Ben 84 RX-7

I started my turn in at Big Bend (turn 1)...and BAM! The panhard bar snapped in two. Off into the dirt I went (without any contact luckily!) Is this a fairly common failure?

Ben

grafddrx7

Don't know alot about first-gens, I'm just glad to hear you didn't wad your car up and that you're allright!!!

There's a guy around here who runs in ITA, and has a company called G-Force engineering that does some suspension stuff for first-gens, so he might be able to help...

Just found his ad in Sportscar magazine... Sells a "GT Panhard" deal, so maybe this is something worth looking into.

Website is gforceengineering.net...

I believe his name is Jim Cusco, and he's in Findlay, Ohio, about 45 minutes from Toledo, if that helps...

Good luck, and keep it outta the kitty litter!!!

Ben 84 RX-7

Thanks! I'll check it out!

cpa7man

iTrader: (2)

Jim Susco, yes very good products. Order his book and he will give you free suspension setup consultation.

I like that "wad your car up". Yea you were lucky. A first gen locked its rear end up and hit the wall at Texas Motor Speedway in qualifying yesterday. Good thing and bad that it was the new soft wall. If we hit it we buy it. Ouch!

grafddrx7

Luckily, from what I remember about LRP, there's alot of run-off area at turn one, so if this was gonna happen, this was probably the best spot...

speedturn

iTrader: (1)

I use G-Force Engineering products on my 1979 IMSA GTU vintage racer, for about 5 years now. His stuff is well engineered, and since he is a trained suspension engineer (GM Institute) he really knows RX-7 suspension better than most racers do. Many top production car and IT car racers run his pieces.

http://www.gforceengineering.net/products.htm

Ben 84 RX-7

What have you guys heard about the ISC panhard setup? Seems to be really similar to the G force one. Yes, Big Bend does have plenty of run off...the only corner at Lime Rock that does! I definitely dodged a bullet on that one!

cpa7man

iTrader: (2)

A lot of good racer use his stuff. ISC is a great place for Mazda racing parts. Mike is very helpful and they have a quick turnaround. I have ordered a few things from them. I think that the advanced shocks with the redesigned front struts and with all of the other gforceengineering stuff would be the hot ticket for first gen handling. Just expensive......how much faster would it be than the ISC setup? I would guess less than a second or two per lap.

Ben 84 RX-7

Did I understand you right...you think the G Force panhard makes that much more difference than the ISC panhard?

cpa7man

iTrader: (2)

No, I think both are just about the same. But if I was going to go with the full setup I would go with Gforce. Susko offers a more complete higher end package. Like I said a lot of guys run the ISC stuff and love it. Also look at ground controll stuff.

Ben 84 RX-7

Gotcha...Thanks for the input!

speedturn

iTrader: (1)

Exactly which part snapped on your old panhard rod?
What brand was your old panhard rod?

Inquiring minds want to know

Re-Speed.com

iTrader: (3)

Yes, Give us the details.

-billy

Ben 84 RX-7

My father has a ground control panhard bar on his car that I took to a fabrication shop and had them make one like it...apparantly the shop isn't that good! It only had 4 races on it. The bar makes a bend and goes under the rear end. There is a brace welded onto it at the bend. It snapped right after the brace ends. I guess you get what you pay for!

DriveFast7

iTrader: (1)

Ouch! I have the Ground Control panhard and it came with a gussett on the bend, facing front of car. We welded a larger, wider gusset same spot, on the bend, but facing rear of car. Have 10 weekends of hot lapping on that car including some with slicks. Hasn't had a problem.

cpa7man

iTrader: (2)

FWIW - The ep first gen I just bought has Ground Control pan hard and 3rd link on it. This class runs slicks and the Ground Control parts have been on this car for at least a dozen races. Very durable to chime in on what Brad said. I'm going to keep what I have and add GForce's turn in spacers and other pieces as the budget permits.

Ben 84 RX-7

Absolutely...keep in mind guys, my bar was NOT a Ground Control bar! It was a Ground Control REPRO that I had a shop make. Stupidly, I didn't ask the guy at the shop what thickness he used for tubing etc. I couldn't find a Ground Control bar since they stopped making them, so I had one made. I will never do that again!

If I had an actual Ground Control bar, I would use it in a hearbeat.

'85 GSL 302

It's rare, but it's been known to happen. I was doing F&C for a NASA race and an IT7 had the same thing happen. He finished the last 3 laps of the race dragging the bar. I think they "meat balled" him one the second lap but he finished anyway.

I don't think it's an issue of the parts being faulty. I think it's more allong the lines of once you start modifing things, you're eventually going to have something break. I wouldn't worry about it in the future, but I'd certainly pay attention to the part that failed and make it stronger next time.

Rob

Re-Speed.com

iTrader: (3)

I would second that. Race car parts break! If you had it made out of 4 inch diameter steel rod it would not have broken, but it would weigh a ton. designing race car parts is always a compromise. No reason to give up on it.

You say it broke at the point where the gusset stopped. That will be a weak spot on the part for two reasons. 1) The welding at that point would have made the part brittle. 2) The part is ridged until the point where the gusset stops then it is just bar again. So there would be allot of stress on the part at that point.

Since the part is toast at this point this is what I would do. 1) Measure the wall thickness of the material. 2) Call and ask the shop what material they made it from. Ask if it was a welded seam tube or a DOM. If it is mild steel or 4100 series material, and if it was tig or mig welded.

Take the above information and make an assessment as to what went wrong. Adjust for your assessment and remake the part.

If you would like, Bring the information back here and I can help you. - Or - Send the part to me and I will make you one.

-billy

T_Racer

iTrader: (1)

Just a quick thought, but I have never seen a GC panhard. We run a G-Force panhard that to the best of my knowledge, goes behind the axle pumpkin, not under. This provides for a straight panhard rod, which is a lot stronger than a bent rod. Good for two reasons, more ground clearance, and able to adjust the panhard height to adjust rear roll center. I know that GC makes great stuff, we run a front setup from them, but think that going under the axle is not the best setup. Maybe there is another reason for this, as I realize that Jay and the folks at GC are very knowledgeable. just another .02.

Travis

DamonB

I disagree with that. Sure racing stressing things immensely, but the part should be designed to fill the job. A part failure isn't a failure of the part itself, it usually lies somewhere else. It could be the failure of the engineer who designed it. When it was designed properly and fails its the fault of the guy who welded it up. When it was designed and welded up properly and fails it's the fault of a bad batch of material. When it was designed and welded up properly, the material was good and the part still fails it's the fault of the user not inspecting the part. It's VERY rare for something to instantly and catastrophically fail. The part will always exhibit some sort of failure mode before hand but you have to make the effort to look.

Inspection is one of the most important things in racing and it's the one that is most often overlooked.

Rx7carl

I run a g-force panhard and have gotten close up with the ISC piece. I love the gforce one, very well engineered. The ISC piece is comparable, but a bit overbuilt IMO. More like the way a guy like me would build it, not being an engineer. Mikes a good and helpful guy, so is Jim SUSKO. I've seen pics of the GC bar and Im not impressed.


Here here Damon! I inspect the car after every session.

Speed Raycer

I'm running a G-Force bar on mine. The only problems I've had with it was the brace bar bending and the body mount weld breaking. The brace wasn't the original bar supplied by Susco and the body mount seems a little bit under engineered, but it works fine.

I've got some pics of an ISC bar I installed on a customers car.

www.izzyscustomcages.com/projects.html

Ben 84 RX-7

Thanks for the links! Scott, I wish your shop wasn't so far from NY!

Rx7carl

I really want one of his cages in my car. I still may bite the bullet and do it.