I installed Eibach Prokit #6363.140 on my G35x with stock struts. The ride is very harsh. When going over bumps, the whole front goes airborne. Dips are not quite as bad.

I read from previous posts that the softer initial rate of the Eibachs could be the cause because there is too much/fast compression for the stock struts to handle. Would replacing the struts with softer ones help?

Eibach #6363.140 Progress rates are:
Front: 259# / 334#
Rear: 359# / 413#

Stock springs
Front: 296#
Rear: 370#

Please provide any suggestions and feedback. The ride is so unacceptable now .

Thanks

 

hummm... spring rates look good, I think you're riding your bump stops. Did you
trim a good inch or replace them? (im not sure if you can trim the sedan's
bump stops. On the coupes you can).

You'll want to get adjustable struts like the D-Specs so that you can
play with the damping. I think you need firmer struts + trim those bump
stops on the front.

edit: btw, before you order the D-specs, make sure it fits your AWD
sedan.

 

Dude you are scaring me, I just received my Eibachs last week, but haven't gotten a chance to have them installed on my G35X yet. How fast are you going over those bumps man? The pro-kit is advertised as being able to keep stock ride comfort ...

 

Thanks for the feedback, Ken. One thing I didn't mention is I'm in the Northeast where the roads are horrible. Yes, it does feel like the car is hitting the bump stops. No, I haven't trimmed them, or done anything with them.

As for speed, I'm not going too fast, mostly on local roads going about 35-40.

According the specs, the springs should be fine. It's the stock struts I believe that is causing the problem. Anyone else with Prokit running stock struts experiencing this?

 

Do You Have Sport Tuned Suspension I Have Sports Tuned And Want Springs Soon Didnt Know Which I Want To Get Yet

 

No, sport suspension is not available on the G35x. Another point is the G35x is 1/2" taller than the Rwd. Perhaps it also has a longer strut? I wonder if the EiBachs are only a problem for the x, but fine for the rwd.

 

pimpingG- yeh, it sounds like your struts/shocks aren't slowing down the
compression rate fast enough in the shorter travel. I would recommend
trimming the front bumpstop by 1inch if you can or getting Koni
bumpstops which are softer and have a progressive rate stop.

If you can find the struts for your car, definitely get it.

 

I was under the impression that the G35x had very different spring rates from the G35 sedan due to higher weight, and that there was no Eibach (or other aftermarket) spring kit made specifically for the G35x. Wouldn't that be the culprit?

 

Yes, that is correct. There are no true springs for the G35x. I am using the springs for the rwd G. Aren't the bumpstops there to prevent damage to other suspension component? Would trimming them cause other problems?

 

The bumpstop is there so the strut does not bottom out completely and so that the
chassis doesn't bottom out either. Typically bumpstops are okay to be trimmed about
1inch, but since i haven't tried this on the x, I can not be for sure.

how much lower does your car ride vs stock height?

 

EiBach says 1.1" if installed on the rwd G35. Since mine is 0.5" taller to begin with, the result when installed on the x is about 1.6" drop.

 

Shouldn't it be the same 1.1" drop? Why would it drop the extra .5"? If your baseline is .5" higher, you'll just be 1.1" lower than your baseline, no?

 

No, it doesn't work like that....
rwd spring is x" tall
awd spring x+0.5"

If rwd drop = x - 1.1"
then awd drop = 1.1 + 0.5

 

I called Tokico inquiring about their D-Spec struts. They said the same struts will fit the G35 as well as the G35x. They also suggested that I trim the bump stops.

Eibach said the pro-kit I'm using is not compatible with the X. However, they were not able to supply additional information as to why. It obviously fits the car. However, the ride isn't right.

I will first inspect the bumpstops and decide on whether to trim or not. If that doesn't help, then I'm putting the stockers back on and sell the EiBachs to a rwd G35 owner.

 

Where did you come up with the oem X rates?

What is weird is that Eibach came out with G35X lowering springs shortly after the car came out, had it's own part number and everything. Now they are no where to be seen on their web site. I wonder they couldn't get the dealers to order any and never went into production with them.

Sounds like the shocks didn't have a lot of dampning control to begin with. Thing is, the X and FX don't use the same front suspension design as the rest of the FM platform vehicles. Meaning their is a chance that your out of luck concerning upgrading the shocks. I have a pair of front oem non sport sedan shocks your welcome to use for a test fit, if they mount up, your in business. Oh, if they work get a set of Tokico D-specs.