What rate springs?

[Pro3racer]

I'm trying to figure out what type of springs to get for my car for next year. I have AGX's, with Ground Control sleeves(not on car yet). The car will see alot of track events, and still be driven on the street(an almost daily driver). I don't care about the roughness of the ride, passengers complain, but I don't care. I have weight reduction done, with a CF hood, no AC(or emissions), no bumpers, no rear speakers or spare stuff, and battery moved to the back. I am thinking 500# in the front, and 400# in the back, but i am really just guessing from stuff i have read. Also, what is the difference in going with a 7" spring vs. a 8" spring in handling? Thanks

 

[90laserRSfwd]

ditch the kyb's in favor of some koni yellow's, 400 in the rear seems aggressive? ask Jtoby he know's about spring rates

 

[Pro3racer]

I was hoping he would chime in. I know the AGX's suck, but unless i find koni's very cheap, it won't happen. A clutch, dsmlink, and eprom have hurt my financially.

 

[RipperXX]

I know the AGX's suck

............

 

[Pro3racer]

They do the job, but they aren't the best, thats for sure. I'm going to try and weigh my car tonight, hopefully i can sneak onto the truck scale and get it weighed

 

[underradar92]

AGX's work ok for a while. Aparrently Koni's are much better (I don't have them) for higher rate springs. I was using 450# F/350#R with AGX's and, though they wore out quickly and were harsh on choppy streets, they were passable on the track. I don't think I'd want much higher rate springs than that, without a better damper.

I also wasn't too pleased with the way the springs unseat when the struts were extended. It never happened in use, but theoretically it could.

What is your current spring rate? My old setup was mildly understeering with a 1" rear sway, and the stock front. Springs for coilovers are pretty affordable, for later fine tuning.

The spring height alone won't noticeably affect handling, the longer ones just weigh more and allow more travel.

 

[Pro3racer]

My current setup is a RM rear sway bar, with poly bushings f/r. I have Pro-kit springs(got them to be stiffer, they are, but i want a tad a lower, and even stiffer). I also have adjustable camber front and rear. I get alot of body roll(well, maybe not body roll, but look at my avatar for example).

 

[staticbrainwash]

Correct me if i'm wrong, but i believe they were unseating because the agx is a stock length strut. So anything lower than 1" on intense handling circumstances will throw them off.

Koni's on the other hand are a shortened shock/strut, built more for stuffer springs and lower cars.

 

[Pro3racer]

can we change this thread a bit, i just went window shopping, and the car will have koni yellows on it next year, they aren't as much as i thought. So, forget about AGX's then. I still need good spring rate numbers. Would 450#F and 350#R be good for me then?

 

[staticbrainwash]

I would think so yeah. Make sure you get the appropriate camber kits as well.

 

[Pro3racer]

I already have the Ingalls kit in the rear(love it), and a machined spindle in the front, i'm not going to go with camber plates yet, thats out of my price range.

 

[underradar92]

Sweet on the Konis, I thought they were shorter, didn't know for sure. FWIW, my springs never unseated, even if it seemed possible, I did have the damping set high though. I rather liked the 450/350 setup, I really like the 12kg/10kg (about 675#/550#) though. My current struts aren't as sophisticated as Koni's so the ride is ummm... firm, on the wagon trails Milwaukee calls "city streets". Don't know how they'd be with Koni's but, I think Koni's can control that sort of spring. Also, if your car is much lighter than stock, (mine is still heavy, by choice) it won't need a lot of spring.

What sort of camber numbers are you planning? I'm rocking -3/-2 right now!

If I'd had my choice I'd not have camber plates, I'd rather get pillow bearing mounts and do the camber tweaks at the spindle, as I've read that camber plates have been known to slip. If you can make a plate, try to find a suitable spherical bearing, and make a fixed plate. That is one of my upcoming winter projects.

Here are a couple shots of me in Canada Corner last year, with the 450/350 deal, for comparison.

I just noticed you are rocking Hoosiers on the track, your lateral g's are going to be higher than what is shown in my pic's, that was on NeoGen's. Here is a list of rates, for your enjoyment. http://www.dsmtuners.com/forums/showthread.php?t=213963&highlight=spring+rates+1g Notice the prokits?

 

[Pro3racer]

Thank you, that post was very informative. I need to change my profile a bit, i don't have hoosiers(i will be tire shopping over winter and spring). The Koni's are shorter, which will help alot with the GC. I think i will go with 450#F and 350#R, but should i go with a 7" or 8" spring? My camber right now sucks ass, the place i took it to would not adjust the front to what i wanted. My rear is -1.4(due to my toe bar being stuck, that is my winter project, haha. The front they said is 0, but i think its more like 1. I would love to have -2 all around. Thanks for your help, winter can't come soon enough(so i can tear the car apart and get to work).

 

[underradar92]

should i go with a 7" or 8" spring? My camber right now sucks ass, the place i took it to would not adjust the front to what i wanted. My rear is -1.4(due to my toe bar being stuck, that is my winter project, haha. The front they said is 0, but i think its more like 1. I would love to have -2 all around. Thanks for your help, winter can't come soon enough(so i can tear the car apart and get to work).

The spring length will probably be determined by how much length is between the top seat and the collars when the struts are extended, more than anything else.

A rule of thumb for camber is (I believe Jtoby reccommended this formula): rear camber is 2/3 of the front, which explains my settings. My stock front was @ less than -1*.

Toe bar? do you mean those sleeves in the gooey rubber trail arm links? Are you planning to do a "toe eliminator" type deal? If so, I do recommend it, even though I can't say how much they help, as I made so many changes at once it's impossible to attribute any improvement to anything in particular. At least that way you can get the spec's you want and toss that squishy/seized crap away.

 

[Elvenhome21]

AGX's work ok for a while. Aparrently Koni's are much better (I don't have them) for higher rate springs. I was using 450# F/350#R with AGX's and, though they wore out quickly and were harsh on choppy streets, they were passable on the track. I don't think I'd want much higher rate springs than that, without a better damper.

I also wasn't too pleased with the way the springs unseat when the struts were extended. It never happened in use, but theoretically it could.

What is your current spring rate? My old setup was mildly understeering with a 1" rear sway, and the stock front. Springs for coilovers are pretty affordable, for later fine tuning.

The spring height alone won't noticeably affect handling, the longer ones just weigh more and allow more travel.

Kyle is very pleased with the Koni coilovers I made for him, he was running agx's with ground controls and said they were shit compared to the konis and 500/400 springs I sent him.

2nd part, use a zip tie in the top coil of the spring and zip it to the top cap so to speak.

4th part, you can fit 10in springs at the VERY most but you cant drop ride height anymore than stock, 8in springs are a lot more common than 7in.


Also with street touring tires at RA i ran 4.5 degrees of camber and was able to lower tire pressure a couple punds and the tires stuck great. compared to less camber and more tire pressure to prevent rolling over.

 

[underradar92]

I keep forgetting to mention, one could also install a set of flat-coiled "zero rate" springs, like these http://www.pegasusautoracing.com/productselection.asp?Product=1875 to take up any gap. They are available in 2.25" and 2.5" diameters.

How is DD-style tire wear @ -4.5* camber? Or is that a little too radical for going too and from work? I've noticed some stock BMW's with seemingly radical camber, but I'd guess the Germans (who are bent on world domination) have magic geometry.

I know a cat who used to re-set camber & toe (on an EVO)for the track, it looked like a buzzkill. He also sold that car and got a lower maintenence ride.

 

[RipperXX]

Not to hijack or anything but has anyone else noticed with the Eibach pro kit springs on the rear they were the same length as the stock spring? The fronts were about 1" shorter but the rears seemed the same.

 

[Elvenhome21]

I switched from 0 camber on the street to 4.5 camber at RA I changed spindles (bigger and longer studs for racing wheels), struts (agx instead of worn out stockers), and pads. and yes its a pita with the toe adjusting but I got it down to a 5 minute single person job.