FatKao

I keep typing RR like a derp, they are RA-1s. I'll measure both @ 23 tomorrow.

Neversatisfied

I know we're on the subject of tires but Greg emailed me back. Sport brakes are ok on an NA but no go on subframe swap

loudes13

I always hated the idea of tearing my sport brakes off my ‘01. The stronger 6 speed is interesting too.

Arca_ex

iTrader: (2)

Printable tire templates are now on the website so you can trace and cut your own.

https://nasaproracing.com/rules/NASA...l_Template.pdf

FatKao

Why would you? All NB2s are the same to PT. You can run sport brakes on an 01 because they are BTM on 03+.

Midtenn

iTrader: (15)

So maybe a market for 15x8.5?

doward

No. 8.5 still too wide.

Sticker 205 R7 on 8” at 30psi:






Meets the “equal to” 226mm rule for under 2400lbs.

FatKao

I got 234mm for a SM7 @23mm on 15x9s, same pressure as before and it's a ~1/32 or 2/32 tire. The RA-1 is pretty much new, one wet race on it.

Midtenn

iTrader: (15)

I saw your build thread post after I made my comment and realized that. With a screaming baby in one arm, I was too lazy to edit my post. Thanks for all the information. I'm doing a slow build S2 car in the hopes WRL actually does something with the ruleset. If not, it looks like I'll be going this route.

cuonice

A-arm equipped cars, like the Miata, will have to take -0.7, but many strut based cars will end up with the below modifiers which cancel out the a-arm penalty. I can't imagine too many E36 running on stock camber arms, though I suppose they could.

Replace, modify, or remove control arms, camber arms/links, toe arms/links = -0.5
Non-OEM metallic and/or spherical design replacement suspension bushing modifications on control/camber/toe arms/links, panhard rods, watts links, and torque arms = -0.2

At least for initial testing, I plan to run my car at 2450/160ish; airdam/wing, no splitter, 205 or 225 R7 on a 9". Tempted to try 2280/148 since that is exactly where my car is now stripped of ballast, but I prefer the way the car scales/handles with some ballast weight on the right. Regardless, any configuration is going to produce a similar lap time and end up being track-dependent.

-Aaron

FatKao

You'd have to use a metal bushing to hit that, just run poly/delrin like we do today on the front lower arms.

cuonice

Metal bushing would get you the -0.2. The camber arm is still -0.5 with delrin/poly.

-Aaron

doward

From what I've seen E36/46 guys post, it sounds like they can run 800-900lb rear springs with OE camber and get the performance they need. It would be an ST5 specific setup, much like the NA/NB miata on stock bars in PTE, but it would work to give them a .7 advantage.

There are several BMWs in existence that can port over to ST5. It will be interesting to see their pace compared to what we know Miatae should be capable of.

cuonice

Robert Manoucherhi, in addition to his PTE Miata, has a GTS2 E36 (national level prep) that would cross over nicely to ST5. We'll have to do some back to back testing between the two cars once the Miata is up to ST5 standards. I think they will be very close. Probably rather be in the E36 at a track like COTA! But Miatas (and their owners) have a way of sneaking up on you...

doward

"We are going to revise the +0.3 Mod Factor from 200 TW non-R compounds tires to just 100 TW or higher."

Getting .3 P:W credit back for running 225 RC1, NT01, Rival, RE71R, etc is a good thing. It completely pays for the comp weight penalty if you run at >2450lbs...

This is pretty huge news, but not quite enough to shift the tire balance. It does create a pretty attractive build option, that will be absurdly fast at the right track:

>2450lb comp weight.
14.0 Base
+.7 A arms
+.3 2450lb+
-.3 100TW+
-.4 BTM aero (No airdam/wing)
14.3 P:W allows 171.4 average whp.
Airdam/wing +.4 brings it down to 14.7 and 166 average (deletes BTM aero credit)
Splitter +.5 brings it down to 15.2 and 161 average
Hoosiers +.3 bring it down to 15.5 and 158 average

Even on a tight track, I think 225 R7s are worth more time than being 150lbs lighter on 205s. So being over 2400 is wise. Being over 2450 earns you a .1 P:W credit.

Therefore, I still think that fastest all-around car is a 2451lb, 225 R7, with aero. This build runs at 15.5:1 and 158 average.

FatKao

Is it possible to build this with a GT255R?



A motor with a high enough redline, a small enough turbo, and a class with relatively tiny HP maxes you can trip his max HP in some useless part of the power band then run way more than you should where it matters. The 'dyno' posted is based on some random MT.net GT255R dyno up to 3,000 RPM and is 149 avg whp by the rule book.

flier129

iTrader: (7)

Anxious to see the best route to 158 avg hp

Also, just to discuss it here, do you think a 225 R7 will be faster than a 205 R7 on power tracks, such as Road Atlanta at a ~158 avg/2451lbs?

OGRacing

iTrader: (1)

I do the same in TTU.

Savington

iTrader: (31)

With some really bitchin' wastegate strategies or a second external wastegate you can get close to that, but Greg just tweaked the ST4 rules to state that FI cars may only use 3 points plus the max RPM, same as <6000rpm cars. That rule might come to ST5 as well.

FatKao

Eh, then you only get 9 free whp instead of 11.