jramosrx7

Just installed a set of M2 coilovers. I bought them from a friend of mine who's taking his car back to stock. Been out a couple of times, and the 550f/450r spring rates are a bit stiff for me for street use. Thinking of going 450f/350r, which I've seen mentioned here.

Question is are the current 450 rears interchangeable to the fronts, so all I have to buy are 350s for the rear? Also, what's a good source for these springs (Eibachs)?

Thanks

rynberg

I believe the front springs are 6-inches and the rears are 7-inches, so they are probably not exchangable. The Eibach ERS series would probably be good, the softest springs they offer in 6-inch are 450 lb/in, so you could do your 450/350 setup.

Max Cooper has the M2 coil-over conversions, he would be a good source of info.

jramosrx7

I pm'd Max several days ago, but have not heard from him. Length of spring was what I thought might be a problem. Hoping it wasn't.

maxcooper

I thought I replied, but I guess it didn't work. The 7" 450 springs work fine in the front. I got some 7" 350 springs for the rear.

-Max

jramosrx7

Thanks, that puts this to rest.

jramosrx7

OOPS!!

Max, what's a good source for the springs, Ground Control?

curlybillbrosie

does the M2 kit allow you to adjust ride height in front and rear? sorry if this is a stupid question, i dont know much about suspension systems yet.

jramosrx7

I don't have much experience here either, but, I believe, the "standard" Ground Control coilover kit on which this is based has a way to adjust perch height, but it's a more cumbersome method. The M2 kit adds a sleeve to the set, which allows easy adjustment of the height.

The simple answer is "yes."

curlybillbrosie

i see. thanks.

Eggie

I have the Ground Control on my car, and it uses a threaded sleeve for height adjustment. Judging from the pics on their website, the M2 looks VERY similar to the GC kit.

ptrhahn

iTrader: (9)

The M2 kit IS a ground control kit. They just anodized the perches black for M2.

xph

I may be the odd duck here, but I like more seperation between the front and rear rates.. I am currently running 550 / 375 and am about to go to 300 in the back. I have found that I have to keep my GAB's set to 7 in the front and 2 in the rear to balance out the car, and that leaves me with no room to adjust for the track conditions

X

maxcooper

If you crunch the numbers to get the suspension frequencies, the 550/450 and 450/375 springs pairings that M2 reccomends work out to be good by the numbers. However, I found my car to be a bit loose with 550/450 setup and stock sway bars. So I tried some different springs and stiffened the front sway bar and ended up with 450/350. That works well for me.

xph, if you are already at 550/375 and find the car to be loose, you might have something wrong with the car. Perhaps the front sway bar is disconnected, your rear bar is way too stiff, or your rear suspension is binding or the travel is too limited. 550/300 will give a very low rear frequency compared to the front.

I can tell you from experience in running 550/250 and 450/250 that it will understeer way too much. It can be fun on low speed turns where you can steer with some power oversteer, but it is scary on high speed turns where you can't just apply throttle to rotate the car. The front just pushes through the turn. Plus, 250 lbs/in springs will coil bind. 300s might also.

-Max

jpandes

Damn, Max is the "Jedi-Master" of springs! I only know, "bumpy or less bumpy"...LOL

xph

I have the Tri-point .188 on the front and the Eibach 19mm on the rear... (this is about 62% stiffer in the front and 50% siffer in the rear than stock if you do the math)... with the shocks set at 7 front and 2 rear, The car is very well balanced... I dont like how mushy the rear is on inital turn in, but the back end is planted firmly throught the corner.. I would like to stiffen the shocks in the rear, but this induces oversteer. So I could stiffen the rear bar, but no-one makes a stiffer bar that I know of.. I have almost no understeer, unless I shock the tires, or have my foot on the brakes =)

X

xph

Oversteer = Foot on Gas sorry...

redrotorR1

Tri-Point ran 600/300 on their championship ASP car. Granted that's with custom-valved double-adjustable Koni's .... so there's a little give-and-take there. But, I'm also in favor of the larger offset spring rates F-R. The car is already tail-happy in corners ... a little understeer would actually be welcomed. And as far as rotating the car in a high-speed corner, that's what trail-braking is for.

Also, running a stiffer rear sway bar is instant oversteer for FD's. I wouldn't touch the rear sway bar unless I absolutely needed the car to rotate faster (which exactly opposite what I want out of it right now).

maxcooper

xph, try swapping the stock rear bar back in. I'm running the Tri-Point 0.188" front bar with the stock 93 base model rear bar. There seem to be some rumors that the 93 Touring had a softer rear bar, and I'm pretty sure the 94-95 models did also. Anyway, softening the rear bar will shift the balance more toward understeer, or back to neutral if it is oversteering now.

The Tri-Point ASP car was for AutoX, where using the throttle to steer the car should work great. That doesn't mean it was fun to drive on fast sweepers on a road racing course. They may have also been running a stiff modular rear sway bar, so that is another thing to consider in the balance on that car. No doubt it was setup very well for the environment in which it was run and they know far more about setup than I do, but that doesn't mean that their spring setup is appropriate for other purposes or sway bar setups.

I can tell you that my car with the stock sway bars, 245F/265R street tires, and the 550/250 or 450/250 springs was downright scary sometimes on the street because the front wouldn't stick when I wanted to apply some throttle. It would just push through the turn so I couldn't accelerate at all .

I ran a track event at Streets of Willow Springs with the 550/250 setup and the rear sway bar disconnected and it was a lot of fun there because I could really use the power oversteer to rotate the car. I actually had a gret time ther because it was the first time I really felt confident driving the car to the limit (though I'm not saying I was really driving it at 10/10ths the whole time ). That was with 285 R-compunds all around, but I ran one session with my 245/265 street tires and it wasn't as fun because of the push. I ran at big Willow with the 450/250 setup and the rear bar connected again and it wasn't that great because the front wouldn't stick.

I guess the best setup depends a lot on what you are doing with the car, but I'd prefer to just get one setup that works reasonably well for most of the environments in which I run the car. The 550/250 and 450/250 setups were just too compromised toward understeer, and I even prefer a little understeer so that I can feel more comfortable with the car. My current 0.188" front bar, stock 93 rear bar, 450/350 springs setup feels like a good all-around setup to me.

-Max

maxcooper

Another quick think you could try is just disconnecting the rear bar. Leave one side connected (or not, but you'll have to safety wire the bar to something if you disconnect both sides). Then use a regular bolt in place of the bolt with the sway bar end link to go through the bottom of the shock on the upper a-arm. The rear ends becomes very sticky and progressive with the bar disconnected. It's great fun that way on a tight course.

-Max

redrotorR1

I've found that my auto-x setup translates okay to time trialing/road racing. I have a complaint about the body roll as is in auto-x; which is equally exacerbated on a road course. My aggressive toe out setting does make me have to setup earlier and hold a steady line.

I'll bet dollars-to-donuts that a lot of the understeer came from the offset tire sizes. I'm no motion ratio expert, but I experience the same things co-driving F-bodies that run offset tire widths (315/335). Really have to be early and trail-brake through any sort of tight turn. I agree that the rear spring rate does have a substantial effect too; but I find that's easily corrected for by stiffening the rear rebound rate. Well, to each his own ...

-Don

xph

I do autox the car... I am really just concerned that with my shock settings, I dont have any useable range to compensate for varing track conditions (bumps, wet, ect...) So I was looking at the shock rate differences at those settings, and was going to replace the rears with the appropriate springs.... in this case that would take me to 550 / 300

X

The stock 94 rear bar is smaller than the 93 r1 rear bar... I have both of these... The Eibach rear bar I have is adjustable, I colud put it back closer to stock levels. I ran the R1 rear bar with the .125 Tripoint bar

xph

I like the 550 / 300 setup, and can see that 600 / 300 is probably the optimum, my shock settings are much closer front to rear on the GAB Super-R's, but I am still a setting or two stiffer in the front than rear, the stiffer springs would sort that out.. I have yet to get out to a high speed track to see if max's understeer woe's are true in my case...

X

ptrhahn

iTrader: (9)

I installed the M2 kit on my koni yellows this weekend. Rates are 500/400, and so far feel perfectly balanced IMO. This is combined w/ Peter Farrells sway bars (60% stiffer up front, not sure on the rear, but its in the "softer" position), and 17" wheels w/ 235/45, 275/40 tires. Absolutely fabulous grip, perfectly livable in the 'burbs. I used trimmed koni bumpstops.

Ride heights are set to 25" front, 25.5" rear at the fender lips. I have an auto-x and a track even in the next 3 weeks, so we'll see how it goes.

Truchoice or Tri=Point are probably the best sources for ERS springs, but i wouldn't go too light on the rear, or you'll loose the force you need to keep it off the bumpstops over dips, undulations and such.

matty

i am about to install koni yellows this weekend. I currently have eibachs on the stock shock. I plan to eventeully convert to coilovers ala M2 conversion kit. My question is how is say a 450/350 setup on the road? I thought the eibachs pro kit are around 290 or less...this is a significant increase in spring rate..how uncomfortable is a setup like this on the road?
The progressive rate springs i currently run on the stock shock allows way too much roll for my taste. I would like to elimintae this but people are telling me that i need to get rid of these eibachs and that the konis wont have an impact on roll..thus i need coilovers. I do about one or two track events a yr along with some drag racing.

ptrhahn

iTrader: (9)

The FD Eibach pro-kits are NOT progressive as most of their pro-kit springs are. they are linear rate, 365 f, 275 r. This is directly from the mouth of an Eibach engineer.

I do not think that spring rate is the whole story as far as harshness on the road. I think it owes more to the valving of the shocks. I actually think my car is LESS harsh w/ the coilovers as opposed to the Prokits, because it isn't crashing over dips and undulations anymore. Koni yellows don't have alot of compression force, and i think they need the stiffer springs.

I'm pretty hot on the rates i have!!