NASA Points Conundrum (TT)

[R13]

So, looking towards the off-season. I've more or less established where I fall in the TTB field this year, and I've got some work to do: ~3s or so at CMP and ~6s at Road Atlanta eek vs. the usual suspects....who unfortunately are the current record-holders for TTB on those tracks.

Some good news: Those time gaps are with me on street tires vs. some hobos in gutted Civics/E36M3 with A6s and Aero
More good news: From where the car sits now, I have 10 points to play with (before submitting a dyno re-class form to hopefully free up more)
The Question: What do I do with them?​

A minimum of 5 of those points will go towards stickier tires (NT01 or R888 so I can still drive to/from events on them since I don't trailer).

So, with the remaining 5 points, I could (within the scope of things I'm willing to do to the car/have a budget for):

• Increase the WIDTH of the better tires by 20mm (275 vs 255 in the rear with a 235 up front), and take ~20lbs out of the car
• Leave the tire width as-is (255R 215F) and drop ~60lbs out of the car (light battery and/or lighter bumper beams most likely)

I know tires are king, but I also know that the rotating mass and gearing change from a 275 rear isn't necessarily a benefit in the scheme of things vs. a 255 for a stock motored car. Chucking weight out will mean the skinnier tires (and brakes and engine) will have less mass to contend with.

Opinions on where I'll get the most mileage there?

(edit: Car already has coilovers, headers, exhaust, HFC, and sway bars)

 

[illwillem]

Personally I would stick with the widths you have now, but get the NT01's not the r888's since your driving to and from the track. I would remove/replace the rear crash beams then get a lighter battery. The beams are the farthest point from the inertial center past the axles Rear being the biggest payoff, then the front. the battery is heavy but sits in the center of the tires low in the chassis so it will count for less. Make sure you replace the front bar with something ridgid if you do lose the beam since that ties the frame rails together. I used a 1/8 steel bar that my splitter also mounts too.

My car is stock motored car and have done everything in that order. I found my biggest time to be from tires compound>weight>more rear tire.

its difficult to tell from your post but do you already have the 235 up front? not sure if you can get nt01 or an r888 in a 225 width.

 

[R13]

Most recently, I've run a 235 in the front, but the same width limit applies to any corner. a 255 costs me nothing points-wise (even running 255 square....which I know won't fit, but for example). Anything wider than that on any corner costs.

I can get a 225/45 17 in either of those tires, but doubt they'll fit without too-much rubbing as they'd be taller than the 235s, and those already rub more than I'd really like. 225/40 would be ideal, but doesn't exist for these or any comparable tire.

 

[9doors]

When you did the math you did take into account the lousy 14pt penalty we take, correct? I ask, since I blow right out of TTB with my setup and am going to have to run TT3.

 

[R13]

When you did the math you did take into account the lousy 14pt penalty we take, correct? I ask, since I blow right out of TTB with my setup and am going to have to run TT3.

Yup, that's including the ** from the TTC base.

Right now, I'm eye-balling some RPF-1s with NT01s as what I'll try to run next year. I'm also planning to float a dyno reclass form past the TT director to see if I can free up any more points, or allow more significant weight loss on account of my craptastic (for TTB) power/weight ratio (11.34 right now: 3030lbs / 267whp)

What knocked you out?

 

[9doors]

unfortunately i threw away my calculations, but all of the little things add up.

 

[DDozier]

What are your Road Atlanta times?

You will be forced to run the 235/40 up front, and stick with the 255's in the rear. There is something else to consider with the new NT-01s, you will have to worry about the front tires rolling over unless you either raise your spring rates or run a much stiffer front bar.

I did run the 205/40/17 NT-01s with a 7/8" front bar set the camber to max in the front and they will outlast your rears two to one. The same setup with the 235/40/17 and the fronts wore very quickly on the outside shoulders. So not sure if you have enough points to add more spring or bar otherwise stay with the 205's. still a big move up from street tires.

- - - Updated - - -

RPF-1s with NT01s as what I'll try to run next year.

Take a look at the TSW rotary forged wheels. They have perfect figments for a 17/8.5 and 17/10 or 18/10. They are light wheels, they make three or four different styles and they are Cheap.

TSW interlagos in a 17/18 setup with NT01s will be under 2 grand. If you like them PM me and I can get you the offsets that work. TSW does not have the correct info for what fits best on our cars.

 

[docjohn]

illwillem has done a lot of good work on his car and is methodical in his approach so his opinion is worth considering.....but if the difference in weight allowed to remove is only 40lbs between the 205 or 215 front and 255 rear combo vs the 235/275 nto1 I would choose the latter.Just be careful with the 235 nto1 they run wide and you really need to match them to a wheel that has a very specific offset .I chickened out and went with ra1 with my rpf1 17/8 and it still rubs the plastic liner along the lip.

 

[stuntman]

IMO i'd go with the 235/275 and 20lb weight loss rather than 215/255 with -60lbs.

Admittedly i'm not up to date with NASA TT rules so there may be better opinions out there but:

-What aero do you have? (front bumper model, rear wing, etc..)
-What coilovers and spring rates?
-What swaybars?

-How many points are the swaybars worth? Can you get some points back if you use a stock rear bar and only an aftermarket front?

Either way I agree with Bellwilliam - get an aluminum rear bumper and if you need to, you can always add weight somewhere else on the car.

 

[g3driver]

We should all as a group petition to reclass the car. I have tried for years and they will not do it. I think the car should be a TTC with only 1 astric. Good luck! BTW if you are using KWV3 you take less points than other coilover because they are not as wide and no external res.

 

[R13]

IMO i'd go with the 235/275 and 20lb weight loss rather than 215/255 with -60lbs.

Admittedly i'm not up to date with NASA TT rules so there may be better opinions out there but:

-What aero do you have? (front bumper model, rear wing, etc..) None (Stock '92 bumper / Rear wing)
-What coilovers and spring rates? KW V3 / 343# springs (spring rates are free, FYI)
-What swaybars? Dali "Type Q" F&R. Swaybars are collectively 2 points regardless of how many and endlinks are not additional.

-How many points are the swaybars worth? Can you get some points back if you use a stock rear bar and only an aftermarket front? Nope

Either way I agree with Bellwilliam - get an aluminum rear bumper and if you need to, you can always add weight somewhere else on the car.

FYI, I'd considered adding a splitter and/or small/type-r-ish wing, but aero mods are high point-cost:
Splitter = 3 points
Rear wing = 4 points
Canards = 2 points
diffuser = 2 points
Adding a flat bottom behind the front axle = 5 points

 

[ryneen]

I agree that the NASA classification to our car is a bit unfair, however, with the few mods that my car currently has, it is still competitive in terms of lap times. For example, at Laguna Seca I've ran 1:40.64 which would put me as 3rd fastest out of all the cars in TT3, TTB and TTC combined for their most recent event http://www.nasa-tt.com/Norcal_Regional_Results/p2047_articleid/257

My time is only 1 second off of the track record for TT3 and I still have room to add more mods within the TT3 classification. Here's a video where I have a few 1:40.xx laps at Laguna Seca. TT3 track record is 1:39.44. With new NT01 tires alone, I know I can get to mid/high 1:39's. The NSX is competitive at Laguna Seca unlike Buttonwillow. Not sure why. http://www.youtube.com/watch?v=UH6Baye-fuk

 

[stuntman]

FYI, I'd considered adding a splitter and/or small/type-r-ish wing, but aero mods are high point-cost:
Splitter = 3 points
Rear wing = 4 points
Canards = 2 points
diffuser = 2 points
Adding a flat bottom behind the front axle = 5 points

Ok to recap. You have 10 points to use.

5 points: used to upgrade to NT01's (215/255).

Options:

5 points: Remove 60lbs
5 points: go to 235/275 and remove 20lbs
3 points: Splitter
4 points: Rear wing
2 points: Canards
2 points:diffuser
5 points: Adding a flat bottom behind the front axle

-Can you use an NSX-R wing without any points since it's a STOCK component?
-If you take the 4 points for a wing, can you use ANY wing?

 

[R13]

NSX-R Wing is not free (i did ask about that specifically since NASA has occasionally been more liberal about "trunk kits" than SCCA)

The wing could be any wing that complies with the other rules regulating wings (can't be more than a speficied amount higher than the roof, can't be wider than the car).

I'm a little hesitant to go big on the aero given I don't have an accusump (just a baffled pan right now). That said, Accusump / oil coolers/ etc would be point-free if I did go that route.

 

[9doors]

My time is only 1 second off of the track record for TT3

This is simply AWESOME.

 

[9doors]

What knocked you out?

Ok, since you did ask, (others have as well) for the record:

A. Tires
NT01 +7
275mm +4

B. Weight Reduction
I haven't weighed her so I don't know my status here compared to the 3153

C. Engine
B-Line CAI +1
CT Headers +2
Angus' Hi-Flow Cats +1
Prospeed muffler +2

D. Drivetrain
OS Giken LSD +1

E. Suspension
KW V3 +2
Dali "Track" front swaybar +2
Suspension bushings +2

F. Brakes/Chassis
Tarox brakes +2
Chassis-stiffening +3 (too many to count...lol)

G. Aero
Flat bottom rearward of front axle +5
Rear diffuser +2
GT rear bumper +1

37pts + our 14pt penalty = 51 = 2 classes = hello TT3...

oh, and there may be even +2 more for the Type-R hood in aero since it does provide downforce...

 

[illwillem]

This is simply AWESOME.

seconded, thats effing cool.

 

[stuntman]

NSX-R Wing is not free (i did ask about that specifically since NASA has occasionally been more liberal about "trunk kits" than SCCA)

The wing could be any wing that complies with the other rules regulating wings (can't be more than a speficied amount higher than the roof, can't be wider than the car).

I'm a little hesitant to go big on the aero given I don't have an accusump (just a baffled pan right now). That said, Accusump / oil coolers/ etc would be point-free if I did go that route.

The baffled pan probably lay does more than an accusump. Accusumps only help to extend the inevitable, of give you a few second cushion before starvation. At the end of the day its your call but you're probably fine with a good baffled pan for a wing on r-comps.

 

[R13]

This is simply AWESOME.

+1!!

(Also, yeah, that's a lot of mods, lol)

The baffled pan probably lay does more than an accusump. Accusumps only help to extend the inevitable, of give you a few second cushion before starvation. At the end of the day its your call but you're probably fine with a good baffled pan for a wing on r-comps.

Iv'e got a little off-season science project planned to see how I actually will feel about putting more g-load on the oil supply in a stock-ish pan.

I gather though that you think a rear wing might be worth-while? I guess I have experienced more oversteer through high speed turns than understeer.

 

[stuntman]

+1!!

(Also, yeah, that's a lot of mods, lol)

Iv'e got a little off-season science project planned to see how I actually will feel about putting more g-load on the oil supply in a stock-ish pan.

I gather though that you think a rear wing might be worth-while? I guess I have experienced more oversteer through high speed turns than understeer.

I'm thinking 215/255 NT01 and the widest wing possible (with the longest chord length) would probably be the best combination. Also get a 575lb front spring in there.

 

[9doors]

Get one of these...

http://www.evasivemotorsports.com/m...OLTEX-GT-WING-4-NSX&Category_Code=VOLTEX_WING

 

[DDozier]

I'm thinking 215/255 NT01

NT01 Front tire sizes:
205/40/17 - no rub and better than any 215 or 225 street tire but will suffer under braking
215/45/17 - at 24.65" tall may be too tall for the NSX
235/40/17 - at 24.40" is on the tall side and will rub the inner fender liners if wheel offset is not perfect and you are on soft springs or soft bar

Most run 205/40/17 & 255/40/17 or 235/40/17 & 275/35/18 with the NT-01s. I run the 235-275 setup and find them to be a great compromise between wear and price.

Dave

 

[R13]

235/40/17 - at 24.40" is on the tall side and will rub the inner fender liners if wheel offset is not perfect and you are on soft springs or soft bar
Dave

What IS the "perfect" offset? I'm guessing it's somewhere in the +40 - +45 range, but was curious since I'm also wheel shopping to accommodate my tire change (will keep a set of "normal" tires on my Advans for driving around/street-tire autocrosses, etc.)

I was looking at the section widths and there wasn't much between the 205 and 215....BUT I've seen any number of bestmotoring videos (right, great information I know :\ ) where they're running a 215/45 on the front with one of those Advan R-comps.

 

[stuntman]

Get one of these...

http://www.evasivemotorsports.com/m...OLTEX-GT-WING-4-NSX&Category_Code=VOLTEX_WING

I'm not sure if I would go with the Type 4 or the dual element Type 5 (scroll down on the link below):

http://www.nsxprime.com/forum/showthread.php/125412-Voltex-Carbon-GT-Wing

I'm starting to like the 2D design of APR's GT250:

http://www.aprperformance.com/index.php?option=com_content&task=view&id=324&Itemid=44

NT01 Front tire sizes:
205/40/17 - no rub and better than any 215 or 225 street tire but will suffer under braking
215/45/17 - at 24.65" tall may be too tall for the NSX
235/40/17 - at 24.40" is on the tall side and will rub the inner fender liners if wheel offset is not perfect and you are on soft springs or soft bar

Most run 205/40/17 & 255/40/17 or 235/40/17 & 275/35/18 with the NT-01s. I run the 235-275 setup and find them to be a great compromise between wear and price.

Dave

I ran a 215/45 before which has a radius of 0.125" more than the 235/40 which fits well and it's not terrible. 205/40 might be the better route though if you dont go 235/275.

 

[9doors]

I'm not sure if I would go with the Type 4 or the dual element Type 5 (scroll down on the link below):

http://www.nsxprime.com/forum/showthread.php/125412-Voltex-Carbon-GT-Wing

I'm starting to like the 2D design of APR's GT250:

http://www.aprperformance.com/index.php?option=com_content&task=view&id=324&Itemid=44

I've also been wondering about the Type 5, since Voltex directly mentions the NSX:http://www.voltex.ne.jp/english/pro_wing.html

I assume the trunk-mounted Gurney flap is still applicable and functional in the case of the Type 5? What are your ideas on the pros and cons of the 4 vs. 5?