Cortex coilovers - softening the spring rate - how far?

[Grant 302]

Right now I'm 5clicks softer than neutral in front of 15-5 = 10 (out of 30), rear I pulled 10 clicks out. Both low speed. Front high speed rebound still at factory setting.

I haven't run that soft on Low Speed yet. I'd try a sweep or two more on the High Speed up front. Might as well also try down to -25/+2 or -23/4 like 2013dibgt did. Next time I'm in or near LA...I might do the same.

Since you have the SA rears, I'd compare notes with Rick. @NFSBOSS

 

[2013dibgt]

Yeah when I tried the other day it was a -25 Compression & probably not even 2 sweeps on Rebound because I was scurd turning the dial with my Allen wrench anymore then that. I didnt find these soft settings bad at all until I started pushing the car a bit harder but at the time in my mind I was at a 5 and 2 on the dials

Today I bumped the damping up to the Cortex inital settings of -15 and 5 sweeps. Definetly better! Maybe a turn more here and there in one direction or the other and I think I'm good. Even on these higher settings the car is far from rough with the 425/225 spring rate combo.

One final note, even if the struts are supposed to be shipped at -15/5 on the dials I would recommend others to turn the dials all the way down then count back up again because I'm pretty certain my setup was not set evenly between the two dampers. The Top Clicker on one side appeared higher then the other.

 

[VoodooBoss]

Right now I'm 5clicks softer than neutral in front of 15-5 = 10 (out of 30), rear I pulled 10 clicks out. Both low speed. Front high speed rebound still at factory setting.

Be careful about using "neutral" as a starting position. They reference their starting point as full stiff, at least with the knob on the strut, and I recommend you base all adjustment off of that. That's turned all the way in. And like Grant keeps mentioning be sure to write it down!

 

[Grant 302]

Not that it's going to help a *LOT*, but I ran the -20 Low Speed up front and I like the High Speed bumped up to +6. Also tested -18/+5.5, -18/+6 yesterday, and today and rolled into one of the adjacent cities where the roads aren't as good. -20/+6 felt pretty well controlled for road imperfections, but definitely too soft for me at turn-in.

I have spreadsheet I created and I'll send it to you.

I was hoping you have some reference numbers for your rear SA street settings that you sent to Doug.

 

[Mad Hatter]

Hmm, for what is worth, I found the cortex Koni setup surprisingly comfortable with the 500 and 300 spring setup. Thats with the shocks on full soft on some pretty bad roads here in Chile. Was going to get a helper spring setup but it looks cheaper to get a 10 in spring for the rear to give me a better adjustment range. I still drive the car on the street and need to stop scraping my belly on the speed bumps.

 

[twistedneck]

Not that it's going to help a *LOT*, but I ran the -20 Low Speed up front and I like the High Speed bumped up to +6. Also tested -18/+5.5, -18/+6 yesterday, and today and rolled into one of the adjacent cities where the roads aren't as good. -20/+6 felt pretty well controlled for road imperfections, but definitely too soft for me at turn-in.

I was hoping you have some reference numbers for your rear SA street settings that you sent to Doug.

Using the correct description i'm at -20/5 in front and assuming the rear with its 60 total clicks -maxing max damping = 0 i'm at -40 in the rear. Front and rear are not bouncing at all and the body roll is minimal on turn in (i am running an 18mm rear bar).

Hmm, for what is worth, I found the cortex Koni setup surprisingly comfortable with the 500 and 300 spring setup. Thats with the shocks on full soft on some pretty bad roads here in Chile. Was going to get a helper spring setup but it looks cheaper to get a 10 in spring for the rear to give me a better adjustment range. I still drive the car on the street and need to stop scraping my belly on the speed bumps.

Single event bumps are not that bad its the two wheel events like road ripples and speed bump types, or even worse uneven concrete seams and up down up down non level freeway or street segments. that can get crazy bumpy!!! here in Michigan some of the roads are nearly impassible for regular cars you can imagine trying it with cortex coilovers setup for track!

 

[twistedneck]

Finally could not take it anymore and ordered the softer springs. Same Eibach springs just longer and lower rate.
1000.250.0375
1000.250.0225

$252 shipped from Summit.

2" longer to account for the lower check load.

Will it be over damped now? we will see.

 

[VoodooBoss]

Finally could not take it anymore and ordered the softer springs. Same Eibach springs just longer and lower rate.
1000.250.0375
1000.250.0225

$252 shipped from Summit.

2" longer to account for the lower check load.

Will it be over damped now? we will see.

I think you'll be fine. I have 450/225 and have noticed the dampers are a lot less harsh now that they have broken in. In fact driving out to Sonoma this past weekend with the dampers turned up a bit my son and I both agreed it now rides better than my Ford Racing dampers with P springs. We have pretty good roads around here and the only time you really notice the stiffer springs is when you hit a big bump. Oh and taking sweepers at 100+ MPH or braking from the same speed.

 

[Grant 302]

Yeah, you'll be fine. Just gotta turn some of those knobs and adjusters your paid for!

 

[twistedneck]

Update - and I can save you guys some time.

Front: I swapped to the longer 10" coil in front with 375 rate vs. the 500 rate 8" coil Cortex shipped with. The 8" was just about free at rebound so I though I had room for a 10".. turns out a 9" was ideal but nobody makes it. So right now, the front sits a little high even with the adjuster backed off 100%, still lower than stock but not low enough - i'll purchase an 8" 375 rate and a helper spring set to go with it. that should do the trick and allow the proper low ride height in front. Also, even though this time I know for a fact there is plenty of rebound load, there is still some slop when I high bad cracking concrete - its improved, but there is still a light clunky noise on both sides. and I double checked the bearings in the plates. so something else going on.. not that I care at this point.

2. Swapped to a longer 10" coil in the rear with lower rate, there is no problem with fit on the rear and you still have room to drop the car as far as you want even with the 10" tall coil. STILL - like an idiot even though I had room I decided not to use the helper springs, yup, I need them.. back off enough so the rear is slightly higher than the front and the 10" tall coil comes free at rebound - clunking around. So now it all has to come apart again. Joy.

Good part? 375 / 225 rate works great and is so much more tolerable over the Michigan roads. a touch of body roll makes the car feel more confident too.

 

[twistedneck]

After driving my 375 front 225 rear setup - I like it a lot and it did the trick for Michigan roads. However, its not balanced front to rear - for what ever reason, I need to drop the rear more than the 25% I started with. I'm going to try 200 rear next.. the rears are a lot easier to change than the fronts. The symptom shows up over large freeway speed dips.. front is usually still active in motion after the rear has already finished. I tried fixing this with a ton of damping low and high speed, then went the other way to way less damping to quicken the front and that worked great except I noticed the car would be great at low speeds but over high speed dips there was a second mini cycling of the front up and down after the first jounce to rebound cycle.. i.e. underdamped. so I can either make the fronts slightly stiffer or soften up the rear a little more.

From a smooth road handling perspective the super Ferrari like twitchy handling is no more - its a lot slower to respond to steering inputs with the 375/225 than the original 500/300.

However the punishment is gone and I can actually drive my car again. If only I lived in Florida, or Canada.

 

[Grant 302]

What rear sway bar are you using? If you haven't gone to an 18mm, a smaller/softer than stock bar might help.

 

[twistedneck]

What rear sway bar are you using? If you haven't gone to an 18mm, a smaller/softer than stock bar might help.

Grant, I'm already on the 18mm rear..

 

[Grant 302]

Grant, I'm already on the 18mm rear..

I probably should know that! Maybe take it off?

Interested in your results either way.