Ulrichw

I've been bitten by the bug and am thinking of investing in track wheels & tires.

I'm thinking of going with Enkei PF01s for the wheels, but trying to make up my mind of whether to go staggered or square.

Here are the pluses and minuses as I seem to have found:
+ staggered: Ability to go large in rear
- staggered: With 18 inch wheels you end up with different wheel diameters front/rear possibly confusing ESC
- staggered: No rotating front/back
- square: Need adjustable swaybars to make up for lack of stagger
- square: Switching back to stock wheels requires changing swaybar adjustment or living with understeer
+ square: More tire options

I'm primarily going to be running track days, but I was thinking if I get really enthusiastic, I might try to go for Nasa TT - any pluses or minuses in a choice now in terms of preparing for that?

I'm still planning on driving the car on the street, so I'm not looking at putting in a track-only suspension. This makes staying with the stock setup (or as close to it as possible) quite attractive.

Given that I'm interested in function over form, any recommendations?

StillIntense

Ulrich, when I did the same thing that you want to do, I talked with the guys at Rehagen Racing, who were very helpful. They recommended going square, with 275 width tires at all four corners. So I have the Boss 302R wheels (18") with Nitto NT-01 275 width tires. Did nothing to the suspension except set the dampers to 5 in front and 4 in the rear. With about 300 track miles on it I would say that is is very neutral, and needs only caster/camber plates for more negative camber to be really where I want it.
I would think that you would be very happy doing what you want to do with the car with this setup.

slidejob

Did you get 300 track miles out of one set of Nitto's? How did you like them? I'm thinking of getting a set for one of my cars? Thanks.

cloud9

I can tell you, the square setup with the stock suspension is less than optimal. I have 17 track days in the Boss running a variety of combinations. The first set I ran was Enkei PF01 18 x 9.5 45mm offset with 275/35/18 R888s all around. The car constantly wanted to snap oversteer in the corners. While it was drivable, it wasn't as easy to drive "flat out". I swapped to a staggered set of Enkeis that same day and immediately ran 2 seconds faster and the car is very neutral. It is NOT neutral with a square setup on the stock suspension. Others have tried it and found they needed to change the sway bars or it will oversteer.

The two setups that I previously posted below are what I ran most of this year. At the end of the day they achieved about the same lap times even though the R6s should have been faster. The wider stance and lighter weight of the Enkeis were the reason the Nittos ran the same lap times as the R6s.

I have been running Enkei PF01s 18 x 10.5 38mm offset rear and 18 x 9.5 35mm offset front. For tires I went with Nitto 555RII 305/35/18 rear and 285/35/18 front. They provide a stagger of 1.25" front to back. The rear tire height is 26.6" which is within .5" of the stock size so it keeps gearing close to stock. The staggered stance and wider offset really provided a much bigger base than the stock setup. The rear tires barely sit outside the fender and with the negative camber, the fronts are tucked inside the fenders nicely with plenty of clearance to the strut. I would have preferred to run an NT01 but they don't have those sizes.

I also have a set of Laguna Seca wheels in black with machined face (19 x 10 and 19 x 9) with 295/30/19 and 265/35/19 Hoosier R6s. Having that 285 up front was far better than the 265 R6, however the added grip of the R6 was basically an offset. The other thing about the Hoosiers is the rear tire is 26.1" tall which is a full inch shorter than the stock Pirelli even in a 19" radius. There are very few choices in 19" R-compound tires.

The net of it is that I will probably make my 302S wheels my street wheels and buy another staggered set of PF01s next spring. I'll run the Nittos on one set and 295/30/18 and 275/35/18 R6s on the other set to get a good comparison of the tires on the same wheel. I am resisting changing the suspension on the Boss until I start getting passed by someone in a modified Boss that has found a better setup. Right now I have the best of both worlds with amazing track performance and street performance. I know as soon as I start messing with the suspension for the track, I'll compromise the streetability.

Ultimately if getting the most life out of your tires is your goal, you should invest in two sets of wheels. That way you just replace the tires that are worn out. If you try to get by on one set of tires, what do you do when you are preparing for a two or three day event with approximately one day of life left on your single set of square track tires? Well, you either dump them and mount fresh tires, or run the risk of ending your weekend early. That's not saving money.

As far as upsetting ESC, I run with AdvanceTrac all the way off and I've had no issues. And finally regarding NASA TT, The Boss is TTA*. You are allowed up to a 295 tire. You would add 10 points for the R6s. The Nittos are +7 with and additional +1 for being 10mm wider than 295.

OLOABoss

Not sure of your experience level or how hard you are pushing the Boss but running a square setup will, IMHO and others who have run this setup, induce a lot of oversteer at the limits. I would not run square without either softening the rear bar or stiffening the front bar or a combination of both. I am a big believer in adj sway bars and if I had to chose I would take them over adj shocks.

Peter

CO_VaporGT_09

The nice thing about this decision, is if you don't like what you choose, you'll wear out the set you get, and have a chance to change your mind.
Also, if you do go with an 18x10 wheel which allows the narrower or wider tire, you have the option of getting a 275 or 285 all around, and if you don't like it can get the wider 295 or 305s and put them on one pair of wheels, then have those narrower tires to swap out when you run down the fronts.

All these tires they're talking about are quite pricey, though, so look into if you want a semi-racing tire like the NT01s, or R6s, or a max performance street tire like the NT05, Hankook RS-3, or Yoko Advans, which give up maximum grip for a bit longer life, and generally are more usable in the rain.

If you are seriously considering NASA time trials in the future, now is the time to review the points rules and make sure you don't make decisions you'll regret later (like buying an adjustable front or rear bar for tuning if you decide to go to a square setup -- the bar would basically be the price of one tire (or less), so not an expensive option if you go that route, and easily put on/taken off).

http://www.nasa-tt.com/

http://www.nasaproracing.com/rules/t...sification.pdf

http://www.nasaproracing.com/rules/time_trial_rules.pdf

Bars:
http://www.stranoparts.com/searchbym...D=80&ModelID=5

OLOABoss

Good call on reading NASA TT rules before doing any mods. As the Boss stands now TTA* you have 12 points to use. Tires are the most important thing and trump all other mods. If you run 285/30 18 R6 that is 9 points 1 point for Torsen if you have the upgraded diff and 2 points for sways. That maxes out your points but it is only 1 option and there are others.

Peter

Ulrichw

Thanks for all the feedback, guys...

Yeah I looked into the rules, too; The way I saw it, by going square I need to add the swaybar which is +2 points (and I do have the Torsen - didn't notice that in the rules, so thanks for that) vs. going with Gary's combo, which is 1 point for the 305 rear.

The NT555RIIs have a treadwear rating around 100, I believe, which means they're +7.

This would potentially leave room for upgrading the shocks. Of course in terms of bang for the buck (or the points, as the case may be) the R6s may be the better choice.

In any case, all of this is pretty hypothetical - I'm currently at a 2:15 lap at Thunderhill on the stock tires with very conservative braking due to some fade. My first steps before even considering competing are to improve the most critical component: the nut behind the wheel (Looking at TTA times I need to be somewhere around 2:00 to be competitive - so that's quite a ways to go)

I'm tending towards Gary's setup at this point - If I decide to go square, I can always get another set of 9.5 inch wide wheels and run 285s all around.

OLOABoss

Tires trump any other upgrade you can do. The 3 point spread between Hoosiers and the 7 points for R888/NT01 etc is not enough to cancel out the Hoosier grip. There is one option that might work, though the Boss is a heavy car, run Hoosier R6 255/35 18 square this would free up some points for Shocks/Springs/Sways. The 255/35 18 Hoosier is the same width as the 275/35 18 just shorter.

TTA* 7 points
Torsen 1 point
Hoosier R6 10 point
255 tire -10 point
Shock/spring/sway. 7 point (figuring a single/double adj shock non inverted non remote res.)
Adj panhard 2 points
Cat back exhaust 2 point

Total 19 points.

Peter

Ulrichw

Thanks for your analysis, and this very interesting tidbit! The 10 points seem pretty useful to get competitive. I'll definitely keep this option in mind.

I think I'm firming up my plan. First steps are brake ducts and camber plates. Next steps, wheels/tires - I think I'll go staggered to avoid having to do anything else to the suspension. Then brake pads/rotors (I'm currently on stock rotors with HP+ pads).

Based on how my driving progresses, I'll have to decide whether to go square. I think your formula may end up being the way to make the car the fastest, but since I'm still intending on driving the car on the street, I'm not sure I really want to go that far in car prep.

OLOABoss

If you want to keep it simple just run stock with either 285 or 295 tires and see how u like it. Some people have a hard time putting $40,000 + at risk on the track in TT and there is nothing wrong with that either.

Peter

Ulrichw

It's not the risk that I'm worried about - at this point I'm still 10-15 secs off of a good lap time, so there's no point in thinking about TT. I figure I'll continue to do trackdays until I feel comfortable enough with the car and its handling to want to take the next step.

What I don't want to do is switch to a no-compromise track suspension - I sold my STI partially because the ride was too uncomfortable on the street. I'd like to keep the Boss at something close to its current comfort level.

OLOABoss

Nothing wrong with fixing the nut behind the wheel still working on that myself.

Peter

roketman

I’m with the staggered set up with Hoosiers. Based on Ford development testing its the way to go.With the additional grip of the Hoosiers you may need to change the rear sway.

Ulrichw

Thanks for your feedback, but I'd like more info, please!

A few questions:
- What sizes did you go with?
- R6 or A6?
- Did you change your sway bars? If so, what did you go with? If not, what do you experience in terms of handling?

I'm not sure I buy the "Ford development testing" argument - My rationale? From what I've read, Ford started out with the premise that they wanted a staggered setup for aesthetic reasons: The aggressive appearance, the stance, etc. They then set out to balance the car as well as possible within these parameters.

I think a square setup could be made to handle just as well, if not better - the car is compromised by a forward-biased weight balance to begin with, so why would you want to start by making the front tires smaller?

BlackMamba03

In regards to you talking about the R6's, how are a 255 tire and a 275 tire the same width?

Ulrichw

Good pics here: http://forums.bimmerforums.com/forum....php?t=1202634

BlackMamba03

Hmm, that's weird that those two size tires are almost identical yet by tire size number they're 30mm apart.

StillIntense

Hmmm. I haven't had a problem with snap oversteer with the square setup. Probably don't drive as aggressively as some of you do, though I do have my moments. The Nitto NT-01s are a great compromise for me, since I drive the Boss to the track (150 miles one way) on the Nittos, and then use them on the track. They give me a bit of rain traction as well, just in case. Also like the square setup because I can get a bit more life out of the tires by rotating them.

OLOABoss

History lesson SCCA AutoX'rs lobbied Hoosier for that size so Hoosier took the 275 mold and shortened it a smidge and Hooray we now had a 255 that was as wide as a 275. Who said anything about truth in advertising. That is probably the biggest loop hole tire wise in NASA classing.

Peter