need help vibration at 4000rpms

[supraevo87]

ok guys i just bought my first dsm and i am in love with it best car ever my problem is that when the car is running it runs smooth up to about 4100rpms then there is a bad vibration threw out the whole car when acceleration and only gets worst as the rpms go higher like i said it runs smooth untill it hits 4100rpms tho im worrid it maybe the balance shaft throwing the engine off does anyone have any ideas wub be any help would be greatly apperiated thank you

 

[XiKeiyaZI]

Is this vibration ONLY at the listed RPM range? Does it stop when you go beyond that RPM range? Does it only occur when accelerating, cruising, decelerating, all? A bit more insight would be great before we start throwing ideas at you.

 

[GsXdSmKingGsX]

I used to have the same problem. Replaced my motor mounts and it went away.

 

[supraevo87]

no it doesnt stop it keeps getting worst as the rpms go up but runs smoth untill 4100rpms and yes it only occurs when accelerating thank u for your help

 

[Rummy636]

I second the motor mount issue. Check the mounts first. Thats the place i would start.

 

[TunaTalon]

One more vote for the motor mounts.

Out of phase balance shafts hit resonance with the chassis at over 2000 RPM running at 2X engine speed. It looks like the Ops vibration is hitting resonance with the chassis at about actual engine RPM.

 

[XiKeiyaZI]

Good call everyone.

OP, look into new motor mounts or even inserts. Either should help resolve your issue.

 

[Sp1kE]

X2 on the out of phase balance shafts.
did the car by chance recently have a timing belt job done?