20 replies to this topic

[kngrsll]

So i went to my first autox in a long time sunday. It was at a high school using their parking lot. The yaris is not the ideal car to use, but it will work. I have lowering springs (just barely stiffer than stock) and tires (azenis rt615 in the front, old kumho 712's in back), so i ran STS (now ST.) Anyways, dunno how i did yet, results are not posted. The car drove fairly well though, i was kinda suprised. It had pretty strong lift off over steering, i assume from the tire combo. And it was under dampened, but thats not surprising considering the stock shocks are probably worn out by now.

I had fun though if i were to sort things out a little, it may be a fun little car to autox. Mainly: dampers, new tires (the same compound lolz), good alignment. A rear sway bar would be nice too...

Are any of you guys doing any racing? Autox, track days, so on??

Got results: 4th in class out of 6 cars, 44th/123 cars raw time, 27th/123 PAX time. Not to bad considering it been 3 years since my last event and i didnt even check the tire pressures on my car. I would have won H stock by a half second, the only thing that puts me out of there is the springs. So, im content!

[Redliner]

Taking the WWKRD approach to race prepping, eh? Not even tire pressures? You lazy arse.

KR: "mmmbly turn car, car turns too much mmmbly"
Engineer: "Umm...WTF does that mean Kimi "

Hell, I bet you could've dialed the oversteer out w/ increased tire pressures in the rear

So i went to my first autox in a long time sunday. It was at a high school using their parking lot. The yaris is not the ideal car to use, but it will work. I have lowering springs (just barely stiffer than stock) and tires (azenis rt615 in the front, old kumho 712's in back), so i ran STS (now ST.) Anyways, dunno how i did yet, results are not posted. The car drove fairly well though, i was kinda suprised. It had pretty strong lift off over steering, i assume from the tire combo. And it was under dampened, but thats not surprising considering the stock shocks are probably worn out by now.

I had fun though if i were to sort things out a little, it may be a fun little car to autox. Mainly: dampers, new tires (the same compound lolz), good alignment. A rear sway bar would be nice too...

Are any of you guys doing any racing? Autox, track days, so on??

Got results: 4th in class out of 6 cars, 44th/123 cars raw time, 27th/123 PAX time. Not to bad considering it been 3 years since my last event and i didnt even check the tire pressures on my car. I would have won H stock by a half second, the only thing that puts me out of there is the springs. So, im content!

[kngrsll]

Taking the WWKRD approach to race prepping, eh? Not even tire pressures? You lazy arse.

KR: "mmmbly turn car, car turns too much mmmbly"
Engineer: "Umm...WTF does that mean Kimi "

Hell, I bet you could've dialed the oversteer out w/ increased tire pressures in the rear

i figured the car was so off, it would not have mattered if i had a proper alignment, perhaps your right. or proper tires.

[Nacho]

Hell, I bet you could've dialed the oversteer out w/ increased tire pressures in the rear

I would think that increasing rear tire pressure would increase oversteer.

[Redliner]

I would think that increasing rear tire pressure would increase oversteer.

You would think so w/ the logic of: decrease in tire contact patch as well as the tire acting like a spring rate (increase tire pressure = increase spring rate)

But my experience has always been to raise rear pressures to increase understeer, decrease to increase oversteer. My theory is that the more the tire walls move (less air), the more oversteer you get...

[kngrsll]

You would think so w/ the logic of: decrease in tire contact patch as well as the tire acting like a spring rate (increase tire pressure = increase spring rate)

But my experience has always been to raise rear pressures to increase understeer, decrease to increase oversteer. My theory is that the more the tire walls move (less air), the more oversteer you get...

you also have an S2k, they are kinda odd to set up anyways, right?

[Redliner]

you also have an S2k, they are kinda odd to set up anyways, right?

Nah, this is my experience from my Prelude which translated over to RWD pretty much the same except for the fact that I start out with more evened pressures of 38/36 instead of 40/35.

Give it a try, see what you think if you autox again...it'll progressively understeer more so drop the front pressures as the day gets hotter

Edit: In fact, I remember one time I codrove my friend's S2000 at an S2000 autocross -- on all seasons Talk about oversteer galore. I was going sideways in the straightaways ...by the end of the day, with tire pressures alone, I was able to get the car into 3rd place behind 2 race-tired/heavily modified (1 w/ a turbo setup!) S2000s Yeah, our S2000 club has shitty autoxers, but still bragging rights for me

[kngrsll]

nice! not sure how i will swing it, but im kinda looking forward to getting back into this!

[TimzSI]

nice! not sure how i will swing it, but im kinda looking forward to getting back into this!

nice work dude. I've never AutoX'd or been on track, but when I bought my car (rx8) it was my intention to do just that. Until I got two wreckless by speed tickets in 2007. :/ And I'm not new to driving or cars, I was just being stupid. Hopefully this year funds will allow it. I hear the DC region is pretty tough even to find track time tho, at Fedex Field in MD. I wonder if there is something closer to Richmond VA that might be a bit easier to get into.

[Nacho]

You would think so w/ the logic of: decrease in tire contact patch as well as the tire acting like a spring rate (increase tire pressure = increase spring rate)

But my experience has always been to raise rear pressures to increase understeer, decrease to increase oversteer. My theory is that the more the tire walls move (less air), the more oversteer you get...

It's still be the opposite, as less give (via more air) will slide more readily. Same reason that drift kiddies stretch their rear tires: less sidewall flex = more easy to slide.

[Nacho]

Nah, this is my experience from my Prelude which translated over to RWD pretty much the same except for the fact that I start out with more evened pressures of 38/36 instead of 40/35.

Give it a try, see what you think if you autox again...it'll progressively understeer more so drop the front pressures as the day gets hotter

you're not making sense. Dropping the front to defeat understeer (increasing oversteer) is the opposite of what you've been saying about less pressure = more tendency to slide..

Either way, more pressures = more tendency to slide. Assuming they were properly inflated to start with.

[Redliner]

you're not making sense. Dropping the front to defeat understeer (increasing oversteer) is the opposite of what you've been saying about less pressure = more tendency to slide..

Either way, more pressures = more tendency to slide. Assuming they were properly inflated to start with.

Yeah, I'll be honest. I don't really understand how tire pressures play a role in handling. I thought they acted like a spring...stiffer = more slide. But it has not worked out in application. I pump up my front tires to 40 to prevent tire roll...and leave it there. When it gets hot (tire pressures increase) I more understeer. Makes perfect sense because it's getting stiffer in the front. So in that regards, my experience matches logic. But the rear does not fit in my head... drop pressures to induce oversteer, raise pressures to increase understeer.

I remember when I first started, and my instructor told me to put in 40F/55R in the back to get the tail around. My car plowed terribly Not to mention I was scared shitless that the tire would blow...

[Nacho]

Yeah, I'll be honest. I don't really understand how tire pressures play a role in handling. I thought they acted like a spring...stiffer = more slide. But it has not worked out in application. I pump up my front tires to 40 to prevent tire roll...and leave it there. When it gets hot (tire pressures increase) I more understeer. Makes perfect sense because it's getting stiffer in the front. So in that regards, my experience matches logic. But the rear does not fit in my head... drop pressures to induce oversteer, raise pressures to increase understeer.

I remember when I first started, and my instructor told me to put in 40F/55R in the back to get the tail around. My car plowed terribly Not to mention I was scared shitless that the tire would blow...

Stiffer = more tendency to slide. For tires and springs and swaybars. You know, assuming they weren't hopelessly soft to begin with.

With a FWD car, the tires will overheat quicker, and have more comparable pressure gains than the rears, so they'll need to be adjusted 'down' faster than the rears.

Honestly, i've not put more than about 40 PSi in anything in a long time, usually sitting closer to a 30-35 pressure.

[cafcwest]

nice work dude. I've never AutoX'd or been on track, but when I bought my car (rx8) it was my intention to do just that. Until I got two wreckless by speed tickets in 2007. :/ And I'm not new to driving or cars, I was just being stupid. Hopefully this year funds will allow it. I hear the DC region is pretty tough even to find track time tho, at Fedex Field in MD. I wonder if there is something closer to Richmond VA that might be a bit easier to get into.

If you decide to come to an auto-x in Richmond, let me know. I use to work with one of the two organizations that puts on events here, and have a good relationship with both. I haven't auto-xed my race car since April 08, but did get in another event later last year in a friends LS2 RX-7. It was gooooooood times.

[yonson]

only racing I get to do is that boring straight line stuff...

I wouldn't know the first thing about setting up a car to use that steering wheel thingy...

[kngrsll]

only racing I get to do is that boring straight line stuff...

I wouldn't know the first thing about setting up a car to use that steering wheel thingy...

best thing to do is start with a stock car with decent handling and learn there. when i started, i had a 240sx that i modded like a typical super street car. anyways, after a few events, i realized that i needed to redo the car. I had some coilovers, pillowball endlinks, 300ZX big brakes, and stuff like that. I sold all those components one at a time and got poly bushings for the stock arms, better springs/shocks, stock brakes with lines and hawk pads, and then bought a diff (which made the single biggest difference.) So i went from a car with every point adjustable on it, to a car that was mostly stock, just upgraded. Anyways, the car got so much easier to drive, and much faster every mod i changed. Before, i was just blindly modifiying, then i had a purpose. but looking back, it would have been alot easier starting from stock.

[yonson]

The first thing I want to do is go to a decent driving school, I'd learn more doing that than anything...

[DrDickAction]

The first thing I want to do is go to a decent driving school, I'd learn more doing that than anything...

I've been lusting over skip barber at laguna seca for so long.

one day

[yonson]

Yeah, that or Bonduraunt

[Dr. Jimmmah!]

I've been lusting over skip barber at laguna seca for so long.

one day

shame a day will run like $2.5k or so..

[kngrsll]

shame a day will run like $2.5k or so..

god i know, i have thought so many times... i choose the wrong damn hobby. it always pulls me back though