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Choosing coilover spring rates for your EVO

Old Feb 20, 2009, 08:34 AM
  #31  
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Originally Posted by EVOlutionary
I do believe that there are times when spring rates can be significantly higher than 10K even for street tires - for some people. On my '04 daily driver (25000 miles per year) I ran somewhere around 13k/15K and they were awesome. BUT - I had a perfectly valved set of Ohlins and was on 285/30/18 Advan Neovas . . . .

If you throw that high of spring rate on your average cheap set of coilovers it would probably destroy them before too long. . . so it is definitely NOT for everyone. But with a good set of coilovers and proper dampening . . . I don't think spring rates in the teens are out of the question. . .

EVOlutionary
I agree with this. My Summit Point Redline street tire record was set with 12K+ rates and a huge rear bar on top of that (in addition to stiffer springs in the rear), but I have Ohlins coilovers and like the car to be on the loose side.
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Old Feb 20, 2009, 08:35 AM
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Originally Posted by EVOlutionary
Not in the rear as long as you don't change ride height. . . . but front - yes. . .


Although this is taking things off topic - I just want to touch on it real quick. Maybe we'll start a new thread. Personally I don't think there is anything wrong with lifting the inside rear wheel off the ground, as long as your car handles fine. All autocross EVOs I know do it at some point. And there have been a lot of EVOs that have won a lot of championships. . . . heck my old silver daily driver did it to the point where even turning a tight corner while decellerating it would do it. . . . and it handled beautifully on the streets as well as the track. . .
There are two different tuning ideas when it comes to this. To lift a wheel or not to lift a wheel, lol. The only reason the evo lifts a wheel is the strange roll center out back. but the suspension design works better with both on the ground. adding a sway bar makes things worse. since the front of the car has mac struts with inherently bad camber curves, a bigger bar would work better up front. it will keep the whole car flat, keep the front camber under control, and if you raise yor rear spring rates accordingly; will turn quite amazingly.
Old Feb 20, 2009, 08:35 AM
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Originally Posted by Mike01gsr
Very good thread andrew, I have a question I have the KW's and when I bought them I bought a set of 8k springs to replace the 6k. So right now I have 9k front and 8k rear do you
think it's worth the time and effort to swap them around?

Great thread!!, anyone have any feed back to my questions above^^
Old Feb 20, 2009, 09:06 AM
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Originally Posted by EVOlutionary
Not in the rear as long as you don't change ride height. . . . but front - yes. . .


Although this is taking things off topic - I just want to touch on it real quick. Maybe we'll start a new thread. Personally I don't think there is anything wrong with lifting the inside rear wheel off the ground, as long as your car handles fine. All autocross EVOs I know do it at some point. And there have been a lot of EVOs that have won a lot of championships. . . . heck my old silver daily driver did it to the point where even turning a tight corner while decellerating it would do it. . . . and it handled beautifully on the streets as well as the track. . .
Somewhat true on the alignment after spring swap, but you need to nail your ride height.

As for having rear lift and it being a problem, you are correct. It's extremely difficult to completely tune it out and not worth jacking front rates to elleventy billion to do so. How much of it you get and where it occurs in the corner will have a big effect on how detrimental it really is. A bit on entry or mid corner is fine, if it's present on corner exit that is not good. At that point you want both tires on the ground to get in the throttle nice and early, otherwise you give away the AWD advantage and effectively shorten the upcoming straight.

There are some decent discussions floating around right now, cool stuff.
Old Feb 20, 2009, 10:11 AM
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Originally Posted by Mike01gsr
Great thread!!, anyone have any feed back to my questions above^^
Yes, i think it's worth it. You will need an alignment, but the car will really feel better this way.

- Andrew
Old Feb 20, 2009, 10:13 AM
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Originally Posted by kekek
As for having rear lift and it being a problem, you are correct. It's extremely difficult to completely tune it out and not worth jacking front rates to elleventy billion to do so. How much of it you get and where it occurs in the corner will have a big effect on how detrimental it really is. A bit on entry or mid corner is fine, if it's present on corner exit that is not good. At that point you want both tires on the ground to get in the throttle nice and early, otherwise you give away the AWD advantage and effectively shorten the upcoming straight.

There are some decent discussions floating around right now, cool stuff.
This is one reason a lot of droop travel is a nice thing to have.

- Andrew
Old Feb 20, 2009, 10:20 AM
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Originally Posted by GTWORX.com
This is one reason a lot of droop travel is a nice thing to have.

- Andrew
True, but if the load is already transferred off the inside tire and all it's merely doing is sitting there with no load it is effectively the same thing mid corner.
Old Feb 20, 2009, 02:27 PM
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Great Thread!
Old Mar 2, 2009, 05:22 PM
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Originally Posted by Yogi_B
Those look to be metric eibachs.

H200 = 200mm long
065 = 65mm ID
T100 = 100 N/mm (10.2kg/mm)

Don't know what that last one is, could be date of manufacture, possibly 25th week 2006 for fronts 43rd week 2006 rears.
Thanks,

After a closer inspection, I realized that the front springs were actually 12K (T120) and the backs were 10K (T100). Luckily, I haven’t had the time to install them yet. So I decided to listen to Andrew and swapped the springs around.

After the swap:

Front
Frontspring.jpg?t=1236042743

Back
IMG_0197.jpg?t=1236042825

Last edited by 18bora; Mar 9, 2009 at 04:47 PM.
Old Mar 2, 2009, 05:25 PM
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NICE SHOCKS! Once you get them dialed in you will be in LOVE!
Old Mar 3, 2009, 10:04 PM
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I currently have the HKS Hipermax RS and I am looking to upgrade the springs to some swift. The current spring rate is Front Spring rate 6kg Rear Spring rate 5kg. I mainly drive this car on the street with the occasional track appearance but I noticed the rear spring rate is softer than stock. I was thinking of going with 7 up front and 9 in the rear? What do you suspension gurus suggest?
Old Mar 4, 2009, 07:38 AM
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I would be worried the rear coilover can't take a jump from 5kg to 9kg without a revalve.



- Andrew
Old Mar 4, 2009, 09:04 AM
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Sorry a bit noobish question but I'm curious to know which coilovers out there can be revalved and would actually be worth the cost of revalving?
Old Mar 4, 2009, 09:24 AM
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Originally Posted by timmiii
I <3 gtworx
That says it all right there ... As always good job Drew.

Originally Posted by kekek
As for having rear lift and it being a problem, you are correct. It's extremely difficult to completely tune it out and not worth jacking front rates to elleventy billion to do so. How much of it you get and where it occurs in the corner will have a big effect on how detrimental it really is. A bit on entry or mid corner is fine, if it's present on corner exit that is not good. At that point you want both tires on the ground to get in the throttle nice and early, otherwise you give away the AWD advantage and effectively shorten the upcoming straight.
I have to agree with this statement, jack up the rates on the front too much and you just end up with a car that understeers even worse and looses total grip. Suspension system is all about balance, sometime you have to compromise in one area to gain in another.
Old Mar 4, 2009, 09:28 AM
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Originally Posted by timmiii
Sorry a bit noobish question but I'm curious to know which coilovers out there can be revalved and would actually be worth the cost of revalving?
Most manufacturer coilovers can be revalved (eg: Ohlins, KW V3, Bilsteins, Konis, AST), I think the exception are Cusco that use Showa shocks. Whether your coilover will need a revalve or not will totally depend on the range of the shock and the change in spring rate you are seeking. Cost usually ranges from $100 - $150 depending on the shock manufacturer and the shop that does the revalve.

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