Where to get springs for Cortex coil overs

[Mad Hatter]

Hi, I was having some problems with my Cortex Koni setup on one of our less civilized tracks. The rear springs seem a little to hard and at one point I think I might be airborne due to the tracks bumps. I had to keep my harness really tight to avoid hitting the roof!! I have 600lbs Front and 450 rear. Where is a good spot to buy Springs?? I was thinking of going to 350 rears since I am running square.

After the hurried installation, saw that the car was running on the rear bump stops. Took them off and it seemed to be fine. Should I cut it down and put them back on just in case??

 

[ArizonaBOSS]

Call Cortex?

Otherwise check out Hyperco. http://www.hypercoils.com/

 

[2012-Boss]

Did Cortex sell you Eibach springs? If so, the part number is printed on the springs and will tell us a lot about the specific application. For example, my rear springs are 450 lb, 2.5" diameter, 7" tall springs the part number is 0700.250.0450 which breaks down as:

0700: 7" tall springs
250: 2.5" diameter
0450: 450 lbs

If I wanted a 350 lb spring, I would order 0700.250.0350.

Post up what you have and we can help point you in the right direction. Believe it or not, if you know the part number for the spring you want, I found the best deals on Amazon.

 

[ArizonaBOSS]

Did Cortex sell you Eibach springs? If so, the part number is printed on the springs and will tell us a lot about the specific application. For example, my rear springs are 450 lb, 2.5" diameter, 7" tall springs the part number is 0700.250.0450 which breaks down as:

0700: 7" tall springs
250: 2.5" diameter
0450: 450 lbs

If I wanted a 350 lb spring, I would order 0700.250.0350.

Post up what you have and we can help point you in the right direction. Believe it or not, if you know the part number for the spring you want, I found the best deals on Amazon.

Be careful there--as you reduce spring rate, you will need to add overall length to make up for the static load difference and keep the same ride height. If you keep the same length with a reduced rate, the car will ride lower. This might not be a big deal depending on how much height adjustment you have available.

 

[2012-Boss]

ArizonaBoss, that is very true. If Mad Hatter is using a 7", 450 lb spring and wants to go to a 350 lb spring, he may need to go to an 8" spring length.

 

[2012-Boss]

After the hurried installation, saw that the car was running on the rear bump stops. Took them off and it seemed to be fine. Should I cut it down and put them back on just in case??

If the kit came with new bump stops, I would not cut them. You may be able to use the adjusters on the coil over to increase your ride height.

 

[Grant 302]

Drew brings up a good point. Its best to try to calculate the difference in static compression before you order.

Not sure about the geometric differences between the rear Konis and JRis, but I have a 10" 350 lb. rear spring with a "0 rate" helper. I specifically asked Filip to be able to adjust into the stock ride height range since I roll to the track.

Once you decide on your rate/spring height, you can get 2.5" dia. springs anywhere. I'd probably also check Pegasus or Maximum Motorsports too as they might have what you want in stock.

 

[Mad Hatter]

Great! Can't wait to get under the car to check. I am pretty sure the bump stop kit is from my old p springs.

 

[Mad Hatter]

I Noticed at the track that the locking allen head screws were gone on the rear as well. Thought that instalation was to fast/cheap.....

The ones that lock the ring into place for ride height. Also driving to track and swapping tires.

 

[steveespo]

Do the Cortex Konis have a bump stop on the shock shaft or do they rely on the factory bump rubber. If the factory rubber is being used then you either have them adjusted too low or your spring is too short for the application. From center of the wheel arch to the ground through the axle centerline a measurement of 26 3/4" is a fair starting point for ride height and will leave about 1 3/4" clearance between the bump rubber and the frame. I would consider this as low as I would want to go with a 350-400 lb spring and normal (LS wing) aero, if you are running a G-Stream Wing I would run 450-550 rear springs and allow 1 1/2" travel minimum. YMMV but check the free length of your springs, may want to increase the length and take up with the adjuster to get your ride height.
Steve

 

[Grant 302]

You could probably remove the stock bumpstop. The Konis look like they come with one on the shaft. I left mine in the way I had them cut down for the P springs just the last 'block' on the bottom.

 

[Mad Hatter]

I am away from the car right now but if I remember right, there is a stopper on the top of the shaft of the Koni and the kit did not come with a bump stop so the ones I have are the ones recommended by Ford Racing for the P springs. I will check the measurements as soon as I can. When I saw the bump stops they were being compressed as the car was jacked up using the rear axle so maybe I jumped the gun a bit. Will check space left on the stop when the car is on the ground.

I have the car at 27in from the ground to the center of the rear wheel arch when running my 305s.

Cheers!

 

[Mad Hatter]

Thanks Grant, did not see your post. I think I will cut them down as you suggested just in case.

 

[2012-Boss]

Measuring with a nitto NT01 in a 305/35/18 like you are running, I am 27 3/4" on the passenger side and 27 13/16" on the drivers side to the top of the rear fender arch.

Notice that the measurements are not equal side to side. However, the adjusters are set at exactly the same place on both sides. If you cannot corner balance, this is how Maximum Motorsport and several others recommend setting ride height. The idea is to minimize weight jacking.

The 27 3/4" rear height is about 1" lower than factory. This will help keep you off the bump stops. Also, the rear is high enough that you can set the front ride height high enough to get the front A-arms parallel to the ground. Keeping the a-arms parallel to the ground at static ride height improves the front suspension geometry if you are using factory length ball joints.

 

[Mad Hatter]

I will try measuring all the corners this weekend. Got in touch with Filip from Cortex and he mentioned the 8" long spring at 250lb/in that they use for street. Can go all the way to 10" if you have a 10" wide rim or less.

I made a mistake on my original post, I have 600lb/in front and 350lb/in rear, not 450!! I will try one more event with the rears on full soft, and then again without the rear swaybar. If I am leaping in the air again will try a 300lb/in rear with 8" length in the rear. Fronts feel fine even on the street with 600lb/in. I am hoping to get the front wheel in the air for corner exit!

If any one had the size of the locking allen head bolt for the rear spring perch on the Koni Cortex setup? Will try Filip again just in case.

 

[Mad Hatter]

Just a quick note. My ride problem was because I had the old bump stops still in from the P springs...How to feel like a dummy! Cut them down and no more jack rabbit bounces.

 

[Tri-bar]

I got the set from Ebach thru Maximum Motorsports. They are wsy softer the stock or Ford racing.

Sent from my LG-D415 using Tapatalk

 

[DocB]

@ Mad Hatter,

Why do you want to get the front wheel in the air for corner exit?

Do you think you will have more lateral grip with one tire on the ground vs two?

Don't you think you will have exceeded the maximum lateral load transfer at/on the front of the car?

 

[VoodooBoss]

Doc I think he's going for this look. ;D

 

[Mad Hatter]

Yessss! thats what I am trying to get!!! Would love to have that much traction coming out of a curve. Tried no rear bar but hated the understeer. Trying with a big front BMR bar and a 24mm GT bar on the rear... Still not happy though.