Ferrari and Cobra fun

[PhillipM]

About 3 months ago my buddy and I took our cars (Ferrari F430 and my Unique 427) on a spirited 100 mile run through the country side. It was the most fun I have ever had driving the car yet. The car performed great, not a single issue. The drive taught me ton about the car performance and handling, it was great and a blast. About half way through the run we passed a young couple standing in their yard talking, it was fun to see their faces as we went by. Just past their house we open it up on a short straight stretch. I wonder what it sounded like to hear a V8 Ferrari and BB427 in full tilt. I bet it was like listening to Beethoven on 4 wheels (or I should say eight wheels).:D I thought I would post one of my more enjoyable experiences driving the car and we cannot wait until the weather improves so we can do it again. Is winter over yet?????:doh: I am ready to feel 500HP kicking me the butt……
Also, the F430 is a great car. He took me for a ride the day he brought it home. If I had a bigger pocket book, there would be a F430 setting alongside my baby (Unique427).

Phillip

[Slither]

Sounds like a lot of fun Phillip[thumb]. Please tell us more about what you learned in the performance and handling area...

[weaver]

Just a couple of good ol Bama boys out for a ride, I like it.

[Naumoff]

Sounds like fun. Snow on the ground here. So don't feel to bad. If it is dry and the sun is out just go for it.[thumb]

[PhillipM]

Slither, performance was great and an absolute blast but the drive taught me a ton. 1: I plan to put an anti-roll bar on the rear. Actually, I plan to move the front to the back and order a new one for the front from Unique. I like driving on the twisty’s and from what I read, a rear anti-roll bar will keep the car flat when cornering. 2: When those secondary’s open, boy does it put a smile on your face and the motor comes alive. It was an
exhilarating experience. 3: I had just completed a 4 wheel alignment a few weeks earlier but still do not feel the front is correct. The rear is right and plants when you set it in a corner, before the rear felt a little twitchy. The front feels light and wants to follow a grove in the road. I will post more about my alignment because I need some expert help. 4: From my experience unloading the rear suspension is something not to do in these cars. The car stays planted when you remain on the gas.

The drive was way under the limits and we use the experience to learn and enjoy an absolute gorgeous day. We have a perfect course we follow every time. The first 10 miles is use to put heat in the tires and brakes. I also bought be a pair of Simpson driving shoes and never drive the car without them. I like the way the pedals feel when I wear the Simpsons.

Alan, I plan to drive the car to Unique soon. I will call before I drive up. I also need a few items before homecoming. I will send you an email once I am ready to place an order.

Tony, maybe the snow will clear soon. I should not complain, it will be almost 60 here later in the week. A rainy winter here.

[Naumoff]

Phillip,

If you can find one that will fit our cars, you need to get a bump steer kit.
That is why the car feels twitchy. I haven't been looking lately but if you find one let me know.

[Slither]

Phillip,

If you can find one that will fit our cars, you need to get a bump steer kit.
That is why the car feels twitchy. I haven't been looking lately but if you find one let me know.

I seem to remember someone complained about bump-steer before, but I thought I read that it was already sorted out a long time ago by front suspension design changes at Unique. Is that not the case? Is it still a problem? Anybody that is in the know please comment here...

[Naumoff]

Paul,
I have a 2005 model. It still has bumpsteer and with the quick steering rack it makes it a little hairy. I like the quick rack but with the short tie rod ends I haven't been able to locate a ready made kit. I might have to make my own.:3g:

[Slither]

Paul,
I have a 2005 model. It still has bumpsteer and with the quick steering rack it makes it a little hairy. I like the quick rack but with the short tie rod ends I haven't been able to locate a ready made kit. I might have to make my own.:3g:

Any front suspension changes since '05?

[JeepSnake]

Refer back to this thread:

http://www.uniquecobra.com/forums/showthread.php?t=6189&highlight=bump+steer

If your car DOES change directions when you hit a bump, then you've got an alignment issue you need to correct. Dad's 427 car was aligned by a so-called expert here in town, and it had uncontrollable bump steer due to bad rearend alignment. Found someone that knew what they were doing, and presto - a dead stable 2001 model Unique 427, no modifications required.

"Twitchiness" in the steering isn't bump steer. Bump steer is when you change directions upon suspension compression or extension. Find someone with a CJ-5 lifted about 4 inches without a drop pitman arm, and you'll find out what bump steer is. Neither of our Uniques has anything of the sort.

The twitchiness is present to some degree on both our cars, but it is chiefly the result of three things:

- rack & pinion steering
- very little damping in the steering
- very little caster in the alignment

R&P is a precise, but high-reversibility system of steering. In other words, forces are transmitted both directions: driver to wheels and wheels to driver. When you hit a pothole and get a yank on the steering wheel, that's reversibility - that's the impact of the pothole transmitting back through the steering system. Reversibility is desirable in a performance car, because that's where "road feel" comes from. One of the reasons that American car manufacturers stuck with worm & sector and recirculating ball worm steering for so long is that worm boxes are inherently low-reversibility systems; we don't want to be yanking Grandpa's arms out of socket while he's cruising around in the Buick.

Additionally, there is next to no damping in the steering. Yes, we've got the Flaming River urethane joint, which helps. But, it's basically a solid connection when compared to a GM style rag joint, or a shock-type damper bolted to the tie rod or center link. Again, you don't want that much damping in a performance car, but on a passenger car you want a lot.

As for caster, it's the same deal. The typical Unique setting is around 1/2 deg. This makes for a nimble, quick to turn, easily steered at low speed vehicle, especially with a 90 inch wheelbase. It also induces a bit of twitchiness. To take away twitchiness, increase high speed stability, and increase the steering's tendancy to return to center, dial in more caster. But, you'll pay for it at lower speeds with higher steering effort and less of that nimble feeling, because you are now literally "jacking" the front end up slightly when you turn the wheels anywhere but straight ahead.

So, how do modern cars seemingly have it all when it comes to steering? Through a combination of exceedingly large (compared to our cars) caster angles and high-effort variable rack & pinion power steering.

The Chevy Monte Carlo was the first domestic to start down this path, upping caster angles to 6 degrees or more. This gave the stability we craved, but upped the steering effort. So, variable ratio power steering (Saginaw type, originally) was thrown on. This allowed for slow ratio, non-twitchy steering at speed, but easy high-ratio steering in parking lots. Of course, the lack of feedback made you feel like you were smashed on Novacaine. So, along comes "high-effort" power rack & pinion. It gives the "road feel" that we're looking for, but the low-speed easy that we desire as well.

So, where does this leave us? With a performance car of the 1960's. It will perform just fine and be enjoyable to drive IF, AND ONLY IF, THE ALIGNMENT IS CORRECT.

If the alignment is off from the proper specs (I use the ones posted here by Rick Bagley), then the car could quite literally become a menace. A couple of months after Dad got his car together, I was following him and saw him almost lose control when he hit an asphalt joint on the interstate. I believe my comment at the time was "Either that car or our alignment man is a piece of sh*t!" After consulting with another car friend, we took the car to Hill's Frontend in Anniston, AL, and suddenly we had a Cobra that was a joy to drive. The Hills took time to learn & understand the Unique. (And on my Chevelle, they knew how to set it up to run on radials - the OEM specs for use with bias tires aren't optimum for modern radials.)

When you find a really sharp alignment guy that's willing to take the time to understand the car and do it right, stay in tight with him. Take him all your business and refer others to him. A good one these days is worth his weight in gold!

[Naumoff]

The bumpsteer is when you are under acceleration in a long sweeping turn and you let off the throttle and the front end comes down and changes the toe and the direction of the car. This is still an issue and to correct this I need to install a bumpsteer kit. It is nothing against the car. A lot of cars have bumpsteer. :)

Here is a good video demonstrating bumpsteer. He is correcting it with rack height adjustment but you can also do it with a tie rod bumpsteer kit.

http://www.youtube.com/watch?v=LO07qmJ9zkk&feature=related

[JeepSnake]

Tony,

What you just described made the hair on the back of my neck stand up! You could be seeing bumpsteer with the front end, but your description just really, really sounds like the behavior Dad's car was exhibiting when we first got it assembled and aligned at that first shop.

His turned out to be a hack-job on the rear alignment. It was toed the wrong direction, and the camber was bad negative, so that bumps or throttle inputs caused direction changes. The night I vividly remember on the interstate was when he hit a patch that wasn't quite perpendicular to the line of travel, so that one rear tire hit the asphalt joint just before the other one did. The back of the car twitched ever so slightly to the left, then swung to the right, hard! Hammering or releasing the throttle in any sort of turn was perilous.

My (limited) experience just gives me the gut feeling that the problem may lie in the alignment. Hope you sort it out, one way or the other!

[Naumoff]

The alignment is dead on. Four wheel laser. Throttle steer is one factor but the goal is to reduce the cars input to the steering. And I am reducing them one by one. And my car is nowhere near as bad as you discribed your experience.

[PhillipM]

Sorry guys for taking so long to re-post and thanks for the information. Your information has taught me a ton. I will post more information about my alignment soon. I feel my issue is not enough front toe. The reason why is because the car was rock solid at higher speeds before the alignment but now when I am on and off the throttle you have to drive it. Note: It has been on 2 alignment machines. Also, I am a suspension novice and still learning.


JeepSnake, like Tony I have never experience an issue like you have described. After my build (before the alignment), I drove the car for almost 200 miles to allow the suspension to settle. I was coming back from a car show on the interstate and the car was so stable between 70 and 80, that I could have let go of the wheel and it would have remained dead center of my lane.