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Old 09-17-2012, 12:50 AM   #1
CoryM
 
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H-stock AutoX. Front or rear swaybar?

Hey guys.

Winter AutoX series is starting soon which means the Yaris will be destroying cones again (yay!). Assuming I haven't misread the rules, I can either upgrade my front bar OR add a rear bar and stay Stock.

I am having a hard time deciding which will be more beneficial. It seems as if most of the roll comes from the back, but in most cars a rear bar will create more oversteer. That being said, the only oversteer I really mind in this car is the "lift-off oversteer" and I wonder if the bar in the back will affect that or not. With a bar in the back, do you notice much less roll from the rear, or just less flex in the torsion beam if you get what I am asking? I think the flex in the torsion beam adds to the "lift-off oversteer". I think it must toe-out when it flexes.

To give an idea of what I am trying to reduce watch here:
http://www.youtube.com/watch?v=hl0pDNP_jb0

At the 50sec mark I do a slight wiggle which starts to upset the car, then decell and left around the cones. That one was pretty mild as it was my first run. I had 3 runs where I was rather sideways into the stop box. I realize this is probably a worst case scenario (or a good example of a Scandinavian flick ) but there have been a few other courses that I run into this so it would be nice to tune it out.

Anyhow, summary: Front or rear bar and why?

Thanks for any input.

PS: Only mods are 205/50r15 RA1s, -2 camber front.
PPS: I know I take too long to get back on the gas when sideways. My reflex is still from RWD so I don't go for the gas until my logical brain takes over. ;)
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Old 09-17-2012, 04:42 AM   #2
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Personally, I think you should keep practicing that lift-off oversteer first. It can be very useful in certain situations. I think everyone here will suggest the rear sway bar upgrade. but again, it is about how you drive. basic trial and error. look for a used rear first and see if it benefits you. if not, you can easily get your money back for it and try upgrading the front. I will say, rear sway bar helps to increase lift-up over steer in turns and reduces understeer
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Old 09-17-2012, 10:54 AM   #3
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Both...The trd rear bar is allowed under the port installed rules and that allows replacement of the front bar.

How are your tires wearing? If you're getting a lot of shoulder wear I'd go for a big front bar and try to keep the tire roll over in check, you'll give up corner exit traction but you'll have much nicer turn in.
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Old 09-17-2012, 11:29 AM   #4
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Bah! I forgot about that new rule.. good call. every driver is different though.
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Old 09-18-2012, 04:29 AM   #5
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in fact, there is someone selling a trd swaybar right now in the classifieds.. good deal too
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Old 09-18-2012, 12:33 PM   #6
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Also your car appears to be quite unstable during the sweeper elements lots of bounce I can hear it in the video sounds like your shocks might be due for replacement.

Look for a decent replacement shock that will work with the stock springs ie Tokico Blues,HTS or you can try to import a set of bilsteins over from Europe(Bilstein catalog) otherwise I've been testing a set of shocks that are showing some great promise with the stock springs but I have no idea when/if there going to be released.
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Old 09-18-2012, 11:28 PM   #7
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Thanks guys. I got more comfortable with getting on the gas and sliding it through that section. Seemed to be the fastest way and I picked up 1.5sec as the day went along. Still had to tell myself to get on the gas though. Too many years of RWD I guess.

I'm still torn with what to do. I guess I should just buy a TRD rear bar and throw it on.
My front tires are not wearing badly at all so far. Outside edge wear, but not too far up the shoulder. I can flip tires any time so that's easy.

My concern is my driving style tends to make this car very tail-happy. Everyone keeps saying I should lower my rear pressures (40/40 in that vid iirc) but any time I do it gets worse. I've always been know to brake late and maybe in this car you just can't do that.

Shocks wise, they are operating as well as OE shocks can. Car is low mileage. This is just my daily driver and winter autoX car so it's only going to get new shocks when these ones are bagged. The pad probably has more elevation change than it shows on video. It rains a lot here so the slopes are pretty big.

Thanks again for the input.
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Old 09-19-2012, 10:06 AM   #8
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If you're already driving tail happy, don't get a rear sway bar. By the sounds of it you're chucking it into the corners too hard and the tail is coming out...

I used to auto-x mine hstock and all I had were better tires.

There was a guy who had a yaris with r-comps and a rsb and he rolled his car has he over drove it and the tail can out...rolled it
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Old 09-19-2012, 10:53 PM   #9
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I'm not too concerned about rolling it at autoX. I've not spun on the RA1s yet and am comfortable catching it (and knowing when enough's enough). I've also never felt a tire leave the ground at autoX. That being said I have absolutely zero interest in track days in this car. I get visions of barrel-rolling down the straight every time I think about running it fast.

I think mostly I just brake too late. Maybe this season fixing that will be my first goal. I think I'll plan on getting the TRD bar and seeing what happens. If I can't teach myself to drive the car when it is set-up better, then what am I doing out there anyhow?

Thanks for the advice guys.
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Old 09-20-2012, 10:29 AM   #10
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I wouldn't worry about rolling on RA-1's they don't have anywhere near enough grip for that to happen.

I don't like to comment on peoples driving because I'm not a good judge of driving but from your video it seems like you don't focus on looking ahead which causes some course elements to catch you by surprise.

If this is your first season, its a write off anyway and most people don't start getting fast they've been racing for awhile so I wouldn't worry about beating the world.

Start with the TRD rear if you feel the front rolls to much after that go with the larger front bar if you still feel you have problems get some better shocks and that's about all your allowed to do in H stock so you would have to jump classes if you wanted go any faster.
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Old 10-15-2012, 12:21 PM   #11
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Just a quick update in case anyone else has the same issues:
I ended up taking the time to do some testing to get my tire pressures correct. Figured I better learn to drive the car when it has more traction rather than tune it to a lousy driving style. End up with 44/36psi and could probably drop another lb out of the back. Going to the next autoX event I figured it would be very tailhappy, but as it turns out it was actually easier to control. I also working on smoothing out my trailbraking and I am already seeing gains. Less on/off and more on/ease-off definitely helps. Ended up placing 35th of 78 in raw times which I am fine with. Probably could have knocked off .5 or so if I hadn't been rusty. Still wouldn't have beat the 2012 Focus though. Things are quick for HS.
From the way the car feels now, I would guess I am going to want both front and rear bars. Going to order a TRD rear bar as soon as I get my new passport and see what happens.

Thanks again for the input. Also for those still running drums: How tight/often are you adjusting them?

Cheers.
Cory
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