Poor road manners

[FatBoy]

Hi,
I have a friend who has recently bought a Contemporary Cobra. On the face of it, it has all the right bits, an ali Shelby 427 with Webers, fancy ali rear suspension, pin drive wheels etc. However, it apparently drives like an absolute pig, to the point of being dangerous. He's had the basic alignment checked, but it drives no better. He has "Billboards" but the supplier, irresponsibly in my view, sold him the version with the very low profile tread pattern. He is running these at 24psi.
The next target is the dampers and springs. I have read on here that 8" 275lb springs are about right for the rear, what is the consensus for the fronts?
I've owned a CCMC Cobra myself, so I know they can be set up very well.
He is starting to lose faith and interest in teh car, which is a shame.
Your thoughts and suggestions would be welcome.
Thanks.
Paul

[SuperHart]

Take this for what it's worth, but the first thing I think he should get rid of is those Billboard tires. When I built my Cobra in 2001 I used el cheapo Cooper Cobra radial tires 235R60-15 on the front and 295R50-15 on the rear with Compomotive wheels. The car drove great. Last year, because I wanted that fancy Goodyear Billboard look, I swapped out the Cobra tires for a brand new set of Billboards. The car drove like a pile of $#!T. NOTHING I did improved the drivability, alignment, altering tire pressure, adjusting ride height, NOTHING. Keeping in mind that my car is street only and never sees the track, coupled with all the aggravation I was experiencing, I finally decided to bag the Billboards and re-install the Cooper Cobra radials. Immediately, the car handled and drove like a dream again. I took a rather large hit on the Billboards to unload them but I learned a huge lesson. There is a reason the Goodyear Billboards are advertised as "race only" and are not DOT approved. Sometimes I think we should actually pay attention to those warnings.

[FatBoy]

Thank you for your prompt and detailed reply. The tyres way well be an issue in this instance, but I had Blue Streaks on my CCMC and it was fine, so I don't necessarily think that is the sole problem, but I take on board your comments.

Thanks again.
Paul

[lovehamr]

Paul, alot of the guys here on this board and others have had great experiences with GY billboards but the alignment does have to be right. You wrote that the car handles like a pig. That's colorful and all but not very descriptive of the actual problem. If you could go a little more in depth on both the car's set up, and what it's doing, more people would step up to help. For instance; what are the alignment specs that he's running now? Does it over or understeer and when? Is it stable driving straight or does it dart around?

Steve

[Rick Parker]

If they are the Goodyear Blue Streak Sport Car Specials, (Chicken scratch tread)speaking from first hand experience, they are great on smooth flat asphalt and can't be beat; but add in any irregularities in the surface, off camber or crowned roads and the car WILL be difficult to keep in a straight line. It takes time to begin to anticipate what it will do.

[Excaliber]

I'd simply raise the air pressure to about 30 psi or better first, just to see. I really don't think the tires are the problem for ill handling, but 24 psi is a bit low depending on other conditions for the car.

[DAVID GAGNARD]

"Race Only" tires will "hunt" on anything but a smooth perfectly flat road, especially bias ply tires!!!!!!!!!!!!!

There is a reason the Goodyear Billboards are advertised as "race only" and are not DOT approved. Sometimes I think we should actually pay attention to those warnings.

Zacctly.......I did the same thing with some Hoosier road race tires, ran them on the street for a break-in period and the car wondered all over the road, and they WERE DOT rated. They were Hoosier Street TDs....Great on the track, terrible on the road....

Try a good set of radial tires and I'm willing to bet 90% of the problems will disappear instantly. Been there, done that.......

David

[Excaliber]

I don't know, my Bill Boards didn't "hunt" near as much as some people seem to think they do. I suspect there are other issues at play here.

Of course the meaning of "handles like a pig" doesn't give us a lot to go on.

[FatBoy]

Thanks for all the responses guys. I'm sorry, I realise that my colourful description of the handling is less than precise, but I haven't driven it yet and the owner is inexperienced in the finer points of automotive handling traits.
However, he has said that the roads around where he lives aren't good and that the car behaves badly, even on straight roads.
I'll try to get to drive it myself and hopefully, I'll be able to report back with something a little more useful.
As has already been said, the Billboards will make a bad situation much worse, but I don't necessarily think they are the only problem. My Kirkham drives fine with them on, although if the road surface gets bumpy, they do start to hunt, especially on a trailling throttle or under braking.

Paul

[KevinW]

Paul, just wondered, could it be bumpsteer at the front, wrong toe-in.caster, or is the rear a problem too? when i changed the caster at the back on my last car by only a degree or so, made a significant difference to the roadholding/cornering - after the mod, much more glued to the road, less skitty.

one easy check - does the car roll easily when pushed by hand? this was a tell tale that geometry wasnt right - shouldnt be any squeeking from the tyres (which happenned on my car - initial setup very poor).

[FatBoy]

Hi Kevin,
Bumpsteer was one of my thoughts. When my CCX kit was first supplied, the front uprights were wrong and the steering arms were at the wrong angle, causing terrible bumpsteer. CCMC were very evasive on the matter, but eventually conceded that the uprights could be wrong and sent another set, which improved matters enormously. My car was supplied around the same time as this one and through the same distributor, so it is possible that this car also had the wrong uprights and the fault was never identified, which might also explain why it has very few miles on it.
It was built for the lead singer of The Prodigy, but he moved on to an “original” continuation Cobra from AC, which is currently for sale through Rod Leach’s Nostalgia.
Paul

[trularin]

From my limited experience, race tires do hunt on anything. I think Dave is right. Borrow if you like a set of radials and see how she does.

Just my humble opinion.

[DAVID GAGNARD]

Originally Posted by Excaliber

I don't know, my Bill Boards didn't "hunt" near as much as some people seem to think they do. I suspect there are other issues at play here.

Of course the meaning of "handles like a pig" doesn't give us a lot to go on.

You'll must have a lot better roads on the islands than we have down here in da swamps of Louisiana.......

Some roads I've driven on with the race tires, I can hold the steering wheel perfectly straight and the car will practically go from one lane to the other all by itself, does get scary at times!!!!!!!!!!!!!

David

[jhv48]

And don't forget to check the alignment of the BACK end of the car.

Mine was off center by 1/2 inch and the car wanted to crab down the road. Spent lots of time and money on tires and front end alignments till I checked out the rear.

Problem solved.

[mdross1]

My car was a wild handling beast when first put on the road with coilovers all around.After a couple of seasons happened to be talking to a road racer,who asked if the car was ever scaled,Scaled! He offered to do mine,he was right,the coilovers were set very wrong.After adjusting all four corners then tightening the drivers sides to compensate for my weight while in the car,it now handles like being on rails.I Yee Haad all the way home.

[Eljaro]

Fatboy,
I had my Contemporary Cobra built in 1993 by now defunct Jim Blackburn (American Speed Specialities) in Norwood, and lots of things were not right when I started to use the car. I know he was also building Cobras for some pop artists at that time. He was a nice guy but his mechanic was sloppy.
The front wheel bearings were the wrong size, the inner diameter of both bearings being larger than the axle stub diameter. The bearings were held in place only by the axial pressure exerted by the axle nut. On turns you could hear the "knack" of the bearings moving around.
So if the car was built by that guy, I would check those bearings.
Also see if the rubber bushings on the front suspension are dried out or misplaced.
On the rear check if there is play in the U-joints, since they will affect the geometry. In case the car has Watts linkage, check that is is moving freely and not binding. I set up my car with a 1º negative camber in the rear, which is the best adjustment.
I did have a set of Goodyear sent with the new car. They were out of round and I had to turn them true in a shop. They were very difficult to balance, and the car behaved really bad. Finally I had to throw the nice Goodyears away.
Best tire is the Avon 66CR. The Coppers should be ok too.

[FatBoy]

Hi Eljaro,
My CCX also came from Jim Blackburn, as did my friends car. To be more precise, his car is the one Jim built for the "pop artist", Liam Howlett of the Prodigy. The registration number was "COB 427". I built my car myself (registration JGC 312C) and it featured in a number of major magazine features, including a 4 page colour feature in Performance Car.
Jim was a "nice guy" if you were on the right side of him i.e. spending money, he could also be quite nasty if you weren't. I don't know if you are aware, but Jim died some years ago.
His build standards weren't always as high as he would have had everyone believe.
Regards,
Paul

[Eljaro]

Paul,
if you read my previous post you will see that I say "now defunct". I know that very well because he passed away owing me quite some money for an ordered front suspension setup which never arrived.
From that moment on I had to take care of the car myself and discovered with time how much was wrong with the built. Learned a lot in the process and now the car is just perfect.
If Jim built that CCX for your friend, just check the front wheel bearings.
Whas that CCX for Liam Howlett painted yellow?

[FatBoy]

Hi,
I did notice your "defunct", but I didn't know whether you meant A.S.S. or Jim. I'm sorry to hear that he departed owing you money. However, even if he were alive, getting money out of Jim would have been a challenge.
The "Prodigy" Cobra was/is metallic grey with black stripes. However, I do remember the yellow car with white stripes, although I don't recall who's it was. I recall that it had a Ford 460 in it. Around the same time, he was also building a metallic burgundy car that had a Jerico gearbox.

Paul

[Eljaro]

I remember that car with the Jerico Gearbox, which was in the shop because the customer had broken the box. I do not know how possibly you can break one of those. No wonder though, since on my car the bellhousing was not aligned with the crankshaft and was hurting the box. Sloppy work all over.
In the end when he passed away many customers lost their money and their engines and partially finished cars. The luck we had was that the CCX car was quite good and solid. He did demo the strength at the Bristol Kit Car show jumping on the hood of the Cobra. That is where I contacted him and ordered the car sometime later.
At that time I also visited Rod Leach and saw his nice cars, but the price was steep, the Pound was high and the engines being used at that time were nothing special.
I do not regret having purchased the CCX. It is a wonderful and solid car. A keeper.