RX-7 PANHARD ROD INSTALLATION

M

MCCAHILLRX7

New member
I HAVE RECENTLY PURCHASED FROM THE WORLDS BIGGEST AUCTION A USED (NEVER INSTALLED) PANHARD ROD FOR MY '83 RX7 AND IT CAME WITH EVERYTHING BUT INSTRUCTIONS. I GET THE CONSEPT BUT CANNOT FIGURE OUT WHERE IM SUPPOSED TO MOUNT THE WELD ON END. IF ANYONE CAN HELP ME I WOULD APPRICIATE IT VERY MUCH. PHOTOS WOULD BE A GREAT HELP.
 
Sorry no photos, got rid of the rx7's a long time ago. If it is a Ground Control brand unit the weld on end mounts on the left hand side. On the inside of the shock/trailing arm mount. Do yourself a favor and gusset the bracket.

I am not familiar with all the various panhard mounts available. The Ground Control unit has a bend in it where it curves around the R&P housing, the bend has a crescent shaped piece of plate welded to it.

Perhaps Ground Control can fax you a set of instructions....or someone else on the forum might have a set of instructions?
 
Buy Mr Quickshoe a beer for that comment about gusseting. The Ground Control unit I had looked pretty sketchy to me as I installed it, but Noooooooooo, I said to myself, "You're no engineer, you bought this for a reason, they know what they're doing"...

Well, guess what, I was wrong, sre enough the thing ripped apart right where I thought it looked sketchy...
rolleyes.gif


Upon calling them, they gave me the old, "We've never heard of a failure" line, then proceeded to tell me that they had an "update" kit...gee thanks, but the timing was suspect. The update kit was a couple puny gusssets.

Find out what you've got. Post dig photos of it here for us. Use "shacknet" (I think) if you need, and we'll help ID it.

Also, you can try going to: Gforceengineering.net or iscracing.net or Gound-control.com

We will get you going!

------------------
Jake Gulick
CarriageHouse Motorsports
ITA 57 RX-7
New England Region
[email protected]

[This message has been edited by lateapex911 (edited June 30, 2004).]

[This message has been edited by lateapex911 (edited June 30, 2004).]
 
Well, if it's a GForce bar, there is no welding required. Course I'm sure Jake knows that. Yea, see if you can post a pic, or a link to pics. I'm sure someone can ID it.
 
I just made the same purchase from the same auction place. Mine is the ISC version. It came with a diagram I can email to you. The ISC version has the extra support bar as a brace.
 
Curious: Who is this worlds biggest auction her these Panhards are purchased ? & what was your cost ?

Questions to those with sucessful Panhard bars which don't break/tear loose. What is cross section & thickness of the extension from the chassis downward that the Panhard ataches to ? What is the cross section/thickness of the diagonal support from this downward member to the far side of the chassis ? What is the cross section/thickness & material of the bar it's self ?

Thanks
wink.gif

David
 
The bar i have appears to be a ground control unit. If I am understanding correctly, you mount it to the lower control mounting bracket? That doesn't seem nearly strong enough to withstand any kind of latteral force. This is why I was thinking I must be wrong. I do have the gussets that came with the bar and they fit right when the bar is mounted to that bracket but even with the gussets it seems bearly strong enough. I think im going to add some additional gussets. Thank you all for your help and of coarse the worlds biggest auction is EBAY.
 
I never had any problems with the mount.

I have only heard of others with failures and was advised by Jay at GC to make certain that I weld in the reinforcement.

FWIW, I believe the force excerted on that rod can not exceed the side force that the tires can handle. If the force of the body trying to go sideways is more than the tires can handle they will loose traction and the bar is now along for the ride. Engineer in a little extra for instantaneous high loads from bumps and such and you should be fine.

The only issue I had was the hammering that the liners in the rod ends took. With the car on the ground give the back end a really good side to side shake, see if you hear any clunking (make sure it is not the exhaust sytem you hear). You can also support the car on jack stands and grab each end of the panhard bar and give it a good up and down yank to check for play in the ends.

Given the IT rules, as I interpret them, the panhard bar is a big compromise. It is not parallel to the ground, nor are the mounts perpendicular to the center line of the car. A big step up from the stock Watts linkage mess, but not quite ideal.
 
Originally posted by GEO46:
Well, if it's a GForce bar, there is no welding required. Course I'm sure Jake knows that. Yea, see if you can post a pic, or a link to pics. I'm sure someone can ID it.
Click to expand...

The GForce GT Panhard mounts require welding. Three mounting points if i remember correctly. The main "bracket" welds on both the drivers and passengers side uniframerail. The axle mounting bracket welds on the bottom of the drivers shock bracket and on the axle itself. The actual bar itself of course mounts via rod ends.
 
Oh really. Then Jim has redisigned the mounting of his kit. Not to mention his "philosophy"(sc). Course, it's been since "02" since I've personelly dealt with his stuff.
 
Jims first panhard was a bolt on, but I suspect there were issues. Most of his products have, through the years been upgraded and beefed up....

The point about the forces being transmitted are basically correct, but I think the momentary loads are way higher than the G loads would lead us to beleive. Assuming that we crner at 1G, and that the force is roughly 50% of the cars weight, you're looking at ABOUT 1250 pounds of force on the mount. Add instantaneous loading from weight transfers, not to mention sliding into and up FIA curbs, and I bet the loads it sees from time to time are at least double that.

This is a great example of a place not to skimp, as any extra weight isn't going to hurt much in that location, and an axle that doesn't rip out is a big deal....

Also, different Panhard rods have different geometry. The current G-Force version include an adjustable roll cnter, and is very close to being paralell with the ground.

------------------
Jake Gulick
CarriageHouse Motorsports
ITA 57 RX-7
New England Region
[email protected]
 
I'd agree that the instantaneous loads are at least 2x what we'd see in steady state cornering. But those rod ends have load ratings north of 9000#. I believe the issue is the flexing, not failure of the mount.

If the panhard bar is 36" long (number pulled out of thin air) and parallel to the ground it is going to pull the axle approximately .014" to one side during the first inch of bump/droop. Doesn't sound like much at all, but if the mounts flex much we not only will have an unpredictable feeling car, the mulitple bending cycles will eventually cause the mount to fail.

Given the rules: Why doesn't someone (or do they?) produce a watts linkage system that has equal length and parallel arms which are adjustable so that roll center height can be adjusted and allow the axle to travel true? Or is it a matter of we can get +/- .020" per inch of travel pretty simply and inexpensively so why bother given the other inherent limitations of the rear suspension that we can't work around within the rules?
 
SDJ (guy that worked in the past for Mazda) in NC does an adjustable Watts link.

I guess no one has a desire to share their Panhard bar material info.
frown.gif
Per previous post.

Thanks
wink.gif

David
 
David,

I have not installed mine, but it is sitting under my desk. If you would like the measurments, I can post them for you.

BTW- I do have the adjustable watts linkage. I have used it during enduros in the past and it completely changed the handling on my car from the stock watts linkage. The car drifts fantastically. I have never driven a car with a panhard rod set up so I was willing to try it.

[This message has been edited by wlfpkrcn (edited July 02, 2004).]
 
My panhard bar (home made) features 1" x 2" recangular box tubing (4130 from aircraft spruce, .065 wall)welded and cross bolted to the drivers frame rail behind the axle. 1" X .065 wall round 4130 tubing is used for both the cross brace and the actual panhard bar. It uses 1/2-20 high strength rod ends both sides. The chassis mounting plates are 2" x4" X 1/8" plate on both sides of both frame rails. The axle mount is also significant, a fabricated box (open on top and front)that slips over the lower trailing arm and shock bracket. The panhard bar clevis ends up behind the shock mount. The fabricated box is held in place by both the shock bolt and trailing arim bolt. There is an additional 3/4" x .065 wall tube connecting the fabricated box to the base of the axle pig (where the pumpkin mounts). It's alot of fabrication, but has lasted 10 years. In big hits I've bent the 1x2 rectangular box tube, and ripped welds OUT of the frame rails (that's why it's welded and bolted.) I heartily suggest adding additional bolts (small 10-32) to the frame rail to floor-pan seam, as I've seen those come undone as well. The rod ends are still original and still tight. Do yourself a favor and make the panhard bar a turn buckle to you can easily adjust axle location.
Hope that helps.
Tak
#29 ITA SFR SCCA
 
Thanks Tak, I appreciate the detailed info.
Is your Panhard adjustable up & down ?

If I am understanding correctly the Ground Control Panhard bar mounts to the drivers side lower control link bracket & on the passengers side to the Watts link bracket on the frame. Non adjustable....

What is the concept of the ISC Racing Panhard bar ?

Have Fun
wink.gif

David
 
Originally posted by ddewhurst:
If I am understanding correctly the Ground Control Panhard bar mounts to the drivers side lower control link bracket & on the passengers side to the Watts link bracket on the frame. Non adjustable....
Click to expand...

Correct, David. Not only is the RC height non-adjustable, but because of the bend in the panhard bar one can not simply back off the jam nuts and turn the bar to center the axle. I also don't recall whether the rodends were rh/lh, really didn't matter since you had to disconnect and turn the rod ends to center the axle.

All that being said, the GC Panhard bar was a big step up over the stock Watts-linkage, it was cheap, but I am certain there are better alternatives.
 
The GC bar doesn't adjust up and down but there is a little sideways adjustment from how far the hiem joint is screwed into the end of the bar. This can be done to center the rear axle under the body.
 
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