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MP4 Track Experience Notes

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7.7K views 39 replies 23 participants last post by  Ritesh  
#1 ·
So, I took my MP4 to the track this weekend. Here are my notes and observations.

Where: Thermal Springs, Palm Springs, CA

Conditions: 90 degrees F, Wet and semi-dry conditions (rained off and on all day)

Strengths:
- The car pulls like a locomotive and it never lets up! Also, when driving on the cam, there is no issue with turbo lag to speak of.
- The chassis is incredible, very stiff diagonally.
- Grip is very good overall.
- Car balance is very good.
- Brake feel is very good.
- Steering feel and response is awesome!
- Overall a great balance of chassis feel, responsiveness and forgiving nature to the car.
- The seating position and steering wheel are the best of any street car I have drivin. And I have owned and actively tracked a 458, 996 GT3 and a 997 GT3 RS v2.

Weaknesses:
- The electronics are horribly intrusive. In track/track mode it feels like a anchor gets dropped out the back of the car. As any relatively advanced driver will attest, you need some slip angle in the car for rotation mid corner that then gets balanced out by application of throttle. The MP4 will allow this! Electronic aids felt like gen 1 Porsche stuff from 10 years ago. (Now, to be fair, I did not know how to turn the electronics entirely off which I understand can be done - this would make a HUGE positive difference in the car!)
- The car needs a differential. Despite the obvious hydraulic balancing that is happening with the car's platform, the car just struggles to lay down the power coming off turns. The lack of diff also contributes to the car moving around so much during braking. This one is the car's biggest shortcoming imo.
- The front damping is too understeer prone. Mid corner the car washes out too much in general - this could easily be remedied if MC would allow users to tweak the suspension rebound settings.
- The airbrake is kinda funny. It definitely works. But, when the car slows more and more the rear comes up as the wing has less downforce.
- Setup changes -the car would benefit so much from camber, toe and ride height changes but they are a major pain to make. With other cars, if you have strings, scales and a camber gauge you can make all manner of setup changes pretty easily. With the MP4 this just isn;t the case. And, I don't care what the car, there is NO one size setup that fits all track scenarios and conditions.

Comparable: I strongly suspect that with same tires the care would clock a Porsche or a 458. But, to be fair, most of that would be on account of the acceleration off corners and overall pull of the car on straights.

Overall: I love the car despite it's foibles. I just wish it had a diff!
 
#2 ·
pkla,

Thank you for posting, this was very informative. I tracked my Mclaren this past Saturday - I don't have near the experience to understand everything. Could you elaborate on the differential? What is the key difference in having one and not? I understand it's used to allow the wheels to rotate at different speeds. How does Mclaren accomplish the task without one?

[Newbie]

Dennis
 
#3 ·
The diff helps with putting power down coming out of the turn by locking the rear end - basically not asking too much of a single tire (power and grip). The challenge with diffs is that they also inhibit the car from rotating. Because even high end diffs don't entirely disengage when off throttle.
 
#4 ·
First - the car of course has a diff, what the OP means is that the Mac should have a limited slip diff, however also acknowledges that a limited slip diff has considerable disadvantages, as by definition, it is pushing the car to go in a straight line, even when the task du jour is to go around a corner - what gives?
Torque vectoring as in the GTR or some Audis now have, to a lesser degree the E diff in the 458, are a possible answer. But none of these would work well with brake steer we have in the 12C, which is of course much safer for the novice driver, but maybe not so for the most advanced driver?
 
#12 ·
I disagree. The laptimes do not tell the whole story. The car is a bullet in the straights which makes up for a ton.

Look, I bought one, too. I love it, too. But, that doesn't mean I'm gonna put on rose colored lenses. Look at laptimes on various tracks set by experienced or pro drivers. The 458 is actually quicker in many cases. I submit that the entire delta is on account of the electronic interference. Without it, I believe the car would clock a 458. (As I have said before, I have owned and driven both in anger on a racetrack)
 
#17 ·
I tracked mine again this past weekend and on the final session started getting the tire warnings that others have complained about. I've just had 11.1 software installed so I wonder if its related - i never got the high temp warnings before even on hotter days and longer tracks?
I'm still not in love with the brakes (mine are steel), there's always a split second of "oh shit, they're not going to haul me down in time" and the feel is very wooden and non-linear (although they are fine on the street)
 
#18 · (Edited)
Well, at the end of the day, some track shortcomings can be justified and explained in that it's not a track car. Not that that should be an excuse, but it is still one of the best performing road cars in existence and what isn't there can be remedied by buying a proper race car. Just my two cents.

Riley Track Day special, anyone?



 
#21 ·
I guess I need to clarify the post a bit...I am not trying to bash the car. Quite the contrary. But, I am also not going to rationalize every attribute of it as wonderful or as intended. The car has faults, they all do. What I am curious about and why I posted is to try and learn from others' experience and address of the issues.

I agree with GT-TT that all but the diff are addressable.

The things I am very wanting for are
1) ability to access the damper settings as it is clearly possible given the two plugins per damper one each for compression and rebound
2) ability to tune the brake steer
 
#40 ·
I guess I need to clarify the post a bit...I am not trying to bash the car. Quite the contrary. But, I am also not going to rationalize every attribute of it as wonderful or as intended. The car has faults, they all do. What I am curious about and why I posted is to try and learn from others' experience and address of the issues.

I agree with GT-TT that all but the diff are addressable.
You don't need to defend your self. Many of us who have track experience feel that the lack of LSD is an issue(Me included). I just wonder if its the fact that we are used to having a LSD and not used to the way a 12C is designed(PACC and brake steer) that is the issue. In other words - Maybe we wouldn't find the lack of LSD an issue if we got used to driving a 12C the way McLaren designed it.:confused:

Finally - A car such as 12C or F458 and specially GTR is designed to be used with most of its "nannies" on. Your lap times will always be faster with the nannies then without.
 
#22 ·
pkla, take a look at this article...

McLaren MP4-12C. Unchained

It tells you how to completely disable the traction control:

"First you need to be stationary with your foot on the brake and the steering wheel centred. You then need to ensure that the toggles that control the Powertrain and Handling modes are both set to Track. Once that’s done you push and hold the Active button on the Dynamics Panel for ten seconds, which causes a message to pop up on the screen in the dash informing you that ESC is being switched off and asks you to confirm your selection. To verify that you do in fact want to get rid of the electronic safety net you then have to push and hold both the buttons that are on the Powertrain and Handling toggles simultaneously for another ten seconds, at which point a red graphic appears on the screen to let you know that you are now on your own and in extreme danger."
 
#25 ·
I would dearly love those who are extolling the virtues of the LSD to identify what exactly are the short comings .. What is needed in behaviour change to 'improve' the experience. ISV has been the only one to detail what the the possible shortcomings of the current setup is, but there are plenty more asking for the mechanical system... If someone could take the time to deliver these details am sure there would be a bundle of us who would appreciate some clarity. What doesn't it do properly on the limit?
 
#27 ·
I am wondering the same, mikey. I think there are two aspects being considered in the debate - feel and outright performance. To my mind, the performance question is related to being able to apportion more torque to the outside, load-bearing wheel, since it inherently has more traction. Brake Steer has been criticized for accomplishing this with the braking system, but I don't see why. At the end of the day, you are limiting wheelspin on the unloaded wheel as a means to an end, which is to let the power naturally flow through the path of least resistance. An LSD accomplishes it differently, but the purpose is the same - to inhibit the inside wheel and let the available power go to the other wheel. In fact, I presume that you actually may have less available power with the LSD because of the extra parasitic loss. Now, the LSD's ability to lock the axles will affect the feel coming off the corner, I think, depending on how it is set up. I can see how some prefer that feel. But then, you have to weigh that against the added weight, complexity and potentially parasitic loss(?).

Additionally, all this has to be considered in the context of systems enabled, or OFF. If you turn everything OFF, again I can see how you might want the LSD's familiar feel as you place the rear of the car on corner exit. But, the 12C was designed to be faster with systems enabled, so Brake Steer is only part of an equation that includes the exceptional calibration of its other electronics. And driven under those circumstances, corner exit is precisely where the 12C excels, in my experience. You can bury the throttle at most apexes, even with considerable steering input and the way it all works together is pretty fascinating. So it's hard for me to fathom that they are leaving any performance on the table, by not having it.

As stated, the P1 does not have an LSD, either. But I'm also not sure if they somehow use negative torque or something from the hybrid system to mimic certain aspects. It's possible.

As you cant tell, I'm no expert. But I have still yet to see a convincing argument detailing how a lack of LSD negatively affects objective performance.
 
#26 ·
The lack of a [mechanical] LSD simply means that you can't drive the car without any electronical nannies. If you turn "everything off", it will still have the electronical diff function active. If that is good or bad is up to everybody's taste. McLaren's paradigma with the 12C has been that the car performs best with the electronics in play.

As an amateur driver, I don't really care because the car is plenty fast and has more than enough traction in track/track and I don't intend to go sideways because this might be fun but is not faster by any means.

Saying that, it still would be interresting to see how the car would perform with a LSD and the electronics calibrated to it.

The Doerr Motorsport 12C has a LSD installed and according to a pro driver I have spoken to about it last week, the car does actually perform worse than stock.



 
#32 ·
The interesting thing for me is that there really can't be any difference between having a system that has its base in electronics or mechanics... the all off mode as we discuss still has the electronic diff working, so a resemblance of the lsd, I think we can all agree there....
I guess what I am driving at (please do excuse the terrible pun) is whether the electronics do a poor job of 'simulating' the diff,.. I could kinda understand it if all that was being done was braking the inside wheel, that wouldn't work well, but clearly there's some transference of torque going on.... how this all happens I don't know, but I will endeavour to find out, as I am getting the impression we're at a limit of knowledge here collectively... I would be delighted if someone were to prove me wrong...

its interesting what you say about the car with the mechanical diff, mcdc... It doesn't surprise me.... I had a long conversation with mr.g some time ago and he summed it up for me by saying... look.. we have access to world championship winning race cars... we know what they feel like on the limit... we know how they behave... we have le mans winning race cars and gt cars...

so are we suggesting therefore that they have not been able to replicate that feel with the system that we have on our cars... i'll be honest I rarely drive the car with traction off completely, as actually the experience in 458 on track and the clear comparisons using the electronics to assist on the limit as opposed to all off showed me unequivocally that to go faster, the electronics was the way forward..

I am firmly in the 'faster is better' camp, which I appreciate is not where everyone is.. I can leave dark stripes at will, in a very nicely balanced powerslide if I want to.. for completeness I will admit that I have a feelng that the car is so balanced when sliding partly down to electronic trickery not pure skill and chassis set up... the electronics we know only let us slip so far... I can also modulate the throttle and get a faster exit if I want... I don't see where we are deficient in that regard..

I like most here am a spirited amateur driver... I firmly believe that test drivers and engineers from one of the most successful motor racing teams understand better than probably all of us how a car behaves and should behave on the limit .. after all chris Goodwin just did the 24h at spa in a car with an lsd and anti roll bars.. i'd love to think i'd be able to give feedback to them on how to improve the cars behaviour on the limit.. sadly I feel I am not qualified...
 
#28 ·
What does the LSD do for you handling wise in a practical level? The LSD helps tremendously with rear grip coming off of the corner. So, when you come off the corner and get on the gas and the LSD locks up, that is when the car has that "hooked up" feeling.

As to the MP4 being faster with the electronics on...ABSOLUTELY POSITIVELY NO WAY IT IS.

On the points around LSD disadvantages - weight, height of driveline and drag, I think these points are all correct. And I do think that the MP4 has a very low center of gravity thanks to these kinds of decisions.

My real point here guys is that the electronics need work or even better let the user adjust the parameters on a continuum.

People here comment about what the car is and isn;t kinda reads like rationalizing. The simple fact imo is that the car is fantastic but needs desperately some electronics tuning.
 
#29 ·
Just to clarify,you say the car needs desperately some electronic tuning?? yet you say you loved tracking the 458 where the electronic tuning is set up make the car seem faster than it really is,or does the race mode cancel all that out and let you use the LSD without interference?
 
#33 ·
I have been trying to follow this thread and it seems some have a preference for a mechanical locking differential and some are happy with the electronic methods.

For me there is a cause/effect approach that leads to response/feel........and we have, as drivers, different interests.

I met, at the MTC, the individual who is tasked with deciding and recommending how the M12 will morph into son of MP12. He started work last year on this new car.

We discussed the interior, ergonomics and general features but spent most time on dynamics and suspension......he had published books on motorcycle suspension which was his downtime hobby.

What was interesting to me was that we discussed the reality of physics which no one can escape from unless a Jedi. Thus how you try and control that reality is a key gateway to pass through in the design and development process.

However other priorities interfere. The elimination of excess weight is one key criteria that drives decisions and , I suspect, the electronic route is seductive if the net physical result is satisfactory.

I suspect Mclaren have an MP12 mule with a mechanical locking diff and it has been compared to the production version..........I think the rules in the GT race series ban electronic intervention hence they use a locking diff.
 
#35 ·
Because some car company has been using diffs for years doesn't make it correct! They may be scared of the die hard head in the sand customers!

But I agree they make good cars. Remember it started with steam.
 
#38 ·
pkla is just another troll trying to drag down the mighty 12c!

Just kidding of course. For those that don't know Pat he was one of the top amature racers in the US and definitely the best driver/engineer/set-up guy I ever had the pleasure to lose to.

Pat or others, I missed the LSD as much under braking as exiting. Braking from 167 mph downhill into T5 at Road America was a handful although a faulty tire gauge had me running 4 lbs light which didn't help. What are your thoughts on the twitchiness in heavy braking zones?

Final thought, as I recall pkla sold his 458 pretty quickly after a short drive in my 12C!
 
#39 · (Edited)
Great to have you here Jim!
Can't say I've noticed the braking issues ... Feels different with the air brake for sure, and I would say feels more planted at the back whilst still at speed.. As the effectiveness gets less at lower speed, the pressure point moves forward I guess, but seems predictable... I guess something similar for us is the kemmel straight at spa..