If you have considered this I would try something else first.

The front ended up a little higher than the back and I still hit the bump stops in the front unless I take it easy.

Has anyone tried the G37x Coupe kit 6390.140 or the new G35x Sedan kit 6399.140 for the g37x Sedan?

 

Havent been here in a while and just found out about the G35X springs and did some research. Here is what i found and posted on the G35 board as well:

This is really weird but i did some research and i found this:

Kit# 6388.140 (2008 G37 Coupe) (from a previous post on this board)
Drop = 1.2 (F), 0.8 (R)

Spring Rates:
Front: 228lbs/in initial, up to 548lbs/in
Rear: 371lbs/in initial, up to 531lbs/in

VS:
the new G35X Sedan springs...(off of eibach site)

Pro-Kit #6399.140
Front: Progressive 40-96 N/mm (228-547 lbs/in)
Rear: Progressive 65-93 N/mm (371-530 lbs/in)


Basically identical numbers between the 08 coupe and the g35 sedan? So all this time people could have just used the coupe springs?

i have a G37X sedan, and i used the kit for the regular G37 sedan. I know the fron springs are all the same in ALL of their applications across all the V36 platform G's, but the spring rate is different for the rear.

I know the 6390.140 kit uses a different rate for the back.
I am actually using that kit on my G37X sedan and i can say im 90% happy. im actually looking to install small spring isolators, or "padding" as you might call them to give the damper just a tiny bit more space of travel. i did it for the back and 3/8th of an inch does wonders. I am trying to come up with a viable solution for the front now.

Also to add to research. I once had just the G37S coupe springs installed, and that was TERRIBLE.

hope all this helps.

 

Where did you get the 3/8th inch Spring Isolators for the rear?

Do you have a part number?

Thanks

 

I'm also running the 6390.140 on my '10 X sedan as well and have had NO issues bottoming out or having poor ride quality. The rear looks slightly lower than the front also, but that may just be because the front wheel well is cut larger than the rear.

The front springs on the 6390.140 are the same as the coupe kit 6388.140 (and I guess the new 6399.140 kit according to IgS). The rears are the same as the 07-08 RWD sedan spring kit, 6383.140.

6390.140 kit includes:
Front spring (6388.001): 228lbs/in - 548lbs/in
Rear spring (6363.002): 359lbs/in - 466lbs/in

 

Is that the new kit made specifically for the X? If so, can you measure from the ground to the highest part of the wheeled arch so we can see the amount of drop? I would greatly appreciate it!

 

6399.140 is the new kit for 07-08 X sedans.
6390.140 is the kit for 09+ rwd sedans (which is what I've got)

I did measure before and after from ground to the edge of the fender.

before:
front: 28.25"
rear: 28.5"

after:
front: 26.875"
rear: 26.5"

So roughly 2" drop all around.

I would imagine with the 6399.140 kit, you'd get about the same drop up front and maybe less in the rear.

 

Thanks for the review and info. I'm trying to decide if I want to go to springs first or all out with coil overs. Seems like most agree coil overs are preferred over springs. But the x is a different beast altogether. Good luck.

 

Hey post some pics. I want to compare it to my car which is dropped on the rwd Eibach springs.

 

Bump for more experience with 6390.140 vs 6399.140 on the AWD sedan. Very curious if the new 6399 set eliminates the rear sag, and if so how much less is he rear drop? The sag was my only complaint about the 6390 set.

 

The picture with the stock wheels is with the Eibach 6390.140 kit. The rear was almost riding on the bump stops.

The picture with the aftermarket wheels is with 6399.140 kit rear springs installed (6388.002) plus one Universal Coil Spring Isolator Type E from Energy Suspension Parts. The car sits flat now.

I am very happy with the back finally. I can easily hit the bump stops in the front still however. Eibach recommended installing the Front Dust Boot BS770043 which increases front travel 10-12mm.

 

Wow, so you ride on the bumpstops if you lower the car to what a BMW 3 series sits at? That is crazy!! What is the point of the springs then??

 

anybody else have experience with the 6399.140?

 

Are you sure it was style E that you bought? That just looks like a tube.

 

http://i1212.photobucket.com/albums/...2/DSC_2076.jpg

6399.140 on G37x sedan

 

Is this with no other suspension mod?

How is the ride?

Still able to align within spec without mods?