STX Rules and Setup Questions

[DocWalt]

In my case I built the car (ok, bolted on suspension and changed springs, lol) to be tail happy to some extent because that's easy to dial out with a front bar. I HATED the understeer of the car on track. Sure, it's technically safer but it was impossible to go faster without driving like a total jackass to make it oversteer.

So now that I've got 5 autocross events under my belt with the car and I understand what it's doing I need to dial back the oversteer. I can't drive the car hard because I have to be a bit gentle to keep the rear from stepping out. I'm still at the limit currently, but the limit is the rear tires, not all four. Ideal balance is all four tires starting to slide at the same time.

Set up the car however it makes you comfortable. I love how my car feels right now, but it's limiting my times and I'd like to catch the local hotshoes. I drove pretty well at the last event and paxed 16th with a lot of VERY good drivers, but I did some side by side comparisons and you can see how much more aggressive they can be with the car. For example (two different classes of car I know, but I should in theory have only been 2 tenths off to PAX the same, and he's a trophy winning driver & car): [ame="https://www.youtube.com/watch?v=QDxbR_sIN68"]04 16 2016 Phila KenVsJon (STX vs STR) - YouTube[/ame]

I think the idea of matching car to driver skill has some merit, but I've always felt that I should be able to drive a pro level car and if I can't, what am I doing wrong? That said, there's certain skills that really high level drivers that take time to learn. Trying to drive a setup that works for those skills when you don't have those skills is a big exercise in frustration

[GeorgeJFrick]

@DocWalt @cjd

I'm currently dialed into understeer, and I need it while I figure a lot of things out and learn. I did the driver's school again and got the MKE 2nd place stx finisher as my instructor. It's taking a lot of time for what he explained to sink in.

It's nice to see you guys put it into words.

It would be great to adjust the bars during a test and tune; to spend the morning with understeer and afternoon with oversteer or vice versa. Maybe someone has a recommendation on the best way to achieve that parts wise.

I'm still processing the videos of my horrible runs. I setup the Aim SoloDL wrong and have no data.

[Thorpedo]

Originally Posted by GeorgeJFrick

@DocWalt @cjd

I'm currently dialed into understeer, and I need it while I figure a lot of things out and learn. I did the driver's school again and got the MKE 2nd place stx finisher as my instructor. It's taking a lot of time for what he explained to sink in.

It's nice to see you guys put it into words.

It would be great to adjust the bars during a test and tune; to spend the morning with understeer and afternoon with oversteer or vice versa. Maybe someone has a recommendation on the best way to achieve that parts wise.

I'm still processing the videos of my horrible runs. I setup the Aim SoloDL wrong and have no data.

I know you probably didn't mean it this way, but it's not a binary relationship like you put it. You don't just "have" understeer at one setting and have oversteer at another. It just affects what actions probably lead to oversteer vs understeer. Yes, I said "probably".

As a new driver your inputs are extremely variable... You would almost never do exactly the same thing twice. The rate at which you turn the wheel, the amount of throttle applied and at what rate, etc. I can run a 60 second course 5 times and have my times vary by 0.1 seconds. During those runs I can sense the difference a single pound of tire pressure difference makes... but it is usually in a few key parts of the course because of the inputs leading up to the corner, as well as what I'm doing during the corner. The weird thing is a tire pressure change may make the car tighter in some sections, and more loose in others..... That is where it gets complicated.

Try to remember that there are 34986534968347869 factors at play... I imagine this is why they call it the car's "attitude" ;p

[DocWalt]

Yeah, I'm not extremely consistent, so that's the biggest thing for me to work on driver wise. That's extremely important for doing any sort of testing... Which is why it's taken me 5 events to decide on what to tweak with the car

[justinco]

Originally Posted by DocWalt

Yeah, I'm not extremely consistent, so that's the biggest thing for me to work on driver wise. That's extremely important for doing any sort of testing... Which is why it's taken me 5 events to decide on what to tweak with the car

One thing I have learned over the years is, learn how to adapt to the car's mechanical behavior. A lot of times, what is perceived as a certain behavior (ie: understeer, oversteer, etc) is often because of the approach to a corner or feature.

If you think you are understeering all over the place, maybe you are going in too hot, or not entering the feature properly. Think about where the car should be pointing when you get to a section of the element (a pin turn, slalom, whatever it might be).

A little exit understeer is not a bad thing, if you can make the car rotate on the brakes or by lifting/weight shifting.

I've driven so many peoples cars, where the owner complains about a horrendous push, but then I get in it and it feels fine and I can usually make it work

HTH

[DocWalt]

Originally Posted by justinco

One thing I have learned over the years is, learn how to adapt to the car's mechanical behavior. A lot of times, what is perceived as a certain behavior (ie: understeer, oversteer, etc) is often because of the approach to a corner or feature.

If you think you are understeering all over the place, maybe you are going in too hot, or not entering the feature properly. Think about where the car should be pointing when you get to a section of the element (a pin turn, slalom, whatever it might be).

A little exit understeer is not a bad thing, if you can make the car rotate on the brakes or by lifting/weight shifting.

I've driven so many peoples cars, where the owner complains about a horrendous push, but then I get in it and it feels fine and I can usually make it work

HTH

I'm definitely one for driving around the car's problems. My GTI drove REALLY weirdly, but I never bothered messing with it. In this case the oversteer is simply holding me back as it's happening pretty much everywhere, no matter what I'm doing behind the wheel. Simply can't push myself to go faster as I don't have confidence in the rear end to stay with what I'm doing. It comes around on the brakes, on the throttle, mid corner, etc.

I just went a touch too aggressive on making the car tail happy

[bslate3]

I recently did a Phase One EVO School at Mineral Wells, TX. The biggest things I learned was the proper way to look ahead and driving at 10/10ths. I wish I'd did this school sooner.

I normally drive a CS BRZ but I had the opportunity last Sunday to drive an STX FRS that is decently set up. That car was SO much fun!

It rained the entire event with more rain in the morning than the afternoon so the results might be a little favored for the afternoon. I ended up 6th in PAX and .2 away from FTD taken by a miata on Hoosier rain tires. The EVO School really helped me be aggressive on my first run and looking ahead.

Hopefully I can go STX next year, it fixes everything annoying with the BRZ!

[OkieSnuffBox]

Originally Posted by justinco

A lot of times, what is perceived as a certain behavior (ie: understeer, oversteer, etc) is often because of the approach to a corner or feature.

This can't be stressed enough.

[sifl]

Originally Posted by Thorpedo

I know you probably didn't mean it this way, but it's not a binary relationship like you put it. You don't just "have" understeer at one setting and have oversteer at another. It just affects what actions probably lead to oversteer vs understeer. Yes, I said "probably".

As a new driver your inputs are extremely variable... You would almost never do exactly the same thing twice. The rate at which you turn the wheel, the amount of throttle applied and at what rate, etc. I can run a 60 second course 5 times and have my times vary by 0.1 seconds. During those runs I can sense the difference a single pound of tire pressure difference makes... but it is usually in a few key parts of the course because of the inputs leading up to the corner, as well as what I'm doing during the corner. The weird thing is a tire pressure change may make the car tighter in some sections, and more loose in others..... That is where it gets complicated.

Try to remember that there are 34986534968347869 factors at play... I imagine this is why they call it the car's "attitude" ;p

Thanks, Thorpedo. Your observation is exactly in line with the advice I've been given by several of the fast drivers locally.

Until I have more consistency on a course, I'm really still learning the course, or my car on that course. Until the consistency is there, I can't really figure out the fine tuning in my approach to driving a section other than just trying to get through it.

In the first event of the season, I took third, had more consistency, and was able to focus on sections, not just on driving my car through the course. Times were:

65.058+4 64.618 64.421
64.464+1 63.938

I know - Plus 4? I'll chalk that up to first time in the BRZ in five months, and with an all new alignment going back to stock endlinks in front and changing my strut mounts (the night before the event, with no measurements ).

I was two seconds off of first, but three seconds ahead of 4th. Interesting first event for sure.

-Peter

[DocWalt]

Got the front bar on, that's not bad besides having to take the undertrays off for the hundredth time. Whiteline's new grease-free bushings are neat. No grease or teflon tape on the bar and not a single squeak or clunk, good stuff. Rides well too, which was my biggest consideration, tbh.

About the performance... It's noticeably more stable, but not by a huge amount. The car still rolls about the same and it will still kick the tail out if I'm aggressive on the throttle. I'm looking forward to my next autocross event now, I should be able to drive a bit more aggressively without having to baby the back of the car.

I feel more confident anyway, and I guess that's what matters lol

[sifl]

I had my alignment fixed today.

Last week's SCCA event when I switched to stock endlinks with my Cusco front 20mm swaybar with stock front lower control arms, RaceComp Engineering Tarmac 2s (about as low as they can go), and the Mooresport Street caster/camber adjustable strut mounts had the front camber at -3.1, caster at 7.2 and the toe was about a sixteenth in (the toe is now fixed). I'm using the stock eccentric strut bolts in the mounting of the hub assembly housing to the strut for the upper bolt and the lower bolt is the stock non-eccentric bolt.

This is as much camber as I can get without the endlinks rubbing on the inside of the fender well while making turns, though the MSI strut mounts could dial in a lot more camber. There is no other rubbing between parts. The camber issue is odd, and one of my friends wanted to look at it compared to their car with a similar setup.

I'm now running the fronts with -3.1 camber, 7.2 caster and a sixteenth total toe out. The rears also are updated to -3 camber, and an eighth total toe in.

Of course, the lever angle for the front swaybar is not adjustable now and I can't dial out preload. I had to have the car corner weighted and adjusted again, but that alteration was minimal.

I'll be racing on an oval tomorrow with very high banks, and then a relatively flat infield road course section. If anything is completely wrong with the setup, I'll know soon!

-Peter

[cjd]

Originally Posted by sifl

The rears also are updated to -3 camber

Though I'm sure it's spring rate dependent, I'm dropping from -2.8 to something less - maybe -2.3. I was having to work super hard on very low pressure to use the outer couple cm of tread in the back, suggesting it's too much. Maybe -2.5 would be smarter as a next step but... -3 will be interesting. Look forward to your thoughts.

[smg1138]

What's considered the best ride height for STX? I'm assuming it's going to be as low as possible without screwing up the suspension geometry, but I'd like to see some numbers. Right now I'm at 5" from the ground to the pinch welds front and back. I'm on RCE T2's and could go a lot lower, but not sure when I'm going to run into diminishing returns.

[jbailey8748]

Originally Posted by smg1138

What's considered the best ride height for STX? I'm assuming it's going to be as low as possible without screwing up the suspension geometry, but I'd like to see some numbers. Right now I'm at 5" from the ground to the pinch welds front and back. I'm on RCE T2's and could go a lot lower, but not sure when I'm going to run into diminishing returns.

Everything I've read about those who tear up their axels seems to suggest anything lower than 1" in the rear is too low for the axle. That beeing said I'm at 3/4" lower from stock in the rear and 1" lower in the front

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