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At Chuckwalla I was a mess swapping wheel sets between classes. 225 RC1s on 9"s for ST, 205 R7 on 8"s for TT.
HUGE swings in weight between the wheelsets, so I was way overweight with the RC1s.
For Buttonwillow I mounted up my last set of freshies on a second set of 15x8, this time in our new TiO2 finish.
New layout for me, 13CCW. I've driven 1 and 25 CCW, as well as 13CW, so it was pretty easy to put together.
For warm up i scrubbed in the stickers to let them cure overnight, with plans to race them on sunday. Ran a 2:02.9x, good for p2 grid spot for qualifying.
Back to the scrub 2016 championship tires for qually and race 1. They've by now got 10-12 cycles on them after the Chuckwalla weekend and 2016 champs.
Confusion on qualifying logistics, I showed up early to get gridded by laptime. 2 HC4 cars buzzed around me and zipped right up to the end of the pit wall.
Apparently SoCal region has a first come first serve qually policy, where the grid cones are ignored... Every other region I've run with uses warm-up times to set the qually grid.
(SoCal has a few peculiar customs I really dislike. No Supersize offer for TT double dipping being the big one, no tech after qually, not a single ST car got compliance dynoed this weekend, etc.)
So myself, Nik, Erin and Adam get jumped in line by a couple slow hondas for qually. They end up ruining both Nik and I's first flyer, so we coast around for a lap, letting Erin and Adam by, among others, before banking another flyer.
Nik squeezes out a 2 flat. I find 9/10ths from my warmup time for a 2:02.0. Still p2.
Tire data from warm up and qually was odd. 205 R7 on 8" wheels like a lot of air. RF corner was getting roasted so I ended up with a totally asymmetric pressure setup for the race.
I was classed at 2250lbs to give me P:W cushion to MCE, claiming 138 average whp. I voluntarily weighed after qually and was 2289 empty.
So I pulled the wiper arms, wiper motor, and about 30lbs of ballast from the passenger side, before adding 5 gallons of fuel. Going for broke and targeting exactly 2250 +/- 1 gallon after the race.
The race was amazing. I got a great start and we were side by side entering T1. I quickly got by Nik in Sweeper with great traffic management through the esses and into sweeper.
He and his car were very fast, very early. Once we were free of traffic, there wasn't much I could do to keep him behind me. I squeezed him to the inside of every turn for about 2 laps, but since we were both parked down on the apex, he was able to motor right by me following Sunset/T1.
Took me a while to reel him in, but my car was very fast mid/late, while his car was cooking the tires from my pressure. It was the best duel i've ever had. I really enjoyed it.
On lap 12 I suffered a broken throttle return spring, causing the throttle to stick wide open entering Sweeper. 4, waaay, off the outside. A 2:16 lap and the battle over. I was able to get the car around a few more times before Erin caught me to hang on to 2nd place.
I was there at the end with great tires applying pressure at every opportunity. I rolled across the scales at 2258, about a gallon over. I feel like I nailed the setup and that was my best drive ever, I had a blast and came away pretty satisfied with a P2 and a lap record, even after the mechanical.
Sourced a replacement TB on sunday morning from an E2 enduro car, but I didn't like the way the car was running during my paddock test drive.
Upon inspection of the broken TB, I found one of the throttle plate screws missing, the spring seat broken and the throttle shaft able to walk side to side about 8mm. Fearing throttle screw ingestion, I decided to load it up and diagnose it properly back at the shop. really poor idle and a stumble on part throttle tip in. Need to run a leakdown test.
I don't think the splitter is worth the .5:1 P:W hit. I could probably remove the splitter and the gurney flap, retain good aero balance, and drop another 66lbs at my current power. Down to 2184lbs/138whp. I think 2184 is achievable for just time, no money.
Ultimately, the goal is 2400/153 or 2450/158 to allow 225/45/15 R7s on wide wheels, with an airdam and wing.
Further optimization in the form of Supermiata OsGiken, 6spd, more rpm will be bolt-on speed too.
Also, for the air damn to work well it needs an under tray to keep it from getting pushed in/keep laminate airflow under the front of the car right? So you would only be dropping the weight of the splitter that protrudes from the airdam. Would you be able to extend the bottom of the dam forward to reduce drag? Or do rules prohibit?
Also, for the air damn to work well it needs an under tray to keep it from getting pushed in/keep laminate airflow under the front of the car right? So you would only be dropping the weight of the splitter that protrudes from the airdam. Would you be able to extend the bottom of the dam forward to reduce drag? Or do rules prohibit?
I have a whole nother front end built to Supermiata S2 rules that swaps on in about 10 minutes. As seen on the previous page.
The weight loss isn’t from any physical differences in splitter vs undertray, it’s the .5 p:w hit I take by having it on the car. Honestly, my Alumalite splitter is probably lighter than my birch plywood undertray.
deleting the splitter from the build sheet would allow me to pull the remainder of my ballast and a couple other tricks like gutted headlights and skinned doors and trunk.
Rules have a 5* tolerance to vertical for the airdam.
After breaking a throttle shaft and ingesting a throttle screw on my freshly build high compression motor a few years ago, I'll never run a stock throttle body on a track car if the rules allow alternates. Either Skunk2 or the one Emilio keeps teasing.
I don't think the splitter is worth the .5:1 P:W hit. I could probably remove the splitter and the gurney flap, retain good aero balance, and drop another 66lbs at my current power. Down to 2184lbs/138whp. I think 2184 is achievable for just time, no money.
Ultimately, the goal is 2400/153 or 2450/158 to allow 225/45/15 R7s on wide wheels, with an airdam and wing.
Further optimization in the form of Supermiata OsGiken, 6spd, more rpm will be bolt-on speed too.
Back to this thought. So splitter isn't worth it because you're down on power for 2251lbs. Or are you thinking no splitter and just airdam/rear-wing will always be the way to go for aero balance for ST5 na/nb miata?
No splitter at 2251lbs puts us around 148rwhp AVG and ~153rwhp peak. That also sounds like a riot and still not too far off to detune for S2
Back to this thought. So splitter isn't worth it because you're down on power for 2251lbs. Or are you thinking no splitter and just airdam/rear-wing will always be the way to go for aero balance for ST5 na/nb miata?
No splitter at 2251lbs puts us around 148rwhp AVG and ~153rwhp peak. That also sounds like a riot and still not too far off to detune for S2
I'm running my current setup only because I am power limited. Current max power available either way is my 138whp average.
With zero dyno cushion I could go as light as 2167lbs with splitter. Giving myself a few horsepower cushion leads me to 2250 to save that extra .1 weight factor.
Delete the splitter and zero cushion leads to 2111lbs, taking a -.6 weight factor. LOL
Unless the momentum car with a splitter has 2 second advantage on raw pace, it's REALLY hard to defend against a car with 60 more whp AND a large ratio advantage.
I squeezed Nik to the inside of every corner, parking him. My 1 move was a very formula 1 race start style drift across the track from corner exit to cover/squeeze him down to the entry point of the next corner. I was able to hold position for about 100ft following those corners before he simply walked right by me. Once I was behind him in his draft, I could have sipped a coffee. The car was so much faster with a tow down every straight.
I had grip to spare in every corner, so his tow allowed me to present a few times, but he had enough power to squirt back to the front on exits. The only place I could pass on merit and not his mistakes was Riverside, the super long sweeper where he had to tiptoe through while I was power limited and had my choice of lines around him.
Running a 16.3 P:W car in a 14.0 class is tough. I am only competitive because of razor edge min weight management and 'good' driving.
Removing the splitter to gain the .5 P:W is a step in the right direction.
Running heavy to gain another .1 or .2 is a step in the right direction.
Reaching 2400lbs also unlocks a big tire size allowance increase. This would keep the current key trait of being on happy tires late in races, while the heavy sedans and FWDs have roasted their tires.
Comp weight pound per tire millimeter:
2250lbs on 205s = 2.74 Current setup
2400lbs on 225s = 2.66 Tires even happier late in the race than they are now.
2450lbs on 225s = 2.72
3020lbs on 245s = 3.08 (Nik's IS300)
Driving Marcus Lutrell's (Flier129) TTE car to a win at VIR during Hyperfest 5/20/18.
I flew in from CA on Saturday. Long, early travel day, after a long night at the Taylor Swift/Camila Cabello/Charlie XCX show in the Rose Bowl.
First time back at VIR in several years. I probably ran a 2:40 in my street car in ~2007?
First session, green track, still damp in spots from overnight rain. 2:16.0
Second session, much warmer, but more comfortable with the track. 2:15.8
Third session, even warmer, but even more comfortable. 2:14.8 with a a big bobble onto the back straight, and a pass onto the front straight, both cost me time. Pretty good everywhere else i think.
Marcus' car continues to improve. I drove it last at Mid O in 2017. It has since been gutted/caged/ballasted, a Halo seat added, along with a fresher used motor.
137whp
2438lbs after session #3
+1 Intake
+5 Header back exhaust
+5 800/500 Xida
+2 RB front bar, SPM rear.
+3 4.3 Torsen
+3 205 R7
Finally found motivation to tear into Button’s throttle body/diagnosis.
To recap:
Throttle plate screw ingested through engine. The second broke tonight during disassembly.
Throttle return spring guide bushing failed. Broke into 4-5 pieces.
Throttle return spring broken, causing throttle to stick open. (Sent me way off track, I managed to limp home 3 more laps for P2)
Compression and leakdown are happy.
Camera scope only found one little nic in the middle of #4. Nothing at the sides that indicate squished throttle blade screw between piston and cylinder head.
So, I’m thinking an oil change and a set of tires makes it ready for Sonoma with Speed Ventures in september. I’ve had that event circled all year, and I’m really excited to finally drive that track.
That gives me cold sweats from when I ingested a throttle screw on my fresh high-compression VVT build. Glad you were lucky enough to get a through and through.
July and August off track. Late August Birthday, the last two years I've flown to Ohio to drive Mid Ohio during a NASA TT/PTE weekend. Probably sitting that out, so I've targeted Sonoma for my next event. I'm skipping NASA Nats at CotA, so the final NASA event will be back at Buttonwillow, hoping for CW13 this time.
Sep 29-30 Sonoma Speedventures/Supermiata
Oct 13-14 ButtonWillow NASA SoCal
Nov 3-4 Auto Club Speedway Speedventures/Supermiata
Nov 17-18 Chuckwalla Speedventures/Supermiata
At one of these, Jpreston is flying out to co-drive or double dip. Publishing for posterity and public ridicule if he backs out.
04-23-2018, 10:47 PM
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