suspension ideas for e39?

[chilopia]

i plan on buying coils soon, possibly megan racing coilovers, but I don't know what else is out there. i have a good idea in my head of what i want but still trying to gather up some knowledge first... ideas? thanks

[Dat Aus]

IMO, EAC coilovers are the way to go. They are both height and damping adjustable for the same price as Bilstein PSS, which are only height adjustable. I've heard good things from members who have them installed.

I will be purchasing these in a few months time, but last time I checked their site said they were sold out. I'm not sure they even make them anymore.

[Solo12]

IMO, EAC coilovers are the way to go. They are both height and damping adjustable for the same price as Bilstein PSS, which are only height adjustable. I've heard good things from members who have them installed.

I will be purchasing these in a few months time, but last time I checked their site said they were sold out. I'm not sure they even make them anymore.

I agree 100%. Also the way the EAC are designed the suspension travel and preload are independent of ride height. So when you raise or lower your car you are not automatically changing the dampening characteristics of the coilover. On most coilovers as you go lower the spring preload increases (b/c spring in being compressed) so you are automatically going to get a stiffer ride the lower you go.

As far as availability of EAC is concerned I ordered some items from them a few months ago and asked about their coilovers. They said they were planning on getting some more in stock, but did not have a firm date. So hopefully they will bring them back.

OP
I am a believer in you get what you pay for I think Megans (NNRs too) are going to be more trouble than they are worth. Some have had Megans and liked them, but most people seem to have had lots of problems with them. I think you should pay more and get something that will last longer, give you a better ride and not cause problems.

Like I said EAC would be my #1 choice, but if they are not available when you want to order then consider BC coilovers with Koyo bearings, they also are designed so the suspension travel and preload are independent of ride height. Its your money, but if I were looking at inexpensive coil overs I would look at the following in this order.

1) EAC coilovers
2) BC coilovers with koyo bearings
3) ST coilovers
4) Bilstein PSS

[Doru]

So when you raise or lower your car you are not automatically changing the dampening characteristics of the coilover. On most coilovers as you go lower the spring preload increases (b/c spring in being compressed) so you are automatically going to get a stiffer ride the lower you go.

I think this is not quite accurate.
If you lower the car, you bring the adjustable "perches" down, and in turn you slacken the spring. When you raise the car, the "perches" are raised, compressing the springs. I know, when I raise my car, whenever I get close to last turns, it's getting harder and harder due to the compressed springs. When I lower it (and I just did a few days ago), the last few turns you can do it by hand, you don't even need the adjusting wrench.

0.02

[Solo12]

I think this is not quite accurate.
If you lower the car, you bring the adjustable "perches" down, and in turn you slacken the spring. When you raise the car, the "perches" are raised, compressing the springs. I know, when I raise my car, whenever I get close to last turns, it's getting harder and harder due to the compressed springs. When I lower it (and I just did a few days ago), the last few turns you can do it by hand, you don't even need the adjusting wrench.

0.02

Interesting so you are saying the spring is compressed more when then suspension is higher. So is the ride more firm when the the car is sitting higher than when the car is lower? Or there is no perceptible difference?

I thought people said the more then lower their car the firmer the ride gets with coil overs. Or is that not the case? If that is the case what causes that as you are saying it is not the spring?

[chilopia]

thanks for the input guys. my budget will probably be around 1500 so if i can find eac's i'll look more into them. and also-- would it be appropriate to buy both the front and rear sway bars or just the rear? what kind of difference would i see if i just went with a rear sway bar and not both?

[Doru]

Interesting so you are saying the spring is compressed more when then suspension is higher. So is the ride more firm when the the car is sitting higher than when the car is lower? Or there is no perceptible difference?

I thought people said the more then lower their car the firmer the ride gets with coil overs. Or is that not the case? If that is the case what causes that as you are saying it is not the spring?

I haven't noticed a difference in "stiffness" between summer height & winter height. The difference is about 2cm or close to 0.8".
I kept the same dampening adjustment.

[DHoang]

I agree 100%. Also the way the EAC are designed the suspension travel and preload are independent of ride height. So when you raise or lower your car you are not automatically changing the dampening characteristics of the coilover. On most coilovers as you go lower the spring preload increases (b/c spring in being compressed) so you are automatically going to get a stiffer ride the lower you go.

It would appear that way, ie, EAC coilovers have height adjusters that is INDEPENDENT of spring preload. At the very bottom of the spring's perch, there's a threaded tube that can be twisted to extend or retract the entire upper damper housing.



Thus it would appear that it's not required to compress the spring to raise the car higher off the ground. One can do so by rotating the last ring next to the blue anodized body and change ride height that way.

Interesting so you are saying the spring is compressed more when then suspension is higher. So is the ride more firm when the the car is sitting higher than when the car is lower? Or there is no perceptible difference?

Yes, traditionally, to raise the car higher off the ground, one would "PRELOAD" or compress the spring more.

I thought people said the more then lower their car the firmer the ride gets with coil overs. Or is that not the case? If that is the case what causes that as you are saying it is not the spring?

When the car's lowered, theoretically, the overall suspension travel is reduced. It is this reduction in travel that causes harshness, not firmness. Big difference between harshness and firmness...harshness is intollerable whereas firmness is.

In theory, if you have 2" of suspension travel, and you roll over a bump that is 1.5" deep, your suspension travel is able to absorb that 1.5" bump, plus have an additional 1/2" of suspension travel remaining. HOwever, if you roll over a bump that's 2.5" high, then in theory, the said suspension will absorb the first 2" it hits, use up all its travel, and thus the remaining 1/2" of bump height will force the car to roll over that distance, and raise the car's frame off the ground by 1/2" remaining.

Conversely, Suppose your suspension is not lowered, w/ your suspension travel now @ 3". By the numbers, there's enough travel to absorb the 2-1/2" high bump, and with 1/2" travel left before bottoming out, when going over this bump, the car is able to maintain its even level as before when going over the bump.

[Jason5driver]

On the single adjust coil-over, as you lower the car, the spring will compress more, due to lowering.
Strut/shock travel is lost, and the spring is at a higher tension.

[Solo12]

thanks for the input guys. my budget will probably be around 1500 so if i can find eac's i'll look more into them. and also-- would it be appropriate to buy both the front and rear sway bars or just the rear? what kind of difference would i see if i just went with a rear sway bar and not both?

I put the EACs at the top of my list based on the company's reputation on this and other forums combined with the way they adjust. BC seems to the the popular option right now in large part because of their price. If you go the BC route I think a lot of people have bought from Tristan at circuit motorsports. He might be a good source as he seems to have had a decent number of e39 customers and seems to be swapping in the Koyo bearings.

Searching may help you regarding the sway bar question it has been discussed before. I am very happy with my Eibach front and rear sway bars I think the car handles great. I know some people feel the Eibach's are too large and they have a negative impact on handling. The previous owner installed them (along with powerflex bushings) on my car so I can't relate the current handling to how it handled with the factory sways. All I know is there is very little body roll and I think the handling is superb (I have oem 17style 42s, no spacers, and oem sport suspension).

I think the other popular choices are an M5 rear sway bar and stock front or m5 rear sway bar with M sport II front sway bar. You might be able to get a good deal on an used M5 rear sway bar from the classifieds here or on the m5 board. Not so sure I would go with poweflex bushings as they sometimes squeak (pretty sure it is them causing the squeaking) and I am not sure they are really necessary.

Overall for suspension and sways I would say reach out to some local members in your area who would be willing to give you a ride in (maybe even drive) a car with set up that you are interested in that way you can get a true idea of how it will perform/feel.

It would appear that way, ie, EAC coilovers have height adjusters that is INDEPENDENT of spring preload. At the very bottom of the spring's perch, there's a threaded tube that can be twisted to extend or retract the entire upper damper housing.

Thus it would appear that it's not required to compress the spring to raise the car higher off the ground. One can do so by rotating the last ring next to the blue anodized body and change ride height that way.

When the car's lowered, theoretically, the overall suspension travel is reduced.

DHoang thanks as always for your detailed explanation. EAC says the travel and preload are independent of height adjustments. And I am under the impression the BC coilovers have a similar design also allowing preload and travel independent of height adjustment. I noticed you mentioned in theory when discussing travel being reduced. So are you of the opinion that having a set up like EAC/BC where preload and travel are independent of height adjustments is an important feature or when looking at coilovers it should not big a big factor in your decision of what set up to go with?

To me it seems like you are getting the adjustability of coilovers so you can set your ride height wherever you want, but you are not necessarily going to have to sacrifice ride harshness to get that ability. Although perhaps that is more of an issue if you are really slamming your car. It just seems like it is a better set up, but perhaps there is a reason KW and Bilstein don't use it.

[Jason5driver]

Independent pre-load/ height and damping adjustments are very important IMO, and would be the only way to go if you are looking at coil-overs.

I would definitely look at the EAC's.
Also look at the KW's, TC Klines, and Ground Controls.

[champaign777]

I will never lower any of my BMW again
It looks nice when it's lowered but the ride is not as before
Plus every time you try to raise or lower your car its a headache
Try to keep it with OEM Sport springs which are the best
my 0.02c

[qcdstick]

I've been running EAC's on my 540 for about a year now. I did not use them to lower the car very much at all (I'm not into the slammed thing at all), but I did drop it an inch or so IIRC. The ride is far from OEM quality, I know when I hop in my dad's 530 with stock suspension the difference in ride quality is noticeable to say the least. However, I will say EAC's are probably far better on ride quality than most coilovers, and I do tend to prefer a harsher ride. The EAC's are great 99% of the time, but some of the bigger bumps they just don't handle as well as the OEM which should be no surprise. It is a price I gladly pay for their increased stiffness for handling, which I LOVE on them. Dive and body roll was reduced very noticeably (I have done swaybars as well, FYI) and the car feels great in hard corners. This winter I found myself pushing harder than my tires could take, because the car felt it just wanted more and more, very solid. Can't wait to get the winter tires off and get some sticky rubber back on there.

The one real annoyance I have with the EAC is the "bounce" you feel when coming to a stop. Like if you let the car roll forward 1/2" and punch the brakes, you can feel the car bouncing just a bit. Same happens when you plop down into the seat, or sometimes if you shut the car door hard you can feel it then too. Very little movement, and it is imprecievable when you are driving due to all the other constant vibrations and movement. Seems they are just lacking what I would call "fine dampening". It is a very minor issue for me, and could possibly be corrected somehow in the setup, but playing with the dampening settings didn't seem to have a appreciable effect.

For the price, you can't beat EAC.




Track day with sticky rubber, M5 front swaybar, Eibach rear swaybar, and EAC coilovers on a freshly re-built suspension. Very little body roll, especially considering I'm pushing warmed up Hankook RS3's near the limit's of their grip.

[ame]http://www.youtube.com/watch?v=Y7r653pK4ks[/ame]

[Jason5driver]

QcdStick,

Pretty cool video?
What track is that, and where?
I am from Cedar Falls...

More pictures of the car?
How do you like the Rs3's?
What other coil-overs have you been on?

Thanks!
Jason

[qcdstick]

The track is Mid America Motorplex in Pacific Junction IA (near Omaha), it was last year's BMWCCA Longest Day Driving School. I had a lot of fun and would highly recommend it. Last year was my first year, and I'm going back this June for sure.

Here is a picture I have from race day.



I put the RS3's on the OEM 17's because they are lighter than my 18" M5 reps by a good margin. I switched to the RS3's at the track due to the long drive across the state. I left the RS3's on between the track and hotel overnight, they work fine on the road but won't last long if you intend to use them as a street tire because they are so soft.


The suspension is pretty stiff... I was surprised the first time I went to jack up the car, the front lifted not much after the rear with the jack on the rear corner. Tire changes go a bit quicker now!


I can't find a picture of the car with the 18's on the coil overs, I'm almost certain I took some. Maybe I lost them when my phone died. I'll have to add that to my to-do list this spring, it's on winter 16's now. In any case, there isn't much to show, you can set the height to whatever you want it to be.