Ive come across a problem, When I put my foot down and on full boost up to 3-4k RPM, The whole car shakes/vibrates, its hard to pin point where the feeling is but the feeling is similar to when you dump the clutch and the tires are trying to catch and it vibrates the car. It happens in every gear and goes away as soon as it goes past 4/5k RPM. If you are cruising in 5th gear 3k rpms and put your foot down, the revs basically dont climb but the engine still makes full boost, and the car vibrates like nuts which is a scary feeling.

Once the car has been driven for around 20 mins over 5k RPM , then the car doesnt do it anymore (Only very occasionally for a split second.. It still does it when its warm or cold until I drive it past 4/5k rpm)

This DOESNT happen if i do not put my foot all the way down, Even if its just a tiny bit up from WOT! Ive thought of many things, But cannot seem to come to anything that could be causing it. The steering wheel also does not shake, so cant be an alignment issue. I dont think it can be spark plugs, as the car works well at high rpms smoothly.

The car is twin turbo and has a power FC and has been rebuilt, aswell as the turbos, So they cant be the issue. I feel like it could be a mount of some sort, but at high speeds the car is smooth and tight. I would also say the diff but again theres no loose feeling or unstable feeling from any of them.

Another thing I notice with it, When I drive normally the BOV is high pressure so there is compressor surge at low rpms, but when this vibration happens the BOV goes off loud every time.

This is my first post on the forum, So if theres any other info you need to help me solve the issue please let me know. Looking forward to some answers!!

 

Sounds like compressor surge or misfire.

 

Could possibly be a misfire, but only happens when the car hasnt been taken past 5-6k rpm a few times during a drive, then it basically never happens