Advanced Suspension Mods

[Advancedynamix]

I think more caster would help my inside wheel to stay more level and have more traction, as well as giving more support to the outside wheel. In this picture you can see my inside wheel has very little contact patch.

[zoom zoom]

io^ psh, that's nothing, my fiance would totally smoke you in her minivan. We were out yesterday and I swear we were on 2 wheels on half of the backroad we were on. She told me "if this was a car you wouldn't be crying about my driving" LOL.... she definately knows how to use the brakes/gas through curves, now if only I could get her to use the brake sooner..

[Dragonhealer]

I think more caster would help my inside wheel to stay more level and have more traction, as well as giving more support to the outside wheel. In this picture you can see my inside wheel has very little contact patch.

I'm not sure you can get enough to be meaningful here, (except to require a power rack ). Any way to transfer more onto the inside front by firming the opposite rear? Stiffer bar?

[Dragonhealer]

HAHAHAHACarolyn just walked buy, " Nice picture, but look at the tires!
he's not transferring enough weight to the front" HAHAHAHAHA......

[Advancedynamix]

I'm not sure you can get enough to be meaningful here, (except to require a power rack ). Any way to transfer more onto the inside front by firming the opposite rear? Stiffer bar?

I want to be able to adjust my caster so that I can run more rake without the car feeling nervious. The rake will put more weight on the front wheels. It will also allow me to run less camber, which would make a difference in this corner, especially with the wider rims, that with the little bit of positive camber on the inside, gained from the caster, would put a little more tire on the wilcox pavement. The steering is very light right now, so I can add a few degrees of caster without my arms getting tired.

HAHAHAHACarolyn just walked buy, " Nice picture, but look at the tires!
he's not transferring enough weight to the front" HAHAHAHAHA......

Carolyn has yet to show me the technique required to weight the front end while powering uphill. lol. That's a trick I gotta see for myself!
The car was hooking up well in this spot with the current engine, but I'm looking to add 50 ft.lbs of torque to the mix, so I'm going to need to get more sticky rubber on the ground. I'm not sure if more rear bar is going to help because the car already rotates a little too easy. Adding torque while making the chassis more apt to rotate sounds like a recipe for more off track exploits. lol.

Ryal, it's good to see you back on the forum! Carolyn should get on here too, after all she does own a Festiva

[Advancedynamix]

this is corner 4 where the car felt very balanced. More rear bar would have reduced the amount of speed I could have carried through this corner and corner 3 just before it. I was really gaining ground here on the cars that would out power me up the straight. On the limit the car was a bit tail happy especially in turn 3, which is last place I want to spin (close to 100mph).

[Dragonhealer]

More caster will certainly do that, and will help on the breaking. What is the best option? Relocate the front anti-roll bar/(trailing link)?

Carolyn's secret weapon is a locker set so tight that you can race with one
axle broken! That and 325 lb/ft of torque!

That inside front wheel.... lets see.. hydrolastic suspension, steering and
body roll inputs, hydrolic pumps, valves...a lot more $$$, more weight,
more complexity......... Citroen !!!

Seriously, except for wider wheels, if you can fit them, I think you are fussing with the last two percent. You have done a magnificent job in a
short time on a limited budget.
We are looking forward to using your
skills on Carolyn's "Grand Am" Monster Slayer Festiva!

[Dragonhealer]

this is corner 4 where the car felt very balanced. More rear bar would have reduced the amount of speed I could have carried through this corner and corner 3 just before it. I was really gaining ground here on the cars that would out power me up the straight. On the limit the car was a bit tail happy especially in turn 3, which is last place I want to spin (close to 100mph).

Is it possible the variation is due to too light a rear? I know, defeats the whole premise of weight forward Which appears to work marvelously
in all other respects!)

[nitrofarm]

Advance when you say more "Rear Bar".Are you saying stiffer torsion bar? I thought a stiffer bar would keep the car from rotating. I hang up now,& just listen to your explanation...

[Advancedynamix]

More caster will certainly do that, and will help on the breaking. What is the best option? Relocate the front anti-roll bar/(trailing link)?

Carolyn's secret weapon is a locker set so tight that you can race with one
axle broken! That and 325 lb/ft of torque!

That inside front wheel.... lets see.. hydrolastic suspension, steering and
body roll inputs, hydrolic pumps, valves...a lot more $$$, more weight,
more complexity......... Citroen !!!

Seriously, except for wider wheels, if you can fit them, I think you are fussing with the last two percent. You have done a magnificent job in a
short time on a limited budget.
We are looking forward to using your
skills on Carolyn's "Grand Am" Monster Slayer Festiva!

Yeah, the front sway bar mounting locations are on removable plates, which could most definitely be altered or replaced with adjustable pieces. Fairly simple.
I'd like to have a nice viscous limited slip in Tweak, and I may have to settle for a helical lsd unless I can get a Mazdaspeed diff to work. Right now it hooks up pretty well for an open diff car with over twice the factory TQ. Just have to see where the limit is.
You left out cantilevered shock mounts driven by stepper motors that are controlled with a programmable self correcting/learning control unit.:p
Thanks! I look forward to helping out as much as I can to construct the monster. You guys help me out a ton, and I wouldn't have been able to fine tune Tweak as fast or efficiently without you. I think we make a great team.

Is it possible the variation is due to too light a rear? I know, defeats the whole premise of weight forward Which appears to work marvelously
in all other respects!)

Actually, the opposite. The rear still has too much weight. It's the momentum of the rear that is bringing it around like a pendulum. This is why I think that being able to run more rake without loosing my caster angle will help. It takes weight off the back, but right now the car feels unstable set up like that (I had a fairly drastic rake angle at the last event on the testing day, but didn't like the way it felt). I also still have some weight I can shed back there too, probably close to 100lbs with glass and the rear bumper and my ultra heavy muffler. After that it'll be time for aero trickery, which should actually be quite effective since the car is so light and punches such a comparatively large hole through the air.

Advance when you say more "Rear Bar".Are you saying stiffer torsion bar? I thought a stiffer bar would keep the car from rotating. I hang up now,& just listen to your explanation...

Yeah, I mean more torsion bar. Stiffer rear bar will cause the car to rotate easier, stiffer front bar will cause the car to push. This is my best explanation on why. More bar in the rear will usually reduce the amount of weight transferred to the outside rear wheel during hard cornering (it stops the outside rear from compressing or squatting), thus providing more traction in the front. More bar will also tend to try and lift the inside rear wheel, since it's the weight of the inside rear wheel and the resistance of it's spring that is acting upon the bar to resist squatting on the outside wheel. All this pressure being applied to the front doesn't come without a loss in grip in the rear. For me, sway bars are a last resort, and Ryal is right in saying that I'm almost at that point, but I still have some tricks up my sleeve. I try to tune the chassis/suspension to it's maximum ability without the use of sway bars, and then I add them when everything else is balanced and working at it's peak. That ensures that I'm not using the bar to correct for other flaws in the setup. The more sway bar you add to a chassis (either end) the less effective the suspension will be at absorbing isolated imperfections in the track/road surface. If I was driving on a NASCAR track this wouldn't be a problem, but road coarses are full of bumps and contours (especially with the way I drive, lol). Above all else, this car is still a daily driven street car, so the suspension must be versatile. Tweak is actually more comfortable to drive on the street than my bone stock 93 Festiva.

[Arnie]

I agree with what's being said here, increase caster. It will help load that inside tire and give more dynamic neg camber (as you already know). But I'd really look into raising your front roll center by bending the control arm ends/ball joint down just a bit. You'll reduce front end roll just through that tweak. I personally don't consider that a non-bolt on mod. Its just slightly modifying a stock piece.

[Advancedynamix]

Wouldn't I have to bend them upward to do that? (raising the ball joint in relation to the control arm fulcrum point) The festiva control arms are very stout in that area and not only would they be hard to bend consistently, but it would most definitely weaken them. They look to be forged steel, not just cast steel and the section your talking about bending is very short, cold bending them would be difficult and heating them would ruin the ball joint. For me it would be easier to make my own control arms. Other members have built control arms for their Festivas, it's a very simple part. In the future I will most definitely make control arms, but I want to see how far I can take the stock parts first.
Bending the ball joint end downward would result an a more exaggerated angle on the control arm. Bending it upward would allow the control arm to rest more level with the ground.

[Safety Guy]

Need pics of Carolyn's car!!!!

Reading through this handling discussion is interesting, though I have a hard time envisioning exactly what's being said.

As for wheels, there were some 13 X 6" BBS wheels for sale recently, but I didn't get them. I think they were around +20mm offset, which sounded a bit "off" to me. Maybe it's good I didn't get them.

I did get a set of MINI wheels: the "phone dials." They're 15 X 5.5" and supposed to be around 12 pounds each. Centerbore is the same as Honda Civic: 1mm larger than Miata/Aspire. I'm thinking 175/55 or 165/60, but I really don't want too short of a sidewall for the real world pothole dangers that await the unwary!

Karl

[Advancedynamix]

Most OEM 15" wheels, especially those on European cars are so over rated for a festiva that you'd have to try to hurt them. Lol. If you pay close attention to the video of tweak " the hills have roads" you'll see I jump off a 4" drop to the dirt where I then e brake the car around at about 45mph and power the car back onto the road. This was done with 45 series tires and that's how I drive the car regularly. Those wheels are still perfectly straight, but I did scratch them up pretty good when I almost flipped the car in the gravel at firebird. Having a featherweight car is awesome.

[Dragonhealer]

Need pics of Carolyn's car!!!!

Karl

Didn't mean to mislead you Karl, Carolyn's secret weapon is in this, as seen at over 100 in "the attitudes" at Miller Motorsports Park.

When asked what it feels like, she said " It feels fine "
http://www.flickr.com/photos/3551904...in/photostream