Choosing coilover spring rates for your EVO
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.
-Tim
Great thread! Comming from you, a lot more people will accept the fact that more rear spring is needed to match the front suspension design with the rear's.
I also believe that having a wheel in the air, lightly loaded or not, is never a good thing. I think that the trypoding effect can be completly tuned out with the correct combination of front spring rate+bar(bigger ft sway bar is key for not going too high with the natural frequency at that end) and not going crazy with the rear bar(stock IMO is about perfect for the car when the rest of the suspension right).
I also believe that having a wheel in the air, lightly loaded or not, is never a good thing. I think that the trypoding effect can be completly tuned out with the correct combination of front spring rate+bar(bigger ft sway bar is key for not going too high with the natural frequency at that end) and not going crazy with the rear bar(stock IMO is about perfect for the car when the rest of the suspension right).
What would be a good bar to look at for the front? I just picked up a set of cheap coilovers for now with a front 12k/10k rear springs. Was going to order 8k spring for the back and put the 10k up front. Looks like I should just swap them around now.
Last edited by Nasty Evolution; Mar 8, 2009 at 09:56 AM.
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- Andrew
I daily drive my revalved Bilstein PSS9's for autox that use 12k/16k rates. not bad at all with exception of joints and pot holes.. ouch! I will be using 285 r-compounds (as Andrew suggests) this year.
I also believe that having a wheel in the air, lightly loaded or not, is never a good thing. I think that the trypoding effect can be completly tuned out with the correct combination of front spring rate+bar(bigger ft sway bar is key for not going too high with the natural frequency at that end) and not going crazy with the rear bar(stock IMO is about perfect for the car when the rest of the suspension right).
I havent seen that to be true. Thats like tuning a FWD car. If thats true, then we would want even weights on both front wheels and basically disregard the rear weights, rather than having a good cross-corner balance. Another thing Ive always thought about lifting a rear wheel is, that means you have too much body movement, and thus youre not stiff enough up front.
I havent seen that to be true. Thats like tuning a FWD car. If thats true, then we would want even weights on both front wheels and basically disregard the rear weights, rather than having a good cross-corner balance. Another thing Ive always thought about lifting a rear wheel is, that means you have too much body movement, and thus youre not stiff enough up front.
If you make the front stiff enough that it doesn't lift the inside rear, it will understeer.
I used an 8kF/10kR setup when I had coilovers and it felt very neutral on the road course.
Then I ditched them b/c of the poor driveability on the street. From this experience, I will never buy coilovers for a street car ever again!
Then I ditched them b/c of the poor driveability on the street. From this experience, I will never buy coilovers for a street car ever again!
Unless you can smash those front tires into the concrete with some good downforce!!
More coming for 2009!!Don't hate coilovers because your particular setup may not have been setup well for street use. . .
Last edited by EVOlutionary; Mar 9, 2009 at 05:26 PM.
I would argue that it is possible to have nearly equal front weights and still have good cross weight balance. I do agree however that setting up an evo is very similar to setting up a FWD car. I think Tom said it best, we drive FWD with attitude. Obviously there are some serious compromises to be made in stock form but once you get past those it's pretty clear what works.
If you make the front stiff enough that it doesn't lift the inside rear, it will understeer.
If you make the front stiff enough that it doesn't lift the inside rear, it will understeer.
I somewhat agree, we can use some tricks of fwd cars. But, the rear suspension on our cars works too well to neglect it by using a straight up fwd train-of-thought. Its not a good idea to try and equalise weights up front. you will get a car that turns different left to right, transfers weight different, ect. Cross weights are the right answer for our cars; And low body movement. You can get the car to turn without picking up a wheel, especially on a road course (auto-x is probably harder to negate tire lift). Even without nifty 35/65 split center diffs.





