Taking to next level and eliminate understeer - Toyota Yaris Forums

regal · 05-22-2009, 03:44 PM

About a month with this combo:

Tokico Blues
TRD Springs
TRD Rear Sway Bar
Scion 15x6 rims
Champiro 328 Summer tires

Now the car is very nice and responsive but at the limits there is still that understeer. Even with the cheap tires I have never broke them loose, understear scares me to push a car past its limits.

Are there any bracings or anything I can add to make this car understeer a little less, it is alsmost perfectly neutral but not quite. I feel if I had 1" shorter springs in the back with a higher spring rate things would be ideal. But seems none are offered. What about these rear braces I see on Micro-image. Its almost like there is too much weight upfront pushing the understeer.

How can I make the car more neutral toward the oversteer direction?

largeorangefont · 05-22-2009, 05:49 PM

Quote:

Originally Posted by regal

About a month with this combo:

Tokico Blues
TRD Springs
TRD Rear Sway Bar
Scion 15x6 rims
Champiro 328 Summer tires

Now the car is very nice and responsive but at the limits there is still that understeer. Even with the cheap tires I have never broke them loose, understear scares me to push a car past its limits.

Are there any bracings or anything I can add to make this car understeer a little less, it is alsmost perfectly neutral but not quite. I feel if I had 1" shorter springs in the back with a higher spring rate things would be ideal. But seems none are offered. What about these rear braces I see on Micro-image. Its almost like there is too much weight upfront pushing the understeer.

How can I make the car more neutral toward the oversteer direction?

The car feels like all the weight is up front because all the weight is up front. Dont waste your time and money on bracing. You will never get the car truly "neutral" but you can make it a bit better.

First and easiest is to get the Ultra Racing rear sway bar (It is bigger than the TRD - Cali Yaris sells them) and run more rear air pressure. Also you could find a set of lowering spring with stiffer rear rates.

Next step would be a performance alignment up front and shim the rear hubs to get a bit more toe out and negative camber out of them.

More drastically, you could step up to coilovers, but the ride will get a bit worse.

jkuchta · 05-22-2009, 06:04 PM

I think just upping the rear tire pressure maybe 3-4 psi more than the fronts will eliminate most of the understeer...

Just be careful though because too much oversteer will make the car all but unrecoverable in the event of lose of rear traction.

It would be best to sort the car out at a trackday!

cali yaris · 05-22-2009, 06:11 PM

Would a little more negative camber in front help make the front stick better as well? That's an easy mod.

aeipee13 · 05-22-2009, 06:43 PM

You could run your rear with a higher offset than the front. Say no more than 2-10mm difference between the front and rear. I know looks-wise it may not be what you want but it will help the car rotate better. I think if you combine everything said earlier with the "reverse staggered offset" (i don't know if there is a term for that setup) you could achieve what you are after.

I'm planning on running the "reverse staggered offset" once I get wheels sorted so if you don't get around to it I will let you know how it feels. My suspension is stock and I will be running only a 23mm rear sway bar,stock suspension , 15x7 et37 or 16x7 et40 on Falken RT615s 205/50/15 or 16. Once Tamago finishes his hub spacers I was going to run the 13mm in the front and the 10mm in the rear.

SailDesign · 05-22-2009, 08:24 PM

What tire pressures are you running? That will make a great difference to the feel, especially with the taller sidewalls on 15" tires (as compared to 16" or 17")
There are a great many things to try before throwing money at springs'n'such. if you have put the mponey into tires instead of suspension mods, it would have been better spent. IMHO

Tamago · 05-22-2009, 09:04 PM

Quote:

Originally Posted by aeipee13

You could run your rear with a higher offset than the front. Say no more than 2-10mm difference between the front and rear. I know looks-wise it may not be what you want but it will help the car rotate better. I think if you combine everything said earlier with the "reverse staggered offset" (i don't know if there is a term for that setup) you could achieve what you are after.

the car is already 25mm skinnier in the rear. IMO making the rear wider (more stable) would be a better start. put that swaybar to work for you!

aeipee13 · 05-23-2009, 01:49 AM

For sure your suggestion is a better start for him. But for me I think the car rotates fairly well stock for an FF. I just wanted to mess around with different offsets after spending a few years reading other Yaris owner's feedback with different suspension/tire/wheel/bar setups. I wanted the car to be tighter in the rear but rotate easier. The sway should handle a lot of the roll while the wider front helps the rear rotate. Right?

No one else has tried it yet so i figure what the hell, give it a shot?

I went with these wheels. http://www.yarisworld.com/forums/showthread.php?t=15883 It turns out you can only get them in Japan according to Simon. I kind of believe him because when i looked them up to check if they were real and not really good knock offs, i couldn't find this size listed. After seeing them in person, they're real.

Quote:

Originally Posted by Tamago

the car is already 25mm skinnier in the rear. IMO making the rear wider (more stable) would be a better start. put that swaybar to work for you!

regal · 05-23-2009, 02:31 AM

what about all these rear braces that micro-image sells, would they help the carf rotate tail out a litle?

aeipee13 · 05-23-2009, 03:06 AM

there are different opinions on braces. I'm not a fan of them. Some people say they feel the car is stiffer others don't. tires and suspension will give you the greatest "change" sway bars little less but still noticeable. In newer cars braces seem pointless but in older ones you can feel the differences. most new cars have stiff a chassis that render braces useless.

I recommend to make whatever mod makes YOU feel better as a driver and gives you the confidence to push your driving skills. Try driving with mods on then take them off and go with how you feel. people will say what the want but its you driving your car and everyone has a different preference. The best drivers i know are good in any car.

aeipee13 · 05-23-2009, 03:09 AM

braces deal with stiffness and bars deal with roll. personally i feel bars help rotation better than braces.

regal · 05-23-2009, 03:12 AM

I suspect removing the front sway bar may help?

aeipee13 · 05-23-2009, 03:17 AM

it will. but you mean going back to stock not removing it all together, right?

regal · 05-23-2009, 03:22 AM

Well the front sway bar is stock, and I suspect it does more harm than good?

aeipee13 · 05-23-2009, 03:27 AM

No, not if you have a bigger rear sway bar. Thing is you need some type of bar there to keep things from rolling too much. A bigger front sway bar will cause more understeer in an FF car.

Right now you have just the rear bar, doesn't the car seem to rotate better than before? Beefing up the front will kind of cancel out the rear bar.

regal · 05-23-2009, 03:44 AM

No the car coms from the factory with a front sway bar, I added the rear one and have not removed thefront sway bar, just considering it,

aeipee13 · 05-23-2009, 04:44 AM

Yeah i know it has a front sway bar to begin with. Just don't remove it. Your front end will roll so bad and feel super mushy causing understeer and possibly become uncontrollable.

I know guys do that with 4X4 but in a Yaris it would be a bad thing.

regal · 05-23-2009, 04:56 AM

OK, sounds like you saved me some heartache. Seems my best bet is to wait for the HTS shocks with a very stiff spring for the rear to be developed.

05-22-2009, 03:44 PM	#1
regal Drives: 09 Yaris 3 Dr White LB Join Date: Mar 2009 Location: PA Posts: 432	Taking to next level and eliminate understeer About a month with this combo: Tokico Blues TRD Springs TRD Rear Sway Bar Scion 15x6 rims Champiro 328 Summer tires Now the car is very nice and responsive but at the limits there is still that understeer. Even with the cheap tires I have never broke them loose, understear scares me to push a car past its limits. Are there any bracings or anything I can add to make this car understeer a little less, it is alsmost perfectly neutral but not quite. I feel if I had 1" shorter springs in the back with a higher spring rate things would be ideal. But seems none are offered. What about these rear braces I see on Micro-image. Its almost like there is too much weight upfront pushing the understeer. How can I make the car more neutral toward the oversteer direction?

05-22-2009, 06:11 PM	#4
cali yaris ULTIMATE View User's Garage Drives: 07 Yaris Turbo Join Date: May 2007 Location: Canoga Park, CA Posts: 14,859	Would a little more negative camber in front help make the front stick better as well? That's an easy mod. __________________ Micro Image forums, online store and shop are now closed. It was a great eight year run, but it was time to focus on other things. I'm still selling parts on eBay under micro*image seller ID and customers can still make requests for anything specific.

05-22-2009, 06:04 PM	#3
jkuchta View User's Garage Drives: 2007 Yaris hatch (red) Join Date: Sep 2007 Location: L.A. Posts: 557	I think just upping the rear tire pressure maybe 3-4 psi more than the fronts will eliminate most of the understeer... Just be careful though because too much oversteer will make the car all but unrecoverable in the event of lose of rear traction. It would be best to sort the car out at a trackday!

05-22-2009, 06:43 PM	#5
aeipee13 DKDC Drives: Yarlet Join Date: Aug 2006 Location: los angeles Posts: 200	You could run your rear with a higher offset than the front. Say no more than 2-10mm difference between the front and rear. I know looks-wise it may not be what you want but it will help the car rotate better. I think if you combine everything said earlier with the "reverse staggered offset" (i don't know if there is a term for that setup) you could achieve what you are after. I'm planning on running the "reverse staggered offset" once I get wheels sorted so if you don't get around to it I will let you know how it feels. My suspension is stock and I will be running only a 23mm rear sway bar,stock suspension , 15x7 et37 or 16x7 et40 on Falken RT615s 205/50/15 or 16. Once Tamago finishes his hub spacers I was going to run the 13mm in the front and the 10mm in the rear.

05-22-2009, 08:24 PM	#6
SailDesign Drives: . Join Date: Feb 2007 Location: . Posts: 1,931	What tire pressures are you running? That will make a great difference to the feel, especially with the taller sidewalls on 15" tires (as compared to 16" or 17") There are a great many things to try before throwing money at springs'n'such. if you have put the mponey into tires instead of suspension mods, it would have been better spent. IMHO

05-23-2009, 02:31 AM	#9
regal Drives: 09 Yaris 3 Dr White LB Join Date: Mar 2009 Location: PA Posts: 432	what about all these rear braces that micro-image sells, would they help the carf rotate tail out a litle?

05-23-2009, 03:06 AM	#10
aeipee13 DKDC Drives: Yarlet Join Date: Aug 2006 Location: los angeles Posts: 200	there are different opinions on braces. I'm not a fan of them. Some people say they feel the car is stiffer others don't. tires and suspension will give you the greatest "change" sway bars little less but still noticeable. In newer cars braces seem pointless but in older ones you can feel the differences. most new cars have stiff a chassis that render braces useless. I recommend to make whatever mod makes YOU feel better as a driver and gives you the confidence to push your driving skills. Try driving with mods on then take them off and go with how you feel. people will say what the want but its you driving your car and everyone has a different preference. The best drivers i know are good in any car.

05-23-2009, 03:09 AM	#11
aeipee13 DKDC Drives: Yarlet Join Date: Aug 2006 Location: los angeles Posts: 200	braces deal with stiffness and bars deal with roll. personally i feel bars help rotation better than braces.

05-23-2009, 03:12 AM	#12
regal Drives: 09 Yaris 3 Dr White LB Join Date: Mar 2009 Location: PA Posts: 432	I suspect removing the front sway bar may help?

05-23-2009, 03:17 AM	#13
aeipee13 DKDC Drives: Yarlet Join Date: Aug 2006 Location: los angeles Posts: 200	it will. but you mean going back to stock not removing it all together, right?

05-23-2009, 03:22 AM	#14
regal Drives: 09 Yaris 3 Dr White LB Join Date: Mar 2009 Location: PA Posts: 432	Well the front sway bar is stock, and I suspect it does more harm than good?

05-23-2009, 03:27 AM	#15
aeipee13 DKDC Drives: Yarlet Join Date: Aug 2006 Location: los angeles Posts: 200	No, not if you have a bigger rear sway bar. Thing is you need some type of bar there to keep things from rolling too much. A bigger front sway bar will cause more understeer in an FF car. Right now you have just the rear bar, doesn't the car seem to rotate better than before? Beefing up the front will kind of cancel out the rear bar.

05-23-2009, 03:44 AM	#16
regal Drives: 09 Yaris 3 Dr White LB Join Date: Mar 2009 Location: PA Posts: 432	No the car coms from the factory with a front sway bar, I added the rear one and have not removed thefront sway bar, just considering it,

05-23-2009, 04:44 AM	#17
aeipee13 DKDC Drives: Yarlet Join Date: Aug 2006 Location: los angeles Posts: 200	Yeah i know it has a front sway bar to begin with. Just don't remove it. Your front end will roll so bad and feel super mushy causing understeer and possibly become uncontrollable. I know guys do that with 4X4 but in a Yaris it would be a bad thing.

05-23-2009, 04:56 AM	#18
regal Drives: 09 Yaris 3 Dr White LB Join Date: Mar 2009 Location: PA Posts: 432	OK, sounds like you saved me some heartache. Seems my best bet is to wait for the HTS shocks with a very stiff spring for the rear to be developed.