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Help Needed, baseline settings for First autocross of the season

Grant 302

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something for everyone to chew on..

Meh. Arbitrary. ;)
 

DaveW

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Two things for the record...

1) I am only going to argue with people so long to make them faster at autocross. I have pretty extensive experience with autocross tires, both 200tw, Hoosier slicks and Hoosier DOT-R (a7 types) and while no championships, I have some national trophies on all 3 kinds.

2) I am not trying to say that temp/pressure changes don't exist, or are not some effect on the car. I am only saying that *for autocross* a consistent pressure before every run is 100x more important than messing with any cold/hot BS and trying to guess the curve. I have mapped pressure rise in autocross conditions both in event and tire test conditions and it is totally inconsistent for the first run or two, and then it almost always stabilizes to within less than a PSI rise.

There is far more to be gained on an autocross run by setting a consistent pressure at a regular time and worrying about the other 1000 variables that can cost time in the short runs we take. It is even worse for a newer driver - I would almost guarantee that there is a driver at that same event who could never check tire pressures and put multiple seconds on the OP in their own car.

DaveW
 

Bill Pemberton

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Dave is in a similar vein as Blacksheep 1( road racing tire guru ) when it comes to Autocross Tires, settings and what actually works. I have been an SCCA member since 1981 and I know there were members in his family auto crossing before that. He pretty much grew up with burnt rubber in his nostrils and folks love him at the Solo Divisionals, Pro Solos, and the Nationals, as he often is changing tires for folks who didn't even get the rubber from him. Where Blacksheep is the King of Road Racing and tire technique, Dave is equally knowledgeable about what works on an Autocross course. We have many knowledgeable folks on TMO and though we lean heavily towards HPDEs, Time Trials and Road Racing , many of the newer members are Autocrossers and I have encouraged Dave to jump in here since he has a lifetime of practical experience with what actually works. He happens to have a strong relationship with even the folks he does not sell racing equipment or tires for, and he runs other manufacturers products so he can keep up on changing trends and technology. In fact, he may kill me , but rumor is he will be on Yokes this year and park his previous brand - gotta run 200 TRW rubber in CAM C.

So whether you take a bit of Grant's thoughts, blend in Dave's comments, or try what works for you, the best thing about TMO is the information you get will be from folks who have done this for quite awhile.
 
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blacksheep-1

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I think I agree with Dave more than disagree, as Grant says, hot dictates cold, and as Dave says, set your pressures at a constant before each run, but you still need to monitor the hots so you know where you are at.
 

Grant 302

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What is strange here, are all the people who in TIMED competition are arguing for the process that promotes LESS grip overall.

The OP’s own data in his last pressure setting really proves the point. Best times of the day with the lowest pressure and the least air in the tires. Seems pretty simple to me.
 

302 Hi Pro

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Interesting comments on optimum tire pressures for Auto-X.

This is just a thought as I’m not a tire expert, but it seems to me that selecting Auto-X tire pressures might be a more difficult task than than selecting tire pressures for a 20-25 minute track sessions v. an average Auto-X sessions of 45-70 seconds. Especially for the first or second Auto-X runs.

Also I suspect that logging temps would be a critical component in either venue, (tires pre & post runs, asphalt & ambient, etc.)

Is it possible the best tire pressure on your last run might not be optimal for your first run? I just don’t know so I would appreciate your thoughts on this.

Thanks,
 

302 Hi Pro

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Possible and I’d say likely. Especially say, starting the day at 65° and ending at 80°.
“Also I suspect that logging temps would be a critical component in either venue, (tires pre & post runs, asphalt & ambient, etc.)”

More true than not.
 

Bill Pemberton

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Gotta go with Dave, as it is very unlikely anyone has his level of Autocross Tire Expertise on the Forum ......including myself who started Autocrossing in 1981, have run at least 7-10 different tire Brands, have been sponsored by 3 Tire companies , have Two Different State Championships, numerous Divisional Championships, and though no National Championships, quite a few National Placed trophies. The problem is it is not simple and I actually find it easier to find correct tire pressures when road racing, and unfortunately a pressure change prior to the last run being the reason the run was the fastest adds to the question - since for most experienced Solo drivers the last run is almost always the fastest.

After all these years I still wander over to chat with Dave W., or another good friend of mine ( Ron Ver Mulm , many time National Champ and Hoosier Distributor ) because the climate has changed so rapidly with the 200 TRW tires and the intense Manufacturer competition.

But the discussion is good as it illustrates this is a fine art and your best bet is to ask the experienced drivers with your tire brand what they are using? If there is a Tire Guy there, like Dave , who travels the US and knows alot of the top Drivers , go bug the heck out of him too. Sometimes the tire Manufacturers have their Marketing Reps at big SCCA Solo Events and don't hesitate to go chat with them -- many of them actually Autocross too ( good Examples are the Marketing Head for Falken and the Marketing Mgr. for BFG who both run regularly).

BS1, it has been easier for me as I am just an ancient Tire Warmer now for my son , and you guessed it , he runs Hoosiers,ha!!
 

Grant 302

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“Also I suspect that logging temps would be a critical component in either venue, (tires pre & post runs, asphalt & ambient, etc.)”

More true than not.
Agreed. And I also understand that not everyone has the time or inclination do so. And perhaps not owning the equipment like pyrometers/probes/etc. But to argue that it does not yield benefits isn’t really helpful.
 

Ludachris

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Two things for the record...

1) I am only going to argue with people so long to make them faster at autocross. I have pretty extensive experience with autocross tires, both 200tw, Hoosier slicks and Hoosier DOT-R (a7 types) and while no championships, I have some national trophies on all 3 kinds.

2) I am not trying to say that temp/pressure changes don't exist, or are not some effect on the car. I am only saying that *for autocross* a consistent pressure before every run is 100x more important than messing with any cold/hot BS and trying to guess the curve. I have mapped pressure rise in autocross conditions both in event and tire test conditions and it is totally inconsistent for the first run or two, and then it almost always stabilizes to within less than a PSI rise.

There is far more to be gained on an autocross run by setting a consistent pressure at a regular time and worrying about the other 1000 variables that can cost time in the short runs we take. It is even worse for a newer driver - I would almost guarantee that there is a driver at that same event who could never check tire pressures and put multiple seconds on the OP in their own car.

DaveW
Appreciate you sharing your experiences here Dave. Please continue to do so.
 

Ludachris

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I wonder what @Norm Peterson would say about that. My understanding is it’s not advisable to use Yellows at full stiff.
I remember on my non-Mustang I would change to close to full stiff when autocrossing but would dial it down for the road course. Wonder if other autocrossers here have done that with Konis.
 

Bill Pemberton

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Actually LudaChris you are correct , it is fairly common in F Street ( the Class used to be called F Stock) to run the Konis on full hard. We set up a bunch of Mustangs at Woodhouse Motorsports because Mark Jorgensen ( at the time our Motorsports Director ) was not only a Top National Pro Solo Driver he had one of the fastest ESP Mustangs in the Land! Virtually everyone was running full stiff or maybe on click off in the rear for Autocross in F Street/Stock. When on a road course that would definitely change. Completely different dynamics with sudden severe stops, turns , braking, slaloms etc. in an autocross.

A lot of guys with Mustangs are moving out of F Street because you can not do much with the suspension ( shocks only or a few specific sway bar changes ) and the car changes it's character with big monster rubber, hp upgrades , etc. CAM C is becoming the class Blue Oval Boys are loving and many of the cars on this Forum are perfect for this Class. All the fun tricks many have done are legal and bingo no fussy Club rules that someone can complain about just because you beat them, ha.
The only stipulation is tires , they have to be 200 TRW, and it looks like before the end of 2020 we will have 315/18s made by Falken, BFG, Bridgestone and Yokohama. Damn I love tire wars , as it keeps prices competitive!
 

Grant 302

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Wow. That sounds like a lot of monkey see monkey do.

I drove a V6 PP stock and after the owner modified it with lowering springs and Yellows on full stiff. And I remember uttering some choice words as I tossed the car around a bit. Told the owner to dial down the shocks, but never drove the car again after that. My recollection is that it felt like way too much high speed rebound...the grip reducing nervous feel over surface imperfections.

Anyway, still curious what Norm would say.
 

Bill Pemberton

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Just wondering how often you Autocross, as you can't do lowering springs in F Street, so the shocks do all the work. Sometimes all the tech thought goes out the window and drivers search and search to get things to work right and since the car is essentially stock except for the ability to change a few things like tires, brake pads , shocks, and a few other items she is how she came out of the box. So if you want to call it monkey see monkey do fine with me , but wandering around almost 1500 Autocrossers in Lincoln, Nebraska every year, one finds out a lot of things that work that often do not meet one's generalized analysis.

Honestly, constantly questioning a guy who is helping Autocrossers Nationwide, has made a successful business of it and is often called upon by SCCA and NASA to assist at events , and helps numerous National Champions is not very friendly and I don't see your purpose. We have Blacksheep1 on here as a Track Tire Guru and good guy and DaveW is the equivalent in the Autocross World , so we are quite lucky to have him here.
 

Ludachris

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I know what has worked for me on my previous platform with Konis when I was autocrossing (it wasn't a case of monkey see, monkey do), but as I said, I'm still new to this platform and not a lot of the stuff I did will translate over, outside of running as wide a tire as you can.

I think what we should keep in mind here is that "ideal" autocross settings will be different than setups for most tracks. And what works on a road course doesn't always translate to an autocross course. The people who have been racking up years of autox experience will be far better resources for input in this thread than me when it comes to settings. I used to run autocross many years ago, but I never really did it competitively, it was more to learn the car. I would defer to those who have more experience and more success.

What's difficult sometimes when participating in forums, is identifying who those people are and how much experience they have. It's not always immediately evident - hopefully more people will fill in their About Me section in their profile with their experience level.

What we should avoid doing here, is telling autocrossers who have had a great deal of success that they're doing things wrong. Or contradict every detail of what they're trying to share here. All that does is drive knowledgeable people who have good information to share away. It's always good to question points made, so long as it's in the spirit of learning and gathering knowledge. But when it's being done mainly to disprove something in order to drive home a theory, that's just argumentative and it's not helpful.
 

drj2k1

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Well, this thread has definitely gotten away from its original purpose. I appreciate the insights shared and food for thought on how to tweak things from both camps. Thanks Dave for getting me started with the tire baseline based on prior autocross experience! Looking forward to sharing more autocross progress with the lowly V6 as the season continues (fingers crossed things continue to get better across the country and we all have a chance to get back to doing what we love).

Best,
J
 

DaveW

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I wonder what @Norm Peterson would say about that. My understanding is it’s not advisable to use Yellows at full stiff.
Wow. That sounds like a lot of monkey see monkey do.

I drove a V6 PP stock and after the owner modified it with lowering springs and Yellows on full stiff. And I remember uttering some choice words as I tossed the car around a bit. Told the owner to dial down the shocks, but never drove the car again after that. My recollection is that it felt like way too much high speed rebound...the grip reducing nervous feel over surface imperfections.

Anyway, still curious what Norm would say.
Trying to bring some actual value and info to this thread. Others can make their own decisions.

A car on lowering springs is not a stock car. Also, if PP means S550, that is a whole other deal.

For an S197 Brembo car in fully stock setup except camber and OTS Koni Yellow, full stiff on all 4 corners was the fastest with Dunlop Zii, Original BFG Rivals (ugh) and RE71R for the drivers that drove the car. We ran the car seriously for 2 seasons in this config and for a period of about 5 years as a backup when the EM car was broken and tested other shock settings and they did not work for us. In this config, the car trophied twice at the solo nationals, several national tours, a prosolo, and managed to make the CAM challenge part of the challenge in fully stock trim one year (quickly getting my ass kicked by better cars and Strano who won all the things that year in a bone stock Camaro, but hey you have to get in the challenge to get run out quickly)

The car is terribly undersprung for autocross in stock form and has massive brake dive. And somewhat camber limited. Circling back to the original post, autocrossers often end up at odd shock*and* tire pressure settings on stock class cars as those are the only tools they have to work with. So, yes the Koni yellow on full stiff is a ton of rebound on top of all the compression Koni builds in and no where near what I would run if the car had some platform control from the springs, but it doesn't and the compromise workedfor me, my wife and a co-driver.

My biggest suggestion to new people in these cars with Koni is start near full stiff and work down from there if needed, but every driver needs to find their own setup.

DaveW
 

Dave_W

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Hi, different Dave W. here. As Dave said, Stock Category autocrossers do some seemingly stupid things, because for suspension we can only change tires, shocks, and one sway bar. So we often make shocks work as springs. Or run so much rebound that the shocks jack down into the bumpstops so those increase the wheel rate. And unlike track events, autocross is all about transitions, some steady-state cornering, and almost no straights. So job #1 is often to remove as much "floppiness" as possible in the chassis with the few tools available.

On running "full stiff" on Koni yellows - I always turn the knob until it stops at full stiff then back off 1/8 to 1/4 turn. Back in the day we were cranking them full stiff on a Neon ACR and the adjuster shaft seized on more than one; when we sent them to Koni they recommended not to drive while dialed to full max. Note that Koni yellows only adjust rebound, with some crosstalk to compression in the top 3/4 to 1/2 turn.

If NNJR was running Meadowlands/Metlife parking lot, the surface is pretty smooth with long undulations if you're crossing the drainage swales. (Pay attention if you can use them as "banking" when walking the course.) I'd agree with (near) full stiff on the shocks as a start. Unless it rains, in which case the sealer can get treacherous, and you want to run closer to full soft.

As far as tire pressures, yes, they do matter, but if you're just starting autocrossing, being +/- 3-4 psi of optimal is good enough; just don't roll the sidewall or run crazy high. It's much more important to learn to drive with "aggressive smoothness" and find the right line on course. The biggest improvement in your first few years of autocrossing will come from more seat time.
 
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