Fiat 500 Forum banner
1 - 19 of 19 Posts

·
Registered
Joined
·
343 Posts
Discussion Starter · #1 ·
Sadly, they are just not worth it, IMHO.

The good:
* The car looks perfect, as it should when coming out of the dealership.
* The car's performance on twisty roads is tremendously improved over my stock Sport suspension.

The bad:
* They probably are overtaxing the struts and dampers.
* The car is too low and the front end is completely scratched from everything it touches.
* The car's behavior on non-perfectly flat roads is completely unpredictable.

Now, the last point is the one that made me decide what to do. In my city, there are NO flat roads. Everything is a bumpy ride. Ever since I got the Eibachs I've been subjected to either massive traffic jams or glass-smooth roads (outside the city) where the Eibachs shine.

But yesterday, I left the office at 3.00 AM. I was doing 50 MPH and the car was completely, utterly unpredictable. Without a flat road, the suspension was working overtime. And I had the feeling bump-steer had increased, and that the suspension was completely unstable, as if there was simply no time to dampen the irregularities, and the car was oscillating. I know, impossible. But trust me on this one, keeping the car going straight aheat at 50 - 60 MPH was a chore. I also felt as if the front end was more prone to diving while braking, which meant that, while my stock Fiat had a bit of roll and a lot of attitude, the new one has great looks, but can't really hold it together in real life conditions.

Actually, it's the first time ever I became nervous about driving my car. I actually had to slow down. From 60 MPH. Not good.

I'm swapping in my stock components this week-end. I'd rather drive like I use to, and get used to my mini-SUV than spend another day like yesterday on Eibachs.

If anyone from Mexico wants a set for cheap, you know where to get them....
 

·
Registered
Joined
·
1,262 Posts
Ive had eibachs on a handful of my cars and I can honestly say the eibachs on my 500 give the best ride of all of them. I didn't notice too much of a difference from stock except that it looks a million times better. Perhaps you need an alignment?
 

·
Registered
Joined
·
93 Posts
Which kit did you have? The 1" drop or the 2" drop? Are you sure it was the right kit for the North American 500? I can see the 2" drop not working correctly with the stock dampers but the 1" kit should be fine. I hope you get the car the way you want in the future. You may want to save up for a coilover kit.
 

·
Registered
Joined
·
22 Posts
Bumpsteer has nothing to do with springs. It concerns the the angle of the tie rods and the instantaneous center. Bumpsteer is typically induced after lowering a car. Some cars are not affected much after lowering and some are...the mini is pretty darn good...the Acura RSX was horrible, as two examples.

Stock dampers with higher rate springs typically never work oout...if the tires are ultra-low profile they also contribute to the discomfort you describe because a tire is an uncontrolled spring.

Factor in the kinematic qualities of the suspension bushings and you may have a recipie for disaster.

Spring, dampers/shocks, tires, bushings...all relate to one another. Any one can throw the system off balance.

In addition, roll forces increase when most garden variety cars are lowerd...at the mac strut end in any event.

so although the car may look good, and ride well on smooth roads, its performance generally falls off in every opther category when lowered without some thought about the entire suspension system, and, roll couple forces between the center of gravity and roll centers.
 

·
Registered
Joined
·
22 Posts
You have to come to the realization that this car, like so many others, are not designed to be lowered. Once you accept that notion you invariably accept a bit more work - brain and back:D

An inch is just a number if you are concerned with good handling. One guide is the angle of the front lower control arms...they should be - in gneral -parralel with the ground. They should never point up toward the wheel...which means the car is lowered too much.

In Front view:

Parallel LCA - in theory - mean that the tire wll move through the same geometric arc in bump and droop among toehr scrubby things, literally.

This is but one guide.

Another is understanding how roll centers affect the center of gravity. When the steering wheel is turned, roll forces are generated by the relationship between static and dynamic roll centers - front and rear. In simple terms, when a car is lowered one inch, the center of gravity is lowered by one inch. however, the roll center may be lowered by 2 inches. If you envision the center of gravity and the roll center connected by a virtual arm you will realize that alonger lever arm means more leverage - the car will lean more after lowering!!! It is nearly impossible for any of us to know exactly where the center of gravity is, but keeping our brains on the above example is a good way to rationalize what is happen as the sterring wheel is turned.

So, we've lowered the car and put on stiffer springs so why should the longer lever arm matter? It matters because we should always be concerned with what the tires see...and they see greater roll forces to some degree and this potentially decreases grip.

Increase track width...this will actually raise static roll center a bit, a good thing - shorter lever arm. A wider track also decreases roll moments and allows a more equitable work load between the inside and outside tire in a turn.

There is much more to the few items above, but keeping an eye on everything is really important.

Heavier springs add greater control...they do not necessarily add more grip. but control is important. Heavier springs need stronger dampers. But, if you increase track width, you can use stock springs with better dampers - not necessarily stronger dampers, just dampers with more fidelity...koni...

Rake...back to CofG and RC relationship. If the front end is lowered more than the back we have rake. Outwardly this means nothing. In theory we are trying to make the lever arm between the rear RC and CofG shorter than the front. This says nothing about where the RC migrates to in roll. The point here is that a shorter lever arm will load the rear tires faster than the front inducing a bit of oversteer. This is enirely dependent on the rear suspension design. A live solid rear axle's Rc location is asically at the bottom of the differential. So it is fairly high...one of the reasons it's so easy to oversteer a pickup truck - there are other reasons but this one is fundamental.

If I were tuning my 500 I would do the following as a beginning: increase front track width by 15-20mm per side, rear by about half that. you can play games with wheel offset and available spacers. A wider front track also relaxes the camber curve potentially eliminating the need for camber plates on the street - track is different.

I would fit a wider wheel and tire combo - 7.5" wide x 16"/17" wheel but which ever is lighter is better.

for a 2,600lb car...lower by 10-15mm front and a little less in rear. I would selct a linear rate spring in the 325lb/in - 360lb/in for the front and 260lb/in-300lb/in rear. The bigger spread in the rear really depends upon driving venue, experience behind the wheel and rear swaybar availability. But I would stay aroound 280lb/in. I have no trouble using Koni dampers...great product!

Fine tuning...a bigger adjustable rear swaybar...less is more. alignment specs...as little toe-in as possible without being toe out...and the accuracy of this spec whiel actually driving is determined by bushing deflection. So I would consider replacing one or both lower control arm bushings with hard rubber or poly...not a fan of poly in some applications.

Rear tow...slightly to-in. This hleps the rear tires to begin to build skip angles in sync with the front tires as they are being turned.

It's late, gotta go. Have fun. Drove my first 500 in NYC this weekend...waiting for the Abath.

My last car was a 2005 JCW mini with some minor work like above. Was a lot of fun. Nearly 200K miles...it's done.

I can draw a picture of the relationship between RC and the CofG to help illustrate what happens...I just need help getting it here. I am a computer moron...sorry. Once you see this illustration you may likely say, "aha!!!" It was sobering to me. I did much less to my cars and had more fun driving them.
 

·
Registered
Joined
·
61 Posts
Nice Post MEB

I installed Eibach Pros (1" drop) and am very pleased with the appearance AND the ride. My fears of ride going to **** were not warranted. I do club racing (not with a Fiat 500 yet) and am familiar with some of the vagaries of which you speak but have no issues whatsoever with the Pro drop.
Rick
 

·
Registered
Joined
·
22 Posts
Thank you.

I re-read my reply this morning and there are so many elements I would like to clarify but two in particular are about the front LCA position and wider track.

Take the "parallel" comment with a grain of salt. We really have to find out what the stock 500's camber curve is like. Most mac struts have ~.5 deg neg camber at normal ride height. When the car leans or the tire hits a bump, the arc the wheel moves through becomes less and less negative and may in fact become positive at some point. We don't necessarily like this for sporting driving and it's definately not an aid on the track.

So a couple of things can happen depending upon what we do...if we lower the car, we essentially eating up some of that camber curve...static camber becomes less and less negative, follow?

So, lets assume we still want to lower the car and static camber is still negative but less so. Lets also assume the the LCA arms are parallel or nearly so.

Lowering usually invloves installing stiffer springs so the car will ulitmately lean less...so the reduction in neg camber pointed out above may not mean much on the road - public road.

We can increase track width as a way of relaxing the camber curve; in a wider arc, the tire takes longer to mover from neg camber to positive, and, roll forces decrease...and static roll center sits a little higher - all very good.

Parallel LCA...as the wheel moves through its arc, the tires - in front view - are literally moving in and out - track width changes! This scrubing action created by the tire move laterally can cause some very unsettled front end conditions. This is not the same as bumpsteer. Typically this condition is bad when the lower control arms are not near parallel because the arc or scrubing action is different in bump and droop...just think about this for a moment. So if one tire hits a bump and moves up while the other hits a dip, one will have a greater scurbing force and this force is registered at the steering wheel as dartiness, uncontrollability.

so the position of the LCA is important but with regard to camber, they both have to be analyzed together to see which one is favored for a given setup on a given driving venue. A track car will likely need more neg camber than a road car...a softly sprung car in reality needs more neg camber than a stiffly sprung car.

Wider track...in front view...pushing the wheels out farther changes SAI = Steering Axis of Inclination or King pin axis. This axis is also defines the camber angle for a mac strut...so when we change camber on a mac strut we are changing SAI.

The bigger point here is that as the tire move farther out, the point where SAI intersects the ground becomes closer to the tire's centroid contact patch. You have to envision that the center of the shock at the SAI angle determines - from above now - the arc the wheel moves through as it is turned...as it precesses the SAI angle.

The point here is that the SAI angle or point at the contact patch is literally the fulcrum around which the wheel moves. As such, there is a force generated at the contact patch.

Now, when a wheel is turned, the tire always wants to return to straight ahead - lets remove steering systems from our thinking for now. What is being described here is a tire's self aligning torque. And this very torque is repsonsible for generating steering feel - along with pneumatic trail. more on the later.

So if you imaging looking down on a tire from above the car, or from below the contact patch, you will see the contact patch distort as the wheel is turned. As cornering speeds increase this distortion increases and SO DOES (should) STEERING WHEEL EFFORT! There becomes a point when the tire begins to saturate and the distortion begins to relax and the steering begins to lighten up telling you the driver that you are approaching the tire's limit of adhesion. This is exactly what car magazines describe as steering feel.

Now, on a front drive car, the SAI angle typically sits outside the tire's centroid axis...but most of the distortion forces occur in this region of the tire. So, we in effect have two points of levarage that can and often do dilute one another. Moving the wheel farther out moves the SAI angle closer to the tires centroid axis creating the potential for better steering feel.

Power or electronic steering systms may also be tuned indelicately leaving us with poor steering feel no matter what we do.

The fidelity or sensitivity that we ad to our setups can make our cars fast because they are predictable. A 2g cornering number is just a number if it cannot be leveraged on the track or road with consistency.

springs = more control...grippy tires = higher cornering force. Controlling roll to a point will help increase cornering power, along with better camber curves, but beyond a given point making a suspension stiffer is really about adding more control. We always have to balance the two...and control (balance) is generally more important. Ya gotta get the car pointed stright ahead as fast as possible.
 

·
Registered
Joined
·
22 Posts
...to be clearer about tire distortion...

The tire distorts when the wheel is turned. Self aligning torque generated by the tire's homogeneous makeup - is rubbery character - tries to keep the tire pointed straight ahead.

The two create an increase in steering effort as cornering forces increase. When a tire saturates, or begins to reverse SIN, both distortion and self aligning torque begin to fall off. High performance tires phase through this with less warning than normal passenger tires for example. The challenge here is that the higher cornering forces available from a high performance tire or DOT R compound tire allow faster speeds. So couple this with a peakier saturation curve and you can quickly over-drive the car...into something not so movable:eek:
 

·
Registered
Joined
·
343 Posts
Discussion Starter · #13 ·
Hmm. I wonder if I have the Sport or the Pro Kit. I'll need to check that out... my springs are red, but many people say the first batch of lowering springs were the wrong color, anyway.
 

·
Registered
Joined
·
1,550 Posts
Hmm. I wonder if I have the Sport or the Pro Kit. I'll need to check that out... my springs are red, but many people say the first batch of lowering springs were the wrong color, anyway.

We could help you with that, if you posted more pictures:p
 

·
Registered
Joined
·
22 Posts
Pro-Kit shoud be black and is a softer than Sport Line...3/4" drop...Sport Line should be red and is stiffer than Pro-Kit...1"-1.5" drop

Both are progressive wound springs. Good for sport driving on the road...linear is still better for the track.
 

·
Registered
Joined
·
2,574 Posts
My prokit is red. I bought them before the sportline was available.
 

·
Registered
Joined
·
343 Posts
Discussion Starter · #18 ·
I think I may have the Pro-Kits. At least that's what I thought I was buying. My set is light red in the front, dark red in the back. But they surely drop the car far more than 3/4". 2" is more like it!

The car is back to stock now. What a RELIEF. FIAT did an awesome job with the suspension, even though the car itself looks even more like a toy now.

The strange thing is - I feel it's now taller than before. Can that be possible? Will it settle down again? I'll try to take some pics...
 

·
Registered
Joined
·
343 Posts
Discussion Starter · #19 ·
The stock suspension ROCKS! After living with it for a while, I can safely say - I don't miss the Eibachs AT ALL.

If you want all out performance, the stock suspension is it. If you want great looks, the Eibachs are the answer, IMHO. I'm posting some pics later.
 
1 - 19 of 19 Posts
Top