It has everything to do with travel. A 8" spring will have 2" less travel than a 10" spring. Car sits 2" lower, you just used up 2" of your shock travel!

 

Not neccesarilly. Since the upper spring perch is adjustable, as long as there is threaded length on the shock body you could just move the perch down. Also it is more the number of coils in the spring and the wire gauge of the spring that determin at what travel the spring will start to coil bind. An 8" spring with few coils and smaller wire diameter could actually travel more than a 10" of the same rate with lots of coils and/or larger wire diameter.

 

No, it has everything to do with ride height. When you set the car down, it will compress the spring the same amount. It just changes the ride height of the car reletive to the lower perch position. That is his problem. He needs an 8" or less front spring to get the car low enough. Travel by definition, is how much the suspension will move once the car is at ride height, and going down the road. A certain amount of travel is in compression, and a certain amount in droop. As long as he is not hitting the bump stops, or topping the strut in any of these conditions, the free height makes no difference.

 

 

You might want to listen to him.

Do a google search if you don't know who Mark is.

 

Thanks for the call Kyle! I am glad you got the suspension sorted and are on your way to the track day. Drop me a line and let me know how the car did. I look forward to getting you some Ohlins for that Elise whe the time comes as well!

Brett Payne
www.Forcedfed.com
925.371.2288

 

You and I just said the same thing. Both springs will compress the same amount if their spring rates are the same, the free height will determine ride height. That's why I said put a 10" spring on a perch that is 2" lower than the perch that the 8" spring is on and you'll have the same ride height. What will determine the travel in this situation is the +/- travel of the shock from full extension to full compression, UNLESS the springs enter a coil bind situation prior to the shock fully compressing... IN WHICH CASE the 10" free height spring will have more travel than the 8" free height spring, IF the wire diameter and number of coils is the same, but the coil spacing is larger.

- Steve

 

Mark, care to elaberate why your going against traditional wisdom by running 750 front/700 rear instead of heavier in the rear? We can assume your running a 25mm rear sway bar.

Dave

 

Yes, for starters I am running 285/30/18 front tires, and 245/40/17 rear tires. I am trying to keep the inside rear tire on the ground as long as possible and achieve really fast transitional response, while still having a setup that will allow the car to rotate mid corner. Experiment as to success of said theory to follow shortly.

 

Mark,
You should also post your updates in the sway bar thread.
BTW -- are you running the bigger front bar?

Keep us appraised of your progress as it is really fun to watch your setup evolve.

Take care,

 

So far I am trying stock bars front and rear and will see what happens with that. I have not posted up any results yet on the sway bar thread because I have yet to do anything. I can say that the staggered width tire setup does not seem to have any ill effects as far as the center diff, or hopping under accelleration that Eric S. had mentioned.
Mark

 

Interesting... must be nice having an active center diff!

Eric

 

Eric,
I am not sure if it is the active diff, but I am guessing it probably is. What exactly were the tire and wheel sizes that you tried this with? The diameters that I am using are virtually the same.
Mark

 

I tried the same tire setup that you're running right now. I would say the difference is the active center diff's ability to manage slip. My viscous coupling locked violently when only one end spun. My solution: make enough power to spin all the tires everywhere...

Eric

 

That's definately the right direction as I have discovered recently. I am still not convinced that the silly high spring rates are needed, but my EVO is a daily driver too.

As for the rear swaybar, I don't think I need it. I might go back to stock, but I have not run on concrete yet, so I want to keep the adjustability for now.