fierce gs

whats the difference?

i know the bar under ur hood and in your trunk are strut bars...what are sway bars then? same thing?

whats the order of which ones to get first if u could only get one bar at a time?


and could someone please explain understeer and oversteer as well as possible. like how do u know when ur experiencing each one? and could u go in depth with how it occurs, etc etc...basically be verrrrry detailed.

thanks

RON430

fierce GS - You will likely get a lot of responses to this but here is a start. The strut bars or braces connect suspension or body components and their job is to reduce chassis flexing. Most of the bars I have seen for Lexus are point to point which means they keep the two points from getting closer together or father apart, the bars have all their strength in tension and compression not torsion. If the two points move rotationally relative to one another, the strut bars are of minimal help. There are bars available for other cars that make a triangle, for example the upper bar will connect back to the firewall, which vastly improves performance. The reason to put these bars on, other than looks, is that you feel the chassis is flexing and adding a somewhat uncontrolled component into the working of the suspension. Ideally you want to control all the stuff that flexes and make all the stuff that isn't supposed to flex not flex.

Stabilizer or sway bars are bars that connect one side of the car to the other. As one side of the car wants to move up or down, the stabilizer introduces a force component to force the other side of the car to do the same, net result is the body stays level. The stronger the bar, the more it ties the two sides of the car together.

In oversteer, the car wants to actually turn more than your input to the steering wheel. Common parlance is that the rear end wants to come around on you. In understeer it is just the opposite, you turn the wheel but you experience front tire scrubbing and the car doesn't seem to want to turn. If you are in NASCAR, oversteer is referred to as loose and understeer is tight. As Neil Bonnet used to say in a car that understeers, you see what you are going to hit in the crash, oversteer you back into it. If you have a car that understeers you can sometimes induce oversteer by nailing the throttle and inducing oversteer by making the rear end move faster than the front (and doing doughnuts if you are so inclined). Inducing it to free up the car while negotiating a road course is called trailing throttle oversteer. Recently had a chance to spend some quality time with several new 2k2 BMW M3s and I finally found a bimmer I wasn't thrilled about. Good power but the suspension has been made a light tighter. Now there is a bimmer with a ride I would refer to as harsh not just firm. But what was more interesting was that bimmer has really put quite a bit of low speed understeer in the new M3. This is normally safer for the average driver as a car that oversteers ends up swapping ends quickly, something that Porsche has fought for years. With a very stiff suspension and understeer you feel like you are fighting the car a lot. Like I said, just really didn't care for it and wouldn't want to live with one day to day on the street. Normally bimmer is the benchmark for suspensions that have high stability and control with no harshness.

Hard to say what to do first as the bars work with the springs and shocks and steering and chassis to make the car handle and have certain ride characteristics. In stock form, my 2k1 GS430 was way too soft for my tastes so the first change was to get a set of Bilsteins from gs4will. They made a significant change. Personally, I am not of the opinion that the GS chassis is so stressed with street tires and street driving that the tower braces have a big effect. I will probably talk to Steve at Carson about the stabilizer bars shortly to reduce roll in high speed cornering (high speed highway off ramps for example). A stiffer set of bars puts a stronger link between boths sides of the car. This will affect ride somewhat (bumps now are transmitted to both sides rather than being isolated) but not as much as other changes. Still using stock springs and with the bilsteins don't really have much complaint and the ride is still very comfortable. Big topic, hope this helps and you will likely be getting other opinions as well. Two things to do are to check out some books on auto suspensions/racing suspensions and then get under your car (safely up in the air of course) and look at the various components and try to figure out how they work. If you want to see some impressive suspension designs try to get under a Lotus or older E-type.

Goods

Ron430:

Very educational post ...

I see by the info .. you're in the San Jose area ... hope to see ya around one of these days.

I've read a ton of posts ... but any one know of any info on Comptech parts for Lexus?

RON430

Goods - Howdy. Who knows, SJ isn't that big but there's a lot of GS's. Don't know about Comptech, you might want to post a thread asking about their parts. Seems like there is someone on this board who has tried just about everything at one time or another.

fierce gs

wow, that was a great post ron..you seem very educated in this stuff..by any chance would u know of any good performance driving/racing classes in southern cali? classes where u get on the track and learn how to control skids and stuff like that..

thanks again,
allen

GSman

iTrader: (2)

Fierce GS

In So. Cal try www.raceschool.com for high performance driving courses.

RON430

fierce GS - Sorry, haven't taken a course in a long time. Not sure that experience with Bondurant thirty years ago applies to whatever they are teaching today (they are in Phoenix now, not that far away). I believe Autoweek does a special issue every year listing schools, might be able to find one in a library or try their web site. I would keep your goals in mind whether they be racing or car control or whatever. If it is not a course that uses your car I would think it would be beneficial to find one where the type of car matches what you are driving. Formula cars are great fun, if you fit, but they are a very different driving experience to a large, heavy, RWD, sedan (Bondurant uses Mustangs in some of their courses). They have made a lot of progress with FWD but it is a lot different when you are at the limits than RWD. You young guys are probably better adept at handling the differences than us old farts, biggest reason why I prefer RWD. AWD is obviously the way to go but a fair amount of the street setups are FWD biased and I still like RWD better, topic for another discussion. I wouldn't overlook SCCA either. Be prepared to get sneers over a GS (although everyone will want you to drive on the burger runs) but SCCA has a fair amount of resources and nothing like hooking with an amateur team to learn about suspensions and setups. On the street we try to figure out what we want the car to do in the majority of situations and set it up that way, assuming you don't just leave the factory settings alone. Racing makes those tenths of a second important so you have different setups for every track and weather conditions dependent on driver desires. But then in racing you don't care about ride quality and it seems like everyone here does, as you should on the street. Best suspension components in the world are useless if you are constantly losing adhesion due to being overly stiff. Might want to try posting for people's opinions on drivers schools as a separate thread, that will probably get you more responses.