SCCA Solo C Street Discussion

[automatic]

Shock tuning question:

I'm running Koni Yellows and I'm still trying to figure out the adjustment settings.

Last event, I ran an event on an oval track and the surface was almost completely free of bumps.

My fronts were set to 1/4 turn to stiff
Rears were 1/2 turn to stiff.

Assuming a perfectly smooth surface, would it have been beneficial to turn the fronts up to fill stiff to have quick rebound for this course?

Would it be beneficial to turn the fronts to full stiff in general assuming a perfectly smooth surface?

There were 2 slalom sections that I felt I was losing time on but I did not want to make an adjustment because competition was so close.

I'm on the bottom (blue car):
[ame="https://www.youtube.com/watch?v=NRbjF2sWSqg"]July 20, 2014: CASC Event #4 Kawartha Downs Serge vs Frankie - YouTube[/ame]

[Jawnathin]

Originally Posted by 7thgear

so after 4 events on the recently installed strano bar, I think it's too thick


while the car is now ultra stable and confidence inspiring, especially at higher speeds, it seems to have no character in the tighter sections.


but I'm wondering whether to chalk that up to the bar, my 235 tires on oem wheels (such wide R1Rs do feel sluggish in really tight sections), or just driving style, maybe I need to throw the car more into such corners.


any thoughts?

First autocross with the Strano bar this past weekend. Coupled with Konis and 225 MPSS. Still waiting for my RS3s to show up. Anyway, the car felt pretty good. Stable when I drove neatly, tossable when I throw/chuck it around. But it was a higher speed event without much slow speed stuff.

Will have a tighter autocross this weekend that should test the front tires/grip, will provide some more feedback on the Strano bar then. Will still be on the same Koni/MPSS setup.

[vroom4]

Gosh, some of you guys didnt get any mileage out of your Z2 or you're deffinition of dead is way different than mine. We have 200+ runs on our Z2 and 7000 street miles. They still have 30% or so left before I designate them as fun run only.

[Biggins]

My ZIIs are at the wear bars and have been for months, and they're still pretty fast. I don't run them often at events anymore, but they have 180 runs with 6k street miles. They definitely last longer than hankooks and yokohamas.

[bimmer635csi]

There was a discussion in another thread where I asked how to compare tires. The response was...

Originally Posted by 7thgear

your placement on the totem pole is generally a good indicator of your car setup, especially if you have other experienced competitors always coming out, so the difference between your time and theirs could be an indicator of improvement.

So I did some analysis of Twins that run in the same groups I do. Here are the results.



The calculation is PAX time based (to be able to compare STX and CS in the same chart). Then divide each driver's time by the smallest time to get a factor above the fastest PAX time (i.e. bigger factor is slower driver). As you can see, I improved enormously compared to the group by changing from Prius Specials (orange circle) to Hankook R-S3s (blue circle).

CS John is the benchmark because he is always the fastest of this group of cars (yes, all three dots are 1.00), but STX Chris is also very consistent over these three events.

This just shows how much a tire change can improve your relative results. I still have a long way to go.

If anyone sees any flaws in my analysis, let me know. I can modify it I suppose before I get too deep, but I intend to continue updating this as the season progresses.

For those of you outside of Texas, be advised that it has been VERY HOT at all of these events, so your results may be different on cooler tracks with different tires.

Cheers,

[DylanFRS]

Originally Posted by bimmer635csi

There was a discussion in another thread where I asked how to compare tires. The response was...



So I did some analysis of Twins that run in the same groups I do. Here are the results.

The calculation is PAX time based (to be able to compare STX and CS in the same chart). Then divide each driver's time by the smallest time to get a factor above the fastest PAX time (i.e. bigger factor is slower driver). As you can see, I improved enormously compared to the group by changing from Prius Specials (orange circle) to Hankook R-S3s (blue circle).

CS John is the benchmark because he is always the fastest of this group of cars (yes, all three dots are 1.00), but STX Chris is also very consistent over these three events.

This just shows how much a tire change can improve your relative results. I still have a long way to go.

If anyone sees any flaws in my analysis, let me know. I can modify it I suppose before I get too deep, but I intend to continue updating this as the season progresses.

For those of you outside of Texas, be advised that it has been VERY HOT at all of these events, so your results may be different on cooler tracks with different tires.

Cheers,

I guess my question would be, how experienced of an autocross driver are you and how long have you been autocrossing this specific car? Because going from the OE tires to the Hankooks would be a big difference, but getting 3 more drives in the car would also show a big improvement.

[bimmer635csi]

Originally Posted by DylanFRS

I guess my question would be, how experienced of an autocross driver are you and how long have you been autocrossing this specific car? Because going from the OE tires to the Hankooks would be a big difference, but getting 3 more drives in the car would also show a big improvement.

I've been autocrossing over 2 years. Probably 30 events or so. Most of that has been in a VW GTI, 3 events in the FR-S and 6 in a BMW 330Ci.

You bring up valid points. But the only way to do this test correctly would be to have a robot driver that could do everything exactly the same in every car on each tire. We can't afford to do that, so this is the best I can do with the given budget and information.

Cheers,

[iLuveKetchup]

I've been out of the loop with the new street classes, but are 04 STi wheels allowed in CS? I know Stock class allowed a difference in offset with non-OEM wheels. Does this apply to C Street? My motivation to going with 04 STi wheels is the weight savings & looks over the OEM wheels.

Edit: nvm I just saw the 1st post "Stock sized wheels within 6mm offset". Thanks!

Edit #2: ah crap. I thought the 04 wheels were 7" wide, but they are. 7.5".

[bimmer635csi]

Originally Posted by iLuveKetchup

I've been out of the loop with the new street classes, but are 04 STi wheels allowed in CS? I know Stock class allowed a difference in offset with non-OEM wheels. Does this apply to C Street? My motivation to going with 04 STi wheels is the weight savings & looks over the OEM wheels.

Edit: nvm I just saw the 1st post "Stock sized wheels within 6mm offset". Thanks!

Edit #2: ah crap. I thought the 04 wheels were 7" wide, but they are. 7.5".

This year, you are allowed to go +/- 1" in diameter though, so they don't have to be "stock size", and the +/- 6mm offset rule was actually a typo and should be +/-7mm now. This was because SCCA finally realized that nobody measures offset in inches anymore.

[iLuveKetchup]

Yes that's right. Not too much benefit with +diameter on a BRZ though.

[7thgear]

Originally Posted by bimmer635csi

If anyone sees any flaws in my analysis, let me know. I can modify it I suppose before I get too deep, but I intend to continue updating this as the season progresses.

too complicated


simply log the raw time difference between yourself and the regular folk that come out to your events


doesn't even have to be the same car or class, just people who are on street tires and that are always coming out.


soon enough you'll have some nice data to work with

[bimmer635csi]

Originally Posted by 7thgear

too complicated


simply log the raw time difference between yourself and the regular folk that come out to your events


doesn't even have to be the same car or class, just people who are on street tires and that are always coming out.


soon enough you'll have some nice data to work with

I'll look into that. I have the raw data already to do my calculations above, so it should be fairly straight forward.


My thinking for comparing FR-S/BRZ cars only was to eliminate the courses that favor power over momentum & vice-versa. Again, only my thinking, but it seemed like if a course was a straight shoot out and back, that might favor the easy-button 370Zs, but if the next course was a 50-ish second course with an average speed of 10 mph, that might favor the twins more. By comparing twins only, that "course favoring factor" is not an issue (or so I thought).


Let me see what else I can cook up tonight (other than chicken that has been in the fridge too long) and see what I can come up with.


Thanks for the input.


Cheers,

[neurokinetik]

For the best of both worlds, use the raw data, normalize it to 60 seconds, then see what your delta is compared to your competitors.

[vroom4]

Less calculating, more driving. When you take top PAX'd time of day, then you can worry about calculating.