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Racing Coilover Spring Rates

Sesshomurai

Hi,
For those who are or have been in competitive racing (with the boss), what spring rates have you found work best?
Based on some initial research, I'm in the 500-550 front, 300-375 rear range. My suspension setup is this:

- Eibach adj. front/rear sway bars 35/18mm, front on tight, rear on middle
- Eibach sportline springs
- Steeda bumpsteer and extended ball joints
- Eibach adj. rear LCA's in middle reloc bracket hole
- BMR relo bracket
- Steeda 3rd link, adj. upper control arm
- Car has a 27" (ground to fender apex) level stance
- 19" 9.5 wheels (currently)
- Hankook RS3 tires

I'm told all of these items play a role in the proper spring/damping settings. Just not sure how/why yet.
I have not (yet) weighed and balanced the car on 4 point scales.

Thanks
 

pufferfish

Supporting Vendor
1,094
66
Maryland
i can't say what you should be running for spring rates. i am still learning about them for our cars, but i believe that high of a rate is based on a small diameter coilover spring? my eibach dealer catalog, says that the sportline spring rates are 183F/103-217R for the 4.12535 (2011-13 GT/V6). there is no specific boss part number.

i don't see any specs on the H&R race springs in my catalog. it only says they are a "firm ride". i will call them.
 

Sesshomurai

pufferfish said:
i can't say what you should be running for spring rates. i am still learning about them for our cars, but i believe that high of a rate is based on a small diameter coilover spring? my eibach dealer catalog, says that the sportline spring rates are 183F/103-217R for the 4.12535 (2011-13 GT/V6). there is no specific boss part number.

i don't see any specs on the H&R race springs in my catalog. it only says they are a "firm ride". i will call them.

Thanks sir. Are you an eibach dealer? Cuz im looking at the multi pro r2's among others.
 

Sesshomurai

ArizonaGT said:
Vorshlag has done a lot of testing with AST's in this encyclopedia-sized thread: http://www.corner-carvers.com/forums/showthread.php?t=44217

Does it have an index? Lol. Thanks!
 

Sesshomurai

This is why i want to setup bosswiki to distill all the useful info into categories.
 

pufferfish

Supporting Vendor
1,094
66
Maryland
I am an Eibach dealer. I was going to suggest the R2. A really nice setup, with lots of tunability built in. The only problem is the spring rates included seem a bit soft. I am away from my trusty catalog right now, but I believe they are in the 250-350 range? The cool thing is they have a double spring. The softer one compresses first to give a smoother ride, but go past that and the second, stronger spring takes over. It's a cool street/track setup. It's the one I will be installing and testing this year at time trials. For more dedicated track cars, I think a spring upgrade would be in order...which they offer lots of rates for, as well as the fact that they are a standard size spring that lots of manufacturers offer.

Another option for a "throw it on and go" coil over is the H&R RSS Club Sport. 630/515 rates out of the box! I do sell that line as well, but not really going after it. I prefer to have intimate knowledge of my products and the Eibach is more familiar to me.
 

pufferfish

Supporting Vendor
1,094
66
Maryland
in case you are interested, the R2 spring rates are 225+150F/250+150R out of the box. the 225/250 is the final spring rate. the 2 springs don't act cumulatively. they will have a profound benefit on street/track cars as well as on bumpy road courses. if the final rate isn't enough, they do offer other rate springs to swap them out with. i have my doubts about running a soft 150lb initial spring rate with something like a 500lb rate behind it. there might be too much of a difference in rate in that instant, which could upset the vehicle. I will be exploring this idea at some point...maybe not this year.
 

Sesshomurai

pufferfish said:
in case you are interested, the R2 spring rates are 225+150F/250+150R out of the box. the 225/250 is the final spring rate. the 2 springs don't act cumulatively. they will have a profound benefit on street/track cars as well as on bumpy road courses. if the final rate isn't enough, they do offer other rate springs to swap them out with. i have my doubts about running a soft 150lb initial spring rate with something like a 500lb rate behind it. there might be too much of a difference in rate in that instant, which could upset the vehicle. I will be exploring this idea at some point...maybe not this year.

Yeah. I had similar thought. I like eibach but trying to make a DD/track system makes it less effective at both maybe.
 

pufferfish

Supporting Vendor
1,094
66
Maryland
its definitely not the first choice for a no compromises race car out of the box. i am interested in seeing if they would work with conventional progressive rate coil over springs for dedicated track duty. their shock/struts on the R2 are much better than their price point suggests. i love the remote reservoir with dual adjustments on it, so you can locate them wherever is convenient and dial in the shock damping without needing to get under the car. my only knock on them is they aren't available in aluminum on the mustangs (they do for Audi).

i am interested to see what you end up going with for a package and spring rates and how they work for you.
 
110
0
The Vorshlag Mustang initially had 450f and 175r spring rates when were running street tires. They eventually went to 550f and 250r when they made the switch to 315mm Hoosiers. I am also looking at the ast 4150 set-up but have not decided on rates yet. There is another member on here that installed the ast 4150's and I think he went with the 450f and 175r and seems to like them alot. He had a nice write-up on his install on s197forums.
 

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