Bilstein Sports or HD's with M-Tech Suspension?

[iananderson02]

Hey all, questions is as it seems. My car is a 1997 ti with the M-Tech package. Going to replace the shocks/struts. Should I use Bilstein HD's or Sports with the factory M-Tech springs?

I've gotten a bit of conflicting info on this subject. One reputable BMW specialist says to use the HD's (they reason the car is not quite low enough to warrant sports). Another say to use sports because the dampening is a bit stiffer and it complements the stiffer M-tech springs better.

Anyone who has done this job before care to comment on their experience?

Thanks in advance...

[cooljess76]

HD's have been known to actually raise the car. I know your mechanic will disagree because technically struts shouldn't affect ride height, but trust me, they will. Get Bilstein sports, IIRC, they're the same price. Heck, if you want to save a few bucks, get bilstein touring class shocks and struts. The difference between the touring class and the sport & HD's is that the touring class is a twin tube design and the sports and HD's are mono tube design. If you plan on getting lowering springs later down the road, get the Bilstein sports. The touring class shocks are similar to OEM and cannot handle the stiffness of lowering springs.

[mgbman69]

Also, the sports can be rebuilt down the road if you ever need them to be.

[Cali330ti]

Sports, Ground Control Sleeves, and some cheap Eibach or H&R's are really amazing at how good of a job they do. I auto-x heavily and attend as much track time as I can. For a budget setup they do the job very well. Not going to get a better shock until you seriously pay for it.

[cooljess76]

Another alternative to Bilstein Sports and most will agree provides a better ride is Koni adjustables. They're a little more expensive, but they allow you to adjust and aren't as harsh of a ride as Bilsteins.

[iananderson02]

I like firm. I've never found bilsteins to be harsh, but again I like FIRM.

[mgbman69]

I would second Jess on the Koni's. I have sports with H&R sport springs on my my Ti and while it's a huge improvment over stock, it's nothing compared to a Koni SA shock.

When money is available I plan to upgrade to Koni/ground control or maybe TCKline SA's if things go really well!

[CirrusSR22]

I have the sport package and I asked all over on Sport vs. HD with the sport package. I basically got that both are fine, but I got more "votes" for the HD so I went for it. No regrets, although it did raise my ride height, but I think it brought it back to factory spec. I have a thread on here about it.

I think the Bilstein HDs are a bit firm. A tad more than I'd like, so I would have gone with the tourings in hindsight. Cheaper and softer, probably more like the factory Boge shocks.

[Cali330ti]

Just my 2 cents for anyone that might read this thread. Don't blindly buy something because someone says it's better or because it has an adjustment knob. Each shock is going to be valved differently to be efficient w/ a spring rate range. Do the research on what you want. If a certain shock rides better it's because it's valved to be softer. It will have a lower spring rate efficiency range. If you're going for ride then it's all good. If you're going for trackability...do the research on the spring rates you plan on using to shock valving.

Keep in mind that Koni's SA is rebound. Not compression. Rebound adjustment isn't going to benefit the everyday driver. Most shocks are also rebuildable w/ custom valving. Buying a used set of Koni or Bilstein sports on the cheap, use the savings to send them in for custom valving would be about the best bang for the buck until you decide on the fancy stuff.

[iananderson02]

Just spoke with Bilstein. They said that sports are for cars with ride heights 1" lower than a "stock" 318ti, all others should use HD's. They said as a general rule of thumb HD's are approx 10-15% stiffer than "factory" shocks on any given cars, Sports are 10-20% stiffer than HD's. Additionally, on some models the sport shock bodies/internals are physically cut 1" shorter to "give back the suspension travel".

So the question is, how much lower is the M-Tec than a standard, non sport ti? Can anybody with a stock car give me measurements from the ground to the bottom side of the fender lips (front and rear, please)? I will provide the measurements for the M-tec car as soon as i get home. Thanks in advance!!

[CirrusSR22]

The sport package drops it by .6" I believe.

[iananderson02]

If .5"-.75" is the drop on the M-Tec then I think the HD's are the way to go. Cool, thanks....

[cooljess76]

Factory Mtech springs are not lowering springs. They don't offer a drop because they're stock. Now if you want to raise your 318ti Sport to 4x4 status, get the HD's. If you want a stock ride, get the tourings. If you want a performance upgrade, get the sports.

[Cali330ti]

Originally Posted by cooljess76

Factory Mtech springs are not lowering springs. They don't offer a drop because they're stock. Now if you want to raise your 318ti Sport to 4x4 status, get the HD's. If you want a stock ride, get the tourings. If you want a performance upgrade, get the sports.

Exactly. And I'll say it again. Chill. Buy a used set. Look for any ti, z3, or z3m. Or piece a front and rear set together. Call Bilstein. Tell them what your application is and what your car's purpose will be. Get specific about it. Stock weight or maybe more due to stereo. You want a combination of a good ride and a performance upgrade as you're very interested to start auto-x or something occasionally. They'll know what valving to do as they are smart folk. Send in your used set and have to spend only 65 per shock for a full rebuild/custom valving. Aside from brakes (which this affects) this is the most important aspect of your car. Throwing together something that isn't right can/will have negative impact. What's the point?

Or do the same w/ the Koni Yellows. Just research what rebound adjustment does and realize it will not have a direct relation to your ride comfort in the way you think it will. It does have great uses under track conditions if you understand what changing it will do. Otherwise I know several people that simply put it at full soft or 1-2 clicks past full soft and leave it.

[iananderson02]

Originally Posted by cooljess76

Factory Mtech springs are not lowering springs. They don't offer a drop because they're stock. Now if you want to raise your 318ti Sport to 4x4 status, get the HD's. If you want a stock ride, get the tourings. If you want a performance upgrade, get the sports.

I understand this completely. However I think you may have misunderstood what Bilstein told me on the phone today. Bilstien has not created a shock that is set up for M-Tech cars specifically. As far as bilstein is concerned "stock ride height" is the compressed length of a Non-Mtech plain old base model 318.

The sport or Mtech models DO SIT LOWER than the base model car. The Mtech spring, when compressed is shorter than the base level springs. Additionally the rear spring pads are 5mm thinner than the base level pads (5mm vs 10mm). So as a result as far as bilstien cares the car does have lowering springs. However, with only .5" drop and no crazy stiffening of the spring the car is not low enough and the springs are not firm enough to warrant the changes made to the shock body of the sport version. If the car was 1" lower than a stock, base model 318 then yes, sports would be warranted.

The body and internals on the sports have been modified to ensure that the shock does not "bottom out" internally when the shorter lower springs compress under load.

The HD's are made with stock dimensions but comparatively higher rebound dampening than a stock non Mtech shock.

I have installed HD's on several cars in the past, everything from BMW 2002s, E30's, Acura Integras, Toyota trucks and lots inbetween. They may provide an increase in ride height over completely blown oil filled shocks but don't, in my experience, provide a higher ride height than healthy stock shocks. I think it is more the fact that old worn out shocks provide a lower than normal ride height and thus it seems higher when the new Bilstien HD's are installed.