Chassis "Band-aids" for Slicks

[alfordvette]

FYI.

Jason of Tubular Fabrication was kind enough to look over my car (GTRA) last Friday night to determine whether it had the "band aids" for slicks. I called Jason about midday on Friday and he came by the Dealership/Shop (Starrformance--across the street from Road Atlanta) where I was working on the car on his way home to look it over. I was getting the car ready for the HPDE at Road Atlanta on Saturday and Sunday sponsored by the Peachstate PCA, which was cancelled due to snow.

Jason spent about 20 minutes looking over my car and talking about the design, fabrication and production of the GTRAs and GTSs by Panoz. He was involved in these processes (and continues to be involved with Panoz) and is very, very knowledgeable about the Panoz cars. Jason pointed many things about my car I would most likely have never known. He also pointed out potential problem areas I need to pay attention to as time goes by. Jason is great guy as evidenced by him taking time out of his day to assist me. I am happy to say, Jason was glad to provide the assistance.

I wanted to let everyone know about Jason and his expertise and, most importantly, to thank him for his assistance. Jason regularly reads the threads on this forum and provides answers to member questions.

Regards.

[David Eastman]

Can you relay to us the potential problems that Jason was speaking about.

Thanks

David

[alfordvette]

I only have a short time to respond due to travel schedule so I apoligize for the lack of detail.

The problems/issues Jason and I discussed concerned weak points in the chassis, mechanical equipment and the roll cage. With respect to the chassis, he said I need to regularly inspect certain stress points. In this regard, the points of interest are welds mostly located around the attachment points of the front wheel assembly. Essentially, we need to inspect the welds before and after events. My car has the "band aids" but Jason said they are not as robust as those on other vehicles is has seen.

With respect to mechanical equipment, the spindles are of major concern as discussed in other threads. My situation may be different than other owners of GTRAs. Panoz had replaced with new mechanical equipment the wheel assemblies and many other parts of the car. In addition, I replaced the engine with a new 302 stroked to 347 built based on Roush specs. (I am keeping the 5.0 as a spare and to use as a teaching tool and play toy for my 2, 3 and 5 year old childern.) Further, because I wanted to minimize safety issues, I had my engine builder go over the entire car. He is a very experienced engine builder and racer. I received his invoice yesterday, but due to work/travel schedule I have not yet had an opportunity to review it. It is fairly detailed with respect to what he did and is two pages in length. After my review, I may be able to provide more helpful information.

With respect to the roll cage, Jason said the early GTRAs used 16 ga. v. 11 ga. steel used on cars built later. He said you can tell by inspecting the roll cage to see if there is a seam. If there is a seam, then the roll cage is 16 ga. steel. I am not sure whether a 16 ga. roll cage means the chassis is also 16 ga. I have not yet had an opportunity to inspect the roll cage on my car.

I hope this helps.

Regards.

[94_panoz_#7]

Wow - thank you for all the compliments Alfordvette! But, I am afraid I must have been a little confusing when I was looking at the car. I want to assure all the owners that all of the roll cages are 1.75" x .090 wall tubing. The tubes that I was pointing out on this particular car are the 1" x 2" tubes that the front upper control arms are mounted to. On the first 5 or 6 cars they were a fairly thin walled tube - 16ga. Those chassis were built in Florida at the place Road Atlanta first contracted with to build the cars. When Panoz Auto started building them we about doubled the wall thickness on those 4 tubes to 10ga.

So, just to re-iterate - none of the cars have 16 gauge tubing for the roll cages, they are all .090 wall. The earlier cars did have ERW which is a lesser strength seamed tubing. The later ones had DOM which is still technically a welded tube, but it is drawn through mandrels which cold works it to eliminate the weld seam and make it much stiffer. To see if your car has ERW tubing you can clean the paint off the sides of the 90 degree bend in the main hoop and look for a dark seam. (during bending the seam is oriented to the side of sharp bends in the "neutral axis" that does not have to stretch or compress as the bend is made)

Once again, thank you for the kind words Alfordvette!

Jason

[alfordvette]

Thanks for the clarification--very helpful for me to get things straight. You gave me so much information in 20 minutes, I probably missed more.

Like I said in an earlier post, Jason is very, very knowledgeable about our Panoz cars and a great resource for information.

Thanks again for your assistance.

Regards.

[DrBro]

James can you verify what was the reason for the rear shock mount strengthening? My WC car does not have the support brace and the GTS cars do not either (at least in the manual). Was it just a fatigue issue or something else??

Dwayne

[Wess-RA]

This is resurrecting an old thread but since I am getting track tires it applies. (Kevin, thanks for pointing me toward this thread.)
A mechanic at the race school stated that I needed new steering arms as they are prone to crack at the stress riser (sharp corner) He mentioned that they machined new ones with a radius-as shown


When talking to Panoz they had not heard of this. Also I noticed their parts manual shows the steering arm without the step down to 1/2". Can you guys check out what your car has?

I have the front frame reinforcements (shown at the beginning of this thread)but am missing the "double shear bracket" for the trailing arms. (yes, the bolt is halfway out so that I could take a measurment on the thread size)


The Panoz guys mentioned that I needed the heim bearings to have a 3/4" threaded end, along with a replacement of all four trailing links. What diameter trailing link do you guys with this mod have? As you can see mine is 1" diameter.
Bigger heim threads means larger diameter trailing link. This is a $450 upgrade from Panoz. Is it really necessary in order to run track tires?
Kind of pricey and unexpected.

[gamacdon]

i have GTR0-0035, it has all extra bracing except for rear shock mount. any comments or explanantions greatly appreciated. thanks

[Wess-RA]

Does you front steering arm look like mine? I have never seen that posted as a mod. This was provided to me verbally.

[eric1h]

This is mine..... Looks much beefier

[Wess-RA]

You're not kiddin'. The school mechanic looks to have been right. This could be a weak point compared to yours. Would you mind checking the trailing arm diameters, if possible.

[eric1h]

Here is a pic of mine, the car is over at the hangar so i can't check the actual diameter tonight, but I'll be over there tomorrow finishing up the paint booth and can check then

[NZGTRA17]

Originally Posted by Wess-RA

Would you mind checking the trailing arm diameters, if possible.

Uwe, my steering arms are the same as Erics. They are 1.25" in cross section prior to the change in section and are 1.015" after change.

My trailing arms or links are 1" in dia the same as yours. The rod end cross section at the threaded portion is 5/8", also the same as yours. My car has been boxed around the link attachment bolts though.

You may want to ask Panoz what part of the arm/link fails. If it is the rod end or the aluminium tube. If it is the rod end, you could upgrade these to chrome moly ends quite easily as any good race shop will have them.

[Wess-RA]

Eric thanks for the photo. Don't waste your time removing the bolt. A local mechanic who has converted several school cars is checking it for me. He has another car on a lift already. Kel, I will check with Panoz on the failure location. I'll give feedback as soon as I get it. Thanks for confirming the dimensions. It appears, I can forego the expense on the trailing links.

Re. the steering arm: I learned that some of the school cars were modified (machined down to have an engineered failure point) so that if they were crashed this would be the failure point-theoretically minimizing damage in other more costly areas. Seems a bit risky, in light of the fact that these cars are no longer in schools and are being made faster by nearly all of us.

[Cobra4B]

Here are my rear trailing arms... I have the reinforcement, but the narrower arms. We purchased the upgraded arms from Panoz and are having them installed at PAS currently.



Our car also has the front reinforcements in place





My steering links