How many track days do you have on your car, and problems you've encountered associated with pushing your car at the track? I have one school day and two track days, only brakes and tires are hurting.
Thanks

 

About 20 in the G35, 6 in the RX-7. Lost track of tires and pads I've gone through.

 

About 30 in the G35. No real problems, other than, as Balzz says, the consumables of brakes and tires.

One of the biggest adjustments to performance driving that you have to make when you start to take your car to the track is the change in mind set that you need to have, the mind set that you have over expectations and what is "good" for a street car, because it is very different on the track.

Generally speaking, our cars are very well engineered, and in particular the engine and drivetrain. Absent missing a gear change or hitting something, driver error items, the car engine and drivetrain will hold up. The suspension is too soft for the track, which is of course as it should be since it was set up for comfortable but "sporty" around town and highway cruising. A few inexpensive mods can do a lot to fix that to a better compromise for some track days.

So that leaves brakes and tires. With your brain set to "street mode" you will bring with you the ambition for 60,000 miles of tire wear, evenly across the entire treadwidth, and brakes that will last at least 40,000 miles before you replace the pads, and rotors that will go over 100,000 miles. Anything less is "bad" driver or cheap quality parts.

With your brain set to "track mode" everything is about tire adhesion and grip. The obsession, and it almost has to be, is with tires and wringing out of them every last bit of performance. Suddenly, it is not about the car as much as it is the tires....they accelerate the car, turn the car, stop the car...everything else about the car is tuned to make the tire do the absolute limit of what four little contact patches on the ground can do.

And that means that as they are pushed to the limits of doing everything they can do all the time, they wear out at an intensely accelerated rate. If they are street tires, they are not designed for what you are doing to them on a track, and they will not last long if you drive "fast". If they are track tires then they are designed essentially to self destruct, to give up of themselves their very bodies over a short time just to maximize performance. So.....four track days may be all they have for you before they go from new to totally done in. Sometimes less. The tire becomes a consumable as much as gasoline and water.

Pads a rotors go through friction and heat that is almost unbelievable compared to street demands. Three laps on stock brakes before they are overwhelmed is a not uncommon experience.

You can make your equipment last longer by not driving as fast. Stay "down" in a slower group like novice or low intermediates, work on skills and smoothness, and have a great time. But if you get up to where the advanced intermediates and advanced drivers are running....the above observations will apply to you.

What kind of times are we talking about? Of course it "all depends" on the track and group compositions etc., but "rough and dirty" you can expect at least a ten seconds per lap difference in average times between groups, with the fastest drivers in a lower group putting down times that just crack into the fastest 2/3 of the next group up (meaning if you are one of the top two or three guys in novice after a few sessions, then you will be slower than 2/3 of the guys/gals in intermediate, typically, in a club or HPDE scenario).

It is an interesting transition, to go from a feeling of relative confidence, and speed, to fighting for your life in the next group up and trying to stay out of the way of faster cars and drivers. Yet you are positively "blasting" along with lap times that are faster and faster and faster. Slowly you get to where you are working up to being among the fastest in your group again, and then when you move up to the next group, ZAP.......same thing happens....lots more attention to that mirror!

But.....if there is a point to this here it comes....you can have a WONDERFUL time tracking your car in a novice or intermediate group, with less wear and tear on the car, and the tires and brakes will last longer. Some judicious upgrades to your brake pads, sway bars, tire inflation pressure attention, etc. will improve handling and you will have a super fun time.

 

Thanks for the great reply. I am keeping up with or going faster than most of the intermediate group. I do have sways and spring/shock upgrades, plus go fast stuff. I plan on keeping the car fairly streetable(no coil-overs, or really tight or really low suspension). Is it worth having seperate wheel/tire combo for the track, or use a nice street tire like GS-D3 or PS2? Anyways, it's nice to hear that I can go to a lot of track days without worrying about the drivetrain, as long as I keep it away from walls, cars, off road excersions.

 

Sounds like you are doing some nifty driving if you are in the upper zone of the intermediate group in a basically stock car. The key to going fast is driver skill and suspension/handling. Power is nice, but it is not the answer alone.
It depends on what wheel you are running now. The key is going to be weight of the wheel tire combo. If you are running an 18" wheel, you want to go as light as you can, one piece forged for strength. If that is too expensive, go with something like an Enkei MAT technology piece. The ambition is 18lbs a wheel for wheel weight if you can get it down, a huge drop from the stockers. Then go with a DOT-R tire like the Toyo RA-1 or the Nitto NT 01. Light. Grippy. Since you would be going with new wheels, some consideration to a larger rim width. You could run 245/40 front and 275/35 rear, no spacers no problems. With reduced weight and increased tire tread, you will be having much crisper response, better braking and better acceleration. Dropping a pound of unsprung weight is like losing 20 lbs of chassis weight. You gotta do it.

 

Wow! Fantastic info for a person like me who is considering tracking my car some more, but needs to know what their in for.

I have a question for you. If I'm running an open diff on my car vs. a limited slip, what can I expect? The reason I ask is that I'm considering running r-compound tires on the track, but worry that the open diff will be the weak link on cornering. Any advice for a track newbie?

 

Thanks for the info Eagle1. Another question. How much difference in grip is there between the DOT R compound and the stickier street tires? Also, should I wait to get a little more seat time before trying R compound tires?
Thanks Again.

 

That's like comparing sex with and without a condom.

There are many differing opinions about when to go to Rs. My personal opinion is that as much as you learn a lot on street tires, when you begin pushing your street tires to the point where they overheat after a couple of laps, you might as well go to Rs. It's tough to learn when you can only drive a few laps before your tires stop working.

 

Well said Eagle1. I have 16 Time Trial events and several track days on my G. I've gone through 3 sets of brakes, 1 set of street tires, currently on my second set of slicks, about 2 gallons of motul 600 and a lot of sweat. After a couple of events on streets then the next must do are slicks. My slicks are worth 3 to 4 seconds per lap consistantly and trust me, you will become addicted to that level of grip. I once flat spotted the left front tire under braking and had to finish the event on my street tires. Horrible feeling that made me carry spares every time I go to the track. What an addiction.

 

That is a good question (again!)

In general a step up from a high performance summer street tire to a DOT-R tire, is good for approximately 5 seconds per lap. All other things being equal.
What is a real mind twist is that the next step up, to full on race slicks, is good for approximately another 5 seconds per lap. That is the good news. The bad news is in two parts. Don't count on getting more than four track days on your DOT-R rubber. You might, but don't count on it. The second is that you get spoiled and find that you would rather cut down on eating so you can afford your next set of them, rather than miss an upcoming track day.

From a driver perspective, it is a good idea to run your car a few sessions on the street tires and get used to playing with inflation pressures, taking tire temp readings etc. Furthermore, you will want to get good enough with those tires to be approaching the limits, and perhaps a few times exceeding them and spinning out (in places on the track where you are not going to be presenting a hazard to yourself with walls and ditches and such, or others such as in fast or vision impaired corners), so that you learn how the tire is communicating with you.....which will be through sound and squeal, scrub, and of course "body language" from the car as the adhesion begins to let go. A street tire is typically a "talker" and will let you know long before it lets go that it is working hard for you and under protest. A DOT R tire on the on the other hand is a bit of a macho brute and the messages are quieter and more subtle, so the experience with the street tires makes you more attuned to what is going on. Slicks are just mean ****** that act like everything is fine up to the very edge of adhesion and then let go....FAST. You learn through amazingly subtle reactions where the edge is, and how to get back from it to stay under control.

So the point really is that you don't want more tire than your driving skill is going to allow you to use, because that is just a waste of money, and it can be unsafe if you match up too much tire and not enough skill or experience.

One last thought for you on this thread. The impact of your tire choice on the rest of the components of your car. It is VERY significant. When a tire is able to provide more adhesion, or grip, it allows the car to a)put more power down in a straight line before spinning as it exceeds the acceleration traction limits of the tire, b)slow the car more rapidly by grabbing the road under hard braking before locking up the wheel as it exceeds the deceleration traction limits of the tire, and c) turn and hold the car in a corner. To put five or ten seconds of additional speed per lap into your car just through the tires is going to throw immensely greater strain on all of the other components of the car working there....suspension, brakes, drivetrain, etc.

The best way to experience this is to go to a track event and do you best, safely, in your car. Then, have an instructor (you trust) take you out in your car and have him do his 80% of best (it is unlikely any instructor under these circumstances is going to do more than that anyway). If you are a novice to intermediate class driver, he will probably do at least ten seconds faster than you do, in your own car. You will be shocked at the sensory difference that ten seconds makes. You will also be impressed by what the very same car can do in the hands of a more skillful driver. And you will be impressed at the forces the car is undergoing.

All those other upgrade parts on suspension really only have one purpose, and that is to help the tire out, to do its job more effectively and safely. Brakes do not stop the car. Tires stop the car. Tires are what grab the road. The brakes stop the wheel from turning...and once they lock up, the tire is not gripping and the job is not being done. The engine does not accelerate the car. Tires accelerate the car. Tires hook up the power from the engine to the road. Once the power exceeds the traction capacity of the tires, they are not gripping and the job is not being done. The steering does not turn the car. Tires are what adhere to the road and redirect the car. Once the suspension of the car is exceeded in its ability to effectively handle cornering forces, he limits of adhesion are reached and the car slides, and with a few exceptions where one deliberately induces rotation, sliding is not good because you cannot be accelerating if you are sliding, and you want to be putting power down as much as you can.

There is almost no performance mod that you can do to the car without being careful to ask, what is this going to do to the tractive qualities and characteristics through the tires. That is one of the most important keys you have to consider. And if the mod is going to provide returns that you are not going to use........consider saving some money, time and complexity, and DON'T DO IT! Limited slip differentials, front strut tower braces, under body ladder braces and adjustable front upper control arms are all, and I sincerely do mean ALL, fabulous performance modifications that even your trusty butt dyno will report back to you...work big gains in performance on this car. However, I believe that each and every one of them only gives those gains at the upper reaches of pushing the car to perform. And at a cost in comfort and convenience on the street. Does everybody need them? Absolutely not. A stiffer set of sway bars and lighter wheels and tires with more treadwidth...if you don't get those I am not sure what is going on in your thought process...but I would be concerned about going on vacation and asking you to be the one to pick up my newspaper in the mornings.

OK, hope that helps. Enjoy the track days and come back and write about them or share some pictures or video.

 

You can expect that you will not be able to put as much power down to the road on corner exit because of the slip on the inside rear tire (the tire closest to the radius center point of the turn). That will be the case no matter what type of tire you run. You will still go faster with the R compound than the street compound, because you will still have better grip for acceleration and braking and cornering. Remember that probably close to 80% of your braking is on the front, and pretty much 80% of your turning is on the front too (it is not 100% because the adhesion of the rear tires is critical to keeping the car balanced in the turn), while the acceleration is 100% from the rear. If you are on the brakes and not the gas (taking out of the equation here the left foot braking conundrum with an open diff) you should have no issue. So straight line braking, no difference. Even with a touch of trail braking, no issue because you are not on the gas. But once you get on the throttle...it depends on the weight balance and the amount of power you are attempting to apply. With the open diff you will start to spin the unloaded wheel and power will shift to the loaded outside wheel...but overall less power will get to the ground, and you will be slower as a result. The grippier tire will help you to keep traction longer on the inside wheel, but it is not going to substitute in results for the difference that having a lsd will provide. Especially at the point coming out of the apex when you want to apply as much power as quickly as you can so that your corner exit speed is maximized heading on to the ensuing straight. That is where you will get the biggest observable difference.

Cheers.

 

Thanks again Eagle1 for the great advice. Do you teach at a track in Cali? Are you a professional driver? Or just incredibly knowledgeable? Either way, it's great to have someone like you on this forum.

 

I'm not trying to prove you wrong, just want your opinion here. Don't you find running the same width front and back helps with the understeer problem? I autocrossed on the stock tires and understeer was horriffic. For the first track day I went to in the G I had 255's all around and it helped reduce the understeer quite a bit, but it was still prevalent (sway bar is on order )

 

Yep, you are correct. The understeer on the stock car is pronounced, and the stagger on the tire size is noticeable in its contribution to that. the engineers at Nissan did that on purpose, and it is proper, if not laudable, for them to have done so. I have a set of forged Volks fitted 275 all around, but I have to use a 3 mm spacer on the fronts to keep it from rubbing on the upper control arm. For autocross purposes I would definitely agree with you to go for a same size all around to help reduce (but not eliminate) that factor. Then go with some bigger sways and if you can, strut tower braces to help tune it out. An adjustment to the front camber to make it more negative will also help to reach neutrality or slightly positive oversteer. Unfortunately, as we know, when you understeer the only solution is to lift on throttle so that the car stops pushing and traction on the front is regained, and that really slows you down. At least with mild oversteer you can quickly flick some opposite turn on to catch and correct the rear end drift, and keep on power (and it is immensely more fun!!!!!)

Think about what the engineers at Nissan have effectively done here with our midship platform car. They took a concept that is capable of some amazing road course/track performance, and essentially "detuned" it. All you need to do to revert the platform to some really eye popping performance is to "undo" some of the idiot proofing they put into the street car. You have to be precise and clear about what you are doing, but it is not at all hard to take it to what the design is intended to provide at its purest. And that is go like stink and under control. The tire stagger is such an easy way to just load up on some more understeer to keep the typical driver out of harm's way, by making the car reach its limits at a much lower speed, a speed so low that the consequences of understeer not appearing until twenty or thirty miles per hour later...and that is probably what this stagger contributes to all by itself...would be far more dire. It is smart business. And safe.

Now, when you have the skills to handle a 300bhp car with neutral handling, it is a different story. But very few people in fact have that skill. Once you attain it, and make a couple of modest changes, the personality of the car changes dramatically. Here is a little video clip from the guys that built a lot of my car including the TT set up, if you want to see what the G35 can do on a track with some other great cars. http://www.govrt.com/VideoGallery/?V...ing_Willow.flv

 

Awesome stuff Eagle1...Here is a question for you...For road racing what are the pros and cons of supercharging vs turbocharging? I've been time Trialing my car for 3yrs now and for next year I'm thinking of picking up the power. I have all the basic bolt ons but your video has added fuel to my horsepower fire.