[Speediance]

As featured on Homepage.

The following is the tale of the search of an amazing suspension....

I am going to start by saying that I've been a lurker on this forum for over 3 years now and in that time, I've had tons of frustrations and solutions. I'm not going to talk about them all, but i'm going to keep this article as informative as possible and something for everyone, from newbies to pros. However the context of this conversation is going to be suspension. And by suspension, I don't just mean a set of coilovers, i'll explain that...

In my opinion the ONE MOST rewarding mod that you can do to your car is a GOOD suspension. I'm sure most of you will agree and have felt from the increase in the average number of traffic tickets, that our stock cars have some PRETTY darn good power. I say that after having gone the performance mod route. I have stett intake, code3 ic, rr midpipes, bastuck exhaust. The power is great, but you can practically never put down that power to the wheels in a controlled and desired fashion. When you have anything over 370 crank HP, the stock suspension is simply inadequate.

Having noticed this after couple of autocrosses and track school, I set out to find an awesome suspension that will remedy all the problems and most importantly constant put a smile on my face. Unfortunately I quickly discovered that a popularity of KWs has nothing to do with performance, but simply because of price point. Pardon me, if I say, but most of those V1,V2,V3s are garbage. I'll explain in a minute...

The following are some points and facts that I gathered so far:
1) You want linear springs in your suspension.
2) Quality of a suspension is mostly determined by the dampers.
3) Not all camber plates are the same. There levels of quality and its a must-have component in a good suspension.
4) There is a certain level of harmony that exists between a shock and a given spring. Just because the shock is adjustable, doesn't mean you should fiddle with it to say "this setting is right for me, but this maybe right for you". By fiddling with damping you are unsettling the harmony and thereby compromising the performance. There is a quite a LOT of *objectivity* in suspension tuning.
5) Upto a certain degree, you can have both good ride and amazing handling. Good ride is all about having good shocks and good cornering depends heavily on the spring rates. But its not necessarily that simple. The key is in going to or asking the RIGHT person who knows and is most preferably a professional who does this for a living. I DID, AND THE FOLLOWING ARE MY EXPERIENCES.
6) One major thing: Just because its stiff doesnt mean its better. A unmatched spring/shock ride that feels stiff is simply garbage, or put in other ways, false-ego-booster.
7) Sway bars should only be used for fine-tuning the suspension; the majority of body-roll reduction or handling characteristics should come from a proper spring-shock combo.

About 2 years ago I drove an M3 with EDC and I thought it was amazing. Then I rode someone's M3 at an autocross and I was convinced that something about that car was so different than our 335s when it came to handling, although our cars have practically identical chassis. So what does the M3 have:
1) Slightly wider wheelbase, but this is because of all the suspension components.
2) LSD!!!! - one huge difference
3) longer rear camber arm, wishbone whatever your favorite vendor calls it. Its also lighter as its made of aluminium.
4) tighter tension rods and better/stiffer front tower brace.
5) better toe link, stronger aluminum guide rods
6) slightly stiffer springs and obviously better shocks compared to 335
7) last but very important are Subframe bushings. 335 ones are real crappy, causing the car to sway side to side under hard acceleration.

Not everyone will run into the inadequacies listed above in their car. For those who really drive hard and pay attention to what's hapenning to the car, they will consider upgrading all these components. Since every little thing bothers me, I upgraded all the pieces and more...

Now lets get into the real meat of the thread. So what did I get finally?

1) ALL M3 suspension components + custom GC pieces
2) Ground Control (GC) coilovers


===== M3 COMPONENTS =====

In the entire following process, Jay at Ground Control was the one who helped me finish it with finesse and precision. He has tons of professional racing experience and has been designing suspensions for over 20 years. He plans to be on the the forum shortly...

Review 1: M3 conversion
Jay and I carefully looked at realOEM and decided all the pieces we needed for the conversion. He quickly pointed out that I would need some custom toe links in the rear and other pieces in order to finish the conversion. He also "upgraded" some of the M3 links to ground control which allow for much more precise alignment and won't slip over time losing alignment (pm for more details).

Note: The stuff you get from Tischer is not exactly guaranteed to fit; BIG risk! Also, Jay was able to get some of these parts at a lower price than most of the vendors out there. Call ground control for pricing.

So how does it feel? Well I will try to review the M3 parts as exclusively as possible, but it will be hard since I got everything done at the same time.

Here are my impressions:
1) The front conversion consists of M3 sway & corresponding bushings, front control arms and links. Its hard to tell a huge difference in the front. Except the M3 links are slightly longer and have more built-in camber. Look at the pictures below to see the difference. AFAIK, Jay had a hard time fitting the M3 bushings for the sway bar. They had to custom design some precise pieces. Look at the pictures below for all the parts and how they fit in my car. The front is now very tight and the extra camber makes turning more fun/precise. However, along with the GC camber plates, my total camber in the front is -2, so I am not sure how much of that comes from the M3 control arms.
2) The rear consists of a lot more parts than the front and hence has the most major difference. The M3 subframe bushings are much better designed than the 335 one. They make a huge difference in the stiffness of the rear. The car doesnt sway left-right anymore under hard acceleration (my car is around 350RWHP), which is primarily due to the crappy 335 bushings.
3) The rear lower wishbone is slightly longer than the 335 wishbone. Better travel.
4) Jay had to design a custom upper link that runs parallel to the wishbone. Look for it in the pictures; its red colored.
5) Its hard to tell the difference due to all the parts individually, however my overall impression is that the rear feels very composed and structurally stiff. Doing a skidpad test, its obvious that I have a lot more traction now.
6) At first I was hesitant to put the M3 sway bar as I had horrible experience with the H&R sway bars, however, along with the GC 550lb rear springs, the M3 sway bar works perfectly well. Its not laterally stiff AT ALL.
7) There are other small custom pieces in the rear as well. Look at the pictures.

===== GROUND CONTROL KIT =====

The kit contains the following:

>> 2 SHORT single adjustable, custom valved Konis in Ground Control short strut housings, seamless DOM steel, powdercoated for corrosion resistance.
>> Complete Shortened Front Strut Housing - Machined from seamless DOM 1026 steel alloy tubing. Heavy-duty sway bar bracket welded on. Our design is much stronger and more rigid than any of the aftermarket housings that are actually modified stock housings, with skip-welded sway bar brackets which are much stronger than stock or oem.
>> Koni Single Adjustable Front Strut - Struts are externally adjustable from underneath the hood, even with the factory framne brace. This strut is prepared for coil over use, and eliminates machining of critical suspension components.
>> Ground Control Threaded Sleeves - This system is designed to eliminate stress risers caused by machining notches into the strut housing. Unlike other companies that claim superiority by cutting threads into a critical component of the suspension, Ground Control uses engineering common sense to maximize the strength of the suspension.
>> Ground Control Adjustable Spring Perch - A unique design, which uses an Allen head bolt to clamp the single threaded perch into the correct position. No secondary pieces are needed to jam the threaded perch into position.
>> 2 SHORT Koni single adjustable rear shocks. KONI Single Adjustable Rear Shocks - Custom made for Ground Control by Koni in Holland, Preadjusted to match rear spring rates using our shock dyno.
>> 1 Pair front Camber Plates. Ground Control Racing Camber / Caster Plates - More camber adjustment than stock, caster adjustment, aircraft bearings, engraved with calibrated degrees, with stainless steel reinforcement. Every component is anodized or plated, including fasteners. Adds extra travel to avoid excessive bottoming out, this is a very well engineered product. The stainless steel reinforcement prevents electrolysis between the steel fender and the aluminum camber plate.
>> 4 Eibach ERS springs, many rates available, with expert consultation at the time of purchase if desired (or you can choose your own)
>> 4 Ground Control bump stops (made in Germany)
>> 2 Rear Ride Height Adjusters
>> 1 Pair rear upper shock mounts (urethane)

This KIT is not pre-made, kind of like the KWs, FK, Bilstein or others which are more like one-size-fits-all. Ground Control can customize the setup for your needs. A street/track setup may include 525/650lb front/rear spring rates. But again, you can work with Jay and he'll get you exactly what you want. The shocks/struts are KONIs custom-valved by ground control. The springs are Eibach Pro linear springs made for ground-control specs. And the camber plates are simply the best that is in market. Vorshlag has been known to steal innovative elements from GC camber plates. They are simply unmatched in quality. I went with 430lb Front and 550lb Rear springs. I have some pictures of Shock-Dyno graphs of the shocks in my setup; scroll below.

REVIEW 2: Ground Control Kit only
I was considering to get the TCKline coilover kit, until I got a chance to drive a E39 328, moderately modded, with a ground control kit. I was so blown away with the performance -- balance and stability during cornering. Mind you I had ridden a car wit TCKline setup as well with 400/500 spring rates. Although TCKline is much better than any KW, Bilstein, or whatever, I thought Ground Control was better than that. So I chose ground control... simple!

First let me say that the ride quality is absolutely wonderful; it feels softer than stock sport suspension. The shocks absorb all the road noise and the ride is absolutely comfortable. Now that was for the ride part, but most of us can sacrifice some ride quality for performance. So how is the performance? Jay dialed in all the "right" setting for the shocks, which is the place where the springs and dampers are in harmony. The shocks are so quick in reacting to road surface changes. The car is simply glued to the road at all times. I am running -2 camber in the front. The cornering is so sharp, the compression of the springs is so predictable. With the ZSP, you could feel the slow weight transfer from side to side and front to rear as well as the oscillations (springiness, so annoying), but with the GC kit its very quick, all the while very little body roll. The canyon runs are so much fun! I feel like I need to learn english like Jeremy Clarkson in order to describe the effects of the GC suspension. This is a perfect street performance setup. I haven't gone to any autocross or track with this setup yet, so I cant say how it is, but I'm eager to try it out.

REVIEW 3: M3 PARTS + GROUND CONTROL E90 KIT
1) The car has pretty much NO body roll; I can flat out take a run at 65MPH which I was able to do at 40MPH max earlier.
2) The M3 components are amazing especially the front of the car feels so responsive and predictable. I think all the M3 components widened the wheel-based slightly; works pretty good.
3) The Front M3 sway bar does magic to the car along with the GC suspension. Steering is so sharp. I don't have exact numbers, but it feels like my slalom speeds have increased by atleast 10-12MPH.
4) The bushings and rear wishbone makes the rear feel extremely controlled and balanced during acceleration and while exiting out of the turn.I love the oversteer that I can get when I turn aggressively.
5) The shocks are ABSOLUTELY amazing in absorbing the road noise and reacting during turns. They react extremely quickly to road conditions. The rebound is so quick. Its so weird that sometimes it doesn't even feel like you are going over a quick dip.
6) At first I was hesitant to put the fat M3 rear sway bar on the car (especially because 335s don't have an LSD), but I'm quite happy with the results. My major complain with the previous H&R bars, was they were too stiff and so they made the rear laterally unresponsive. As in, the threshold of traction was very unpredictable. Now all that is gone. Again, I dont have numbers, but doing a skidpad test, I can distinctly feel increased G-force. Also the point at which the rear starts coming out (oversteer) is gradual and predictable. I'm quite happy with the sway bar.
7) During the weekend morning canyon runs, the car is just so much fun. Car just glides through the corners effortlessly, so agile and so predictable.

Conclusion:
Not much to say here, except that I SIMPLY love the new suspension. The ride is so smooth on street and highways, but at the same time, its uncompromised and almost-raw in performance. If anyone has questions, I'd be happy to answer them. It was an absolute pleasure to work with Jay at Ground Control. He is the man behind all the work that happened on my car! Their work was extremely high quality just like their products and especially their design.

Picture captions:

1) Inside Ground Control
2) Linear and Progressive Bumpstops
3) Massive collection of GC-spec springs made by Eibach
4) A typical ground control front coilovers
5) My ride before the conversion
6) Jay holding a Koni shock
7) Shot of me holding one of the shims
8) A koni strut on a shock dyno
9) Strut compressed
10) Shock dyno graph of various struts. Each graph comes in a pair. The top is compression graph and the bottom is rebound. The graph of the strut in my kit is the orange one (the inner-most set).
11) All M3 components laid out on floor. the 3 sway bars are (left to right), H&R, stock 335, M3.
12) Front tension links, As you can see M3 ones have more camber.
13) Some machining of the front control arms as they were slightly off.
14) Front Sway bar bushing and housing, custom designed.
15) Front GC suspension going in...
16) Stock M3 strut
17) headlight regulator rods
18) Stock 335 rear
19) Rear M3 sway bar going in. The bushing that came with it was too stiff and wouldnt work, so they had to cut in and then reuse it.
20) One of the custom designed links in the rear. Notice the adjustability and inherently better design than the stock piece.

[Speediance]

More pictures...

All the new parts are M3 ones, the old/dirty ones are stock parts. All the red pieces are either custom ground-control or part of the E90 kit.

[Speediance]

Ground control pics...

[Hedges]

Wow nice read!

[Alpina_B3_Lux]

Great review, very informative!

I'm also planning to install most of the M3 suspension parts on my E90, so it's great to know that there's so much added value in thes. I'll however combine it with a Bilstein coilover (B16 Ride control) as I need it to be TÜV approved.

Alpina_B3_Lux

[doctor_vino]

How can I get a hold of Jay?

[enrita]

very nice indeed

[mike-y]

very nice. I've been very happy with the ground control setup I have on my honda. I'm using their upper mounts, coilover sleeves, and shock bushings on custom-valved koni yellows. Good to see they have a kit out for the e90/92 now.

[zsapphire7]

wow nice... how much does a setup like this cost?

[stressdoc]

Great to see interest in suspension, and a treatment of the whole system/package.
A comparison with some of the systems that HP Autowerks has would be interesting.
I think I would prefer Swift springs to the Eibachs. You may further enhance handling by weight reduction, including brake parts.

At some point it would be cool to run a proper side-by side comparison test, with independent drivers doing slalom, skidpad, etc. With photo/video documentation, so you can compare body roll, transitions, etc. Handling is much more complex to assess than acceleration in the 1/4 mile, but perhaps more interesting.

[Speediance]

Originally Posted by zsapphire7

wow nice... how much does a setup like this cost?

The M3 parts are around the same price as you get from Tischer. There is a certain bottom line on parts cost. Cant go lower than that. As for the GC kit, its $1850. AFAIK, GC is planning to sell an M3 conversion kit as well.

[Speediance]

Originally Posted by Alpina_B3_Lux

Great review, very informative!

I'm also planning to install most of the M3 suspension parts on my E90, so it's great to know that there's so much added value in thes. I'll however combine it with a Bilstein coilover (B16 Ride control) as I need it to be TÜV approved.

Alpina_B3_Lux

Thats great. But I would strongly urge you to drive a setup that you are considering to buy before you do so. Also make sure that the kit has M3-style rear shocks if you do the entire M3 conversion in the rear.

[Speediance]

Originally Posted by doctor_vino

How can I get a hold of Jay?

I think the best way is to call Ground Control directly. Goto www.ground-control.com and get the number.

[zsapphire7]

Originally Posted by Speediance

The M3 parts are around the same price as you get from Tischer. There is a certain bottom line on parts cost. Cant go lower than that. As for the GC kit, its $1850. AFAIK, GC is planning to sell an M3 conversion kit as well.

Awsome.... I like how the struts are custom valved to your spring selections and dynoed. I heard there is a lot of variance between dampers even ones sold in the same kit. Id like to ensure I get a properly matched/valved damper to a spring rate of my choosing. I wonder if the HPautowerks damper sets come with dyno charts for the dampers..

[Speediance]

Originally Posted by stressdoc

Great to see interest in suspension, and a treatment of the whole system/package.
A comparison with some of the systems that HP Autowerks has would be interesting.
I think I would prefer Swift springs to the Eibachs. You may further enhance handling by weight reduction, including brake parts.

At some point it would be cool to run a proper side-by side comparison test, with independent drivers doing slalom, skidpad, etc. With photo/video documentation, so you can compare body roll, transitions, etc. Handling is much more complex to assess than acceleration in the 1/4 mile, but perhaps more interesting.

I dont imagine that springs alone would make a drastic difference to your suspension. The ground-control shocks are designed to work with the Eibach springs, which are custom-designed by Eibach according to GC-specs.

Going back to the spring-shock harmony topic, it would do no good to a suspension if you simply change the spring and the shock doesnt work with it. I would take a carefully tuned kit, well-designed for years by professionals who are world-renowned in the racing community, over some adhoc combo that a random person on a forums suggests.

Also, one more thing to say about comparisons. I'm sure as you know this is easier said than done. There are just too many variables in suspension tuning. Even 2 same exact setups can have different results based on the aggresiveness of alignment and driver skills. Also bodyroll is not an objective criteria when talking about different setups which have especially different spring rates. The only way is for the same driver to take different cars around a given track, 10-15 runs and get the best laptime. But you are right, it'd be awesome get some objective numbers.

Quick note: Compared to a TC Kline 400/500 F/R with Vorshlag camber plates, which I had a chance to ride in, my setup is superior. Its hard to say why I say "superior", but rest assured, if you got a chance to ride the two setups you would say the same. Its a very subjective thing, and it would all depend on how sensitive you are to everything that goes on during cornering and weight transfers.

[Speediance]

Originally Posted by zsapphire7

Awsome.... I like how the struts are custom valved to your spring selections and dynoed. I heard there is a lot of variance between dampers even ones sold in the same kit. Id like to ensure I get a properly matched/valved damper to a spring rate of my choosing. I wonder if the HPautowerks damper sets come with dyno charts for the dampers..

I think you'd be hard pressed to find anywhere other than Ground Control, where you can see the Dynochart of any components in your suspension. When you talk to Jay or anyone at ground control, they will hook you up with the right shock/strut that goes with the springs rates of your choosing. Just describe to them what you are looking for in the suspension and YOU WILL GET IT...

[Alpina_B3_Lux]

Originally Posted by Speediance

Thats great. But I would strongly urge you to drive a setup that you are considering to buy before you do so. Also make sure that the kit has M3-style rear shocks if you do the entire M3 conversion in the rear.

I've driven the Bilstein B16 extensively and was very positively impressed. I've also had a ride in a car with the same coilover and most of the M3 components and it seemed (to me, but I'm no expert) to work well together.

Pursuant to HP Autowerks, the OEM shocks work also with other coilovers and the M3 parts...we'll see!

Alpina_B3_Lux

[Soni]

OMG I know Jay over 18 years ago when I used to live in SF and owned a 240Z. Back then they were still at Marine County, and yes, they are well known as one of the best suspesnsion specialist. Too bad I am living in Toronto now, or else I would have gone to him long time ago. As a matter of fact, I just called him and talked to him and he still remember me this old customer Glad to know that now he has some parts for our cars.

[undecided]

If the driveshaft is not replaced by a longer one? Same goes for the front with the steering.

Does that make sense?

[Speediance]

Originally Posted by undecided

If the driveshaft is not replaced by a longer one? Same goes for the front with the steering.

Does that make sense?

Sorry, but I'm not sure if I understand your question...

Are you referring to my comment regarding M3 parts making the wheelbase wider? I didnt say it makes things longer (front to back), I said wider (left to right).

[undecided]

Do you think the stock suspension could benefit from a simple replacement of the stock bushings with better ones like the ones you used in your conversion?

[Speediance]

Originally Posted by undecided

Do you think the stock suspension could benefit from a simple replacement of the stock bushings with better ones like the ones you used in your conversion?

YUP!!! I'm assuming you are talking about subframe bushings. Read my impression in the "review 1: M3 conversion", there is part about M3 bushings. They are much better designed than the 335 ones (they use hydraulics). But they are quite hard to replace from what I've heard. And require dropping the entire rear subframe. For that labor cost you might as well add other M3 parts