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-   -   Slapping / bouncing feeling when driving slow or changing gears (https://www.ft86club.com/forums/showthread.php?t=147587)

letmethefuqin 11-15-2021 07:58 AM

Slapping / bouncing feeling when driving slow or changing gears
 
Be patient with me here,
Iím not to client about gearboxes

Ever since I swiped my clutch out it bunny hops like mad in every great change
At first I thought it was in the tune, but the tuner canít find an error (I have logs - Ecutek)

So looks to be mechanical
Iíll drive 10km 9í a straight road in 1st at about 2500
Very light pressure on the throttle and the car feels like itís driving but something slapping back and forth / bouncing

Canít figure out what is causing this any suggestions ?

Also before the gear box and clutch change the car always felt like it had a lightened fly wheel which it didnít, but I felt I had to previously keep the revs up, that seemed to work itís self out after a re tune though I feel

However in this case it feels possibly more mechanical

Anyone had something similar ?




2012 86 GTS
Heavy duty sprung clutch
Forged fork
Aftermarket pivot
Super pro rear?? Bush
Mtec springs
Motul oil

Rear diff bush compressors

Tcoat 11-15-2021 08:14 AM

What make clutch?

humfrz 11-15-2021 03:31 PM

What you say, there, @Ultramaroon - ??

Ultramaroon 11-15-2021 03:39 PM

I think @Tcoat's already asked the important question. If it's not a stock clutch, all bets are off.

letmethefuqin 11-15-2021 07:07 PM

Quote:

Originally Posted by Ultramaroon (Post 3481620)
I think @Tcoat's already asked the important question. If it's not a stock clutch, all bets are off.

Just Went and Checked,

It Appears to be a MANTIC Stage 1

RToyo86 11-15-2021 07:25 PM

What condition is your trans mount in?
Stock one has a decent amount of slop and can cause bucking in the driveline.

radroach 11-15-2021 08:07 PM

Quote:

Originally Posted by letmethefuqin (Post 3481426)
Rear diff bush compressors

If you have the rear diff bushings but not the rest of the parts set in the "Positive Traction Kit" from whiteline, you might be getting more play in your rear crossmember and subframe bushings.

I essentially had that problem when I installed whiteline subframe inserts but didn't do the differential bushing until later, the diff was moving around a lot more from stiffening the other parts in the driveline and made it difficult to drive.

Also agree with above that you might be getting slop from the transmission bushing.

Turdinator 11-15-2021 08:52 PM

Quote:

Originally Posted by letmethefuqin (Post 3481426)
Ever since I swiped my clutch out it bunny hops like mad in every great change

This sounds to me like the new clutch is more aggressive than your old one and you need to adjust to it and possibly give it time to bed in also.


Quote:

Originally Posted by letmethefuqin (Post 3481426)
Iíll drive 10km 9í a straight road in 1st at about 2500
Very light pressure on the throttle and the car feels like itís driving but something slapping back and forth / bouncing

This sounds like drivetrain slop. These cars had some even from brand new. How many kms has your car done? It may just need some bushes replaced.


Quote:

Originally Posted by letmethefuqin (Post 3481426)
Also before the gear box and clutch change the car always felt like it had a lightened fly wheel which it didnít, but I felt I had to previously keep the revs up, that seemed to work itís self out after a re tune though I feel

Subaru motors have small, lightweight crankshafts and usually feel more like a lightened flywheel compared to a normal inline 4cyl engine.

soundman98 11-15-2021 11:14 PM

was the drive shaft removed at any point for any of this work?

was it clocked correctly?

Tcoat 11-16-2021 07:40 AM

Quote:

Originally Posted by letmethefuqin (Post 3481691)
Just Went and Checked,

It Appears to be a MANTIC Stage 1

Quote:

Originally Posted by Turdinator (Post 3481715)
This sounds to me like the new clutch is more aggressive than your old one and you need to adjust to it and possibly give it time to bed in also.



This sounds like drivetrain slop. These cars had some even from brand new. How many kms has your car done? It may just need some bushes replaced.



Subaru motors have small, lightweight crankshafts and usually feel more like a lightened flywheel compared to a normal inline 4cyl engine.

Not familiar with that brand but a quick look shows that it is indeed quite aggressive. As Turd says you may need a bit longer "break in" period for it.

If that doesn't do it then like a few have said you could move onto bushings but the most probable cause is what you changed so start with the clutch itself and work back from there.

Ultramaroon 11-16-2021 12:40 PM

The whole driveline is pretty squishy. Couple that with the CV-joint lash and, as @Tcoat has experienced with me hooning in wet patches, it's a recipe for some nasty flutter. I suggest simply going back to a less aggressive (stock) clutch. It's rated specifically for the strength of the transmission anyway.

x808drifter 11-17-2021 01:48 AM

Quote:

Originally Posted by Tcoat (Post 3481461)
What make clutch?

https://satoshimatrix.files.wordpres...0017.png?w=584


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