Will do. Not gunna lie I was quite jealous hearing you guys talk about CTD as well as watching some recent vids. Looks like you'll had an absolute blast! I better be there next year.

Alright enough of me cluttering up this great thread. I need this space to be filled with swaybar info for my own knowledge rather than us flirting with each other

 

Any progress here?

 

Im currently building an Evo 9 as hill climb car. Dry weight is right at 2600 lbs. Engine is out, so now's the time to do swaybars. In your opinion, should I use the large H&R adjustable bars (F=25mm, R=27mm) as my baseline? Dampers are JRZ 650 front, 800 rear. The car came with stock front and Hotchkis hollow 24mm.

Any suggestions for the baseline?

Thanks in advance.

 

Is there a rule of thumb that can be used to determine when you have enough rear spring?

I am running ohlins 10k/8k with 25 mm rear sway bar on full stiff. This combo feels great but soft. The car still wants to roll over and dance through high speed sweepers. I still see tripod action and I feel significant brake dive running 255 BFG r1s tires.

I'm tempted to move to 12k front to reduce dive and roll. This should also help with the three wheel motion. I'm curious if I can continue with the stiffer front spring and still get the car to behave well with the 10k from the front moved to the rear.

I ask because the rear is pretty much gutted plus I have that 25 mm bar back there.

Thoughts?

 

Why are you running these flip flopped spring rates? Seems like you should be 8/10, 10/12 or max'd at 12/14

Im no expert, but due to the EVO's rear shock mount location we should always running the higher rate or at least even in the rear

Just curious=)

 

Yea yea yea I've heard that too but mostly from autox guys trying to get their cars to rotate. I can guarantee you that if I flip flopped them putting 8K springs in the front would NOT help my on track performance as I am already pushing the 10K springs to the limit.

Today, with the rear sway bar the car starts to oversteer at apex when getting on the throttle which feels pretty darn perfect because I like a loose car however I need more spring. The question is how much spring do I need in the rear when the back of the car is pretty much gutted yet the front is still full weight. Will a 12k spring in the rear really help my on track performance? At some point .... I'm not sure what it is... adding spring to the rear isn't going to do much except take away from compliance. Below is a picture of my car going through a fairly tight left hander at 100mph. The rear is stepping out and actually leaving trailing marks but I'm ok with that. I just want the car to stay a bit flatter. I'd also like to combat brake dive a bit more.

 

for a sticky tire like that you'll need at least a 12F/14R and you would also benefit from putting the rsb to the lowest setting, or going back to stock, due to it being so stiff the rear end is actually losing grip (big no no) causing you to oversteer.

 

With a heavy front spring and light rear spring, the rsb is a bandaid to the issue of an improper suspension setup. You need more spring in the rear because of the weight distribution of the car and design of the system.

You're break dive issue has less to do with spring rate, and more to do with the valve compression of the shock.

 

there are many ways to get the car to rotate. you've obviously chosen to stand the rear tires up to get the car to rotate, so your rear spring rate is going to be lower than someone who cambers the rears in looking for more grip.

 

do you have a roll center adjuster?

 

As long as you can keep both rear tires on the ground during corner exit, I don't see why having a softer rear spring is a bad thing on the track.

As stated previously, AutoX has a stiff rear spring to help rotate the car.

Our cars our quite light in the rear and all of the easy weight to remove is in the rear of the car. Why would we want to decrease grip by putting a spring that "matches" the front when the issues on the front of the car are entirely different?

On turn-in, is it not the objective to have the front outside suspension compress an entire length to near bumpstop for maximum grip/weight transfer to the loaded tire? So, size the spring/valving/sway to accomplish that for a set tire and then try to achieve the same thing in the rear on corner exit.

Keeping the car flat with stiff springs and swaybars seems to be counter-productive to loading up the loaded tires whether it is the front or the back.

I would think that the front springs should be sized for the weight the front of the car throws around at turn-in and the rear springs would be sized around the torque/rpm/gear at corner-exit that you would expect at a track. Not necessarily the currently assumed standard of getting the front/rear rate to line up when taking into account the rear LCA is a lever arm.

Edit: This looks useful: http://www.raetech.com/Instrumentati..._Load_Cell.php

 

I do have the rck. I understand motion ratio and what not but there has to be a point at which increasing rear spring wont benefit me. Will i really need 14k rear springs to balance 12k fronts?

 

I like the idea of adding a 12k front spring and front sway bar. Moving up to a 10k rear spring and possibly upgrading the rear diff.

 

^ get a proper alignment before wasting time/money on other stuff. start with the easy stuff first. try the stock RSB too.

I don't know how you are oversteering on corner 2 at BHF. that should be almost a flat out corner for you.

 

from what it sounds like, those will all be good mods for you to fix specifically what you mentioned before, save for the rear diff. but that's just a damn good mod to have