Secrets of the Mirage

[mymomswagon]

3 degrees of camber gave the car a lot of front grip. Lowering the car by about 3" will get the suspension back into the range it was designed to work in. And maybe keep both of the front wheels on the ground.

saw this from around the trailer, clear air under 2 wheels.

[Loren]

Some quick math with measured corner weights and spring rates tells me that the front springs that come with the coilover kit (4kg/mm) are perfect for 2" of compression travel.

What this all boils down to is that my coilover kit seems to be pretty well thought-out. I can run as low as probably 2.5-3" of ground clearance if I wanted to and probably not scrape on "perfect world" flat surfaces.

My decision of how much to lower the car comes down to purely asthetics and "how much do I want to scrape speed bumps and the dip at the end of my driveway?"

I'll probably compromise with something like 2.5".

[Loren]

I planned to swap the rear springs today, ended up getting both front and rear done. I need to to some fine-tuning of the ride height and set the alignment yet.

Initial impressions: Steering feels sluggish... I'm betting that I added some more static camber and now have some toe-in. It felt a little bouncy at first. I added some shock stiffness, and that feels better. Otherwise... oh, y'all are gonna HATE it! It feels like it can do anything, and nothing feels dramatic. It's much more composed than it was.

I was careful to pay attention to droop travel when I set the shock length and perch heights. Ended up right in the middle of the shock travel. The rear has 5" of travel, and 2.5" of droop. The front has 4.5" of travel and right about 2" of droop.

I think I'm going to like it.

[Loren]

Finished tweaking the suspension today. It's about 2" lower than stock. Still has 6" of ground clearance. Stock rake was about 3/4", now is about 1/2".

Ended up with the shock travel perfectly centered. 2.25" of compression and extension in the front. 2.5" in the rear.

Front camber is around 3-3.2 degrees. 1/8" total toe out. Rear suspension is not adjustable.

Car feels GREAT! Wheel hop problem is completely gone. Feels very composed and happy. Puts power down very acceptably even in 1st gear hairpins. (yeah, I know, it doesn't have any power to put down... but, it used to POGO in that situation!)

And it looks sort of like this:

[Native]

Needs a teal fender.

[Loren]

I actually bought some red vinyl to wrap a mirror in memory of the Fastiva. Wrapping a mirror is a daunting idea, though.

[Native]

Wrapping a mirror is a daunting idea

Truth.

[BrilloHeadBen]

Do you have any left over spray paint?

[Loren]

Probably have some paint. Not gonna use it.

[jbrannon7]

Probably have some paint. Not gonna use it.

Yep, wouldn't be prudent.

[Native]

Not at this juncture...

[Loren]

[twistedwankel]

So long as you beat Mike in his hyper miler powered by WI cheese and lithium with dryer duct battery I vote an unequivocal

[Loren]

Gave the new suspension a shakedown today with Philip. 10 runs, no issues. Philip thinks the car needs to "rotate" more. I think neither of us were actually pushing the car to the limit consistently enough to say for sure what it might need. But, it gets around a course quite nicely.

I didn't take any time to really align the camera, so I got crappy video. The front one shows fender clearance, and the fact that it's got LOTS of droop travel that it didn't used to have. The rear one doesn't show much at all... except for that cone I hit.

https://youtu.be/hd6wKSiZuhI

https://youtu.be/esvse7eQdho

[Loren]

Damned event photographers.

Looks like our work is not done yet, kids.

[Carracer]

Need more low.

[jbrannon7]

Appears the car is just too top heavy.

[Loren]

Appears the car is just too top heavy.

Probably.

But, I don't think it's so top-heavy that it can't be fixed.

Going lower is certainly an option. Even in this photo, you can see that the fully loaded side still has PLENTY of ground clearance. And the suspension also has plenty of adjustment left. If I wanted to scrape every speed bump, I could lower the car another 2.5-3". Give up another inch of compression travel. And probably go a long way towards solving the problem. But, I don't want to be that low. I could probbably go another inch lower, though. I wouldn't like the wheel tuck that comes with it. But, I don't think it would be too bad, otherwise. As it is, it doesn't scrape anything with 5" of ground clearance. I could live with 4".

Even keeping the ride height the same and shifting the shock travel 1" so that it can extend another inch would probably help. Remember, I've only got 2" of extension travel in the front right now. That's what's pulling that inside front wheel up. If it had more travel, it would still be in the ground. (it wouldn't have significant weight on it, but it wouldn't be in the air)

I keep reading about roll centers vs CG height. I'm going to take some measurements and try to find my roll center. I don't know where my front CG is, but I can assume that it's somewhere between 1/3 of the total body height and half the hood height, and I'm betting I can't get the roll center anywhere near that. But, getting closer to it is supposed to help reduce body roll. Can't find any kind of quantification for that... how much will it reduce body roll? How much will it help? Don't know. But, it's worth experimenting with.

Gotta take some measurements and draw some pictures. Got nothing else on my agenda for today.

[Native]

Spacers for wider front track?

[Loren]

Spacers for wider front track?

Thats on the list, but I can only go maybe 1/4" before I hit fenders. Not ready for fender flares yet! They will clearly become a necessity to run wider tires and "really" develop this car, though. Tough commitment to make. I guess the front fenders are bolt-on, though.