on Flickr

[Magpie]

SMP Gardner Layout


QR Clubman PB

[NitroDann]

I havnt read the whole thread so im sorry if its been answered but what did you actually overheat?

[MattR]

Getting brake fade and not cooking pads so not getting the heat out of the brakes as I see it.

With the potential of the car an upgrade will more than likely be needed to do more than a few laps.

[NitroDann]

im sorry I dont know what you are suggesting is actually overheating.

[MattR]

The calipers, rotors and hubs are retaining too much heat. A problem when the car is too quick for the brakes.

Same as what happens with zed cars in group s historics and the old series production cars of the 60's and 70's. The brakes go away as the heat build up can't be dissapated and then affects the overall performance of the brakes in a bad way.

[Magpie]

nitroDann thanks for that link on Miata Turbo, it has been good reading.

The issue is not getting rid of the heat quick enough so getting some fade. May also look at changing the brake fluid. I doubt the issue is mechanical fade as the pads can take the heat, rather the heat is moving from the pads/rotors/calipers into the only cool thing available, the fluid.

I'll post some photos of the rotors for some comments.

[MattR]

Mark if the fluid is boiling you will know. The pedal goes to floor pretty quick.

The fluid getting hot is because the brakes aren't getting rid of the heat. You may get some benefit from better rotors and keeping the calipers. But will get benefit from an upgrade.

I use the Penrite fluid and it has never boiled.

The problem will be heat retension in the brakes and not dissapating quickly enough. As I said before you are now starting to push the car and the brakes are suffering because of it, which is a good thing.

If you can get some heat paint and paint on the rotor edge to see what temps you are getting. If the pads aren't cooking, the rotors aren't cracking from heat, and you are not seeing stupidly high peak temperatures, above 850 or so, then it is the system not getting rid of the heat fast enough and it keeps building up.

As per my post above the curse of the old series production cars and plenty of historic racers who are hamstrung by the rules.

[Magpie]

Brake temp paint good suggestion.