i have a stock 04 g35c. one road that i drive on has some rolling dips, nothing extreme... but i noticed that if i take it fast, say 80-90mph, the car bottoms out in the dips.

why is this? is it because the spring rate is too low?
would a suspension like hipermax rs fix it?

 

Stiffer springs, stiffer shocks, or both. That's pretty suprising though. Usually it's pretty hard to bottom out a car unless you're hitting a hard bump.

 

are you bottoming out bump stops or is the car bottoming out?

 

that is because of the spring rate is too low, damping rate is too low, and the shock length is too short when the cars on the road. stock shocks can extend quite a bit but can only compress about 3inch or so when on road.

With shock length adjustable coilovers, you can set the shock length where you want it at, so u can have much larger room for compression but it will have shorter extension, which may lead ur wheels to go up in the air.. but usually ok unless u have to twist around a hilly driveway or something

 

What They Said But I Still Have A Problem Of Bottoming Out In My Girlfriend I Dont Think I Can Fix That.

 

take the hill slower....

when you go over a hill, your body and everything but the suspension/wheels rises, though only a few inches. Once your over the peak, gravity hits with a force of it and your cars mass which bearsdown on the springs.

It is obvious that the force exceeds the force the springs/shocks can handle and in turn you are bottoming out.

 

ive done it in my old car, fun but scary. gives you that wierd feeling in your stomach

 

thanks for the replies.
anotherazn, im not sure what you're asking..

the entire car seems to lift off the road and then the whole thing evenly falls back down with the rolls in the pavement. when it comes down if im going too quick, at about 80mph, the car goes so low it feels like it stops on something then bounces back up.

the road is level but bumpy but gradual sort of way. it seems like other cars such as my sentra, neon/srt4s, etc take can go faster without this issue, which is confusing to me. hopefully these hipermax rs's will help me stick to the road?