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Too stiff in the rear - Video

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Old Aug 5, 2009, 08:52 AM
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Too stiff in the rear - Video

I decided to try an adjustment to the rear shocks on my car....

With my 450lb(8K) Front, and 550lb(10K) rear I have to run my 25mm Progress rear bar at full soft. Along with that I've had my bump setting at the minimum on the rear shocks. I decided to see what would happen if I increased the rear bump to the same as the front, which was about 3/4 full.

The results are at the end of this video...

http://www.vimeo.com/5948752
Old Aug 5, 2009, 09:04 AM
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been there done that during a couple autocrosses
Old Aug 5, 2009, 09:12 AM
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Originally Posted by jid2
I decided to try an adjustment to the rear shocks on my car....

With my 450lb(8K) Front, and 550lb(10K) rear I have to run my 25mm Progress rear bar at full soft. Along with that I've had my bump setting at the minimum on the rear shocks. I decided to see what would happen if I increased the rear bump to the same as the front, which was about 3/4 full.

The results are at the end of this video...

http://www.vimeo.com/5948752
looked like it came out of nowhere.

I'm not convinced that the current trend of reversing spring rates is necessarily the best/fastest. If you have to have rebound settings way different from front to back to get a neutral car something's off. I had less of a difference front to rear than 'out of the box' set ups, but not swapped. then again what do I know
Old Aug 5, 2009, 09:24 AM
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It totally came from nowhere. I came in pretty fast, but the car was stable for the whole turn-in phase - then mid corner I felt the back end start to rotate and I tried to feed-in a mellow counter steer. But it didn't catch it.

The spring rate balance I run is based off a stock rear swaybar. But I was too lazy to swap out my 25mm Progress. That's the real issue. I've been fixing more major issues, and finally I'm getting back to setup adjustments. I'm going to try a smaller adjustable rear bar because having the ability to adjust the rear bar is nice. But I may just put the stock bar back on. We'll see.

Last edited by jid2; Aug 5, 2009 at 09:27 AM.
Old Aug 5, 2009, 10:04 AM
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Originally Posted by jid2
I decided to try an adjustment to the rear shocks on my car....

The results are at the end of this video...

http://www.vimeo.com/5948752
That looked like a preventable spin but your hands were too slow. Check out my video from thill. Not perfect, but I saved it:
http://motorsports.briansarmy.ciscoe...thill-t4-save/

In that video I had 9/11k springs with Gerrard Ohlins and the 25mm Progress bar on medium stiff. I've since added 10mm spacers in the front to loosen it up a bit more.
Old Aug 5, 2009, 10:11 AM
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looks like an AMAZING track!
Old Aug 5, 2009, 10:13 AM
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looks fun
Old Aug 5, 2009, 10:16 AM
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Originally Posted by redvolution
That looked like a preventable spin but your hands were too slow. Check out my video from thill. Not perfect, but I saved it:
http://motorsports.briansarmy.ciscoe...thill-t4-save/

In that video I had 9/11k springs with Gerrard Ohlins and the 25mm Progress bar on medium stiff. I've since added 10mm spacers in the front to loosen it up a bit more.
I can't get that video to play?

You are probably right about catching it. I've been over it in my head - with more throttle and a little more countersteer I think I could have slid the car through the corner. But I don't like the setup that loose
Old Aug 5, 2009, 10:19 AM
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Originally Posted by inco9nito99
looks like an AMAZING track!
It would be better with actual runoff on the back section, and new pavement. But it is has some cool elements for sure. Big elevation drop coming down the hill into the two hairpin corners, then racing back up the hill into the left-right-left section It's good stuff.
Old Aug 5, 2009, 01:26 PM
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Wow, in watching both vids, I gotta say my car has never handled like that. If I throw my car into a corner too fast it usually converts to an expected 4-wheel drift sideways to scrub the speed. I counter with steering input and start to build throttle back in to pull it out.

Maybe setup differences, maybe driver style or preference? And I've ran the same suspension setup all year, both with street tires, r-comps and hoosiers. I'm not a fan of a loose rear myself (any accidental puns totally intended)
Old Aug 5, 2009, 01:36 PM
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Originally Posted by EvolvedMR
looked like it came out of nowhere.

I'm not convinced that the current trend of reversing spring rates is necessarily the best/fastest. If you have to have rebound settings way different from front to back to get a neutral car something's off. I had less of a difference front to rear than 'out of the box' set ups, but not swapped. then again what do I know
KW's do not use the same exact valving front and rear, so 1/2 turn front is not the same as 1/2 turn rear. They shouldn't be compared to each other that way.

Also, the stock rear spring on the KW's is only 6k with valving to match....

I'll watch the video when i get home. Sounds fun.

- drew
Old Aug 5, 2009, 01:53 PM
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Wow, Jared, I knew you were a crappy driver... but jeez. Looked like fun! The Utah crowd misses you man. Wes got some of the lowering brackets and he loves em, I sat in his car and now I demand you make some for the GR STi!
Old Aug 5, 2009, 02:10 PM
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Originally Posted by boomn29
Wow, in watching both vids, I gotta say my car has never handled like that. If I throw my car into a corner too fast it usually converts to an expected 4-wheel drift sideways to scrub the speed. I counter with steering input and start to build throttle back in to pull it out.

Maybe setup differences, maybe driver style or preference? And I've ran the same suspension setup all year, both with street tires, r-comps and hoosiers. I'm not a fan of a loose rear myself (any accidental puns totally intended)

Coming from both FWD background and RWD background, I prefer the typical RWD "touch of controllable oversteer" to the FWD "understeer until it snap oversteers" way of seeing the world.

I want (and for the most part have setup my car to) a touch of oversteer that's controllable (meaning, like you describe, a bit of countersteer and throttle holds it or pulls you out).

Getting there (and staying there) is a huge battle though, involving stiffening up the rear a lot, playing with front and rear camber and sway bars and tire settings (air pressure differentials, etc.).

Of course, any new track and tire setup really messes with this "balance" as I found out a couple weeks ago where I looped it until I realized that my air pressures were way too high for the surface. Once I let air out the car felt like my car again.

I need a notebook/blackberry app/iphone app to keep track of my car settings, environment settings, track conditions, etc. so that I can log this stuff better... as a mistake can be very dangerous :-/
Old Aug 5, 2009, 02:23 PM
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Originally Posted by goofygrin
I need a notebook/blackberry app/iphone app to keep track of my car settings, environment settings, track conditions, etc. so that I can log this stuff better... as a mistake can be very dangerous :-/
AMEN!

I try to keep it all in my head; but that's just not cutting it!
Old Aug 5, 2009, 02:35 PM
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Originally Posted by GTWORX.com
KW's do not use the same exact valving front and rear, so 1/2 turn front is not the same as 1/2 turn rear. They shouldn't be compared to each other that way.

Also, the stock rear spring on the KW's is only 6k with valving to match....

I'll watch the video when i get home. Sounds fun.

- drew
I think he's running Robi's clubsports if i'm not mistaken, default is 8kF/9kR


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