Another possibility

Many times when there are braces with no readily apparent function, they are there for NVH reasons. It doesn't take much to chase a few annoying structural vibrations off to frequencies and/or locations where they are less noticeable, once you know where to attach the bracing to. There may even be some advantage in making the bracing somewhat asymmetrical - at least then the two sides of the car aren't both chasing their nuisance vibrations off to the same new frequency and location(s). Two small vibrations are usually less bothersome than one big one.


Norm

 

What does NVH stand for? I assume the v is vibration and the h is for maybe harmonics?

 

Noise. Vibration. Harshness.

 

My baro sensor came from the factory attached next to the other sensors behind the brake booster and I have a 1987 carb car.

 

The TBI Map sensor is on the firewall in that brace bolt hole.



Notice there is no brace. And that was back when the car was mostly stock.

 

the discussion was that it was mislabled or misinterpreted at its conception.. one person or engineer calling it a wanderbar and being spelled wonderbar..

 

I see. Makes as much sense as anything else.

JamesC

 

Odd. Was the Baro sensor mounted adjacent to the VAC sensor there? I've had two 87 LG4s and they all had the Baro on the right. One was a Z28 and had the brace there (I put it onto my SC that is shown in the pic).

 

Here is a pic of my underhood showing the sensors all on the left.

 

Must be a year thing. All of the later TBI cars mounted the MAP to the brace hole on the cowl. Carb and earlier engines mounted it on the relay bracket near the booster

Add to the list the fender braces on 91-92 birds. Goes from the base of the battery box on both sides to the top hole on the nose stud strip. You can see the pass brace in this pic

 

GM has always made these "last minute changes" to their cars. I just learned to accept it and enjoy an oddity or two.

 

You've got BOTH the VAC and MAP on the left? And you converted your LG4 to the serp drive? Looks good.


Don't get someone confused: Carb=Vacuum sensor / TBI=Manifold Absolute Pressure sensor. That's why the carb'd cars needed the additional Barometric Pressure sensor.

 

I did convert to the serpentine set up after I got tired of all the damn belts. Although I did keep my old set up and put it away.

Everything is stock under my hood with the exception of the air cleaner lid, slp headers, serpentine set up, and the addition of the "wonder/wander" bar and the cowl to fender brace.

Still debating on intalling the final brace which goes from the right strut tower to the frame. I really would like to know the effectiveness of it.

 

Every time I find one of these braces that I don't have, I have fabricated one and installed it on 83 BB Camaro. I don't know why, I guess they must be there for a reason. The next one will be the bar on the passenger side mid strut tower to frame. Gosh I did it again, sorry for digging this up.

 

GM didn't just put stuff on cars for the hell of it- every one of those braces served a function that was important enough to justify designing, testing, manufacturing, and installing them onto the cars. these cars aren't built very stout, so adding as many braces as you can to them can only be a good thing.

 

I'm thinking that pass side firewall brace is there because they recognized a weakness there because of the large hole in the firewall for the ac duct and the gap for the channel drain.
Many third gens seem to have a problem with leakage there, maybe the seam gets distorted by hard cornering. I might add that brace to my 85.

 

Yep I made and installed that brace. All the holes are already there.

 

Great Post. Now its time to start bracing the car where ever I can. Obviously, subframe connectors and wonder bar are not going to be enough.

 

I wonder if the braces were dependant on the engine/trans setup. I would guess a 5.0l with a manual would stress the unibody differently than say a 2.8 with auto.

 

That might be, if anyone one has the k member braces they don't want, let me know. I can always make them if need be.

 

I remember reading back in the day it was called a "wonderbar" because of how effective it was for such a small effort. Basically a less intrusive strut tower brace. Which I believe is a better improvement. But on another note the wonderbar puts the weight lower in the chassis.

 

Like I've always said, every 3rd gen should have a wonderbar. TDS makes the best ones.

 

It seems that all of these little braces are for the steering box or strut towers. I would think that adding a wonder bar and triangulated strut tower brace would allow you to remove the brace connecting the tower to cowl, upper cor support to battery tray/wheel arch and strut tower to frame. Any thoughts on that?

 

Remove for what purpose?

JamesC

 

Not needed anymore. Those small braces seem to be for keeping the strut tower or wheel arch in the same position which is what a triangulated strut tower brace does.

 

My car is equipped with all the pieces you mention. Personally I didn't feel the need to remove anything. Seems to me they can only help, but each to his own opinion.

JamesC

 

Id be curious to see how much they twist/flex w/o and with the braces. If someone has a go pro, they could rig it and some arrows under the hood, indicating how much twist/flex there is.

 

Well, maybe you're misunderstanding my question or I didn't ask it well enough. Does a triangulated strut tower brace do the same job and if so wouldn't it do a better job than multiple stamped sheet metal pieces or 1/4" rod?

And as a separate question, if you welded up the heater core ,blower motor and heater hose openings the firewall would be stronger, would you still need the cowl to hood bracket piece?

 

I have no idea. Perhaps someone with an engineering background could chime in. Also, as an aside, remember that after market strut mounts should be in place before the STB to eliminate as much flex as possible.

Best of luck in attempting to find answers.

JamesC

 

Just to add some confusion: My '91 1LE came with all the braces pictured but did NOT come with a "wonderbar" from the factory. The one other '91 1LE I have seen did not have one either.