has anyone attempted to get some oversteer by disconnecting their front sway (torsion) bar? i have a w211 e63 wagon. i have often thought about just disconnecting one side of the torsion bar to see what happens. no tracks are open right now (being close to winter) so, i cannot assess this in a proper manner and am not eager to find out on the street or highway how it works. anyone tried or (being in CA that you may be) trying it? with the weight distribution as it is, i think data from a sedan would not be super accurate for employment on a wagon. even ideas or thoughts are welcome!
have a great thanksgiving.
peter

 

unless you're drag racing...you'll want sway bars. you'll have lots of understeer without them.

 

It's a very strange lifting / leaning sensation with out the bars. Tested this one time on a car I was building and that was just a drive around the block !!

 

if i lose the front sway bar, i'll have oversteer. lose the back, i'll get understeer.
the body roll, though, in both cases will increase substantially and, as it's a wagon and there are no spring kits for it, i cannot increase the front rate if i take out the bar. i think, though, the SICAMG answered for me. it's probably just way too big a change.

 

No it doesn’t work that way.

Taking off the front bar will not get you oversteer

 

it does work that way. sorry.
not that you're going to believe me based on what i say; but, let's just start with it. i've been road racing for 22 years and autocrossing for 33. i have the track record in my class (ITB) at local track. granted this has all been in front wheel drive cars where virtually everyone removes their front bar, puts in bigger springs and puts a huge bar in the back for less understeer and, in lots of cases, a bit of oversteer. when i want a bit less oversteer, i reduce the tire pressure in the back. it works. i've tried softer springs and bigger bars up front. less roll for sure but turn in is harder and understeer enhanced. i have experimented a lot. i used to run a huge one in front with "performance/race" springs from neuspeed for autocrossing. roll was almost zero but it ploughed into corners. here's something i found in a 2 second google search "Many hard core FWD road racers do not run a front sway bar, and use the biggest rear bar they can find. Along with proper spring rates and shock settings, it helps shift the cornering balance away from understeer and towards neutral/overtseer. Also helps reduce corner exit wheel spin (along with a good LSD). Generally speaking, most auto-xers prefer a front bar to prevent tail-happiness during those quick transitions. Driver preference."
also, even though it's not racing but is more a street sort of thing, look up drifting. this is, also, from googling "no front sway bar" "Removing your front sway bar makes the rear more loose in comparison to the front. This allows you to oversteer more easily... which is why you've noticed a lot of low powered drifters doing it. Note that this will also mean that it is easier to spin out. Give it a try if you want, though you definitely don't need it."
i bring up the drifting thing because that's pretty much a game for RWD cars like my E63. i do not want to be drifting very much or at all. it's slow. (yes, i know this sounds silly as it's a station wagon and i don't drive it like a race car on the street.)
if you want more authoritative sources, i'll find them from Carrol Smith or other gurus. but, yes, this is exactly how it works.

besides increased body roll, what do you think will happen if you remove either of the sway bars?? i don't mean to seem contentious at all.

 

oh boy....

"If I disconnect the front bar I'll get more oversteer"

No no you will not in fact you will increase understeer. Why? you haven't increased the spring rate and the car will roll enough that you will induce roll camber and reduce the front end traction

You already answered your question in your google search "Many hard core FWD road racers do not run a front sway bar, and use the biggest rear bar they can find. Along with proper spring rates and shock settings," that's the key. In a perfect world no one would use a roll bar in a race car, they are traction reducers

Your ITB car weighs about half of your wagon as a 62% front weight bias and a shorter wheel base. You got huge weight transfer when you took off the bar and got roll induced oversteer, nothing more. On the longer heavier wagon with MUCH softer springs you won't get oversteer because you are not exceeding the rear axles traction limits. Unless you run Railcar rates (North of 1200lbs/in) you need the bars in a street car. Carrol Smith, Allan Staniforth, Fred Phun, Joe Stimola (Rest his soul) and others all agree on this

Glad you have been racing so long. What series?

 

i think you bring up valid points. i am still not sure you're correct, though. i have to chew on it. i have 850lb/in springs in the front. no not much compression in the front. but, yes, almost all FWD racecars cars are set up so that rear lifts a tire. however, it's slip angle is not immense. just a lot more than the fronts so, oversteer. (i am not sure what you are meaning by exceeding limits--do you mean sliding?)
i donated all of my books (like the ones you mentioned as well a few others) and all of my racecar engineering mags to the university race team...i'll have to see if i can get at them.
btw, what is the weight bias in the w211 AMG wagons? i know that they are heavy; the wheels feel like they weigh more than my entire B car. (it's SCCA)
i do agree with the roll issue. if it rolls too much, yes, i definitely lose traction and that is, for sure!, understeer.
to be continued?

 

I am very correct in my statements. Removing the front bar WILL make the car understeer more

 

btw...drifters...don't run without sway bars. those who do have other things to worry about regarding their suspension and they're compensating incorrectly by removing any sway bar

 

drifters run huge front bars and big adjustable rear bars along with low spring rates to slow the translation speed down. Setting up a drift car is fun

 

before i get the references (yours), here's wikipedia:

Main functions[edit]

Anti-roll bars provide two main functions. The first function is the reduction of body lean. The reduction of body lean is dependent on the total roll stiffness of the vehicle. Increasing the total roll stiffness of a vehicle does not change the steady state total load (weight) transfer from the inside wheels to the outside wheels, it only reduces body lean. The total lateral load transfer is determined by the CG height and track width.

The other function of anti-roll bars is to tune the handling balance of a car. Understeer or oversteer behavior can be tuned out by changing the proportion of the total roll stiffness that comes from the front and rear axles. Increasing the proportion of roll stiffness at the front increases the proportion of the total load transfer that the front axle reacts to—and decreases the proportion that the rear axle reacts to. In general, this makes the outer front wheel run at a comparatively higher slip angle, and the outer rear wheel to run at a comparatively lower slip angle, which is an understeer effect. Increasing the proportion of roll stiffness at the rear axle has the opposite effect and decreases understeer.

all that i wrote is correct. while what you wrote is somewhat correct (the camber change stuff), what is written above CLEARLY agrees with the idea that putting more bar on the back RELATIVE to the front will result in GENERALLY oversteer. your imperious statements are, simply, overstated and binary. i shall find Puhn's stuff and a bunch of stuff that is far more precise (there is a Canadian that wrote some huge tomes about this. Yes, i have read them.) i shall also quote Smith and Millikens.

stay tuned, please.

in the mean time, though, if you want to re-write wikipedia, go ahead.

 

yeah, i guess that everything i found about drifting and posted just pales to your unfounded (as now, perhaps it's not) statements. please validate what you write with some sort of credence?

 

LOL, the wiki is a HUGE generalization. its also lacking a few things that affect balance like Roll Couple, Chassis stiffness, tire stiffness (Why do bias plys have larger slip angles for $500), Roll centers, roll centers vertical movement due to suspension loading, suspension geometry (ie using anti squat and anti dive as tuning tools) Its not the Binary cave man explanation "Put bigger bar in back car oversteer". Its all about balance, need and intent

Bars are tuning aids that's it. they are not primary control, wanna control roll? You can do it with the springs. Bars work as traction reducers, they are never a traction adder

I mean if you want to reduce total lateral grip AND get the car to rotate sure take the front bar off and put a section of railroad track across the rear wheels and it very well might get tossed into "Oversteer"

 

btw, have either of you ever built or raced a car???

 

dude, i think you're missing the entire concept. i originally started this post to ask, simply, if anyone had done it. you flat out assaulted me as if i was a moron. you not only challenged the idea that removing the front bar (and by doing so, biased roll resistance towards the back) would entirely cause understeer with the, correct, idea that there would be camber ****ed assedeness. however, the bias towards the back you described as only as a slide. that's just not correct. anyway, you came at me as if you are entirely correct. you are not. like i wrote, above, if you want to re-write wikipedia, go right ahead. the whole point of this was question. then, it became sort of a debate...which is great. however, you had to make grandiose statements. who made you king? bring on the math. quote Smith or Millkens. let's go! seriously. let's go! i started the salvo with wikipedia (you disdain it? fix it!!!)

 

You were asked what series did/do you race in, you ignored it. I gave you plenty of references including people That I have worked with or employed. But hey you know better.

I'm out. Good luck with your Tooning....

 

i told you i race itb in scca. that's written above. what is your problem? you challenge stuff and then don't read it.
btw, where do you race???

 

this seems to be getting WAY out of hand. i do not want to offend any of you. i just want to debate. i do not like, publicly, apologizing because i think i am correct. however, if this has gone too far and is offending people, let us stop. please? let us continue with our disparate ideas and conclusions. peace.

 

deleted comment. it was rude.

 

i own 2 race cars and was a proam drifter in formula d. also still friends with professional formula d drifters and they all have sway bars, big sway bars. i don't cone chase, i do road courses. what may work for you in chasing cones will not work in a road course or a 130mph drifting enbankment.

your statements are valid for your case, but not anywhere else. you asked for thoughts from others. whats the point of asking if you seem to be seeking the answers that side with you rather than looking at what works for everyone and just accept that what you like doesn't work for others.

 

and i do agree with all statements from @AMGPilot . all statements are correct in my personal experience as well as all who i know who do all forms of motorsports. but again...when i hear autoX setups from my friends who have won multiple regional trophies and a few national trophies', their setup for autox is entirely different than a road course or for drifting. autox suspension setup is very different.

 

i like that . i am glad that you replied. thank you.

 

i don't chase cones anymore. i race road courses and have been for 22 years or so. i have the track record at a close track. my car, with the former driver has the lap records at 5 tracks. it works better than any other car in the NER SCCA ITB (improved touring B) class with 5 NER road racing championships under its tires. i am not sure why you think i haven't done road racing. or this car with this setup won't work. yes, it cannot do 135mph. not even close.

 

ok. it has been decided that wikipedia is not a good enough source.
i am going to quote Carrol Smith from Tune to Win.
page 135
"C- Understeer
Corner entry understeer--won't point in and gets progressively worse
Common complaint. Can be caused by:
...
Front roll stiffness too high
...
Too little roll resistance-falling over on outside front due to track width ratio or diagonal load transfer. Can often be reduced by increasing roll resistance even though doing so will increase lateral load transfer."

as i wrote above, i do agree with AMGPilot's assessment that front roll will be an issue and camber change will be horrible. Smith addressed this in his last points about understeer. Again, i agree with AMGPilot on that. However, Smith's first point still stands that high front roll stiffness results in understeer.

Smith again (page 137)
"Too much anti-roll bar -front
Initial corner entry understeer which usually becomes progressively worse as the driver tries to tighten the corner radius."
"Too much anti-roll bar--rear
Corner exit oversteer."

i think that it is clear that original assertion (maybe "wildly") that lower roll resistance in front compared to back leads towards oversteer. yes, there are compounding factors.

now, please do not give any more of your wisdom without some sort of expertise. i have quoted numerous sources while you both just say nay (that you know better). it's really the time to stop being no it alls and put in some references.