Hi there,

on a friends RA-R-ltd there is considerable vibration when DCCD is active. There is a DCCDpro.com controller on it. When put in free, there is only a very slight vibration. However, in both auto and manual mode there is considerable vibration, especially at about 2000rpm. Its really bad, and the whole car shakes and the noice is severe.

From the "seat of pants" feeling, Id say the vibration has ground zero in the rear then comes forward. Like the rear diff is the source, then the entire drivetrain starts to vibrate. But its really hard to explain ofcourse.



Can there be damage on the diff causing this? Or does others have this problem as well? I dont have this on my DCCD car.......





99RA-R-ltd, lightwheight flywheel, upgraded clutch, VF34, custom 3" exhaust, suretrac diff rear, rear subframe bushing inserts (poly), rear sub frame lock bolts, Tein very stiff coilovers, 22/22 whiteline antirollbar, anti lift kit, roll center kit.


Little history here guys, recent investment, the problem was there when it was purchased.

 

Incorrect rear diff ratio?

 

Ok, what car is it again?
Is it an STI RA or is it an STI type R?
It definately isnt an RA-R, thats for sure

 

Thats something that needs to be checked out, thanks for the tip. The diff has been changed actually. The only question is why the clutch pack has not been worn out from it... But I guess that depends how long its been that way.



STI RA, haha. To many names on these cars, hard to keep up

 

Have you disconnected the controller?

Tony

 

No, but simply putting it on the lowest setting (off) solves the problem..

 

Im thinking that its your controller thats the issue here, so totally disconnect it.

Tony

 

Im sorry, I dont understand. Why would that help him? By installing another one? I dont know if the stock one works or not..

 

Diff ratio is correct. Any other ideas?

 

The car doesnt have a dccd as standard yes?
The dccdpro is an aftermarket unit, disable this aftermarket unit as it could be what is causing the issue (either not correctly installed or its faulty causing an issue with the electronic clutch).

Tony

 

The car has DCCD standard, but with an aftermarket controller that appears to work just fine.


However, I cant see how the controller would cause this problem as the drivetrain is vibrating at a very selected rpm?


Edit:

Im beginning to think bearings or axles?

 

Still, worth disconnecting it just to eliminate it as a cause? DCCD controllers probably do take rpm in to account.

 

It cant just be eliminated, it would need to be replaced. Eliminating it eliminates the problem, but then there is no centerdiff LSD.

The controller does not take RPM into account.

The centerdiff is strong and the controller works like a charm in both manual and auto mode.

 

Totally disable the dccd pro as it is most likely the cause of your issues, of not then google dccd pro vibration and see that you are not alone! Then disable the dccdpro and have all the wiring checked or revert back to the decent none vibrating Subaru item

Tony

 

Tony, I googled, but could not find anything, except a Nasioc thread which is my own, and nobody has replied that they have the same problems... If you found someone else and have a link for it, that would be much appreciated!




However, do you have a thery as for why the controller should be the problem? Ive been wrapping it around in my head for a while, and I just cant make sence of it.. In a straight line, the centerdiff has virtually no difference in speed between F and R shafts, so no matter what crazyness the centerdiffcontroller was sending out them two wires, there really should not be room for problems.. in turns that could be a whole other story, still..


And why only between 1500-2200rpm? To me it sounds more like a mechanical thing like a trannymount, to stiff bushings or perhaps failed centerdiff bearings. I guess well just need to put his car on a lift and try to simulate somehow.