Sleeper_08

This is my third season tracking my car and I switched from 285/40/18 BFG KDW2s to 275/40/18 Nitto NT01 R-comps for this season.

Last weekend was my first time on R-comps and I am lapping faster but not as fast as I hoped.

Presently I'm running -1.5 front camber and about 1/8 toe in. I seem to remember reading somewhere that the R-comps work better with more negative camber.

Your suggestions on what to set the front end at, remembering that this is also my "daily driver", would be greatly appreciated.

marcuskeeler

What is the car not doing Colin? is it understeering, oversteering, unstable under braking? Where do you need the car to be faster or where is it you feel it is lacking?

steelcomp

Are you taking tire temps? Those will tell you what you need to know. Typically more traction is going to cause more weight distribution, more body roll, and more suspsnsion deflection, given everything else the same. I know some guys run as much as 2* with Rcomps, but not knowing their suspension vs. yours, it's not a fair comparison. Each car is going to be different. Personally, I'm running 1.6* with 275-40 PS2's and they wear perfectly even as a DD. Never got a chance to temp check them on the track, but I'd guess thyey could use more neg. under track conditions. (1.5 is still within stock spec limits) I would imagine you're going to want more neg. camber, but again...invest in an inexpensive IR temp gun and read your temps immediately after your laps. If your outside edge temps are a lot higher than your inside temps, add some camber. If the opposite, take some out. If the center of your tires is hotter than the outsides, too much air. If the opposite, too little. This is a generalization, and you have to also apply the type of track your're on, but a good basic rule of thumb to follow.
Also wouldn't run that much toe...just barely a 1/16" is what I run. YMMV there, also.

Just to add as an example...I also run 255/45 Cooper Zeon's on my stock 18" Bullits, and with the same camber settings, they wear on the inside edge where the PS2's wear perfectly even. The Coopers don't generate the same traction and don't cause as much body roll and suspension deflection as the PS2's, therefore they don't need as much neg. camber.

marcuskeeler

Good advice. An IR temp gun isn't really the best temp sensor system to use for tires though, you want to be measuring the rubber beneath the surface for best results, to see where the rubber is really being worked.
A tire temp probe is the way forward when you're on the hunt for ultimate tire efficiency.

steelcomp

Agreed...the IR is just a quick and easy way to see where things stand for the weekend warrior. A good temp probe is arguably one of the most valuable tools in the pits.

Import_Slaya

Set your toe to dead 0 for your street setting. Assuming you have camber plates, as you add negative camber for the track, you will gain ~1/16" of toe-out. You will be pleasantly surprised at the difference some toe-out makes with our cars during initial turn-in. I've run 1/8" toe-out at the track and actually liked how the car turned-in more than with 1/16" toe-out.

For camber, depends on your tires, springs and sways (and the track, among other things), but -2 degrees of negative is the minimum to aim for with your tire. I usually run anywhere from -2.5 to -3.0 degrees of negative at the track (with RA1's, NT01's and now on the NT05).

steelcomp

Hows the high speed stability with toe out? How about hard braking? I've wanted to try it, just haven't gotten to it.

Argonaut

Like Marcus said - what is the car doing? When I switched from Falken RT615s to NT01s the first thing I noticed was more understeer. The car had better overall grip but understeered quite badly at the limit. I played around with air pressures and shock settings but couldn't balance it much. I also adjusted my driving style a bit - with an understeering car you can "toss" it into a corner very aggressively and not worry about losing the rear. I retired the car from track duty without having tried additional camber or a stiffer rear bar - the two things that would have been next on my list.

Sleeper_08

Thank you all for your considered responses.

Marcus

The short answer is that the combination of the car and driver is not going as fast as I would like. Especially when compared to a certain silver Mustang running "only" NT05s

My backside is not terribly sensitive but it does feel like it is understeering more. After two hours tire wear was just to the tips of the sidewall diamonds on all tires except the left front. Tire pressures were around 39 hot front and rear.

The left front has worn the diamonds right off. The track we were running, TMP, seems to be hard on left fronts.

With the NT01s I was expecting to see cornering lateral Gs above 1.0 G and I only touched 1.0 G once. There was a fair bit of time at 0.9 G. On a flat track should these tires corner at better than 1 G?

My plan is;
1) take the car in tomorrow and have the front set to - 2.5 camber and 0 toe
2) try to borrow or buy a needle type pyrometer by Friday or as a minimum get an infra red one
3) My brother and I are taking the car to Mosport, a high speed track, this Friday. He has over 10,000 laps there and will set my new Mosport benchmark on the NT01s. Last year on the KDW2s he got down to 1:42 and my best was 1:48.
4) The next time Marcus and I are TMP, if it is OK with him;
a) have him drive my car for a few laps
b) put my data logger and video on his car for a few laps

Import_Slaya

When I was running 1/8" out, above ~125-130 or so it started feeling a little twitchy. Under hard braking especially it was a little more noticeable. Nothing terrible, but enough where I wanted to just try a little less.

Now that I'm on the West coast and the tracks don't have quite the same top end speeds, I'm actually missing that extra bit of toe out and will go back to 1/16" toe-out for the street (1/8" for the track) next time I have a chance to string the car.