Nürburgring Nordschleife BTG 07:37.38 Mazda MX-5 Miata NC 2,0

G´day,

Quickest lap of this trip. A lot thanks to a almost free track on an event organized by Ringweekends, Destination Nurburgring Ringmeisters Prime! Great event in every single way.

There isn´t "soooo" much done since 2017, the significant things;
- More track time for both the car & myself
- 245/40 17 track tyres, road legal, on 17x9.
- Approx 10kg lighter
- New exhaust with catalytic converter (w/o cat before) & CAI. Propbably similar power as before, didn´t measure old setup.
- Had to fit a dB-insert due to having 134db (Titanium) and I´ve dyno-measured losses to 1,9hp with the insert fitted :-(.
- Rev limit increased to 8000rpm. 8000rpm? On a stock engine? Yes, that is to avoid shifting a few seconds before braking. The car is actually loosing a significant amount of power at those revs compared to peak power at approx 6900-7000rpm. However, it is still quicker than shifting to the next gear, driving for a second or two, braking, just to find yourself changing back to the same gear again + the extra hustle and balance/momentum/harmony disturbance.

The car, a Mazda MX-5 NC 2,0 Sport Roadster Coupé 2007.
Complete Modifications list from stock:
- ECU Remap
- Full Race-exhaust with race-cat and CAI
- Larger coolant radiator with aluminum reservoir
- 245/40 17 track tyres, road legal, on 17x9
- Coilovers with 13/8 Springs
- Aftermarket ARB front, no ARB rear
- 6-Pot at front, OEM at the back, 2 piece discs (oem size), race fluid & pads, cooling
- Carbon fibre drivers seat, no passenger seat
- Aftermarket steering wheel
- Approx 1090kg incl ½tank of fuel and 80kg driver (Yes, driver lost some :-)).
- 5 Speed Gearbox with close ratios gear kit (Originally a 6-speed)
- 4,1 FD without LSD (yes, open diff)
- Light flywheel, OEM clutch
- AC and PS delete
- Cro-moly rollbar, welded
- CF Roof (not retractable anymore)
- Lightened & reinforced front subframe
- Seam-welded rear subframe
- Seamwelded door-openings
- Additional bracing underneath
- Small boot spoiler
- Small front lip

Take care and enjoy!

[RobertSerwanski]

Things are progressing slowly with the car, so thought I´ll respond to another common question regarding the open differential.
Yes, it has a completely open diff.

I would like to say that a LSD isn´t needed if a car is setup properly but for the sake of not being killed by the world wide web I´ll put it like this: If you have a naturally aspirated car with low power in relation to the grip you have and also run on real racetracks where avg speed is higher than eg autocross etc - you actually don´t need a LSD.

The LSD actually robs you from power (simplified). It tries to equalize the speed between the right and rear driven wheel (and will continue to do so until you are driving in a straight line) thus actually works against you steering input. So, everything else equal, you need to steer more (thus also slowing down more) in order to achieve the same rotation/turning radius, because the LSD tries to straighten you out. And the more you steer, the more speed you lose.

Yes, some will debate that a "torque biasing LSD" instead of a "friction plate LSD" will have less of these tendencies and I could agree to some extent but then you have the case of thinking that you always have an LSD but you haven´t because both wheels need to be on the ground so it starts to become unpredictable because you can go from full "lock" to no lock, when you think you have lock.

An open diff is very predictable, it will always spin the inner wheel if there isn´t enough traction and that scenario can be modulated with the right foot potentiometer. So, putting an LSD in this particular car, for driving on the Nurburgring, would actually make it slower.

Yes, slower.

"Then why do all "real" sportcars have LSDs" (and MX-5s do too from the factory BTW). - Well, I am not saying they are bad by default because they aren´t. I am just saying that in my particular application and intended use it would actually slow me down. In a daily driven car or in a car where I also want to drift around (dry or wet), AutoX or play around with in the local roundabouts I would choose a car with LSD, any LSD, every day of the week.

And here is the plot-twist...
I have actually considered an LSD.
Why? Well, I like to have fun and drive when it rains on the trackday too. Since the grip is much lower in the wet, which is the same effect as having a lot more horsepower, the car would benefit from an LSD in those cases.
It is also a safety-thing actually. If I end up in a wide drift because of any reason, it might be hard to hold it with an open diff thus I would risk one-wheel-spinning, getting grip in the back, and getting understeer that would push the front wide (read: Hitting the armco nose-first) instead of keeping the drift around the corner and continuing.

So, what would I choose IF a go down that line? I would go for a friction plate LSD with as many surface areas as possible for stable behaviour and low maintanence but I would set it up to just do a tiny-tiny amount of locking. As little as possible. That bare minimum lock to help out in those cases in the wet or when jumping over curbs etc, but not robbing speed/creating understeer according to the explanation above.

I hope you enjoy reading this.

Kind Regards,
Robert

[RobertSerwanski]

Hi everyone, I see a lot of questions and theories reagarding my gearbox and it is actually pretty fun to read but I thought I could help out and clear out some questions marks.

The car originally had a OEM 6 speed and can be seen driven with that box in other videos.

Today the car has a classic 5 speed H-pattern and a different final drive.
It started life as a standard NC 5-speed box but the gear rations inside are different than stock, they are closer. I only use 2nd, 3rd and 4th on the Ring and that is done on purpose. 4th gear is 1:1 ratio so the least amount of energy losses through the gearbox hence I want to have that as the top gear for all those up-hill sections etc. All other gears matches perfectly now with my increased rev-limiter and larger OD tyres (245/40 17). Yes, I could have put a shorted FD and used 3-5 instead but that would have been worse overall since I need to shift more ofter and will again run out of revs before braking points and have greater energy losses in 5th as it isn´t 1:1.

No dog-box, no dog leg or any other animals in my MX-5 :-).

I hope this clears out some thoughts...

Cheers!

[jamesshives]

This is the cleanest lap of the Nordschliefe I have ever watched. Absolutely incredible! One to be remembered

[mgcharoudin]

This was great to watch and to see you drive it irl! Too bad you didn't have a passenger seat, so I could not stalk you for a passenger lap :p

[Bbeavis]

Ok who disliked this video? Was it a Mustang owner?

[NippyMoto]

Holy shit you really are the definition of driver mod.

[lucienmenair]

Oh how I wish I could see the pass on that 911 at 2:17 from the Porsche's perspective. Dayummmm. Also, that GT-R was absolutely flying.

[BTGDale]

Legendary. Proper nice work with the car and the driving. CHAPEAU mon ami!

[pathfinder]

This was so mesmerizing, I couldn’t stop watching, and the SOUNDS! Awesome👌🏼

[Lecgx]

you were catching that nissan gtr on corners

[aXemanKTM]

Great driving, man!
I had a great time talking to you during the past 2 days, I hope we'll meet again. Thanks for your love for sharing and for being such a cool guy, keep it on!

[OoNVGoO]

Unbelievable stuff. Robert's previous videos actually led me to buy an NC. Much love <3

[bobs]

car and driver. That is so fast for a Miata! Looked absolutely fun to drive...

[crodrcable]

I thought you’d never lift off the gas!!! Impressive! Car is a screamer! Love Miatas.

[Cobra_]

when people say the Miata is a "girl's car" I'm going to show them this

[agolac]

I keep watching this over and over again. You are a King!!!!

[Maroulis]

The portion of the track that is done at full throttle is crazy! Very good grip from the car and incredible “courage” from the driver!

[driver]

Awesome drive, I love how the engine screams like it will explode any second but keeps going. I tracked mine 2.0 untill 177.000mi and swap to 2.5 now .

[sriceman]

Anyone notice his throttle to brake ratio? The man was on FULL THROTTLE almost the entire run!😳 He barely touched the brakes!😆
Wow! 🤯

[jaspervos]

Fastest boat ever!!! brilliant driving 😍