Advanced Suspension Mods

[nitrofarm]

Charlie it came off real easy with a punch,but It wont pass over the welded portion at the top of the rod.Remember these are the Cabriolet Gas Adjust.

Just ground the dust seal caps down, adjuster sleeves fit like a glove now.

[Advancedynamix]

what determines the firmness of the spring? I thought that was the rate of the spring. I figured the lower the rate, the softer the feel.. The higher the rate, the firmer the feel. I want it to be firm but, not 350# firm like the ebay civic coilover springs. I can see how the rate of the spring would affect sag & height but, to me it seems like length of spring and adjustable sleeve would have the biggest role in height. If I relied on a really low spring rate to lower the car, it seems I'd have a really soft feeling low car.

I went with 200# 10" spring in front and 175# 8" springs out back. I plan on adjusting my height with the adjustable coilover sleeves. I'm looking for low street stance. I don't expect maximum comfort and I don't need it to be most efficient on the race track.

Good question, and it's simple.

Spring rate rises as the spring is compressed. That means that a 150lb spring takes 150lbs to compress 1", but the rate will rise from there. Your car will only compress or "sag" the spring until the spring pressure equals the weight placed on that spring. That will be your dynamic or working spring rate. If you have 120lb springs on your car, the dynamic spring rate will be the same as if you had 150lb springs on the car. the difference is that the 150lb springs will sag 2" and the 120Lb springs will compress 3'', but the end result is a 175ish lb dynamic spring rate (these numbers are just for example purposes and not factual figures).
On an adjustable spring style of shock, you are relying on the sag of the spring to give you adjustability. For full adjustability the car should rest lightly on the bump stops with the adjusters at their lowest setting (while still holding the springs securely, NO SPRING FLOAT!) To raise the car you add prelaod to the spring, which will compress it and effectively raise the rate of the spring. This doesn't make the car stiffer, it simply raises the ride height until the rate exceeds the weight placed on that spring, then your suspension has been handicapped. Not all springs react equally, so the progression at which the rate rises depends on the spring itself, which is why I can't provide actual numbers for this stuff.
Now, when the base rate of the spring exceeds the weight applied to it by the car, the suspension will be stiffer, but for most driving conditions (race tracks included) this is a terrible mistake and only hinders the suspension. For years, I have seen road racing teams (even on a professional level) effectively eliminate the cars suspension by putting heavier springs on the car and heavier sway bars until the cars suspension is almost rigid. This is not the best way to tune suspension and it has been proven on many different platforms, that working suspension will keep the car on the track at much higher speeds than solid suspension.
That being said, your spring rate is directly proportionate to the weight of the vehicle and the lever ratio of your suspension. Higher initial spring rates will just sag less to get to the dynamic weight (the pressure that is actually holding the car up). This pressure only changes if you change the weight of the car or the lever ratio of your suspension system.
To control the attitude of the car under driving conditions, it is best to use shock valving and/or bump stops. This is why springs only cost about 100 bucks a piece for top of the line racing springs, but shock absorbers can climb well over 10,000 dollars a corner for top of the line components (don't believe me? Look up a set of used Penske shocks on ebay, now imagine what these teams pay to have Penske custom make shocks for them). Shock absorbers are where the magic is in a cars ability to do what we ask it to do in any situation. Getting the dampening right, that's the ticket to success. Springs simply hold the car where you want it, and sway bars make up for a compromise between performance and versatility.
Progressive wound and multiple rate springs are good for a wide range of driving conditions, but bump stops are a less expensive way to accomplish the same task.


Also, My car's fastest lap times have been with 150lb rear springs and 200lb fronts. I have tried all the way up to 250lb front and 200lb rear, with bad results on every track that I tried higher rates on as well as on the skid pad. I have tested with 2 different types of street tires (nakang ns2 and Federal Formoza) as well as 2 different "R" compound DOT race tires (Toyo Proxes R888, and Yoko A048 ) and Bias ply racing slicks (Hoosier R35). I have put over 20K track miles on the car, in various configurations and I have access to a several skid pads for testing. I've used up over 2 dozen tires in 2 years on the track alone. This is my hobby, but I take it pretty serious (all the while having a blast of coarse, ). The R&D that has gone into the stuff I post is very extensive, but it's not written in stone so if you find something that works better for you, I encourage you to share. These cars are magic on the track when they are set up properly.

Hope that clears things up.

[Advancedynamix]

Charlie it came off real easy with a punch,but It wont pass over the welded portion at the top of the rod.Remember these are the Cabriolet Gas Adjust.

HMMM, I wonder if yours are different than mine, because mine were welded to the shock iirc.

[Zanzer]

[Die-Laughing]

That gives me a better idea.. I completely forgot about bumpstops and I wasn't aware how important they are. It sounds like bumpstops will be very useful to me. What is the proper way to setup a bumpstop? It sounds like I should put the car together in the lowest setting and make my bumpstop that length and then add preload to get the height where I want it. I guess this is where your spring rate & length comes into play. It sounds like I didn't completely fail with my 200#F / 175#R setup. I cheaped out on shocks but, I'll have to make due.

[zoom zoom]

Wow Charlie that last one was incredible. It's gonna take a few reads to get that to sink in! Thanks for all your input! This is a hobby for me too, just on a much lower and slower level Haha, I'm not tossing a thousand dollars into a new suspension setup every couple weeks :p Your words are not taken lightly and keep me motivated and pointed in the right direction(I think lol), thanks!

[Advancedynamix]

That gives me a better idea.. I completely forgot about bumpstops and I wasn't aware how important they are. It sounds like bumpstops will be very useful to me. What is the proper way to setup a bumpstop? It sounds like I should put the car together in the lowest setting and make my bumpstop that length and then add preload to get the height where I want it. I guess this is where your spring rate & length comes into play. It sounds like I didn't completely fail with my 200#F / 175#R setup. I cheaped out on shocks but, I'll have to make due.

There is no real right or wrong way to set up bump stops, just use common sense ( they are intended to add progressive resistance to the dampeners, not to stop the shock from traveling). Get several styles and test them all out. I prefer VW New Beetle stops because they are cheap, long and easy to trim.
If you got KYB GR2 front struts for a mk2 VW then I think you'll be very pleased with your choice. The dampening will be drastically better than stock Festiva struts and they will allow more drop and negative camber.
I like my 200lb springs on my B6t/ gseries swapped car, but I find this rate a bit stiff for a my b3 cars. I am currently running 185lb front/120lb rear on my 89 DD. 185 lb is still a bit stiff for the front of this car (no a/c, 4 speed) so I think I'll get some 165lb springs instead. I want more spring sag in the front, and these 185's only sag about an inch. I'm looking forward to running the 185lb springs and Bilstein 36mm struts on the front of my B6t car when I get the engine built for it ( Tweak is currently broken).

[Advancedynamix]

Wow Charlie that last one was incredible. It's gonna take a few reads to get that to sink in! Thanks for all your input! This is a hobby for me too, just on a much lower and slower level Haha, I'm not tossing a thousand dollars into a new suspension setup every couple weeks :p Your words are not taken lightly and keep me motivated and pointed in the right direction(I think lol), thanks!

Your welcome. If any car community should know suspension, it should be this one. These little cars have amazing potential, and they are so easy to improve. Mazda did a great job at designing a FWD supercar, they just had to make this little supercar capable of climbing mountains and carrying5 passengers across entire continents. This versatility has it's price, compromise. I can't provide affordable suspension parts for everyone, but I can provide the knowledge and share the experience necessary to educate everyone on what needs to be done in order to fine tune these awesome cars for their personal goals. What's awesome about the Festiva is that it has such great suspension that it can be fine tuned for performance, while also increasing the cars comfort, stability and driveabilty. Heck, a 16v engine (be it b6 or BP, or FE3) on a G- series trans improves the cars handling and stability drastically, by placing more weight bias where the car needs it, over the front wheels. Improving these cars is so easy, and cheap. I'm still really excited about this and it has been over 3 years now since I started Tweaking Tweak. Lol. I've never been so excited about a car that I've tuned, and this is the least impressive by far when it comes to curb appeal. To hell with fancy sports cars, I'll take my Festy ( or 5) any day.

[zoom zoom]

ok charlie, I've got an issue, interested in your opinion here.. What I have right now..

stock axle(as far as i know it came from advance NEW a couple weeks ago)
stock lca
stock inner/outter tie rods
02 kia rio struts(stock) with the exception of the lower hole reamed out to give me negative camber.


When I installed the rio struts, they just bolted in! but when I installed the lca and axle, I had to plug in the lca (tie rod already hooked up) then twisted the knuckle up into the strut. I can do that now, but I think this is where my steering issue is comming from and I want to fix it.

Anyway, with the knuckle angled out due to the reamed out strut holes for negative camber, the tie rods don't line up straight. So the outter ball joint is in a bind when the suspension is fully decompressed! Since I've been riding in the upper part of the strut, I've probably been topping out the struts on acceleration and the ball joints are doing weird things to my steering during hard pulls.

Is there an easy fix for the tie rods, or do I just need to lower the car a little (1-1 1/2") by putting rio springs on stock struts? I'll still be riding in the upper range of the struts and probably won't have any sag doing that. Also, that pic is with the axle totally compressed, if I push the lca up beside the knuckle it looks like it lines up with the hole, but do you think I'll need to swap to aspire lcas anyway to keep the axle from having a chance of bottoming out?

[mazda121BP]

Tilt in the top instead of moving out the bottom... Or get longer control arms? I hope this helps and isn't just my stupidity

[zoom zoom]

If I angle the knuckle the other way the tie rod will fit, but ill go back to 0/positive camber. I'll probably put the Rio springs on Festy struts for now but I'd really like to find a way to get that inch and a half of lift back. With stock knuckles stock lcas work so I'm gonna go that route to make sure the tie rods have been my issue. Gotta get aspire lcas and upgrade to bigger vented rotors soon though!

[bhazard]

You tried Rio struts with uncut Rio springs? That's good for a 3" lift or so.

I didn't cut my springs when I first put Rio struts in. The lift was so extreme it destroyed my drivers side axle.

[Advancedynamix]

Matt, I'm a little confused as to your problem. If you angle the tops of the knuckles inward then that gives you negative camber, outward is positive. You should always adjust with the top hole on the knuckle/ strut mount. Your tie rod should fit buy turning the strut/knuckle unless your lift is binding it. If you use Capri knuckles you'll get another inch of lift and vented rotors, but I'd use aspire calipers on them because Capri calipers are troublesome.
Maybe Movin would be better to ask, as he knows lifts. Right now, my festys are all stock or lowered, so I can't picture what your having trouble with.

[zoom zoom]

where I had the car lifted so much that the steering arm was lower than normal, and twisting the knuckle inward(to get the negative camber) clocked the steering arm boss so much that the outter tie rod end was beyond it's range of movement upward. It was in the knuckle, pulled up as far as it would go, and still was a little shy of being able to screw into the inner tie rod.

When I installed the lca the tie rods stayed attached, and the lca was stuck in the knuckle, then twisted up into the box in the frame, and I had to fight it to get it in place. Wish i had taken a pic before i took the struts apart :\

[sketchman]

You're saying the knuckle was so low that the tie rod end wouldn't attach to the inner?
You couldn't attach everything but the tie rod end and then jack up that knuckle to get it in line?