lowered my nismo now there is a thumping at 70 mph
 

i'm hoping ya'll can help answer a question. i dropped my car 1' front and .5' in the rear with springs, and now i hear a thumping sound at 70 mph like something is flapping under the car. has anyone ran into this? i have looked under it and see nothing loose. could it be the front spoiler vibrating now that it is closer to the ground. if you drive below 70 it goes away. i have not tried it above 70.

thanks for your help.

-danny

Thumping or rattling? I can't imagine how a drop that small would create any major problems

It maybe the undertray...check and see if all the clips are still buttoned up. They will pop loose at high speeds and the undertray will flap when there is enough turbulence.

Slow squirrels?

:shakes head:

thumping. like you ran over something and it's flopping around under the car. i guess i'll put it back on the lift and bang around and see if something is loose.

thanks guys for your help.

nope. no dead animals under the car.

-danny

this!!!!

when mine came loose at 80mph it would sound like a horrible thumping. but it only got worse the faster i went.

Fixed it
 

Well I fixed the problem. Yesterday I put the z on the lift and took a peak under the front. What I found was some missing plastic barrel clips missing under the radiator support. So I installed some threaded inserts into the aluminum under the radiator. Three bolts and three fender washers solved the plastic under belly from flapping above 70.

Good deal!! :tup:

Fixed for now, but I still see a ZSpeed udertray in your future!