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      03-18-2013, 02:43 PM   #1
Raucky2000
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High Frt Spring Rates

Is there anyone out there running a high spring rate on the front of the car?
Like 14kg or 16kg?
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      03-18-2013, 02:54 PM   #2
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I currently run 12 kg on the front for DOT-R tires. KW recommended 14 kg for full slicks.

Are you thinking about going that direction?
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      03-18-2013, 03:22 PM   #3
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Well I'm running 285/30-18 DZII tires but ill be on concrete at the larger events (auto-x). I have to much dive on the frt with my current setup of 450/700 IMHO.

I ordered a set of swift 14kg spring for the front as a guess to test out.
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      03-18-2013, 03:47 PM   #4
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Are you sure it's front dive and not rear lift? They can feel the same since the ultimate affect is forward pitch. Shocks should be able to slow that down as well. Speaking of which, what kind of shocks are you running to handle that #785lb spring? I would also be on the lookout for loss of mechanical grip in the corners even if you fix the fore/aft weight transfer you are working on.
Keep us posted on the experiment. I've also accumulated a garage full of springs over the years.
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      03-18-2013, 04:06 PM   #5
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Yeah it is forward dive from the rear springs/shocks lifting. I'm running TCK DA shocks and an H&R front bar but no rear bar.

My rebound setting on the rear shocks is just right IMO and its over powering the front.
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      03-18-2013, 05:25 PM   #6
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Where would you source the springs?

I'd check with TC kline if those konis can handle a 800-900lb spring.
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      03-18-2013, 06:05 PM   #7
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Swift and a few other brands out there make springs that stiff. I have a set of Swift springs coming my way.
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      03-18-2013, 06:11 PM   #8
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I'm not sure I follow. Haven't done set up on suspension but it seems you think the problem is rear lift. If that is the case the front isn't overcompressing and higher rate spring isn't going to help as much as rear rebound to slow that transfer or a different braking technique to balance the car slightly better.
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      03-18-2013, 06:26 PM   #9
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I need that much rear spring rate and compression/rebound to handle tossing the car and hard first/second gear accelerations. Auto-X racing is the American version of football, where everything is hard, fast, and not pretty all the time.

My front corner weights come in right around 1,000lbs each so having a 800ish lb front springs shouldn't be a problem. The shocks will still work and the chassis will have less movement, which in every other car I've raced has made it better. Time will tell obviously.
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      03-18-2013, 07:36 PM   #10
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Are you keeping rears at 700#?
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      03-19-2013, 04:19 AM   #11
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I'm going to keep the 700 rear just to see how just changing the front effects the car, but I'm totally open to changing the rears.

^What kind of rear spring rate does KW suggest on Rcomps and full slick?
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      04-15-2013, 09:28 PM   #12
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Did you ever switch to the 14k fronts? How does it feel?
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      04-15-2013, 09:42 PM   #13
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Quote:
Originally Posted by sensi09 View Post
Where would you source the springs?

I'd check with TC kline if those konis can handle a 800-900lb spring.
TCKR DA front struts can not. 500-550 is about max, anything more is off the the service center to upgrade the valving. In our Redline Time Attack days 500 lb springs caused an underdamped issue with Koni DA's on the front. Rears will max out at around 900 lb.

If you get 60mm ID Swift, you will also need to machine your front strut lower perches.
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      04-16-2013, 02:56 AM   #14
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Quote:
Originally Posted by HP Autowerks View Post
TCKR DA front struts can not. 500-550 is about max, anything more is off the the service center to upgrade the valving. In our Redline Time Attack days 500 lb springs caused an underdamped issue with Koni DA's on the front. Rears will max out at around 900 lb.

If you get 60mm ID Swift, you will also need to machine your front strut lower perches.
Good info, but I'm guessing that tck may have their konis valved differently. They offer up to a 650lb spring for the front on their site.

I'm curious, what rates did you run on your time attack cars?
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      04-16-2013, 02:57 AM   #15
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^Ha didn't realize hpa offers tck. Disregard my last post then...i'm sure you guys know better.
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      04-16-2013, 11:58 AM   #16
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Quote:
Originally Posted by sensi09 View Post
Good info, but I'm guessing that tck may have their konis valved differently. They offer up to a 650lb spring for the front on their site.

I'm curious, what rates did you run on your time attack cars?
We have had TCK products on several of our cars, including one competed in Time Attack. Rates end up at 500F and 900R with revalved Koni DA's.
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