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Discussion Starter · #1 ·
I have a question for the suspension gurus out there. I have a stock suspension on my STI except for a Whiteline 27-29mm front and 22-24-26mm rear swaybar. I don't have any other suspension modifications planned at this time other than various hardened bushings. I have the front set to 29mm and I have the rear set to 24mm. My car is an every day driver. The swaybar setup feels pretty good on tight turns as I can coax the back out (perhaps too easily) to get the car to rotate round a corner, but on long sweeping turns like on an on or off ramp, the car feels like the back wants to step out too soon. I would say that the car is biased towards oversteer. I almost never have any understeer.

So here is the question. What adjustments do I make with the swaybar settings to move the balance of the car from oversteer to neutral? I would much prefer to have a neutral setup for my everyday driving. Notice I am not asking what is the 'best' or 'ideal' setup. A neutral set-up should allow me to maintain higher speeds in turns, especially long sweeping ones, without having any tires slip. I have read the SOG suspension dissertation and other threads, but I have not found my answer. The STI has unique camber curves as posted elsewhere and the generic answer to 'reduce the RSB stiffness' may not necessarily be the right answer.

Thanks
 

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I think i might have to write a guide about this, but there are many ways to make the car rotate better or worse. You have your sways and with the settings you are at, there are a few things you can do. 1) you camber curve is still stock so, you can always dial in more front camber. If you have never had a performance alignment, get one ;) they are worth every penny. I would recommend as much camber as you can get (about -.7 to -1 w/o bolts). you can do that, could always reduce your RSB stiffness. What are your tire pressures? you can change those a little to effect handling. i realize the RSB is the "generic" answer with without knowing how you drive your car, what your specific setup is its hard to tell you what to change.

I mean, you can always adjust your driving style. If you are getting oversteer, you might want to let off the gas ;)

other than that what are you looking to hear? you can play with camber and you can play with the RSB, and the pressures... if you are still on stock suspension thats about all you can do.
 

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It's interesting that you would experience oversteer with that setup, especially with a stock alignment (no front camber). No offense, but it sounds to me like it's the driver and not the car. Focus on smoother turn-in and taking the proper line through a turn (not to mention the right speed ;)) I have those same sways on the same settings, as well as Ohlins coilovers (spring rates biased a bit more towards the rear than stock) and lots of front camber and I can STILL get my car to understeer if I enter a turn with too much speed, although it's very neutral at sane public road speeds.
 

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I have a stock setup with the Whiteline sways. With them at 29F/24R I still get quite a bit of understeer. That's with -0.9 camber up front. I can't imagine how you would have oversteer.
but i agree with both Dan and Spaze suggestions.
 

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spazegun2213 said:
I think i might have to write a guide about this, but there are many ways to make the car rotate better or worse. You have your sways and with the settings you are at, there are a few things you can do. 1) you camber curve is still stock so, you can always dial in more front camber. If you have never had a performance alignment, get one ;) they are worth every penny. I would recommend as much camber as you can get (about -.7 to -1 w/o bolts). you can do that, could always reduce your RSB stiffness. What are your tire pressures? you can change those a little to effect handling. i realize the RSB is the "generic" answer with without knowing how you drive your car, what your specific setup is its hard to tell you what to change.

I mean, you can always adjust your driving style. If you are getting oversteer, you might want to let off the gas ;)

other than that what are you looking to hear? you can play with camber and you can play with the RSB, and the pressures... if you are still on stock suspension thats about all you can do.
Maybe I'm not catching what you are saying (I do this), but wouldn't adding negative camber (given stock alignment settings) have the opposite effect of reducing oversteer? Or are you saying a performance alignment is a good thing, get that done, then adjust sways to fit the driver? I'm probably misunderstanding.

To all:
On my '05 I had ~.8-1.0 deg of negative camber in the front, WL Adjustable 24mm front and rear bars set to full stiff. I couldn't dream of labeling my car a understeering car, in fact I could coax out the rear on demand. Could I get my car to understeer? Sure, overcook a corner. Understeer was never a problem with the set up I described above.

That being said I understand the feeling Good2Go gets in fast sweepers where the back end "seems" like it wants to step out. My car felt the same way. I was able to quell the behavior by dropping a stiffness setting in the rear. Personally I like the way the car performed on the track, auto-x, and street so I put the rear back to full stiffness. Maybe it's just suits my driving style/technique (or lack there of :lol: )
 

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Discussion Starter · #6 · (Edited)
Thanks for all of the responses so far. Anyone can get their car to understeer if they enter a turn too hot and use steering input that is more jerky than smooth. My car is no different. I pay particular attention to smooth and gradual steering and throttle inputs so that I do not induce understeer. What I am focusing on here particularly are long sweeping turns. I can get throttle on oversteer as well as lift off oversteer, especially with the front diff tending to pull the nose into the turn when lifting. I think most would agree that oversteer is not usually safe for everyday driving on long sweeping turns.

I had the dealership do a full re-alignment earlier this year since my rear tires were wearing unevenly. My current alignment is set for -0.5 degrees camber front and back. I am also running the stock tire pressure specs of 36 psi front and 30 psi rear. I am open to having a performance alignment like spazegun2213 suggested, but I am concerned about poor tire wear. Anyone care to comment on their tire wear situation after having a performance alignment? What alignment specs would you recommend?

I will initially try to reduce my RSB stiffness and also reduce my rear tire pressures by a few psi. Keep the responses coming.

Edit: I apparently lied about my alignment setting here. Please disregard the -0.5 number. I was going from memory, sorry. I requested the alignment report and the results are on page 2.
 

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Do not reduce your tire pressures. That rear pressure is already too low IMO. I still can't see exactly how you are experiencing this noticeable oversteer. Lift throttle oversteer is simply going to happen, it's pretty difficult to avoid in any car. I guess you should try bumping your rear sway down to a softer setting. Taking your front sway down to the 27mm setting will also help make your front end feel a little less twitchy and sensitive to steering input.
 

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Good2Go said:
What I am focusing on here particularly are long sweeping turns. I can get throttle on oversteer as well as lift off oversteer, especially with the front diff tending to pull the nose into the turn when lifting.
Lifting off during a sweeping turn? Sounds like your having to correct for too much/too little throttle.

I cant imagine that you have any oversteer at all with that setup. Unless you getting intense wheel lift(and not noticing). Probably not.

I dont think your even close to the limit of this car.
 

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Good2Go said:
I think most would agree that oversteer is not usually safe for everyday driving on long sweeping turns.
Talk to any high HP rwd car owner, they live with it just fine. You can control over and understeer in ANY car. Its all driving style.


Good2Go said:
I had the dealership do a full re-alignment earlier this year since my rear tires were wearing unevenly. My current alignment is set for -0.5 degrees camber front and back.
good god child! no wonder your rear end is loose!! remove the bolts from the rear (you must have camber bolts in the rear to have -.5) and put them in the front. you should get -1.5 all the way around which will GREATLY improve the handling dynamics of your car


Good2Go said:
I am also running the stock tire pressure specs of 36 psi front and 30 psi rear.
I think thats a little low to, but for 70's try like 38-34. pressure is not an end all.. and should be adjusted last as more of a fine tuning thing (IMO at least).


Good2Go said:
I am open to having a performance alignment like spazegun2213 suggested, but I am concerned about poor tire wear. Anyone care to comment on their tire wear situation after having a performance alignment? What alignment specs would you recommend?
well you get what you pay for, if you run to much camber the car will perform great on the track, and be a handful on the road while having sucky tire life. However, to little camber makes your tires last longer and makes you feel like you are on an ice rink. -1.5 all around is just fine (-1.5 is OEM rear spec), and i know a few people running -2 up front with no problems.


good luck, but at first i would suggest running the RSB at a lower setting AND getting your car realigned. The reason an alignment is SO important is our cars handle like crap. We have LOADS of grip to compensate, but in the end we are a sedan with a poor camber curve. Big sways reduce the roll and thus help our cars keep positive camber, but in your case, you have very little positive camber to keep.

How is that clear is mud?
 

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Good2Go said:
I had the dealership do a full re-alignment earlier this year since my rear tires were wearing unevenly. My current alignment is set for -0.5 degrees camber front and back.
No mention of toe? 0.5 is too low in back, should be closer to 1.5. I don't think the stock suspension will even let you go that low without mods so I highly doubt your dealership did a proper job. I'd recommend you check in with the local SCCA clubs and find out who does thier allignments. 1.5 in the back and 0.5 with zero toe is pretty stable.
 

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Hey,

I have the same setup as you with my bars set at 29mm front, 26mm rear. I have 2 degrees neg camber in the front, so I have a bit more grip. What I've learn autocrossing my car is that tire pressure makes a HUGE difference in your car's balance. This is what I found:

44F, 39R = nice oversteer
44F, 42R = mild oversteer
44F, 44R = neutral

Note: All of these pressures are cold settings and for autocross runs only. For normal use, I take these numbers down 4-5 PSI.

I hope this helps!

LateBraking
 

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LateBraking said:
Hey,

44F, 39R = nice oversteer
44F, 42R = mild oversteer
44F, 44R = neutral

Note: All of these pressures are cold settings and for autocross runs only. For normal use, I take these numbers down 4-5 PSI.
You mean hot settings right?
 

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Nope, these are the cold settings I start out the day with. I usually spray the tries down between runs depending how hot they are getting.

44F, 39R = nice oversteer
44F, 42R = mild oversteer
44F, 44R = neutral

LateBraking
 

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Damn, those are some high tire pressures. What tires are you using? My V710s prefer 30 front 28 rear (hot).
 

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I'm using the stock RE070's. The tire wear with those settings has been perfect. They have lasted 15 autocrosses, 3 track days, and 18,000 miles in the last year and a half. I should still have enough tread for 2-3 more autocrosses.

Next year I'm planning on moving to the Kumho Ectsa v710s as well. I'm really looking forward to moving up to them. I've read that they do like a lower pressue.
 

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LateBraking said:
I'm using the stock RE070's. The tire wear with those settings has been perfect. They have lasted 15 autocrosses, 3 track days, and 18,000 miles in the last year and a half. I should still have enough tread for 2-3 more autocrosses.

Next year I'm planning on moving to the Kumho Ectsa v710s as well. I'm really looking forward to moving up to them. I've read that they do like a lower pressue.
Oh ok... makes sense. Take along a pyrometer to work out the pressure and if it gets hot where you are, make *sure* to bring a weed sprayer full of water :)
 

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LateBraking said:
I'm using the stock RE070's. The tire wear with those settings has been perfect. They have lasted 15 autocrosses, 3 track days, and 18,000 miles in the last year and a half. I should still have enough tread for 2-3 more autocrosses.

Next year I'm planning on moving to the Kumho Ectsa v710s as well. I'm really looking forward to moving up to them. I've read that they do like a lower pressue.
Man... with that kinda wear I almost think I need to get another set of 070's. That incredible.

Maybe I'm getting faster wear because I run at lower pressures... typically ~38. Also, one of the places I run is on concrete, which is like driving on a cheese grater.
 

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It's interesting that you have an oversteer problem. I just did two track days last weekend. Saturday at Autobahn North, Sunday at Autobahn South. I have the 27-29 front and 22-26 rear sway bars. I ran with them at 29 and 26. My cold pressures on the 070's were 35 front, 36 rear. That got heated up to about 42-44 all around.

With that setup I found the car to be quite neutral. So neutral in fact that I was getting on the throttle shortly after the apex, if not at the apex, and often times I was at WOT before exiting the corner. The car felt pretty well glued the entire time. The only times I got a bit loose were when my apex speed on a right sweeper was a little too high. But it was easily corrected with a *slight* lift and counter steer. I'm on stock alignment btw.

Could your oversteer be caused by a higher apex speed and possibly a little too quick to the loud pedal? I also tend to trail brake, which may make my apex speeds lower than yours, so I can get onto the throttle harder, sooner.
 
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