Unique at Thunderhill Raceway - Dec 1, 2008

[jmillington]

I took my recently acquired Unique Cobra 427 to Thunderhill Raceway (in northern California) yesterday, Dec 1, 2008 - I've posted a picture below.

There are more pictures at
http://www.flickr.com/photos/jmillington/sets/72157610655255432/
the slideshow feature on flickr is pretty cool.

From a couple of the pictures, you can see I'm getting some body roll on the hard corners - more than I'd like. I'll be ordering the rear sway bar to help with this.

I adjusted the tire pressure on the Hoosier Street TDs after each run to get the heat even across the tire surfaces. I ended up with 27 lbs in the rear tires and 29 lbs in the front tires (hot).

I'm surprised the tire pressures were that high as it seems that most recommendations are lower than that?

The front temperatures ended up being pretty even across the surface, while the rears were hottest on the inside of the tires, and got progressively cooler towards the outside.

Cheers,
Jim M

http://xs434.xs.to/xs434/08492/_hop4832743.jpg

[RJacobsen]

Very cool Jim, I recently became aware of the track at Thunderhill, I definitely plan to be there when the car is ready.

[TurnpikeBoy]

Did you manage to kick that Corvette's (behind you) tush? Looking good, Jim.

Lots of thread info in here about bars - quick search will provide you with stuff to think about. These cars do seem to have a lot of body roll, until you get the right size bars and springs under them.

Are your Hoosiers 15"? And how do you find them, traction-wise? After several auto-cross sessions, I'm torn between buying some Mickey Thompson S/R's or just going to 17" wheels and tires. The typical BFGoodrich tires just cannot be made to work on my car, and I need to find decent alternatives. Would rather stay with the 15" look, but not at the expense of real traction. Not sure the MT's are the answer, but cheaper to try them first.

Pics do look good!



-Roger

[pgermond]

Jim,

Good for you. I know the car and I don't think it has ever had a work out like that in its lifetime.

[Slither]

Very cool Jim, I recently became aware of the track at Thunderhill, I definitely plan to be there when the car is ready.


Speaking of which, how are ya coming along on it Rod?

[thumb] or :doh: ??

Hope y'all are well out there!

[eliminator]

Big time body roll, really evident in the pictures taken of the rear.
May need a little shock and spring work too!! Definitely need the sway bar in the rear first , I would probably put the front bar on the rear and purchase a 7/8" bar for the front. Get rid of the rubber sway bar bushings in the front. Then you can go....:3g:

[jmillington]

Thanks all. :)

Rod, NCRC has reduced their track day pricing to fill the grid. They found that by lowering the price, the grid fills up, and it ends up being a better deal for all.

For $99, you get five 20 minute sessions on the track!
Check it out at http://www.ncracing.org

Rick, what size is the front sway bar on our Uniques, and how easy is it to move to the rear?

As for purchasing a 7/8" bar for the front, do you mean that I should purchase the "rear" sway bar from Unique and install it on the front, and not install the rubber bushings?

Thanks for any help/info! :BEER:

[hound dog]

Talk about body roll! This is from an excursion to Carolina Motorsports Park a while back. I'm not sure if I'm getting body roll coming out of turn 1 or just a bunch of torque helping lift the left front. I do have the sway bar on the front but don't remember about the back. I'll have to check. But since body roll was commented on here I thought I'd ask ya'll what you think?
h dog

[jmillington]

Looks like you're getting some front end loft and a little lateral body roll, but nothing like

http://xs434.xs.to/xs434/08494/_hop4628484.jpg

http://xs434.xs.to/xs434/08494/_hop6335105.jpg

Hey, are the numbers on your car removable? If so, where'd you get them?
Thanks!

[TurnpikeBoy]

The front bar typically supplied is a 3/4" bar - early on there were some 5/8" bars but they went away quite a long time ago.

Front bars are largely like springs - might take a couple to find the results you like. The first step up is a 7/8", which were difficult to find a year ago. The change with a 7/8" bar is pretty dramatic from the 3/4" - a 1" would probably be just as dramatic over the 7/8".

Game plan Rick is referencing is to take your 3/4" front bar and mount it in the rear, then get a bigger bar for the front. This works well, and will make a huge change in how the car handles, let alone do away with all that roll.

The Weavers can set you up with the parts and mountings.

[jmillington]

Roger, thanks for the info!

The Hoosiers are 15" Street TD bias ply tires.

They seemed to stick pretty well and gave advance warning before they started to let loose, but as others have noted, they tend to "hunt" a bit.

When I gave the car a test ride on the street after putting the 15" Diamond Racing rims and Hoosier Street TDs on the Cobra, I was quite surprised at how much they wanted to follow any slight grooving or inconsistencies in the road surface, making the Cobra a bit "nervous", kind of unexpectedly darting left and right slightly.

On the track, it seems that the tires would make the Cobra "judder" when the brakes were applied, before settling in on a path, which was a bit alarming at first, but I got used to it.

It seems to me that if you don't mind the look of the 17" rims, that the tire selections available would ultimately make for better traction at the track, at the expense of "the look" and I would expect a bit harsher ride with a lower profile tire.

I'll be calling Unique to order the sway bar and parts.


Did you manage to kick that Corvette's (behind you) tush? Looking good, Jim.

Lots of thread info in here about bars - quick search will provide you with stuff to think about. These cars do seem to have a lot of body roll, until you get the right size bars and springs under them.

Are your Hoosiers 15"? And how do you find them, traction-wise? After several auto-cross sessions, I'm torn between buying some Mickey Thompson S/R's or just going to 17" wheels and tires. The typical BFGoodrich tires just cannot be made to work on my car, and I need to find decent alternatives. Would rather stay with the 15" look, but not at the expense of real traction. Not sure the MT's are the answer, but cheaper to try them first.

Pics do look good!



-Roger

[hound dog]

Yep, think we could both use a little help in the roll department.
h dog

[jmillington]

Here's a picture of my Unique at Thunderhill after installing the rear sway bar I purchased from the Weavers; much less lean and the Cobra handles much better!

http://xs541.xs.to/xs541/09312/kg4r0218670.jpg

[pgermond]

Looking good! It really is great to see that car out on the track [thumb]

[pgermond]

Check this out - close to home...... http://www.clubcobra.com/forums/showthread.php?t=100559