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Phil Ehlen
03-24-1998, 08:21 AM
suspension! After reading an (admitidly poorly written) article in a rag called Sport Compact Car (don't ask why or how I came about having this second rate car magazine). The article was about three of Yokahama's tires. They tested them on an accident avoidance course, and used a 2.8 Z3, a Boxster, and an M3. Surprise, they like the Boxster the best (said it was the tightest), followed by the M3, then the Z3. Worst of all, they said the Z3's stock suspension was so soft, it made the car more suitable for cruising.<p>Admitidly, I don't take much of what is in this particular mag to heart, and I don't necessarily see anything wrong with having a cruiser. But, that's not what I bought. And, the article kind of cemented a nagging feeling I had about the stock suspension, anyway.<p>I know we've been through this, and I will be compiling responses from the archived posts. But, does anyone have experience with sport suspension upgrades on a Z3 (I know you're out there!).<p>I am leaning toward Racing Dynamics springs and Bilstien Shocks. I won't be racing (autoX is in my future, however). I just want a good, safe ride at speed. I don't really want to lower the car more than 3/4".<p>BTW here's everything I am considering:<p><TABLE><br> <TR><br> <TD>Sachs motorsport coilover suspension</TD><br> <TD>$1595.95</TD><br> </TR><br> <TR><br> <TD>H&R adjustable coil over suspension kits</TD><br> <TD>??$2100 - 2400</TD><br> </TR><br> <TR><br> <TD>Racing dynamics springs / Bilstien shocks</TD><br> <TD>??$625 - 725</TD><br> </TR><br></TABLE><p><br>Following this upgrade, I will do the sway bar upgrade.<p>Any thoughts??<p>--Phil

Bruce
03-24-1998, 08:26 AM
<i>:: BTW here's everything I am considering:<p>: <TABLE><br>: <TR><br>: <TD>Sachs motorsport coilover suspension</TD><br>: <TD>$1595.95</TD><br>: </TR><br>: <TR><br>: <TD>H&R adjustable coil over suspension kits</TD><br>: <TD>??$2100 - 2400</TD><br>: </TR><br>: <TR><br>: <TD>Racing dynamics springs / Bilstien shocks</TD><br>: <TD>??$625 - 725</TD><br>: </TR><br>: </TABLE><br></i><p>since you are in that price ballpark, go for a Dinan Stage 2 suspension kit

Bruce
03-24-1998, 08:27 AM
<i><br>Sachs motorsport coilover suspension$1595.95<br>H&R adjustable coil over suspension kits??$2100 - 2400<br>Racing dynamics springs / Bilstien shocks??$625 - 725<br></i><p>since you are in that price ballpark, go for a Dinan Stage 2 suspension kit

Robert
03-24-1998, 08:37 AM
<font color=gray>suspension! After reading an (admitidly poorly written) article in a rag called Sport Compact Car (don't ask why or how I came about having this second rate car magazine). The article was about three of Yokahama's tires. They tested them on an accident avoidance course, and used a 2.8 Z3, a Boxster, and an M3. Surprise, they like the Boxster the best (said it was the tightest), followed by the M3, then the Z3. Worst of all, they said the Z3's stock suspension was so soft, it made the car more suitable for cruising.<p>: Admitidly, I don't take much of what is in this particular mag to heart, and I don't necessarily see anything wrong with having a cruiser. But, that's not what I bought. And, the article kind of cemented a nagging feeling I had about the stock suspension, anyway.<p>: I know we've been through this, and I will be compiling responses from the archived posts. But, does anyone have experience with sport suspension upgrades on a Z3 (I know you're out there!).<p>: I am leaning toward Racing Dynamics springs and Bilstien Shocks. I won't be racing (autoX is in my future, however). I just want a good, safe ride at speed. I don't really want to lower the car more than 3/4".</font><p>Thicker swaybars make a big difference on the Z3. Best of all they don't take anything away from the comfort/cruising aspect of the suspension. You can install them yourself and most of the aftermarket ones I've heard of are adjustable. I had the <a href="http://www.mz3.net/upgrades/swaybars/index.html">racing dynamics swaybars</a> and was vey impressed by them. After I added the swaybars, and <a href="http://www.mz3.net/upgrades/strut-brace/index.html">strutbrace</a> and <a href="http://www.mz3.net/upgrades/wheels/index.html">17" wheels</a> I did not feel the need for different springs and shocks.

Karl Seeger
03-24-1998, 10:14 AM
I have done some work on my Z3 and here are my results...<p>1) Strut Brace, Reduced front end shake just before heavy understeer.<p>2) Sway Bars, The BEST improvement for body roll, improved the use of LARGER tires & wheels.<p>3) Koni Struts/Shocks, Helped reduce the "softness" of the stock springs. These struts/shocks are adjustable and will not INCREASE ride height (Bilstines WILL).<p>4) Offset Strut Bushings, These are the same bushings the M3 and M Roadster use. Changes the steering geometry for quicker turn in with LARGER tires.<p>5) 17x8 Wheels, Increased stiffness across the tire patch, increases roll stiffness.<p>6) 235/17ZR40 tires, Wider contact patch, shorter side wall, increased roll stiffness.<p>7) Springs, lower center of gravity, increased roll stiffness.<p>Don't go out and buy LARGER wheels and tires without as least changing the sway bars! I did and I did not get the performance increase I did AFTER I installed the sway bars.<p>Also Bilstines are HARD!!! They will increase the ride height. If you do Bilstines, LOWER the car (shorter springs).<p>I have NOT done springs. Lowered cars (I had one) are a b$#!%&. Curbs, speed bumps and potholes are dangeous to not only airdams but can ALSO cause problems to items UNDER the car (i.e. oil pans).<p>I have been looking for springs that are stiffer and the same height as stock. No luck. Also all of the springs I have found lower the car 1 1/4" to 1 1/2". If you find something less than 1" LET ME KNOW!!<p>IMHO the "stock" ride in the Z3 is firm. There is extra body roll and the springs are a little soft for the stock tire size. But most people (the people who could care less about performance handling) will find the car more than aceptable.<p>A few minor changes can turn this car into a prize fighter!<p>-Karl

Kessler
03-24-1998, 10:24 AM
<i>: I am leaning toward Racing Dynamics springs and Bilstien Shocks. I won't be racing (autoX is in my future, however). I just want a good, safe ride at speed. I don't really want to lower the car more than 3/4".<p></i><br>Be aware that by SCCA rules, anything more than shocks and front swaybar will put you out of stock class. I don't know about BMW CCA rules. Not an issue unless you are serious about competing, but still worth mentioning.<p>- Dave Kessler<br>- '88 Porsche 911, '97 BMW Z3 2.8l

Phil Ehlen
03-24-1998, 11:13 AM
<FONT COLOR=TEAL><br> I have done some work on my Z3 and here are my results...<p> 1) Strut Brace, Reduced front end shake just before heavy understeer.<p> 2) Sway Bars, The BEST improvement for body roll, improved the use of LARGER tires & wheels.<p> 3) Koni Struts/Shocks, Helped reduce the "softness" of the stock springs. These struts/shocks are adjustable and will not INCREASE ride height (Bilstines WILL).<p> 4) Offset Strut Bushings, These are the same bushings the M3 and M Roadster use. Changes the steering geometry for quicker turn in with LARGER tires.<p> 5) 17x8 Wheels, Increased stiffness across the tire patch, increases roll stiffness.<p> 6) 235/17ZR40 tires, Wider contact patch, shorter side wall, increased roll stiffness.<p> 7) Springs, lower center of gravity, increased roll stiffness.<p> Don't go out and buy LARGER wheels and tires without as least changing the sway bars! I did and I did not get the performance increase I did AFTER I installed the sway bars.<p> Also Bilstines are HARD!!! They will increase the ride height. If you do Bilstines, LOWER the car (shorter springs).<p> I have NOT done springs. Lowered cars (I had one) are a b$#!%&. Curbs, speed bumps and potholes are dangeous to not only airdams but can ALSO cause problems to items UNDER the car (i.e. oil pans).<p> I have been looking for springs that are stiffer and the same height as stock. No luck. Also all of the springs I have found lower the car 1 1/4" to 1 1/2". If you find something less than 1" LET ME KNOW!!<p> IMHO the "stock" ride in the Z3 is firm. There is extra body roll and the springs are a little soft for the stock tire size. But most people (the people who could care less about performance handling) will find the car more than aceptable.<p> A few minor changes can turn this car into a prize fighter!<p> -Karl</FONT><p>I don't like the roll I am experiencing. I currently have the 16" wheels and stock tires. When it is time to replace the tires, I <EM>plan</EM> on uping the tire size to 17".<p>It sounds to me like the best incremental approach it to get the sway bar kit (front and back?), and shocks. I say incremental, meaning that if I am unsatisfied with the improvement, I can go to the next step and see what happens (i.e. tires, then springs).<p>If I go with the Bilstiens, then lower sport springs would be useful to keep the ride height from <B>increasing</B>.<p>I agree that I a drop of any signifigance (> 1/2" - 3/4") would be a possible problem for street use (my primary use). Especially when the exhaust crimp removal is in my future (it has been posted that this will cause the exhaust pipe at the rear axle to be lower than stock).<p>Thanks!<p>If you don't mind, I will be using some of your input in a page at my site dealing with this upgrade scenario.<p><br>--Phil

Karl Seeger
03-24-1998, 11:43 AM
I agree, go with the Sway Bars first. I used Racing Dynamics F/R. Check Robert's installation information about the rear bar clamp!<p>I did ALL of the work myself...The sway bars are not that bad but watch out for the struts! You have to get a spring compresser (I rented one) and they are tough!! BMW used locktight "red" on ALL of the parts so be prepared to spend lost of time turning bolts.<p>Also I went to my local dealer's parts department and got all of the torque specs. Very important and very nice of my dealer!<p>If you want to repost this go ahead! Just correct my spelling!!<p>-Karl

Karl Seeger
03-24-1998, 11:48 AM
I think I put myself in to a "Stock Prepared" class with two of my "upgrades". The Offset strut bushings and vented front rotors (the 1.9 has solid rotors, mine now has vented).<p>When I supercharge the car all bets are off! I don't think I can win in a stock prepared class but I do know I will learn and have fun.<p>-Karl

FredR
03-24-1998, 11:52 AM
I'll start by saying that I haven't done any suspension modes to my Z3..... yet! <p>I agree that that doing the small things first is the way to go. I plan on doing sway bars first. Body roll and the initial compliance of the suspension bushings cause the very quick turn-in during the initial input of steering(a very upsetting feeling). Tire pressures also play into this situation, don't be afraid to go up on the tire pressures in small increments until you find the balance between ride and handling. <p>As for springs and shocks I'll probably stay with the original. My fanny is not sensitive enough to tell the difference in handling, but I can tell the lose of ride quality. One word of caution about coil-over units: they allow you to adjust for ride height, and corner weights, but without scales and alignment equipment you wont be able to take advantage of this adjustability. IMHO<br> <br><i>: suspension! After reading an (admitidly poorly written) article in a rag called Sport Compact Car (don't ask why or how I came about having this second rate car magazine). The article was about three of Yokahama's tires. They tested them on an accident avoidance course, and used a 2.8 Z3, a Boxster, and an M3. Surprise, they like the Boxster the best (said it was the tightest), followed by the M3, then the Z3. Worst of all, they said the Z3's stock suspension was so soft, it made the car more suitable for cruising.<p>: Admitidly, I don't take much of what is in this particular mag to heart, and I don't necessarily see anything wrong with having a cruiser. But, that's not what I bought. And, the article kind of cemented a nagging feeling I had about the stock suspension, anyway.<p>: I know we've been through this, and I will be compiling responses from the archived posts. But, does anyone have experience with sport suspension upgrades on a Z3 (I know you're out there!).<p>: I am leaning toward Racing Dynamics springs and Bilstien Shocks. I won't be racing (autoX is in my future, however). I just want a good, safe ride at speed. I don't really want to lower the car more than 3/4".<p>: BTW here's everything I am considering:<p>: <TABLE><br>: <TR><br>: <TD>Sachs motorsport coilover suspension</TD><br>: <TD>$1595.95</TD><br>: </TR><br>: <TR><br>: <TD>H&R adjustable coil over suspension kits</TD><br>: <TD>??$2100 - 2400</TD><br>: </TR><br>: <TR><br>: <TD>Racing dynamics springs / Bilstien shocks</TD><br>: <TD>??$625 - 725</TD><br>: </TR><br>: </TABLE><p>: <br>: Following this upgrade, I will do the sway bar upgrade.<p>: Any thoughts??<p>: --Phil<p></i>

Phil Ehlen
03-24-1998, 02:40 PM
Thanks, <p>I am mostly trying to get rid of some of the factory ride lean. I really doubt I will go so far as the coilover suspensions components, as they seem a little overkill for my applicaiton.<p>I have more or less decided on upgrading the F/R sway bars, followed closely (if not at the same time) by upgraded shocks.<p>I'll keep everyone posted.<p>--Phil

Matt D.
03-24-1998, 02:55 PM
Phil, There's really nothing wrong with wanting to modify the suspension on your Z3, but do yourself a big favor first.Get a copy of the rulebook for whatever club will be sanctioning the autocrosses you plan on running. This is always the first step.Find out what mods are legal and what will bump you into the next class.I think it's always more fun to be competitive than to get your doors blown off. It's been years since I've autocrossed, but I used to compete in 20+ events a year. I've prepared cars for three different classes - stock, street prepared and race prepared.The guy who plans on putting a supercharger on his Z3 is going to be in Mod class (at least when I was running) going up against formula cars and such.What's even more humiliating is doing all that work and then getting blown away by a well prepped stock class Civic driven by someone who really knows what he's doing.I've seen it happen plenty. My advice - the best money that you can spend would probably be on a good driver's school and a set of sticky DOT race rubber. Next would be shocks.Springs will put you in another league altogether.If you are going to do any serious autocrossing get a rulebook before you jump in. Good luck ...Matt

Bruce
03-24-1998, 06:34 PM
<i>: Be aware that by SCCA rules, anything more than shocks and front swaybar will put you out of stock class. I don't know about BMW CCA rules. Not an issue unless you are serious about competing, but still worth mentioning.</i><p>yes that is true, but you can also put racing tires (R1s and A032Rs) on and still be stock...everything beyond those 3 upgrades move you into the prepared classes


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