blownbird01

Anyone here remove the brace that runs from the panhard mount to the driverside frame? I want to get rid of this for exhaust clearance. I have an aftermarket panhard bar so it should be strong enough to handle the load. The car is not a road race car. More of a drag car. If this can be done without causing any problems, let me know. Thanks.

Z28barnett

That upper panhard bar is there for a good reason. Removing it is a very bad idea in my opinion.

Let me explain, the entire rear axle is prevented from shooting sideways out from under the car by the panhard rod. That force is sent into the panhard bracket. The upper panhard braces the bracket and shares the load in tension and compression. Without the upper bar the force gains a lever arm of 3-4" on the panhard bracket and the load on the bracket increases by 100% + the effect of the increase of the lever arm. That could break the bracket and twist it off of the body.

The handling will not change alot until you break the bracket. At that time everything will go to hell in a hurry. It could cause a bad wreck, and it will fail in a turn.

It is your car, and I don't mean to bust your chops, but this is very bad idea. Would you drive on a bridge if they were cuting out the braces along the side? It is the same effect here.

Z28

blownbird01

Z28 barnett, thanks for the advice. I'm going to take it out, but I'll fab up a new one for exhaust clearance. John, you are an ***. Don't forget who's garage you expect to use when its time to do your car. Also dont forget what I'll do to your motor when I'm building it. Sorry, I don't know how those nuts got in there. HAHAHAHA!

Injuneer

BMR sells a modified upper panhard rod brace and relocation kit for added exhaust clearance.

http://www.bmrfabrication.com/F-bodySuspension.htm

I was always a little hesitant to pull the brace out, but a friend on mine did it on his 30th SS convertible, and it was running 8.60@160mph with a 1.30 60-ft and no problems. Obvioulsy, the car was only driven in a straight line (more of a drag car ) . For street use, I'd think twice.

Jon A

For street/drag that BMR brace is fine, but I'd recommend against it highly for autocrossing and especially for roadracing/track days. Geometry-wise it takes the small negatives of a PHB and amplifies them greatly.

RE AND CHERYL

Your an idiot for removing that brace. The bracket is not that strong without it. That panard bar transfers a great deal of side loads into the chassis even in normal driving. And like was pointed out earlier, when it fails there will be no warning and you would be lucky to not destroy your car.

The BMR piece is a good idea. But the geometry is off for stock springs and even worse for a lowered car. Idealy you bar should be level with the car sitting on the ground.

mongse_1

If it's a straightline car (like you said above), then take it out, it's dead weight. If you plan on autocrossing or roadracing or even driving fast around corners on the street, keep it in. Mine is in a pile along w/ my sway bars, ABS, power steering, etc.

blownbird01

I dont think I deserve idiot status. I was just wandering what the guys are doing that are not road racing. I could'nt give a sh*t about road racing. I am a drag racer. I dont drive fast around turns because that does nothing for me. All that matters is how fast you get to a given speed, not how fast you can take a turn mith it! I will be removing the bar but I'm going to fab up a new one for clearance. Thanks for the input.

RE AND CHERYL

IF your gonna drive it on the street at all, you need to keep it. Even if it's a drag only car. I wouldn't remove it. You say your removing it for exhaust clearance. Why do you need exhaust on a drag only car.

blownbird01

Its not a drag only car. I drive it on the street. It is not a daily driver though.

Norm Peterson

Wrong answer.

The vertical bracket that the brace SUPPORTS is constantly being loaded. First one way, then the other, even in straight running as the suspension moves. And even a strip-only car has to turn occasionally, as in onto the return road, into the staging lanes, pits, etc. That's called fatigue, and even though the loads I've described above aren't that big, they have a cumulative effect over time. If 'fatigue' turns into 'fatigue failure' the results really aren't going to be pretty (the failure will be where it attaches to the chassis, or it may even tear out a piece of the chassis). Actually, the factory did a pretty good job on that brace, as it's not that heavy to begin with, and it's weight that's pretty much right over the wheels that need traction anyway.

Full disclosure: 30+ years of structural analysis, including fatigue evaluations.

While I do appreciate that you did recommend keeping it for hard cornering conditions, you didn't go far enough. The possible consequences really dictate that the brace be kept at least in some form regardless of the car's use.

Norm

mongse_1

Hmm, guess a couple of my friends who have been running w/o them for the last year or so are in trouble. Mine is still out, still laying in a pile and still ain't going in my car. If I start to have problems, I'll reinforce it..wouldn't be anything new on my car.

TriPinTaZ

LOL mine has been out of the car for over a year now.

Norm Peterson

They are at somewhat greater risk.

I'm not saying it will fail right away, next week, or even next year. Just that it will give out sooner that it would if braced in any manner at all. As a hint, I'm sure that you've more than doubled the stress where the bracket attaches to the chassis, and you can figure that doubling the stress throws away 94% - 97% of the time it takes to use up all of the available fatigue life (and then, somewhere, a crack will start). Take comfort in the fact that GM kept some conservatism in their design. But don't get too comfortable about it. You might not get a lot of warning.

Out of curiosity, when the time comes for you to sell that car, will you be freely informing all prospective buyers that this brace had been removed and the car driven that way for a while, and that the car has used up more of its fatigue life in that area than the mileage and any other descriptions suggest? We both know if you don't mention it, nobody's going to look at that area or think to ask. . . . Actually, in this age of too many lawyers, you'd better get a signed document from the purchaser acknowledging his awareness of that sort of unauthorized structural modification and its potential consequences. IOW, protect yourself.

Norm

mongse_1

Threre's a lot of other "unauthorized structural modifications" done to the car that would be of more concern that a panhard brace. Hell, I'm trying to figure out a way to move the panhard bar itself. It's a lot easier to put rear bars on the car if that damn bar was out of the way.