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  #1  
Old 19-12-2013, 06:45 PM
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Default Car bouncing

Hey guys, just finished a tuning sesh at MC motorplex, and figure that I have a reasonably good neutral setup with good turn in, except I can't quite figure out what is going on under MAX power corner exits.

instead of the rear end sliding out on early power application, it slides out by 10-20 degrees, then there is some kind of bouncing going on. I thought it was the dccd pro diff setting increasing the lock and as a result of some kind of diff wind up unloading under heavy pwr with not much grip, but really there doesn't seem to be much difference if I set it to off ( open ) or on , regarding the bouncing.

I tried increasing the damper / compression setting up to about 80% of max, and was able to get a stable drift with clutch riding to initiate, and the bouncing ( up and down ) is less, but if I'm not riding the clutch, and I allow the boost to kick in with my foot glued to the floor, it still got some kind of jerkiness ( between the front end and the read end ) going on.

any ideas ?

Hit 1.39 Bar and 397PS on the VF28 too wohooOO!
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Old 19-12-2013, 07:04 PM
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395ps on a VF28..... 291kw (390hp)

Crack

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Old 19-12-2013, 07:54 PM
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What tyre pressures?
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Old 19-12-2013, 09:42 PM
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Quote:
Originally Posted by dachopper View Post
Hey guys, just finished a tuning sesh at MC motorplex, and figure that I have a reasonably good neutral setup with good turn in, except I can't quite figure out what is going on under MAX power corner exits.

instead of the rear end sliding out on early power application, it slides out by 10-20 degrees, then there is some kind of bouncing going on. I thought it was the dccd pro diff setting increasing the lock and as a result of some kind of diff wind up unloading under heavy pwr with not much grip, but really there doesn't seem to be much difference if I set it to off ( open ) or on , regarding the bouncing.

I tried increasing the damper / compression setting up to about 80% of max, and was able to get a stable drift with clutch riding to initiate, and the bouncing ( up and down ) is less, but if I'm not riding the clutch, and I allow the boost to kick in with my foot glued to the floor, it still got some kind of jerkiness ( between the front end and the read end ) going on.

any ideas ?

Hit 1.39 Bar and 397PS on the VF28 too wohooOO!
Sounds like the car is Jacking? I don't have any great technical explanation off the top of my head, other than your roll centre being too high and vertical reaction forces are too high causing that 'jerky' ride. Sorry if That sounds rubbish, but have a read on it might be something there for you to make sense of.

My second thought is natural frequency but thats prob also rubbish :/


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Old 19-12-2013, 10:41 PM
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Hellastiffswaybars.
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Old 19-12-2013, 10:58 PM
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Why are you riding the clutch when exiting a corner?

I suggest you learn to drive by getting someone that knows what they're doing in the car with you. Everything you have described sounds awful.

Sounds like you are just trying to smash it out of corners ( MAX POwER KHUnTS!!! ) so your car starts sliding then starts to grip and then starts bouncing.

It will be more you than your car.
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Old 20-12-2013, 07:36 AM
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mine has started doing this since changing springs.. front end was awesomely planted before with 22 sways and antilift kit. these "sports springs" have stance but the standard ones held road waaay better and have more tavel for potholes and what not.. yuk yuk yuk.. does the front end bounce/chirp inside wheel and wants to understeer more than usual.. i had it balanced out soooo good too! ive stewed over this and come up to my own conclusion that maybe lowering the centre of gravity has changed how the weight of the chassis is distributed to the individual wheels and the stiffer sways give it less ability to lean meaning that the weight transers lower in a more sideways fashion across the centre of the wheel instead of leaning down onto it therefore breaking the grip easier, pushing it across and the bouncing is the continual loading/unloading of the wheel as it breaks and gains traction. i think randomly interchanging suspension parts will most likely wreck the handling unless the mods are planned with prior experience in how different combinations perform. aaannd welcome! enjoy your grenade!
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Last edited by drewgong; 20-12-2013 at 07:49 AM.
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Old 20-12-2013, 07:55 AM
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Quote:
Originally Posted by XT43 View Post
Why are you riding the clutch when exiting a corner?

I suggest you learn to drive by getting someone that knows what they're doing in the car with you. Everything you have described sounds awful.

Sounds like you are just trying to smash it out of corners ( MAX POwER KHUnTS!!! ) so your car starts sliding then starts to grip and then starts bouncing.

It will be more you than your car.

wrx jesus here has never hit boost on a public road and would never dare to EVER think of dropping the clutch half way through a corner! this guys obviously young and using his wrx as a thrash hack.. and probably loves it. flame him now. please be aware mate that hoon behavior is not condoned as its a bad wrap on all of us
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Last edited by drewgong; 20-12-2013 at 07:58 AM.
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Old 20-12-2013, 08:23 AM
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Quote:
Originally Posted by drewgong View Post
wrx jesus here has never hit boost on a public road and would never dare to EVER think of dropping the clutch half way through a corner! this guys obviously young and using his wrx as a thrash hack.. and probably loves it. flame him now. please be aware mate that hoon behavior is not condoned as its a bad wrap on all of us
LOL dipshit, if your grade 2 level of education enabled you to read properly you'd understand that he was riding the clutch in order to try and stop the bouncing when exiting the corner.
If Dachopper wants, seeing as he just lives down the road from me, I'd be more than happy to take his car through my Oconnor special stage where I scrub my rcomps in and bed in my brakes.
As for you, go have another bong and do some more sick cunt helis in the gravel and hi 5 yourself for being a retard.
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  #10  
Old 20-12-2013, 08:36 AM
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http://www.perth-wrx.com/vb/general-...ring-dccd.html

Sound familiar?

Besides the 400hp....
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