Advanced Suspension Mods

[Advancedynamix]

To be honest, I'm not sure. My engine/ trans is centered, but getting the axles to work took machine work that most people without a machine shop won't be able to easily do. I won't be doing that again that's for sure. Could it have worked out to tweaks advantage? That is very possible, as the handling characteristics of this car are phenomenal. Time will tell when I can compare cars with different engine mounting but the same suspension.

[Christ]

Adv - I was asking about centering the engine. The new forum is a bit of a changeup and I didn't quote the post properly, but you mentioned something about needing to move the engine to one side if you wanted to center the axles during the discussion about camber changes with different control arms.

I was asking if it would be better in general for an engine swap to center the weight of the engine/trans or to center it for the axles. Given that you only have about 3/4" to move around left to right and still have things working as they should.

[Advancedynamix]

If you have to buy all 4 I may buy the rears from you or exchange them in trade for labor on some modified rear KYB shocks. I'm saving the rear shock bodies to modify for a three way adjustable front strut setup(koni race inserts).
With that cat out of the bag, next year I will be testing a few other strut and shock combinations . I am building a set of bilstein40mm twin tube front shocks as well as a set of Koni2 way adjustable front shocks. I'll also be building a set of three way adjustable rear shocks. These setups will be used to get an even greater understanding of the potential of this chassis.

[alpaccino]

You must spread some Reputation around before giving it to Advancedynamix again.

Dern it.

If you are talking to me, i'm just learning and asking questions from my master during the process, lol

Good Question. The reason I didn't use the VW coilovers for the rear is because they are too long. With the car at the ride height That I wanted to run, they are bottomed out. Also, the KYB setup that I have uses the 1 7/8" springs which are not only a much lighter setup (very important on a FWD car) but also are lower profile and allow for a wider tire and more adjustment in the rear than the 2.5" coilovers do.

This setup allows for a 7" Wide rim in the rear without any cutting to the bodywork. This is a 15x7" rim with a 38MM offset tucked into the fender of a Festiva. Try that with a 2.5" coilover.

Thanks for that,i will see if i can get just the two front coilovers

[Advancedynamix]

This brings up a point... which is actually better, centered for weight, or centered for axle spacing?

I don't understand what your asking.

Did you roll those rear fender lips?

Yes, I used several different diameters of aluminum round stock to roll and stretch the rear fenders. It takes patience and I didn't do a perfect job, but I was in too much of a hurry. If you are patient and do a little at a time you can stretch the festiva rear fenders out an inch or more without any noticeable change in body lines.

[rbrown]

This setup allows for a 7" Wide rim in the rear without any cutting to the bodywork. This is a 15x7" rim with a 38MM offset tucked into the fender of a Festiva. Try that with a 2.5" coilover.

Did you roll those rear fender lips?

[Christ]

This brings up a point... which is actually better, centered for weight, or centered for axle spacing?

[Christ]

You must spread some Reputation around before giving it to Advancedynamix again.

Dern it.

[Advancedynamix]

Good Question. The reason I didn't use the VW coilovers for the rear is because they are too long. With the car at the ride height That I wanted to run, they are bottomed out. Also, the KYB setup that I have uses the 1 7/8" springs which are not only a much lighter setup (very important on a FWD car) but also are lower profile and allow for a wider tire and more adjustment in the rear than the 2.5" coilovers do.

This setup allows for a 7" Wide rim in the rear without any cutting to the bodywork. This is a 15x7" rim with a 38MM offset tucked into the fender of a Festiva. Try that with a 2.5" coilover.

[alpaccino]

A lot of people are interested in the way I've modified my rear shocks, well, here is an example of the versatility of the setup.

There is an entire BP engine in the back, with other spare parts, tools and a pallet and a couple of tires. I just turned my rear spring adjusters three turns to accommodate all the weight. No rubbing.

Advancedynamix, i am in dialog which raceland via email they are saying that the kit comes with all four coilovers and they don't sell just the front two (which for me is great for the price) i was wondering what was the reason why you didn't used the rear coilovers, and since i would still have to do some machine work, couldn't i just modify the rear coilovers to fit if thats the prob?

[Advancedynamix]

I used them with the stock festiva sway bar and Capri knuckles/ brakes. I couldn't use them with my aspire swap because my drivers side axle was too short, but my engine/ tranny should be mounted a quarter inch toward the passenger side to center the axles. I bet aspire arms will work with a car that is setup differently. I never used r compound tires with the aspire arms so I don't have a comparison of the two. In theory they should work better.

[Safety Guy]

A long time ago I believe someone used Aspire control arms, stabilizer bar and axles on his Festiva, with the obvious increase in front track.

Karl

[Advancedynamix]

Here is a picture to illustrate what Christ mentioned about the shape of the control arm not affecting the centerline between the ball joint and the control arm mounting point.


However, if bending the control arm shortens the control arm it will change the amount of camber gained through suspension travel. It would reduce the amount of negative camber gained by bringing the ball joint closer to the vertical centerline of the upper strut mount. (not good)
Another note, Aspire control arms are longer than Festiva arms and actually offer more camber gain. Just switching to aspire arms will help more than any control arm bending will accomplish (if your axle length lets you get away with this).

[Advancedynamix]

He's saying that it doesn't actually change the arc, it just puts you in a more desirable part of the arc so that the up and down movement of the tire doesn't translate into as much in and out movement of the hub relative to the car body, but it doesn't work that way... The moment arc of a control arm is defined as the centerline between the mounting points and the center of the ball in the joint. Bending the control arm, while putting the control arm itself back into reasonable alignment, doesn't change the position of the centerline laterally from the ball joint back to the mounting point. That is determined by the strut length in a MacPherson strut setup.

However, if your bend moves the centerline of the ball joint closer to the mounting point, it will change the arc length negative, and obviously if it moves the centerline further from the mounting point, the arc length is changed positive. Positive increase in arc length means more travel to achieve the same degree change in the lateral centerline.

Yeah, that's exactly what I was thinking. One other note, if you think of the arc being relative to a perpendicular plain to the control arm, it would make sense that the car would begin to lose negative camber after the control arm has passed the centerline, however this isn't the case with the Festiva chassis. Because the strut upper mounting point is inward of the ball joint (strut travel is not perpendicular to control arm), the car will continue to gain negative camber as the ball joint moves toward upper strut mount (strut being compressed through it's travel, or a shorter strut being used). This arc is actually ideal "as is" for a stock Festiva Body. The car does well at maintaining a contact patch with weight on the outside wheel and uses all available wheel well. It's the inside wheel on a corner that begins to loose traction. I think this can be remedied by deleting the sway bar (replacing it with isolated links like a kia rio has) and increasing the caster angle. This would keep the inside wheel planted to the ground rather than trying to lift it. it would require stiffer front springs or different bump stops to control body roll though.
Thanks guys for contributing to the brainstorming. With a few simple adjustments I think it's possible to improve my lap time considerably.

[rbrown]

Awesome.