spring rate, would this be good?
 

ok guys, i have ground control coil over with 550/450, i would have the chance to have 350 in the back instead of 450, would a 550/350 be better than 550/450?

thanks a lot

puma

Depends on your particular driving style and personal preference. Most people balance a 550 front with a 350 rear. The 450 rear might be a bit stiff. Did you say you already have the 550/450 setup installed on the car? If so, how do you like it? If the rear seems a bit stiff or twitchy, then maybe the 350s would suit you better.

yeah, i think you are right, i will try it.

yes, i have the 450 now on the car.

i can't compare, i never tried anything else

thanks a lot

puma

I had 550/450 and decided to soften the rear. 550/350 sounds like a good setup to try.

-Max

Yes, the guys gave me some crap at GC when I bout mine.. They seem to like the 100 in lb diff... I am running 550 / 375 (the 350 were on back order). I have found that I have to mis-match my gabs to 6 (front) and 2 (rear) to balance the car... I am planning on going with 600/375 to try and even these out, as I need the full range of adjustability for track conditions, and the 4 position stagger leaves me short...

Dan

I would be interested to know what are good rates to start out with as well, as I am planning on ordering a coil-over system soon. And while off the subject, how do you like your CCWs?

Max,

I took a look at your website, and saw that you are running M2's kit. How do you like it? Were you able to choose your own spring rates? Any problems whatsoever? Does the system come with spherical pillow ball mounts all the way around?

Another kit I am considering is 's kit. From what I am told, this set is identical to M2's (made by the same guy at the same company) but includes the spherical pillow ball mounts as stock. The price is $650.

Thanks in advance.

-Kyle

Bumparino.

The other kit is from rotamotasports.com, in abreviated form, of course.

-Kyle

The CCWs are great. As I learned from the book The Unfair Advantage... the more rubber you can run, the better. 285 all around is nice.

I have been rethinking my spring setup lately. Clearly, shops like M2 have lots of experience with the car and recommend 550/450 or 450/375. My experience with the 550/450 setup was that it made the rear end loose, but I think I may have simply been missing a key element of the setup. It seems like the springs that M2 recommends result in the "right" balance when you calculate it out. That means about the same wheel stiffness front/rear to go along with the 50/50-ish weight distribution. The motion ratios of the front and rear suspensions are different, so that's why you use different springs to get the same wheel stiffness.

So why did 550/450 feel scary to me? I think the answer is sway bars. You probably need a stiff front sway bar to go along with these springs to keep the car balanced. I was running the stock sway bars, so it didn't work for me.

I still like the car kind of soft. Softer springs make the car easier to drive than stiff ones. But you need stiff springs to run the ride height low, so 550/450 is probably appropriate if you plan to run the car low. I run my car a little higher, and I like the ease of driving that comes from softer springs, so I have ordered some 350 springs to put in the rear as a match for my 450 fronts. I did this under the assumption that I would complement the setup with some stiffer sway bars. 375 might be better (as this is what is commonly recommended), but I like the rear end soft for traction, so I am going to try 350 and see how it works out.

For sway bars, I have some Widefoot front mounts (which ave the effect of stiffening the front bar a bit). You need better mounts to run a stiff bar (or even the stock bar by many accounts), and I think the Widefoot mounts are the best. I also ordered a Tri-Point modular front bar with a 0.188" wall thickness torsion bar. The end links have 5 holes to connect the end links, which gives you some adjustment. M2 offers a nice modular front bar as well. I also ordered their rear bar (which may be the Racing Beat bar) which has two positions to connect the end links. I will probably run the rear bar on soft to avoid overpowering the front bar. I like the traction you get with the rear end soft.

So, I am hoping this setup will give me what I want:
- 450F/350R springs
- TP modular, adjustable front bar (0.188")
- TP adjustable rear bar

Keep in mind that the 93 rear bar is quite a bit stiffer than the 94+ rear bar. That should allow stiffer springs in the rear of the 94+ before it gets loose. ScuderiaCiriani.com has lots of info on the various sway bars available.

550/350 will probably work fine with the stock sway bars (93 or 94+). You can probably close the gap (between front and rear stiffness) and maintain balance with stiffer sway bars, particularly a stiffer front bar. I think that M2 and other vendors often recommend stiffer rear springs under the assumption that you will also be running different sway bars. If you aren't going to run stiffer bars, you want a wider gap.

-Max

I run 450 front and 300 rear. Used to run 550/450. This sucked even with a bigger front sway bar and widefoot with 17x 10 rears and 17X9 front wheels. It wasn't loose, it was just too damn harsh on the street. May be the Tokicos IL5 had something to do with it. I run the new combo with Konis Yellow and I love it. The rears just stick and stick and the weight transfer to the front and back is just awesome.

You do get upper mounts, but they aren't pillow balls. They are aluminum with rubber bushings for the end of the shock rod. They are probably a little softer and quieter for the street than pillow balls would be (the rear shock towers in particular contribute a great deal of noise to the interior). The rest of my suspension is solid bushings, though, so I guess I would rather have true pillow balls.

In comparing to other kits, don't assume that "upper mounts" means pillow ball upper mounts, as the M2 shows this isn't always the case.

I've got no complaints about the M2 coil-over kit. I do wish I had chosen some softer shocks to convert, however (GAB super-Rs are not good for the street). You can choose your spring rates as fair as I know, but they are most likely to have 550/450 and 450/375 spring combos available for fastest shipment. It might take longer to get other rates, or not -- I don't really know what kind of inventory they keep on those.

They make 550/450 springs in the stock sizes now for you AutoXers and "I don't want adj coil-overs" guys.

-Max

I am thinking about getting the GC conversion because I already have Koni Yellows and want to get as close to stock as possible without throwing things out of balance. How does 450/300 compare to stock? I mainly want the ride height adjustability and I think my stock uppers are starting to sag. I already replaced them with a low mileage set but I guess the way I drive I really need something a little more solid. I am getting some rubbing on my left front under hard cornering, this is all stock except Koni Yellows. I figure if I get slightly stiffer springs and a solid front swaybar with widefoot mounts and stay with the stock ride height, I should be all set. However I don't want anything too harsh. I normally run the yellows one full turn from soft up front and half a turn in the rear, and I'm happy with the way this feels. Ideas?

Ok I found the stock spring rates are 280/200 roughly. I also read that Koni Yellows can only handle about 20% over stock spring rates. Since everyone seems to be running around with nearly 100% over stock spring rates, this apparently isn't true. However they were designed from the get-go to work with stock springs, so how come no one is running near stock spring rates with the GC setup? Does this setup sacrifice wheel travel? I was thinking of running something like 350/250. Is this too soft? If so, why? I would think anything stiffer than stock wouldn't be too soft. I have a street driven car and I want it to handle well over bumps, but I also want somethings stiff enough to control wider wheels and tires (255/40/17 all around would be nice, or at least 245/45 on stock wheels) for the future and not have to worry about rubbing. I don't need to lower the car though, so this shouldn't be too much to ask. Ideas?

I have been running 8" 250 lbs/in Eibach ERS springs in the rear, and they seem to coil-bind a lot. The area between the coils is all roughed up from them binding. I think the stock springs can compress a lot more before they bind, so the soft rate works okay there. But it doesn't seem to work with 2.5" springs on the coil-overs. I don't think my 7" 450 rears
ever reached coil bind, and I am hoping the 7" 350 Hypercoil springs I ordered won't coil bind, either, but only time will tell.

-Max

Max,
Whats the difference between running 8" vs 7" springs? Do you get more travel out of longer springs? As far as ride height, I would never drop the car more than 1" and would most likely just stay at stock height, so would I want to get the longest ones possible that still allow for this?

A 7" spring of a given rate will bind in a shorter distance than an 8" spring of the same rate, typically. You should use the longest springs you can, but you are limited by ride height. I could run 9" springs in the back if I was okay with the 4x4 look, but 7" springs are about right for the GAB super-R shocks converted with the M2 kit with moderately stiff rates (say 350-450). You could go longer with softer springs, but I ran into binding with 8" 250 springs. You can get all the info about distance-to-bind, etc. from Eibach or Hyperco, or whoever makes or sells the springs.

The lengths and stiffnesses are a little different for the front, but I was able to use my 7" 450 springs on the front with no problems. I also have some 6" 550 springs for the front.

-Max

Hey Nathan

You should call Tri Point about the spring rates for the Konis. They are the West coast rebuild center for Koni.

They recommend running max. 20% stiffer springs over stock before having to re-valve the shock.

Hey Nathan

Just wanted to correct myself.

I talk to Tri Point about the konis and spring rates. They told me that the konis can handle up to 500 lbs/in springs rate. They also said that's getting close to their limits.

Sorry about the bad info

Later,

GTS