Race Tracking Your Supra - Information exchange

[kaj]

What do you all use to air up at the track?

I’m considering buying a compressor but don’t want one that sucks.

Also, any suggestions for starting tire pressure for PS4S on track?

I use this since all of my hand tools are DeWalt. This runs off the cigarette lighter or a battery. I set the PSI and it runs to that pressure and stops. It even adds as extra 0.2 psi or so to compensate for air loss when you remove it lol

Relevant video with respect to set up and oversteer/understeer being down to driver preference:

It's true even at the highest levels of motorsport. Both can be fast.

My limited understanding is that, all else being equal and assuming you are not bottoming out, increasing roll stiffness of either axle should increase overall grip and responsiveness up to a point, but it also means that outside tire on that axle is doing more of the work and will be overloaded sooner. So if the car is oversteering too much and you add a slightly stiffer front bar, you could in theory make it more balanced and gain overall grip.

I think the issue a lot of people run into is that the aftermarket front sway bars are very stiff compared to stock and designed to be run with an equally stiff aftermarket rear sway bar. So if you just do the front, you could still in theory be quicker, but if you don't adjust your driving style to account for what may now be an understeer bias, you are just going to overheat your front tires, which will of course make you slower. If I were only going to do the front, I would look for the softest sway bar on the softest setting (which would still probably be noticeably stiffer than stock).

From what people who know better than I have told me, stiffer suspension helps with transitions but usually results is a reduction of overall grip.
Most of us find a balance in how much overall grip we're willing to give up versus response of the car.
For me, I take a look at the tracks I run and determine how much steady-state grip I'm going to need, on average, versus transitioning.
Right now, my stock setup has worked really well together and I think, in my case, I would lose too much grip by swapping to a different sway bar.
I would obviously have to do back to back comparisons to see for sure, which I might do next year, once I have time to play around and the weather is better.

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[Rta95]

More questions from me, sorry lol. So I'm just following the handling packages Jackie Ding has on his site to slowly upgrade my car. Question I had is, is there anything else you'd add to the handling package 2 (https://phdracing.store/collections...s/ta90-level-2-package?variant=33198191313005) if your car was lowered on springs too? Figured not really but just wanted to be sure. I learn something new everyday from these forums and suspension geometry/physics is still something I'm wrapping my head around lol. And another question, is there anything from that package you don't think is actually entirely THAT necessary? Again to put in to context, I do autocross and a handful of track days/single lap time trials, but nothing that hyper competitive. All for fun really.

 

[Evolution]

Finally in a position to buy some 18 squared wheels now that the advans are sold.

T7/Apex are the two that offer a 18x10 squared setup for stock suspension, right?

I got some brand new sm-10s, 18x10 if you are interested. Still haven't decided if I am going to keep them. Haha.

 

[racebuild]

stiffer springs than people suggest and front and sway sways both on max
I slide through some corners when doing a time trial or hot lap and have to counter steer power on.

I have over 10 years of chassis setup experience 80% of them being BMW and never have I needed to go anything more than full soft setting on sways with preset adjustments. On the race sway bars which are hollow bar slider/blade type the most we’ve needed was ~10% over full soft.

For street style (preset adj) sway bars I’ve always looked for the smallest increase over factory that is adjustable, purely for fine tuning if I needed it.

I also don’t over spring the car, with a race damper (jrz/mcs) you don’t need a ton of spring especially if you’re on a street tire.

Over sprung/overly stiff roll couple = increased force to the tires. To keep it very simple higher roll stiffness = less grip… the reason you’re sliding in/out of corners.

Roll stiffness is not to be confused with chassis stiffness, or roll center.

I’m already working on something to settle the rear end, it’s something I’ve applied to every bmw chassis I’ve setup in the past that wanted the “extra sauce”.

 

[Joker328]

I use this since all of my hand tools are DeWalt. This runs off the cigarette lighter or a battery. I set the PSI and it runs to that pressure and stops. It even adds as extra 0.2 psi or so to compensate for air loss when you remove it lol

From what people who know better than I have told me, stiffer suspension helps with transitions but usually results is a reduction of overall grip.
Most of us find a balance in how much overall grip we're willing to give up versus response of the car.
For me, I take a look at the tracks I run and determine how much steady-state grip I'm going to need, on average, versus transitioning.
Right now, my stock setup has worked really well together and I think, in my case, I would lose too much grip by swapping to a different sway bar.
I would obviously have to do back to back comparisons to see for sure, which I might do next year, once I have time to play around and the weather is better.

Yeah, I edited my original post as I think I confused some things. One important thing I have read is that "Lateral load transfer in one axle will change with the proportion of the roll stiffnesses on that axle, not the roll stiffnesses themselves." So putting proportionally stiffer sway bars on both axles shouldn't do much to overall weight transfer/grip, but if stiffening one or the other improves balance between front and rear, you may actually be faster.

 

[FLtrackdays]

What do you all use to air up at the track?

I’m considering buying a compressor but don’t want one that sucks.

Also, any suggestions for starting tire pressure for PS4S on track?

Some to consider:
https://www.roadandtrack.com/gear/g44735782/best-portable-tire-inflators/
Personally… I’d start my pressure at 30-32 psi in the early colder morning. As I get faster & the day gets hotter, begin to bleed the pressure down all day long to maintain less than 36 psi hot. A lot of it is feel. Definitely go lower if you start to feel too much slide.

So, lowering springs and sway bars? Or does someone make a standard spring for OEM struts that is more stiff?

Stuff you already know but to share with others. “If you plan on attending any track events, a set of coilovers is a much better purchase than lowering springs.“ - Completely agree with them (link below) & wish I did it sooner. Bonus: the Ohlins come with linear springs. Great combo with my sway bars.

https://www.vividracing.com/blog/lowering-springs-vs-coilovers-whats-right-for-your-car/

 

[Deighvid]

Finally in a position to buy some 18 squared wheels now that the advans are sold.

T7/Apex are the two that offer a 18x10 squared setup for stock suspension, right?

You need spacers for the wheels to clear the stock suspension.

 

[Islindur]

Wonder if running only front Eibach sway on soft (194% increase over stock) with revalved Ohlins R&T with rates around 650/1100, square 295 r18 tire and full verus aero (normal splitter) would still be understeery... When I did rear sway on my 2.0 as an addition to front (coz well, understeer with only front) car became very tailhappy with stock dampers/eibach springs so dunno if I wanna install rear again on new 3.0 Supra.... but dont want the car to be understeery again, wonder if higher spring rates at bak and square tires would be enough counter balance
Any opinions?

 

[Rocksandblues]

this thing absolutely walked me on the straight but I was faster on every other part of the track. He is a good driver- has been to several race schools
At my home track I have a top ten time of all time Only members that are faster are VERY good drivers- one has a c7 ZR1 and the other races a 911 cup car in an actual series.
Only had a Garmin a couple months but in top 5 where ever I go (I know not everyone uses it- but summit main has 130+ so far this year)
My point is less douch bag and I guess defending or proving my set up is fast.
I know there are faster cars and faster drivers !! I concede there are different ways to set up a race car.
If you watch nascar on road tracks. They jump curbs- a wheel or two come off, but they remain level and they absolutely slide thru corners when pushing. I am NOT a nascar level driver.
It works for me but I will absolutely get an MCS coil set up before long Then I might start bragging

 

[Isaleus]

Signed up for a whole weekend track day that is a month away with 5/32nds of tread on my rears with the original pilot super sports on them. Fronts still have plenty 7/32nds

Should I be worried about cooking them the first day and failing tech the second day due to the tires?

If so I can check them 2 weeks before the event and slap on a new set of rears but just trying to get the most life out of the originals as I can.

 

[Traxion]

Should I be worried about cooking them the first day and failing tech the second day due to the tires?

The fronts will take more of a beating than rears if it's a turn heavy course. I ran oem PSS for a while and they'll start chunking the edges before you use up tread. I'd say you should be fine. Most groups do a single tech inspection for the whole weekend so it'd be up to you to check them and deem them safe or not. If you haven't tracked much before honestly I would say you're not going to find the real limit anyway. And if you overdrive and spin out you have fundamental issues that you need a coach for.

 

[kaj]

The fronts will take more of a beating than rears if it's a turn heavy course. I ran oem PSS for a while and they'll start chunking the edges before you use up tread. I'd say you should be fine. Most groups do a single tech inspection for the whole weekend so it'd be up to you to check them and deem them safe or not. If you haven't tracked much before honestly I would say you're not going to find the real limit anyway. And if you overdrive and spin out you have fundamental issues that you need a coach for.

at least worn tires are less likely to chunk

 

[Isaleus]

The fronts will take more of a beating than rears if it's a turn heavy course. I ran oem PSS for a while and they'll start chunking the edges before you use up tread. I'd say you should be fine. Most groups do a single tech inspection for the whole weekend so it'd be up to you to check them and deem them safe or not. If you haven't tracked much before honestly I would say you're not going to find the real limit anyway. And if you overdrive and spin out you have fundamental issues that you need a coach for.

only Toyota’s free hpde experience. Which was one hell of a drug. Appreciate the advice.

 

[FLtrackdays]

only Toyota’s free hpde experience. Which was one hell of a drug. Appreciate the advice.

Once you’re running faster lap times, your tires, pads, gas, etc, will go much quicker…. Next thing you know you’ll be bringing an extra set Happy to hear you enjoyed her in her proper environment. She’s dressed up for grocery getting but gets along with the other track cars real quick ?

Wonder if running only front Eibach sway on soft (194% increase over stock) with revalved Ohlins R&T with rates around 650/1100, square 295 r18 tire and full verus aero (normal splitter) would still be understeery... When I did rear sway on my 2.0 as an addition to front (coz well, understeer with only front) car became very tailhappy with stock dampers/eibach springs so dunno if I wanna install rear again on new 3.0 Supra.... but dont want the car to be understeery again, wonder if higher spring rates at bak and square tires would be enough counter balance
Any opinions?

Love how you mention the ”soft” settings with the Eibach sway bars. Big difference over stock. My car is only tail happy at the sharpest hairpin turns with all this delicious B58 torque. Totally induced by me. Throttle modulation while braking or after braking should solve your problem quickly and you obviously know to get back on throttle as soon as possible to settle her down. I personally dig it after coming from a tail happy S2K. I was worried this Supra would feel too heavy or disconnected. Not the case. Just my personal 2 cents that you slap on those Ohlins with their springs and you’d be just as surprised as me. Even better the MCS (they say).

Honestly it feels more like my MX5 (less tail happy) and less like the quick tail snapping S2K for sure. I do have all SPL parts btw. Additionally, if you run some real aero like Bryan (Razor) then this will plant you even more on those high speed turns. Hope that helps brother.

this thing absolutely walked me on the straight but I was faster on every other part of the track. He is a good driver- has been to several race schools
At my home track I have a top ten time of all time Only members that are faster are VERY good drivers- one has a c7 ZR1 and the other races a 911 cup car in an actual series.
Only had a Garmin a couple months but in top 5 where ever I go (I know not everyone uses it- but summit main has 130+ so far this year)
My point is less douch bag and I guess defending or proving my set up is fast.
I know there are faster cars and faster drivers !! I concede there are different ways to set up a race car.
If you watch nascar on road tracks. They jump curbs- a wheel or two come off, but they remain level and they absolutely slide thru corners when pushing. I am NOT a nascar level driver.
It works for me but I will absolutely get an MCS coil set up before long Then I might start bragging

Don’t include me in the doubters ? I love your (style) setup! Those Catalyst numbers don’t lie and why I love my Catalyst as well. Gives me something more to shoot for and feel satisfied at the same time how well our cars can preform ?

 

[Islindur]

Love how you mention the ”soft” settings with the Eibach sway bars. Big difference over stock. My car is only tail happy at the sharpest hairpin turns with all this delicious B58 torque. Totally induced by me. Throttle modulation while braking or after braking should solve your problem quickly and you obviously know to get back on throttle as soon as possible to settle her down. I personally dig it after coming from a tail happy S2K. I was worried this Supra would feel too heavy or disconnected. Not the case. Just my personal 2 cents that you slap on those Ohlins with their springs and you’d be just as surprised as me. Even better the MCS (they say).

Honestly it feels more like my MX5 (less tail happy) and less like the quick tail snapping S2K for sure. I do have all SPL parts btw. Additionally, if you run some real aero like Bryan (Razor) then this will plant you even more on those high speed turns. Hope that helps brother.

Well, had understeer with only front, gonna do full aero now but rear wing effect >> splitter effect so... bit worried there Dunno if power alone will make it oversteer biased with all that torque or not rly...

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