For those in points-based classes (TT, PT, etc.), if you had the option of running either 20mm wider tires and no aero (no wing or splitter), or 20mm narrower tires WITH a wing and splitter, which would you choose?

Important details:
-~230whp FWD car
-Nitto NT01 or Toyo RA1 tires
-225/45 vs 205/50 sized tires

 

It would depend. Full aero in NASA TT/PT is +10 pts (modified front fascia, splitter, and wing) where depending on your base class, 225 tires could only be +1 pt (TTF), or +7 pts (TTG).

What base class are you in? I know for S2000's a rear wing makes a world of difference, no clue with FWD aero through I imagine it's similar.

 

this would be way more beneficial.

Run a 205 Hoosier R6 for the same points you would take for a 225 Ra1.

The 205 hoosier R6 is faster, and is actually wider then a 225 Ra1.

 

Base class = TTB, so my base tire size is 265.

I can probably get by without the "modified front fascia" though it wouldn't be ideal for a splitter.

Jimmy, your suggestion is excellent. Somehow the points work out such that I could add a wing with the Hoosiers. The rear of the car is where I feel it needs the most aero improvement, so that would be perfect. Because of my base class, I actually "recoup" more points by using the 205 Hoosiers vs. the 225 Toyos (-6 for Hoosiers, -3 for Toyos). Score! Somehow I totally f*cked up my calculations before this...

Alright, now on the purchasing side of things...
WTF are "Spec Miata R6s" and why are they $45 less per tire?

 

The 205 Hoosiers are going to have way more grip than the Toyos. 205 R6 vs 225 RA-1 is a no brainer, other than the cost. Winning helps with the cost if things stay the same this year.

If you are looking to spend points they are always, IMO, best spent on weight. 6 points is 80 pounds on what I'm assuming is a weight somewhere between 2100 and 2300. Thats at least one second a lap.

Lighter weight helps in all aspects of performance, I'm currently de-modding the heck out of my car.

I think if you want to get anything out of the +3 for a splitter you are pretty much stuck with doing the +3 front spoiler. As I understand a splitter is more effective the closer you get it to the ground.

You could try moving some static weight to the back if you are having rear grip issues. What's your static F/R weight distribution?

 

It is how it works out on most cars.

 

Because I have an engine swap, the car is classed based on weight and dyno chart, so I can't really play with weight (other than moving it around). The car is fairly light anyway, running at 2365 with driver. Static F/R distribution is ~62/38 if I remember right. The problem I have in the rear is high-speed stability, like the uphill esses at VIR. It just feels a bit loose near the top of the hill, but everywhere else is pretty good.

The cost is something I'm going to have to consider for now, until the contingency thing gets figured out. $840 for a set of Hoosiers vs. $600 or so for RA1s is a BIG difference. I've found a few other options ($750 Hankook Z214s, $580 BFG R1s), but I haven't been able to find much firm data on how they compare, or how long they last.

 

If the choice is strictly between tire width and aero, I would probably go with aero for TT and wider tire for PT.

Aero stablizes the car and inspires confidence. You only need one or two good laps to count in TT. The 205's could be fast, especially in such a lightweight car. For PT, if the race is 20+ mins long, then the ability of the tire to withstand heat would be more crucial.

 

Ah, another good point Wai, thanks!

 

This is one of my gripes about the Nasa reclassing system... why can't they allow the drivers to spend points on weight just as if they had an ordinary base class? I really don't understand what the difference is

So... everyone who reclasses their car based on dyno readings/comp weight, can no longer fine tune their points total in regards to weight, unless they want to change by a whole *(magnitude of 7 points).

 

i was given 3 or 4 different weights and HP levels that i could run at, more if i so decided.

 

So with the dyno reclass, you don't have to take any engine points unless you add something after the dyno? How does NASA figure out what mods were on your car when you dyno'd it?

 

Does not matter. You submitt a dyno number and get a new base class for the car. When you do your points you ignore engine and weight mods and just take points for suspension, tires, trans, etc. If you think about it this is what makes NASA PT/TT the best series in road racing. You can be competative in class with a worn out dog of a motor, saving HUGE cubic dollars. See where you run in an Improved Touring car with a 130k mile street motor.

You have to be dyno compliant when checked with either a dyno, or at track GPS monitoring. So you can basicly do anything you want with power as long as you do not go over the number you were reclassed at.

You can not use extra points for weight reduction after dyno classing because they are looking at a P/W number when they do the classing. However, Greg will give you a lot of choices. Basicly a range of base classes with weights for each one.

For example I have weights for base classes of PTE**, PTD, PTD*, and PTD**. Stinky, I said weight because 6 points is almost a * so you could just move the weight down and the base class up. Put the most rubber on the road at the lightest weight possible before worrying about anything else. My mod list this year is going to end up being Hoosier tires (going to try a 245 tire sometime this year) springs, shocks, rear control arms, spherical bushings, and thats it. Light weight rules.

 

thanks for the info!

 

adam, its all made simple for you in H2
but as wai said, in TT aero> tire width. why not try it both ways and see what you like better. granted you'll have to buy a splitter and wing that you might possibly sell, but that stuff should sell fairly easily. heck, it could even play into what track your at as to what set up you run (aero or tire)

 

I should clarify on my base class; its actually TTB* (turbo). I would almost definitely get slaughtered in TTA, knowing the cars in Mid-Atlantic. TTB I stand some kind of chance, and TTD (where the car is classed without the turbo) I feel I could actually be fairly competitive.

Other than the *, I have +6 for trans and LSD and +7 for shocks/springs/swaybars. Given that right there with a bare minimum I'm at +20 and a bump up, I have to do something to lose points, and the only way to do that is go down significantly in tire size. In the future it might be fun to try throwing some SERIOUS rubber at the car (275s or something stupid like that) and get serious about aero and see how it does in TTA, as I know there are some other Hondas running in it in other areas.

I'm on a tighter budget this year (and not doing too many events), so I kind of have to pick one and stay with it...for this year. From a theoretical point though, you're right Spence, it would be something to do some testing on to really figure out what works best for me.

H2 = $$$$$, TT = $$

 

Please explain your logic.

Safety, same, I'm assuming you have a cage in your car if you are running TTB and since everyone is all about safety these days I'm sure you have a suit, helmet, HANS and required safety gear you'd use if you went wheel to wheel.
Tires, same
Entry fee, same
Getting to and from the track, same
Vehicle prep, same
Fun factor, H2 by a long shot.

You can race on a budget, H2 has a diverse field and you'll have someone to race with if you are at the front of the field or the back of the field. Keep your car registered and just drive it to the races, that's what AAA premium or a credit card are for. If the car gets that balled up rent a Uhaul truck and I'm sure we can get enough guys to lift the remains into the truck.

Z

 

Mostly correct, with one big exception: entry fee. Instructor = free TT entry, minus transponder rental. I would also have to have the cage redone for H2, and that is way outside the budget right now.