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yes 5pt, ah gotcha. nhra guideline is behind the front of the hole in seat minimum 20% but us nhra guys have to also have the back of the fixed back seat secured to the cage/rollbarQuote:
Originally Posted by Catmaigne
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Cage in and harnesses installed. I had to drill into the floor for the sub belts but it wasn't a big deal.
Also demoed everything at NJMP Lightning yesterday and managed to slash 1.5s from my old PB thanks to these Bridgestones. New camera and lap timer as well. The audio is a little goofy since I left the wind noise suppression on, my bad.
Traffic at this Track Night was really bad and there were a bunch of black flags. My best lap came later in my 3rd/final session, but I know I can break into the 13's if I do a full trackday with more time and get lucky with no traffic on the first 2-3 laps (when these tires are the fastest). Optimal was showing 1:14.1.
https://youtu.be/vqhyIsf5z3E
Attachment 40647
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Awesome, onboard videos are great, appreciate you sharing them with us. Love the telemetry(sp) setup and NO brake noise!
Nolan
I did another track day at Thunderbolt over the weekend with some coworkers and friends. I wasn't chasing times since I spent most of the day giving ride-alongs, but I did manage to get within 0.5s of my PB from June. I also got to chase around a S2000 that was prepped for time attack most of the session. Those Club TR cars are no joke!
https://www.youtube.com/watch?v=HeMQCZvGUEA
Also, I think I need more camber again since the shoulders are wearing quick. What was good for the RS4 kinda sucks for the RE71RS since the grip is so much higher. I'm at -2.2 now but I want to put it back to -2.7.
Awesome, thanks for sharing.
Some pics from recent trackdays.
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Also redid the alignment since tire wear was 1 to 1.5/32 more on the outer shoulders than inner. It should also reduce some understeer. About a half degree more camber and I evened out the caster since it's maxed on the left side. Hair more toe out but it's only about 1/32" total and I didn't feel like readjusting lol.
Before:
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After:
Attachment 40653
I guess its just my eyes, but in both photos, the negative camber seems very noticeable. Seems like the inside of the tire shoulders would be wearing more?
The 1st photo is at the end of the front straight and probably in the braking zone since the front suspension is compressed and the rear is lifted more than usual. There's no avoiding camber gain when the nose dives under braking unfortunately and you will lose some braking grip. People try to work around it by increasing the front spring rate a ton or running tall bumpstops, but both of those things will make the car horrible over curbing or create understeer. They also try to boost the caster a ton so they can run the camber lower (caster creates camber gain only with the wheel turned), but the gain is really small in comparison, creates jacking issues, and makes the steering uncomfortably heavy. I did a calculation and found that +1 degree of caster for my car only adds about -0.13 degrees of camber with the steering wheel rotated 90 degrees which is most turns. Not worth it imo, static camber is way more important.Quote:
Originally Posted by JOATMON
Attachment 40654
I looked at the 2nd pic closer and added some lines. Red is the ground, green is body roll, and blue is the wheel axis. The blue and red are a hair over 90 deg apart so a little more neg camber would help the tire bite more and reduce the angle a little. The tire sidewalls also deflect in the turn so the outside edge gets pushed into the ground while the inside edge can curl upwards. Larger tire sidewalls and running too wide of a tire for a given wheel width make the effect worse meaning you'll need even more camber to compensate.
Attachment 40655
I run a 285/30 on a 10.5" wide wheel. The short sidewall and light stretch let me get away with less camber than if I was running a 315/30 (assuming equal grip), but the -2.1 still wasn't enough for these RE71RS tires. I measured a couple spots that used to be 0.200" when the tire was new and saw that the outside shoulders were about 0.030-0.040" more worn than the insides, so I definitely need more camber. The best way to set camber is by using a tire pyrometer to measure temperatures across the tread, but getting the temps right doesn't necessarily mean even wear. I'd rather have even wear since it'll get me the longest tire life since these things are so expensive lol.
Also, I just ordered another set of RE71RS in 295/30 for next season. Tirerack had new old stock tires from 2021 marked down to $220ea ($385ea usually) so I jumped on it.
I made some wheel spats to try to direct air out from under the nose and out the side. They are angled but it's hard to tell from the pic. Still need to add more brackets to make them more rigid.
Attachment 40656
Eventually I want to build an airdam shaped like this and relocate the brake ducts to the bumper with naca inlets. It's kinda like what you'd see on a 3rd gen, C5, and C4.
Attachment 40657
Thanks for the lesson, never too old to learn. Makes perfect sense. If you lived near by I'd get you to make mine drive better. LOL
Nolan