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Old 09-25-2007, 10:37 PM   #1
Boy Blue
 
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First track day, did not go so well. Need some suggestions

So i just recently did my first track day in a car. It was allot of fun BUT... I seemed to be over driving my tires allot. So much so that I started chunking my left front. I put the tire pressure up to max. 50 PSI to give a harder sidewall. I lowered it later on in the day to 40 hopeing for better grip, that is when it started to chunk out. I was running Falken 512. 205-50-R15

The car also seemed to lean allot more than i had expected.
Suspension mods: TRD lowering springs and a TRD rear sway bar.

So my question is what do i need to do to the Yaris to help it on the track..

Tires for sure, need something more track oriented. anything else?

Here are a few pics from the track day.







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Old 09-26-2007, 12:00 AM   #2
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First off, the obvious checks: Did you strip all the junk under the rear locking panel? If you did, put it back in. If you didn't, take it out. Change the weight distribution and see if more or less rear weight helps with your traction issues.

Second, yeah... go get some Hoosier A6's or something for dedicated track-tires if you're running in G-stock still. The 512's are great if you can't use R-compound sub-140-treadwear tires, but if you can, use the sticky meat.
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Old 09-26-2007, 12:10 AM   #3
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True, 512's arent always that good for hard corners. I did that to many tims and eventually my tire went flat one night for no reason..... Inflated it and back to normal.... that was the strangest thing ever next to running over something and my tire making a poping sounds at 70mph..... stopped, saw a flat, drove 3 miles on the flat to the gas station, filled it with air to 40psi and it stayed at 40psi for 2 more days.

MADE NO Sense!!!! lol
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Old 09-26-2007, 12:40 AM   #4
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If I read that right, you have stock shocks/struts? I have TRD sport shocks/struts, with the Tanabe DF210's and my car doesn't roll that much.

Also, +1 on removing everything from the rear. If you don't have time to take out the back seats too, at least fold it down and slide it forward -- move the weight forward as much as possible.

Finally, I had more tire pressure in back (40) to help move the back end around at the track, and I got pretty neutral steering?

Is your car under- or over-steering in the turns?
What was the ambient temp at the track?
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Old 09-26-2007, 03:41 AM   #5
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I guess the tires play a bit part, I have Falken 512's too, from what I understand they are really good street tires, they do just fine in our tropical rains, but probably not quite at home on a track.

Lafiro, I'm guessing you cornered hard enough that it pulled the edge of the tire away from the rim, and let air out!!!
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Old 09-26-2007, 03:49 AM   #6
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hmmm, i also have the TRD struts/shocks, but paired with Tein S.Tech's. i don't appear to have a lot of body roll (i do have the Tanabe front strut bar too). however, i will start to understeer when i corner hard (OEM tires and steelies still). i would suggest getting some aftermarket struts/shocks.
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Old 09-26-2007, 09:36 AM   #7
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I did not remove the spare or any of the trays from the rear of the car...
I was running stock shocks.
The track temperature was warm, but not hot.
Not sure if I completely understand the under/oversteering thing..
Going into the corner I would push the car through, sliding on the tire till the apex of the corner, comming out I would be spinning and pushing through as well. (maybe my cornering speed was too quick?)

Is a front strut bar really going to make enough of a difference?
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Old 09-26-2007, 10:57 AM   #8
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I would get tires first, take it out, and see where you stand/what you feel your lacking. Your understeering, excessive exit tire spinning and line tracking will all be enormously affected by switching to a true UHP tire.
Another good reason for taking this step and then reevaluting is how much your ability/performance will be able to be "improved upon" in the driver department. Street tires leave you sliding and howling away, kind of a controlled clusterf*ck. The right tires will give you such a vast increase in control and feedback, you'll start to be able to see more clearly when both good and bad descisions are made and their outcome. Between predicatable traction charactoristics, tire pressure and weight distribution experimentation and techniques you'll be busy for a while.
Best of luck and enjoy!
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Old 09-26-2007, 01:32 PM   #9
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a set of nitto NT01's or toyo RA1's or R888's would be nice and a set of coilovers and may be up grade the brakes in the near future
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Old 09-26-2007, 01:39 PM   #10
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Quote:
Originally Posted by blueskana View Post
I would get tires first, take it out, and see where you stand/what you feel your lacking. Your understeering, excessive exit tire spinning and line tracking will all be enormously affected by switching to a true UHP tire.
Another good reason for taking this step and then reevaluting is how much your ability/performance will be able to be "improved upon" in the driver department. Street tires leave you sliding and howling away, kind of a controlled clusterf*ck. The right tires will give you such a vast increase in control and feedback, you'll start to be able to see more clearly when both good and bad descisions are made and their outcome. Between predicatable traction charactoristics, tire pressure and weight distribution experimentation and techniques you'll be busy for a while.
Best of luck and enjoy!
yeah, i would do that. forgot you already have your springs and wheel set up (that way you won't rub by getting too large wheels, then lowering the car). but yes, tires, i think will make a BIG difference (like how i'm understeering pretty bad with the crappy OEM tires).

Quote:
Originally Posted by Boy Blue View Post
I did not remove the spare or any of the trays from the rear of the car...
I was running stock shocks.
The track temperature was warm, but not hot.
Not sure if I completely understand the under/oversteering thing..
Going into the corner I would push the car through, sliding on the tire till the apex of the corner, comming out I would be spinning and pushing through as well. (maybe my cornering speed was too quick?)

Is a front strut bar really going to make enough of a difference?
understeering is when you turn the steering wheel to turn in, but the front tires lose traction and you end up going straight or not turning in as much. oversteering is when you are cornering, and the rear tires lose traction and you end up "fish tailing". if you're familiar with NASCAR terms, i believe understeer is being "tight" in the corners, and oversteer is being "loose" in the corners.

yes, i think a strut bar, when properly installed, will make a difference. furthermore, when we installed my TRD struts/shocks, we didn't get to put in the rear shocks, so i was still using the OEM shocks in the rear and the TRD struts in the front. i drove around like this for a few weeks. i'll tell you that when we finally installed the rear shocks, i immediately felt the difference. with the OEM shocks, understeer was more present than with the TRD shocks. now my problem, like i said earlier, is my OEM tires.

i think spring rate and strut/shock dampening will have a big affect on cornering abilities. too much spring rate in the front will cause understeer, while too much in the rear will cause oversteer (can someone confirm this?).
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Old 09-26-2007, 02:07 PM   #11
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Ok so Tires first then some new shocks and possible a front strut bar.
Thanks for the advise guys, I will have to start shopping for some parts.

How many track days will a set of track only tires normaly last?

Last edited by Boy Blue; 09-26-2007 at 02:35 PM.
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Old 09-26-2007, 02:58 PM   #12
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Depends on the specific tire, how hard you drive them, and the vehicle/set-up. On our car; a pretty long time! I know there are some track-monkey regulars on here who can chime in with specific tires they are using, suspension set-ups and expected tire-life.
Enjoy.
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Old 09-26-2007, 03:10 PM   #13
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Carry a lot less speed into each corner entry. Your front tires have to do the task of steering, so don't try to make them do yet another thing in slowing the car down. Your tires are chunking badly because you are using your tires to scrub speed away in a corner. Very very bad - there is only so much that bit of tire contact patch can do. Do most of your braking in a straightline in the lead up to the corner entry and get the correct speed to accelerate the car out of it.

Setup wise you can change the camber of your car, it helps to give even treadwear across the tire.

However I've been down this road before - driving the car properly helps reduce much of the tire shoulder wear associated with track driving.
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Old 09-26-2007, 03:32 PM   #14
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+1

"do all your braking before you turn"

So, with all the posts explaining over/understeer, which were you experiencing with your car?
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Old 09-26-2007, 06:48 PM   #15
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Quote:
Originally Posted by cali yaris View Post
+1


So, with all the posts explaining over/understeer, which were you experiencing with your car?
understeering
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Old 09-26-2007, 08:21 PM   #16
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ok, thanks

1. lighten the rear
2. stiffen the rear
3. use higher tire pressure in the rear.

All of these will make the rear end come around more easily and get you closer to neutral steering.
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Old 09-27-2007, 11:14 AM   #17
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+1 on the tire wear as well; how and where you are wearing/damaging/contacting the tires is a valuable insight into not only what YOU are doing TO the tire/car, steering input wise, but also how the TIRE is reacting. Once you start changing input, messing with pressure and weight, you can learn alot from what the tire is telling you... often giving you information you can't get any other way. You'll also get a feel for what the tires personality and limitations are, and with experimentation and a chance to drive other tires, be able to compare and compile experience on the the #1 component that connects you to the road.
Good luck.
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Old 09-27-2007, 12:04 PM   #18
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Guys, is there a formula for figuring out what tire pressure to use front/rear?

Someone told me do 4 lbs more in front to correct understeer, but y'all are saying increase in back...
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