GJSGS4

I want to take some of the float out of the '99 GS4 suspension, but don't want to decrease ground clearance by lowering with springs. I understand to decrease float the ride will need to somewhat stiffer, but want to stay in the stiffness range of L-tuned. Has anyone just installed shocks? What kind of schock and did it reduce the floating? Is there a shock and spring combo like L-tuned that reduces float, but doesn't lower the car?

GS4Will

RON430 has bilsteins sport shocks + factory springs and TRD sways and like the ride...i think this is you answer

RON430

GJSGS4 - William is right. I originally just switched out to the bilsteins sport shocks and they made a dramatic difference. The ride is no where near as floaty but definitely not harsh. I am not sure about the L tune shocks but Bilsteins alone make a tremendous difference. I am not interested in dropping, at least not so far, and from the investigation I did, the L tune springs are not much different in rate from the stock springs but they just progress faster because of the shorter suspension travel because of the drop. I wanted a little flatter cornering and got the TRD sway bars. There has been some comment about harshness with the TRD sways but I haven't noticed it. I still have the stock springs, 16 inch wheels, and the bilsteins. The TRD sways have made a very noticeable improvement in the cornering stability and overall have given the car a very BMW like "planted" feel. I would not in any way describe this setup as harsh at all (and of course I have kept the ground clearance as stock). Everyone's tastes are different but I would definitely start with the bilsteins and then look at the sways if you desire more cornering stability. The vast majority of the float will be gone but there will still be a controlled luxury car ride. I am pretty happy right now.

GJSGS4

RON430 - Thanks for the info. Your advice sounds like a logical approach. Did you consider the Bilstein Heavy Duty shocks instead of Sport? Any idea why the heavy duty rear shocks are double the price of the sport shock? Any leads/links on who has good prices on Bilstein's?

RON430

Let's see if gs4will can answer some of it. I have used bilsteins for a number of years but not sure if I am that big a pro at part numbers and prices. I recall some confusion on the pricing in the past. I thought that the sport shocks were above the HDs in pricing but there was some confusion in the pricing relative to the part numbers. My limited knowledge was that the HDs were closer to OEMs and the sport were specifically tuned for performance handling. I can't remember ever getting a set of HDs. Through quite a few BMWs and a camaro or two it was always the sport setting. As far as pricing, gs4will may also have something to add but it seems like the last time he recommended http://www.shox.com. Can't vouch for them but spending some time on the web will probably net some good prices that should be competitive and one or two that are list from the totally clueless. Seems like there are always a few vendors like that although sometimes you are paying for the guys who have the parts in stock versus the guys who will order them after you order them. Hey William, you got something to add?

GJSGS4

I had looked around on the web, the prices and part numbers are listed below. They say the HD are stiffer than stock and the sport are 15% - 30% stiffer than HD. I thought someone might have experieice with the Heavy Duty Bilsteins on a GS4. See how much the rear HD cost?


Make: LEXUS
Model: GS 300/400
Year: 98-00
Blank: Heavy Duty
Front: BE5-2743 $118 ea.
Rear: BE5-2744 $209 ea.

Blank: Sport
Front: BE5-2802 $104 ea.
Rear: BE5-2803 $118 ea.

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GS4Will

gjs,

ron is right there with your answers, esp he used to be a beemer guy he knows suspension and handling..not sure what shox.com is selling the sport model for now, but last time i checked, it is a bit better than what you listed i think

bottom line, you want the sport model version

www.turnermotorsports.com has good prices too, though they cater to bmws, the guys there are very helpful too, and they can get any bilsteins

whitels

The info below may also help- as copied from a bimmer site:



http://www.bmws.freeservers.com/suspension.htm



Okay boys and girls, here's my two cents on suspension modifications. This is aimed at e24 and e28 owners for the most part. First you've pinpoint your goals, do you want to subtly improve upon your stock setup or create an all out track monster, or somewhere in between. The difference can be measured in performance, $$$, and comfort. First you need to upgrade wheels and tires if your still running TRX's, these tires are out of date and can be down right dangerous. My wife had a blow out with a TRX that looked new, but had dry rotted from the inside, there was less than 5% of the tire left on the rim, and if it had been on the front it could have killed her.

If you want a sporty daily driver I would highly suggest 15"x7" rims, and 205/60/ZR15 tires, this is a nice compromise between comfort, $$$, and performance. If you plan on doing driving schools or club racing, then look at 16"x7.5"/8" or even 17"s wheels and tires. Keep in mind you want to run a rim with about a 20mm offset to avoid clearance problems, and a 245 tire is as large as your gonna be able to stuff under the fender without clearance problems. Running 16" or 17" rims will stiffen the ride characteristics considerably, and you still may have to roll the fenders to avoid tire rubbing.

If your not gonna track the car then I might be tempted to look at creating an 'is' if you have a 528e or 535i. This can be pretty much accomplished by swapping shocks to Bilstein HD's, and the results will be improved handling, yet still a compliant ride. If you already own a 'is' or want to track the car, then you need to look into springs and sway bars, etc. Below I put together two lists of suggestions for upgrades from my own experiences, trials and errors. These are listed in the order they should be completed for maximum benefit.

Daily Driver Setup, an extension of the 535is:

1. Wheels and tires - 205/60/ZR15's on 20mm rims are ideal

2. Bilstein HD shocks, or Boge Turbo gas

3. Performance springs, H&R's work well (use Bilstein sports if you go with lower springs)

Driving school, autocross setup (note: the farther you go down this list the lower your lap times will get, and the harsher you ride will get as well.)

1. Wheels and tires- 225/50/ZR16's up to 245/40/ZR17's on 20mm offset rims

2. Bilstein sport or Koni shocks

3. Eibach, RD or H&R springs (all aftermarket e28 springs run about 225 in/lbs., H&R maybe slightly more)

4. Larger sway bars, use Suspension Techniques kit ( 22mm front/16mm rear bar dia.) or M5 bars ( 25mm fr./18mm rear) which will require reinforcing the stock mounts by welding them, or they may rip out. Stock e28 bars measure 19mm fr. and 15.5mm rear. Some 535is's came with a little known sport package that included a 21mm fr. bar, and sport springs.

5. Front stress bar

6. Urethane bushings and differential mount

7. Camber plates on the front, and offset or adjustable bushings on the rear

8. Coil over shocks and struts, which you can specify your own spring rate. Many run 450 in/lbs. versus 225 in/lbs. spring rate for regular Eibachs. See www.ground-control.com for more info.

9. Roll bar, rear stress bar, harnesses, etc.

10. For more info on stiffening the chassis click here

NOTE: I didn't mention brakes, which should ALWAYS be upgrade first, click here


Here are some proven guidelines which will show you just what changes will give you the desired result:
Adjustment More Understeer More Oversteer

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Front tire pressure Lower Higher
Rear tire pressure Higher Lower
Front tire section Smaller Larger
Rear tire section Larger Smaller
Front wheel width Narrower Wider
Rear wheel width Wider Narrower
Front wheel camber More positive More negative
Rear wheel camber More negative More positive
Front springs Stiffer Softer
Rear springs Softer Stiffer
Front sway bar Thicker/stiffer Thinner/softer
Rear sway bar Thinner/softer Thicker/stiffer
Weight distribution More forward More rearward
Front aerodynamics More downforce Less downforce
Rear aerodynamics Less downforce More downforce

whitels

RON430

Did you consider the Bilstein HD at all since you'd be using the stock springs? I know you're very happy with the SP right now- just want to get more of your thought process when you made the decision to go the SP route.

In my case, my main irritation with my stock suspension is the jiggle on the freeway over irregular surface. I have very stiff tires right now (soon to be replaced) and it feels like their dribbling on the coarse pavement at high speeds. When freeway is smooth it's fine and I don't mind the occasional floating feel since I came from the LS camp. But in all honesty, I feel more solid in the LS at 120mph than in the GS at the same speed.

Hope you don't mind us picking your brain.

RON430

whitels - Wish I could say I had a thought process. The truth is I have never had the HD shocks. I am not sure why but lost in the cave paintings was the very first recommendation I ever got on bilsteins was to go for the sports. I don't even think I know anyone who ever got the HDs. The biggest problem we have here is comparing everyone's tastes in handling. I have no complaints on BMW ride/handling. Give them credit. But bilstein sports improve both areas in my opinion. I think the stock units are Boge and I have read good things about them but I was never that impressed with them. I think it is absolutely great that people want to make their cars their own with mods, any mods. Shocks can have a big impact on ride but bilstein has an uncanny talent for increasing control, not harshness. The other two areas I have seen over the years that will affect harshness are obviously springs and tires. I am still comfortable with the springing on the GS, I think most guys do it for looks, not handling. If I were going to fool with ride height, it would be with well designed coil overs and start at stock height and very slowly lower. I don't need to scrape anywhere for the sack of handling in Lexus, personal opinion. The tires issue may also be styling more than anything. These big wheels just don't leave much room for rubber. As the side wall decreases, the tire maker has to increase stiffness to keep you off the rim. For handling, I look at contact patch. Full tread tires have far more tread squirm than sidewall flex, I also doubt there are very many instances on the street where you can push a Lexus hard enough to feel sidewall deflection. Besides, as much as we downplay the factory, the propeller heads with the big computers are not stupid. They actually account for both chassis flex and tire deflection in the modelling of ride. Race cars have very stiff chassis, duh. But anyone who wants to drive one on the street for a daily driver has a different set of priorities and tastes than I have. Ride and handling take into account all the issues mentioned in the bimmer letter above and it is important to keep balance. I had those TRXs. Funny, I thought they were pretty good tires, just teaches you about being on the bleeding edge of tire technology. Blowouts because they are old is keeping something too long. Like I said, if we could get all these aftermarket suspension types to skidpad test, at least we could see what of all these marvelous geejaws is worth the money.