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Things that were new at Chuckwalla:
G-Loc R18 front.
4" splitter and new airdam.
APR GT250 Singular AeroWing kit.
Brakes were awesome. I have fallen in love with the R18 pad in Snoopy and Bullet. Waited for my R10s to wear out before switching over. I love the added bite. I have a stock 1.8 non-sport brake system for NASA points, so the higher mu means I have to stand on the pedal less to get the same bite. That allows easier modulation since I am not flexing my leg, firewall, etc so much.
The car is still on 1000/500 springs, stock bars.
I am going to drop down to 900lb fronts and add back the RB 54107 and 14mm SPM bars to make it even easier to drive/fine tune. I also want to cut some mor eout of my doors and look over the car for other weight.
Yas. Everything is just better with that aero package, I still feel like I haven't gotten used to how hard I can stand on the brakes at higher speeds now.
I'm on 1000/500 right now with the SuperMiata bar kit, anything in specific that prompted you to want to go back down to 900 in the front?
Yas. Everything is just better with that aero package, I still feel like I haven't gotten used to how hard I can stand on the brakes at higher speeds now.
I'm on 1000/500 right now with the SuperMiata bar kit, anything in specific that prompted you to want to go back down to 900 in the front?
I don't own the APR foil, It was Sean from GWR's. I had borrowed it for Taxi and SLB. I won't have this aero package permanently as i'll be going back to an airdam only, BBFW spoiler package for SPM S2, so 900/500 works better.
Chuckwalla CCW video chopped. First time driving Counter. Would love some tips from the bros.
Big bobble entering the front straight is obvious, cost .200.
I pushed wide through the bowl, cost me .165.
Still my fastest lap. second session golden conditions. Got hot and windy later.
No other major deltas to other laps. I ran a bunch under 2:02 so I have lots of comparison sectors.
hah. Not just you. I’m adding ballast for racing as is, I’d like to add a bunch more to bring the MOI inward from the ends of the car.
Things on on the chopping block:
headlights
wiper system
trunk webbing/latch/hinge
hood latch/webbing
door innards(keep crash beams for w2w)
switch to lighter Supermiata Crossflow rad
I think I can get well below 2200lbs with driver pretty easy.
Also on the menu is a safety gear refresh:
-Halo seat. My Sparco Evo is well past due. I added a back brace in 2016 to get up to NASA tech minimum.
Considering Sparco Circuit II and OMP HTE-R400. Waiting on Vegas to get back so I can see/test the seat fitment in that car. (It’s also an NB set up for a rearward seating position for Emilio. He and I like similar recline and leg-pedal distance, I just need more steering wheel spacer.)
-Fire system:
2 nozzle system mandatory for Supermiata 2018. Good idea anyways.
-Relocate my master kill switch and maybe add a secondary activation.
Most of of my guesses were spot on. Targeting 15.5:1 was good. The class max is 14:1, but miatas get a couple hits due to superior suspension design(upper A arms +.7) and light weight(+.3 or .4), bumping them to 15.0 or 15.1.
Adding a 4” max splitter costs another .5.
My plan is to run light, since I don’t have much horsepressures. This means I’m allowed a max section width of 226mm.
So I made a Go/No go gauge from the NASA template.
Looks like im good to run 205 R7s under 2400lbs as long as I mount them on 8” or narrower wheels.
So that’s what I’ll start with.
14:1 base
+.7 A-arms: 14.7
+.4 under 2450lbs: 15.1
+.5 splitter, 4" max: 15.6
2250lbs(Less than this gets another .1 P:W hit)
144 average whp (I make 143 peak now, might add a BP5A cam to reach ~148 peak, 144 average)
205/50/15 Hoosier R7
15x8" wheel to pinch them down to 226mm. Otherwise I have to run over 2400lbs.
GT250 wing
900-1100/500 Xidas
RB 54107 front, 14mm SPM rear sway bars.
1.8 Brakes, GLoc R18/R10
4.3 Torsen
lap time expectations:
Chuckwalla 1:58
Buttonwillow CW13 1:54
ACS Roval 1:56
1100/500 would be the go-to setup on 205 R7s on an ST car.
My car is an S2 Supermiata, with S1 aero added for nasa. I still need to look at what events with each series I want to drive. Not chasing anything other than fun. I like the ST rule book and have tires laying around. Not making a serious effort unless something flips and I decide to build a motor and tow to Austin, so I’ll have some compromises built in to allow double dipping back to SPM S2.
225 RC1 will hate me for running the current 1000s and adding a big front bar in S2 trim.
"We are going to revise the +0.3 Mod Factor from 200 TW non-R compounds tires to just 100 TW or higher."
This is pretty huge, and again helps a Supermiata cross over. lol
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...
Lets look at 2250lb options first:
14.0 P:W Base
A arms +.7
>2250lbs +.4
100TW+ -.3
14.8 P:W allows 152 average
Splitter +.5 makes it 15.3 and 147 average.
Hoosier R7s +.3 makes it 15.6 and 144 average
If I decide to build a higher power motor and run at 2450+:
>2450lb options.
14.0 Base
+.7 A arms
+.3 >2450
-.3 100TW+
14.7 P:W allows 166.7 average.
Splitter +.5 brings it down to 15.2 and 161 average
Hoosiers +.3 bring it down to 15.5 and 158 average
I am still not sold that .3 P:W is worth giving up Hoosiers, but it is interesting.
That's cool to them actually make changes for 100tw. I still think the delta between RC/Rival-S(-0.3) vs R7 to A7(-1.0 in ST4) isn't quite real-life accurate.
With your experience does it make sense to go the Hoosier / aero / low hp route or no aero, rc1, 175hp dyno curve for st5?
if it's go 175, could you take a trackspeed kit and get it to produce a 175hp plateau? Like a no aero supermiata s1 car on 8" 225 RC1?
Andrew thinks an alternate wast-gate spring will allow his 6258 kit to make 175 average. (If it only gets down to ~180, you can shape the curve to bring the average down to 175, so there is some flexibility in ST. In PT you have hard peak caps, so we almost always left 2-3% on the table.)
Over 2400lbs, ST5 allows 257mm of tire. Thats a 225 R7, or a narrow 245 like RC1/RS4.
I think that fastest car is a 2451lb, 225 R7, with aero. This build runs at 15.5:1 and 158 average. I don't know the best/easiest way to get 158, but it's probably simple cams in a healthy NB motor.
That's cool to them actually make changes for 100tw. I still think the delta between RC/Rival-S(-0.3) vs R7 to A7(-1.0 in ST4) is quite real-life accurate.
Agreed. It's not enough, but it helps close the gap for regional events or when you're saving the R7s from the heat cycles.
Andrew thinks an alternate wast-gate spring will allow his 6258 kit to make 175 average. (If it only gets down to ~180, you can shape the curve to bring the average down to 175, so there is some flexibility in ST. In PT you have hard peak caps, so we almost always left 2-3% on the table.)
Over 2400lbs, ST5 allows 257mm of tire. Thats a 225 R7, or a narrow 245 like RC1/RS4.
I think that fastest car is a 2451lb, 225 R7, with aero. This build runs at 15.5:1 and 158 average. I don't know the best/easiest way to get 158, but it's probably simple cams in a healthy NB motor.
Don't forget to have a '-10 HP' tune or a bunch of ballast handy for when you get put on the NASA MCE Dyno..
11-22-2017, 05:48 PM
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