My MNR Vortx (R1 engine) has a pretty strong vibration throughout the car when you get up to about 90mph or so and it doesn't seem to go away if you go faster but I've not done more than about 105 in it yet. I've had tyres fitted recently and no change to the vibration so I assume it's not the wheels. It's entirely speed dependent, not revs.

The car has a quaife reverse box and (I think) a TRT prop but I'm not 100% sure as I don't know the history of it. this is my first kitcar so I don't know how much vibration is normal but it's pretty ferocious!

Any thoughts? My first thought was the prop was out of balance but I remember reading somewhere that the reverse box can add some vibration. I'm a bit worried about the prop failing and finding it's way into my internal organs

Hard to tell without stripping out your paneling and checking it all.

Could well be the angle or height of reverse box/props needs fine tuning

You have checked oil in reverse box?

Is it through the car or through the steering wheel
Mine shook through the car , slight play in prop uj

Hi
Get the props checked out for balance & concentricity
whilst they are out check the reverse box.
Good luck.

Well I finally got round to having a good look at the car this morning. Basically there is a lot of play in the bearing on the output side of the quaife reverse box. This is without a doubt the cause of the problem.

I'm going to take it out and get it rebuilt (either to put back in or to sell maybe). Anyone have any tips on removing it or anything I need to know? I only looked at it from above as I didn't remove the whole floor of the car but access looks pretty awkward.

[Edited on 30/8/14 by T0MMY]

Just to update this thread; I had the reverse box rebuilt by Quaife which has improved the vibration problem and moved it to a higher speed but not completely removed it! There is still a small amount of play in the output shaft bearing of the box but far less than before; should there be none at all?

Does anyone have a quaife reverse box and manage to have no vibration at very high speed? What else should I be looking at? The prop still has its balance weights and appears to be in phase.