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Front Spring Rate?????

Old 12-15-04, 02:17 AM
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Front Spring Rate?????

i'm getting ready to order new front springs for my 81 GSL (presently just have RB springs) and i need a good rate to start out with. the only thing is i'm gonna be running a lot of autox's and some track days here and there and i really don't wanna have to change spring that often at this point.

my present suspension set up right now is:
RB springs and swaybars, ground contol camber plates, tokico shocks, with kumho v700 tires on diamond racing wheels. with a gforce panhard bar to be installed soon.

Thanks in advance for any advice
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Old 12-15-04, 07:58 AM
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There is no one set of spring rates that is perfect and fits everybodies cars. Front springs must work in harmony with swaybars and rear springs and suspension linkage. If the car was balanced feeling, and then if you change any one of those things, it will upset the harmony with everything else until you get it all balanced again.

Is your car balanced the way you like now, or is it pushing understeer, or is it loose oversteer? If it oversteers too much now, then first try removing the rear swaybar. If it still oversteers, then put in the G-Force Tri-Link and the G-Force panhard bar.

After you make a change to things like the panhard bar, you will find that it changes your rear roll center significantly. After you make a change like that, then you look at how the car is behaving, then you change the spring rates to try and get the car back closer to neutral.

Last edited by speedturn; 12-15-04 at 08:01 AM.
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Old 12-15-04, 12:20 PM
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the car tends to understeer in tigher corners due to heavy weight transfer under braking. and the car was loose in the higher speed corners, or at least it was until i unhooked the rear sway bar earlier this summer. thats what i'm feeling in the car, but i'm just looking for a rate that would be a good starting point that i can work with, not the 130 lb RB springs that i have now

thanks again for your thoughts
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Old 12-15-04, 02:45 PM
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I've run 350 lbs/inch and 400 lbs/inch in the front with 175 lbs/inch in the rear (road race 1st gen). Our racing class required the use of the stock front swaybar so I would have preffered a lower spring rate and a stiffer swaybar if allowed. I'd say 250 lbs/inch would be an OK place to start for a more aggressive spring up front when used with a good aftermarket swaybar.

-Trent
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Old 12-15-04, 04:02 PM
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From your first post, it appears you don't want to change the rear springs too right now.

so, wait until you put in the panhard bar (you really need turn in spacers to correct the front roll center too.) Then drive the car on a track day where you can get a really good feel for it, and only then make a change on the front springs.
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Old 12-15-04, 11:01 PM
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i mainly just wanted to try another front spring rate because it seems that most of my problems, from what i can tell, are from to much weight transfer in the front of the car. i'm presently running 150 lb rear springs, which from what i'm told isn't a bad starting point. thanks for the good advice, i have a much better plan of attack with the car for now. now it just needs to warm up so i can get my panhard bar installed and go have some more fun at some tracks days trying to get the car sorted out.

thanks again
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Old 01-12-05, 09:16 PM
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Rob you're wanting to do what I did last year. I started off with Koni front bar, no rear bar, old school Rotary Engineering springs, camber plates, the stock wats linkage and Tokico HP's. My car was extremely tail happy on the old hard street tires. I was wanting to test the waters with some higher spring rates as well.

I forget the exact batting order but basically amounted to getting some Azenis, fabricating some spacers so I could install some coil over springs and then finding some springs. I've tried a couple of different springs and I'm currrently running 400# on the front and 170# in the rear (which btw were advertised as 150# but measured 170#). I eventually got some Illuminas as well.

Speed is right about the turn-in spacers - but if you autox they're not legal for street prepared.

The results for me were good. I started the year off probably 6 seconds off the pace and at the last event of the year I snagged FTD ....... small pond though.

Oh although not a daily driver I do drive this car to work regularly. The big springs are a ton better than the old RE springs.
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