Advanced Suspension Mods

[Advancedynamix]

do you have the ebay link for the bushings?

All bushings on this setup were are home made.

So with a fast Damp slow Rebound in the valving.Does it roll more in a very high speed gradual curve?

Yeah, there is more roll on long sweepers, but not nearly as much as with most suspension setups. The rear shock length regulates the amount of body roll, instead of using a sway bar. This allows the car to easily soak up imperfections in the track (i.e. rumble curbs or when I hang a wheel off into the dirt) without upsetting the car. Body roll isn't always a bad thing either.

[QUOTE the raceland coilovers come apart fairly easily so they don't need to worry about overheating the strut insert when they weld in the bushings. You'll need a loose knuckle to have them match the pattern.

Am I the Dunce of the class?Or the only student paying attention? Where is this step? Did you seperate that steel clamp that surrounds the strut? All I see is the elongated upper hole.Or is that a HAT BUSHING in the lower hole? drool[/quote]

I made 1.250" o.d. bushings for the lower holes out of steel round stock. I did this because I set the strut body up in a mill and indicated off the top hole, I then used a 1.250 end mill to plunge holes in the proper spacing to fit a festiva/aspire/capri/rio/323 ect ect spindle. I then elongated the upper hole to allow for camber adjustment. Then I bolted the strut body to a knuckle, and bolted the bushings to the knuckle as well and welded the bushings to the strut body. This makes the VW strut fit the Mazda/ford bolt center properly and allows for lots of camber adjustment. I'll try to find more pictures of the process, sorry if it's confusing. It was just my way to make those lower strut mount holes line up the properly. I tend to overbuild things, but I'm not easy on equipment so it pays off in the long run.


Here you can see how there is a bushing welded in to fill in the 1.250 holes that were plunged through the bracket. I did this to drill out the stock hole entirely since the hole was in the wrong location for a festiva. I think other people have just opened up the holes a bit to accomplish the same thing. I am extremely hard on my suspension, so I wanted to add strength to this area. I check the welds regularly and haven't noticed any indications of fatigue.

[Arnie]

Great thread and great custom work!

Reducing rear droop is a very common suspension mod for FWD touring cars in Europe. My friend used to run a Clio race team and that's something they also did. I'm also impressed with the use of the narrow ID springs/setup you use as it solves a lot of clearance issues. Gives you a bit more room to play with available wheel offsets or spacers. I had clearance issues using the TEIN coilovers on the rear of my car using Miata wheels. I had to run a rear spacer to get the proper clearance.

Have you played with increasing caster a bit? I never got a chance to play with that on my Festiva but was on the to do list.

[nitrofarm]

Thanks for the clarification !

[Advancedynamix]

Great thread and great custom work!

Reducing rear droop is a very common suspension mod for FWD touring cars in Europe. My friend used to run a Clio race team and that's something they also did. I'm also impressed with the use of the narrow ID springs/setup you use as it solves a lot of clearance issues. Gives you a bit more room to play with available wheel offsets or spacers. I had clearance issues using the TEIN coilovers on the rear of my car using Miata wheels. I had to run a rear spacer to get the proper clearance.

Have you played with increasing caster a bit? I never got a chance to play with that on my Festiva but was on the to do list.

I haven't played with Caster much on this setup. The car could use a little more caster to gain some camber under hard turning. I chew up the outsides of my tires pretty good. As far as stability goes though, this car is rock solid at speed. It would be nice to be able to add caster when I increase rake, I have found that the car gets nervous with too much rake and i think that it's due to the reduced caster angle. Being able to add more rake without sacrificing stability would allow me to put more power to the ground and carry more corner speed. It also would be an aero improvement. Now to just make adjustable caster plates that still look completely stock.

[Arnie]

Geometry ideas, Group N style

So you're still getting outside tire wear? How much neg camber are you running?

A common problem that most people who lower their cars (respectively over lower) are the geometry compromises such as camber curve and roll center. Judging from your pic of your car mid corner, you look fairly low so I can imagine that your control arms are past "horizontal" and that your outside wheel will be pretty much folding under in a turn. Basically, from the get go you're already in the "bad" portion of the car's camber curve. I never plotted the curve on the Festiva but I'm fairly certain you're there. Being that low you've also lowered your front roll center. Its probably subterranean, so you'll also be getting a lot of roll through that.

I was looking at some pics of a member's Festiva and thought of a couple of "Group N" type mods you might be able to make to help roll center, get you into the decent meat of the camber curve and get more caster.



You can do two things to raise roll center and help camber curve issues.

1. relocate inside pickup point. Since you're a metal smith of some talent you could see about raising the inside pick up point a bit. You'll have to see if there is actually enough room above the control arm to do so. But raising that pickup point about 5-10mm would help tremendously.

2. Bend control arm/ball joint downwards a few mm. You can see in this pic that there is potential to move the ball joint on the control arm down past the sway bar mounting point. Depending on the arm material, you can just put the arm in a press and cold bend that area downward. This is a sneakier method that no scrutineer will see!



Looking at this photo, I was thinking about how you could gain caster without having to go the adjustable top mount method.

1. In addition to bending the ball joint area downwards for roll center correction, you can also move them forward a bit. Maybe 10mm. This will increase your caster. You'll need to adjust your toe afterwards, of course.

2. Relocated the sway bar front mounts. Looking at this pic, the sway bar also functions to located the strut position. I'm thinking, if you could move the front sway bar mount forward a bit, it would pull the whole suspension assembly (control arm/strut) forward. Only question is, is there room and material for you to do this?

I can't remember, but is there a bushing replacement for the inside control arm pickup point? If you could get a poly replacement in there, it would definitely help reduce dynamic caster loss on braking too.

[Advancedynamix]

There is a poly bushing for the sway bar pick up point, it's sold Tein I think. I don't have them in my car but they are most certainly a worthwhile replacement.
My camber is set at -2.3 to -2.8 depending on the coarse. With my current setup the camber gain is nearly a degree per inch tapering to .5 dpi at the bottom of the shock travel. Like I've said before, the design of this chassis is exceptional. My tyre wear isn't from a loss of camber, I'm simply exceeding the lateral load capacity of these tyres. They are folding under when pushed to the limit. More pressure helps with that, but traction is sacrificed, so that tells me that they are at their limit. My temps and treadwear are very even, I just use a lot of sidewall too. Lol.
Adjustable sway bar mounts with poly bushings would help a lot. I think more caster could provide a little more support under hard long corners where I'm currently rolling the sidewall. It would be a simple part to make that would bolt to any festiva.

I will make some chassis adjustments when I build the dedicated track car, but this car will remain stock aside from bolt ons and the removable lower rad support. I'm using this car to test the absolute limits of the stock festiva chassis dimensions. This chassis can handle more rubber than it has room for without losing it's form. The next test will be 7" wide slicks slightly more spring and 100 more hp. It keeps up with 600hp awd turbo Porsches now ( in the corners, not the straights). Not too bad for an essential stock chassis econo box!
I want this car to represent what is possible with simple bolt on modifications. It's a very well setup chassis from the start, it's not hard for me to out corner Miata track cars that have more track specific modifications and more tire. That's an awesome testimony to the capabilities of this chassis.

Thanks for the input, and suggestions. I'm going to start planning out some adjustable sway bar plates and order some poly bushings ( she can get a little squirmy under hard braking).

[zoom zoom]

Absolutely speechless.

I'm not familiar enough with basic dynamics to understand advanceddynamics.

[nitrofarm]

Advance I'm glad your talking sway bar mount points again..Its still a gray area for me.My pea brain cant get past the fact. That the sway bar is the control arm.And the control arm is the sway bar.So when we start talking about adjusting the sway bar. I automatically think we are actually changing the LCA attach point.Which way are you going to move it.Fore/Aft or UP/Down? Thinking out-loud,I cant really envision much Fore/Aft adjustment.Because going to far would start to put the inner LCA bushing into a bind right? But you said you want some more Caster during hard corners.So I could see how a little would help this.
And if you move the LCA Up/Down (which I have picked many peoples brains about). Isn't that actually like changing the Anti-Squat,on a true Independent front suspension. ie "H" arms......See why I confuse my self into a corner. :nono: The reason I assume this is because of the "Torque" Being applied to the very front of the car via the control/sway bar. See where I'm going.Or am I a blind man walking into traffic drool

[Advancedynamix]

Advance I'm glad your talking sway bar mount points again..Its still a gray area for me.My pea brain cant get past the fact. That the sway bar is the control arm.And the control arm is the sway bar.So when we start talking about adjusting the sway bar. I automatically think we are actually changing the LCA attach point.Which way are you going to move it.Fore/Aft or UP/Down? Thinking out-loud,I cant really envision much Fore/Aft adjustment.Because going to far would start to put the inner LCA bushing into a bind right? But you said you want some more Caster during hard corners.So I could see how a little would help this.
And if you move the LCA Up/Down (which I have picked many peoples brains about). Isn't that actually like changing the Anti-Squat,on a true Independent front suspension. ie "H" arms......See why I confuse my self into a corner. :nono: The reason I assume this is because of the "Torque" Being applied to the very front of the car via the control/sway bar. See where I'm going.Or am I a blind man walking into traffic drool

You bring up some good questions. For this car I would only move the sway bar (or front control arm mounting point with the way you are viewing it) for and aft to adjust the caster angle. Since it doesn't need to move much (1/4" max) the LCA mounting bushing should be able to compensate. It will only change the attitude of the LCA by a few degrees. They may show fatigue prematurely, but anyone who is going to make use of the extra caster angle will be wearing them prematurely anyway. Lol.
I won't be moving the control arm mounting point on this car. I want to keep Tweak simple, and to make that modification justifiable would require a complete re-engineering of the front of the car (find pictures of that silver pride 4 door that was converted to a 2 door and has a B6d on carbs to see what I mean by that). The stock festiva doesn't have enough fender well to accommodate much higher roll center, and the strut mount is also too low for that mod. However, as Arnie pointed out, modifying the control arm itself to essentially raise the ball joint while lowering the control arm is a way to make the suspension more usable. This would have several benefits. I'm not comfortable with bending the control arms though. I think he was talking in terms of meeting the requirements of a spec class, so it would have to be a stock part. In that case bending the stock part would be an option, and has been done successfully on other cars. I may build adjustable LCAs in the future, with removable ball joints (323/Capri parts). But for now, I'm going to show what can be done with stuff anyone can buy.
You can't think of the Festiva front suspension like an H arm or A arm system. That's why your getting confused. It's essentially a trailing arm system. The sway bar acts like a drag link or trailing arm while the control arm supports lateral forces and acts to add camber as the suspension is compressed. It's a multi-link suspension that is not only very effective, but also extremely light weight. This front suspension system is one of the Festivas "secret weapons".
A trailing arm setup is the best setup for traction, that's why everything from the VW bug to complex 4-6 link trucks hook up so well. To have a front drive car with a trailing link is like magic! I've never driven another 1700ish lb car with 160ft.lbs of tq and an open diff that could hook up, and this car begs for more! Unbelievable!
A trailing arm/link suspension will use the engines TQ to apply downward pressure to the driving wheels. Easiest way to grasp this concept is to watch a motocross race, the torque of the engine is driving the wheel down as the bikes are accelerating. The "swing arm" on a dirtbike is an example of the purest form of a trailing arm. Traction bars and drag links are also examples of trailing arm type suspension. Trailing arms also do a great job at bump absorption since the arc of the suspension travel is naturally absorbing the energy that's coming at it from the front. And last but not least, a trailing arm suspension is better at controlling body roll than an A arm or H arm suspension. Because that energy is opposite it's natural path of travel, it is less apt to roll than other types of suspension designs.
So here's the kicker, the festiva has this great suspension design on all 4 corners! The rear is also a trailing arm! Excellent!
So you may be wondering, if the trailing arm is so great why do manufacturers use anything else? That's because the trailing arm is difficult to package. As a vehicle gets heavier the strength requirements for the trailing arm suspension become such that it's not cost effective to design this into a vehicle. Also, as a vehicle gets heavier it is usually less dependent on all available driving traction. Trailing arm suspensions are also difficult to design when wide tires are necessary (the festiva is perfect example of that, lol). That doesn't mean that trailing arms aren't used widely, because they most definitely are, but some great cars like the corvette lots of Ferraris formula cars (except formula V) and many many other great handling cars use other means to control the rough stuff. Most of those cars couldn't package a trailing arm suspension.
Sorry for the long winded rant.

[nitrofarm]

^ Thanks for the much needed lecture my friend. You are wealth of knowledge and a HUGE asset to this community. Have a great weekend!

[Advancedynamix]

It's possible to do this to a set of R888's in less than 1000 miles (with absolutely no burnouts). lol.

You can see that my tire pressure is too high, but I'm still folding the tire over, hence the remaining tread on the outside of the contact patch, but the wear all the way down on the sidewall. My cure for this is going to be some 13x7" wheels to support the sidewalls better. These 5.5" rims are too narrow. But, this goes to show that the stock Festiva chassis (no cage, no strut bars, no sway bars and stock rubber bushings) is rigid enough to destroy more rubber than will fit under the car! Phenomenal!

[Arnie]

Yeah, that's nasty. I agree, the 5.5" wheel is probably too narrow if you're using that much sidewall. Toyo sidewalls are a bit softer, too compared to others, so that doesn't help your situation. 6.5 to 7" would be a nice setup if you can find a wheel with a decent offset.

I agree that the Festiva suspension is actually a pretty nice and flexible design. Obviously, i wish there were more off the shelf options in coilovers, for example. But I do like the coilspring rear/trailing arm. Its still fairly compact but the coilspring setup makes suspension tweaks a lot easier. My Peugeot uses a torsion bar rear suspension. Its even more compact but tweaking torsion bars is a pain and expensive compared to coilsprings.

Great discussion!

[Advancedynamix]

Yeah, the only other choice I have in this size (185/60-13) is the Yoko AO48. We don't get a lot of small track tires in this country unfortunately. The only reason we get those two selections is because they are common on Formula Fords over here.
The AO48 has a softer sidewall than the r888, so I know better than to go that route.
Wide 13" rims in the proper offset are another hard thing to come by over here. I'm currently having Team Dynamics (U.K.) make me a set of 13x7 wheels in a 35mm offset to see how that works out. If I like them I may order a dozen or so sets to sell here in the states because I know of a bunch of small car enthusiasts who could use them here.
With the 7" wide rims I'll have more tire options. Several compounds/manufacture of slicks are available in a 7" width and around 20-21" diameter, as well as the legendary Nitto NT01. I'm not sure how the car will like the 7" wide 13's but we'll see. I have 15x7's on it for the street, but the smaller diameter may hit the knuckles.
You get a lot of cool sub compact and compact cars in Germany that we never saw here. I'd love to have a 205 or 206, Cleo, Lupo or Polo, MG Metro, or any of the other neat econo boxes that are not much for concern in Europe, but would get stares here. lol.

[Arnie]

I love all the hatch options here. Clio Cups are wonderful, even the Twingo RS is really nice. Pugs aren't as good as they used to be (not like the 205 GTi/106 XSi or Rallye). Small VW's like the Lupo GTi and Polo GTi are fun luxury versions of hot hatches. Heck, even the new Scirocco is not bad. I'm so happy to be back and to have all these small car options. What's nice is a lot of these cars are either rallied or have a single make series so there are performance options out there. Its like wagons. No one likes wagons in the US, but in Europe, they're basically like the Pick-up. The performance wagon options here are just awesome.

Can team dynamics make the wheels with double BCD's? As much as I don't like those types of wheels, it would definitely help with getting people to buy. And of course choosing an offset that can cover a couple of options with perhaps an addition of a thin spacer (hate spacers too! lol). Or would you go with 4x100/Aspire BCD?

I also have tire limitations too on my Pug if I stay with 14" wheels. Semis are Kumho V70, Toyo R888 and yoko A048 in 185/55-15 or 185/60-14.

yes, the smaller diameter may be an issue. it will depend entirely on what the lower clevis looks like on the strut used. I had contact issues with the TEIN setup on the front knuckles using 13". Had to go with 14" Miata Daisies.

Here are pics of some Honda 13"ers on the TEINs I had, 13x5, 40ET:

so how close are your 13"s to contacting things? This close?












Here's my Pug:

[Advancedynamix]

Right now my 13's are 38mm offset at 5.5" width. There is plenty of room now, but I know with the 7" rims I'll be cutting it real close, and may need to use spacers or at least get creative with a flapper disk on my strut. I should be able to get away with less camber though, so things should clear. Fingers are crossed. lol.

I don't think Team dynamics drills dual patterns into their rims, but I don't know for sure. They will build the wheel in any bolt pattern you choose though, and most smaller front drive cars here in the states are 4x100 or can be converted relatively easily. The rear drive cars that use 13's are spoiled with wide options in ET0-15 offsets. heck, I even have several sets of 13x6" BBS wheels. Wish they were a higher offset.

That's a nice Pug you have there, I'm a little jealous. If i went to Germany I could probably just look at the cars you guys have for days! a friend of mine had one of the few R5 turbo's that made it over here and it was so much fun. I think the U.S. market is starting to accept and welcome sub compacts again. The smart car doesn't sell like it does in Europe, but they have lasted longer than a few years and now the 500 is selling pretty well. I see Hyundai accents everywhere and the new Chevy sonic seems to be selling well. VW has been teasing us with the Polo for years and ford gives us the boring version of the Fiesta (they wont even send the 2 door over for the rally drivers!) but both those cars are almost midsized now. It'd be nice to have a bare bones 2000lb sub compact with a nice turbo engine to play with. One can dream. Until then, it's Festivas for me.