The Roadster NA Journey Begins

Magpie · Postby **Magpie** » Tue May 05, 2015 7:58 pm

Sailaholic good point, no the 36 tooth trigger wheel has never been tried since the first tune and it did not work. May have to go back down that path and get it installed. Will try new COP's tomorrow at QR and see if the miss develops again.

By the way made it home, tomorrow get ready for mid week sprints at QR then happy laps on Sat at Lakeside.

timk · Postby **timk** » Tue May 05, 2015 9:00 pm

I run the 36-1 wheel and get the occasional miss on Toyota COPs, seems to be a common theme?? I have tried two low mileage sets of genuine Denso ones.

Have you guys got the miss datalogged? I wouldn't mind comparing notes.

I have bought some LS3 coils to try, will let you know how I get on.

timk · Postby **timk** » Tue May 05, 2015 9:01 pm

I assume you guys run them wasted? Maybe they don't like double the usual duty cycle?

Magpie · Postby **Magpie** » Tue May 05, 2015 9:13 pm

Plan is to get a button to turn on/off the logging on the PS1000 as it can log at a greater frequency than the innovate. AFR's are fine,it appears to be a problem that gets worse over time. The car had heaps of time to cool down between sessions.

I'll check the settings in the PS1000 tomorrow.

sailaholic · Postby **sailaholic** » Tue May 05, 2015 10:18 pm

Tim my miss issues is masked / removed by adding significant extra fuel and is there at idle and light loads. Unknown if it's still there at heavy loads but masked by the extra fuel at WOT.

We therefore assume it's a problem on the injector side. We've swapped the injectors out for brand new rx8 440s and it got a little better but not huge.

Next step was to go through and reexamine all the earth points, make sure the are clean and probably run some big earth cables just to be sure.

I'm also running my coils in DF not wasted spark.

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timk · Postby **timk** » Tue May 05, 2015 10:21 pm

More interested in RPM signal.

timk · Postby **timk** » Tue May 05, 2015 10:22 pm

Ah cool, at least that can be ruled out!

Sorry on phone hence short replies!

Cheers

MattR · Postby **MattR** » Wed May 06, 2015 2:24 pm

Magpie wrote:About 10 laps per session. The discs were showing heat stress and the handbrake does not work, so the rears have been worn a bit.

Turn 1 by the end of the day was fun, 192 down the straight and about 160 at the apex. Warren's advice for turn 2 gained me at least 1.5 secs. However, the suggestion involves braking later and harder, hence the fade at 4/5. Had fade a few times at 6 as well.

Warren's other advice and video comments were very helpful and he pointed out a car with limited power any mistake will be amplified, however you can break a lot later.

Mark,
Could the brake problems be due to the fact that the brakes were always a bit marginal, but this is the first time that the car has been dríven to near its potential????

It maybe the time to step up to a set up more like Zoom Zoom's where bigger brakes again have been thrown at the car, or look at going to a pad that will cope better with the higher temperatures with the subsequent compromise of changing rotors more often. Rotors are generally very soft these days and are as consumable an item as the pads are.

The brake fade is generally the inability of the brakes to cool sufficiently between stops. If they are too small it doesn't matter how many vents you have forcing air through them, they will not cool enough between stops. Also material will make a big difference to the heat dissipation. That's why I chose the Z32 callipers over the cast iron callipers of the R33 GTR, as the Z32 callipers are alloy and get rid of heat quicker. I also run the larger rotor to get rid of the heat as quick as possible.

And if you go that route, then you will be changing master cylinders and can get rid of the booster so you can get a much better feel of what the pedal is doing :lol:

Dweezle · Postby **Dweezle** » Wed May 06, 2015 2:35 pm

This is very interesting.

Is this all really necessary??
I only ask as i have been trying to get a better idea of what brakes people are running on different mx5s and it seems some chase larger brakes and others have little issue with stock sized brakes.

Magpie you are on NA8 sized rotors correct??

I am using stock NA6 rotor and caliper sizes and on a 4-5 lap Supersprint run experianced no noticeable pad fade on the GP Circuit.

Could it be a seized caliper pin or similar or just me not using the middle pedal hard enough??

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MattR · Postby **MattR** » Wed May 06, 2015 2:45 pm

Marks car has about double the power of a standard car and as such is probably still too quick for his brakes when dríven to its full potential, which should be in the region of 1:48 for the GP circuit going on the times I have done and compared to other cars I have raced against and their level of modification.

My NA6 is standard engine wise and I use standard brakes with Hawk HPS pads for road and track and don't suffer any fade, but the brakes are still more than good enough for the capabilities of the car.

for yourself, odds on the brakes aren't being used hard enough. One way to get some more out of the brakes is to brake later, easier said than done. But one way is to lift off where you think you need to brake and count to three slowly. The self preservation will kick in and you will be braking at 2 or 2 and half, but that will be anything up to 65 metres later depending on the approach speed. Once you are comfortable with your new braking marker you can stay on the throttle until the new later point, and then when comfortable with that, lift off and count to three before braking to repeat the process. When you have a real brown pants moment, you have gotten to pretty much your limits for the braking.

Dweezle · Postby **Dweezle** » Wed May 06, 2015 2:57 pm

Thanks for the advice.

Will have to give that a go.

Does seem strange to be getting brake fade while still being above 2 mins with that sort of power??

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MattR · Postby **MattR** » Wed May 06, 2015 2:59 pm

I would suggest that that day was the hardest the car had ever been dríven, and the brakes showed up as a weakness for only the first time due to repeated heavy use.

Dan · Postby **Dan** » Wed May 06, 2015 3:16 pm

Dweezle wrote:Thanks for the advice.

Will have to give that a go.

Does seem strange to be getting brake fade while still being above 2 mins with that sort of power??

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You do realise that a higher time means he's probably doing MORE braking right?