Tunnel Brace

[S.D.M.F]

Hi guys,

I had a full 3" system put in my car recently and when I picked it up the tunnel brace wasn't reinstalled. I was told the new exhaust would possibly rattle on it.
Is it necessary to have the brace fitted? Or it wont make any difference leaving it off?
I have seen an aftermarket BMR brace which is meant to have more clearance.

So do I need it or not?

Thanks.

[BuildItYourSelf]

I left mine off. But I did make a hanger in its place when I did the mid muffler. The hanger don't add much structure.
It helps yes but not necessary.
Kind of like "sub frame connectors" that don't connect sub frames at all. More like extra floor support for no reason.

[morpheousssv]

dual 3" and I spaced down the brace with some 1/4" washers, works a treat and no rattles at all

[-Ray-]

My exhaust was loosened, placed heavy cardboard between brace and exhaust. Tighten exhaust. Removed cardboard. Not hitting.

[Ben2009GT]

Pic of 3" not hitting tunnel brace.

[texn884]

Pic of 3" not hitting tunnel brace.

HI Ben, does that floor bracing help and can you tell the difference?

[Chewy]

My subframe braces are in my garage...

[Crazy Paul]

Hi guys,
I had a full 3" system put in my car recently and when I picked it up the tunnel brace wasn't reinstalled. I was told the new exhaust would possibly rattle on it.
Is it necessary to have the brace fitted? Or it wont make any difference leaving it off?
So do I need it or not?

If the stock tunnel plate had no structural purpose then it would have been made from normal mild steel (YS=250Mpa approx.)
You'll see below that the material Holden used for the tunnel plate has a Yield Strength 2 to 3 times that of mild steel.
Advanced high strength steel
•YS = 650MPa, TS = 980MPa

Thread: Holden VE & G8 Body Structure and Metallurgy
http://www.g8nation.com/showthread.php?t=39051

[S.D.M.F]

Thanks for the replies.
Next time I have it up on a hoist i'll see how close it is and either try using some washers to space it down a bit or look into the aftermarket ones.

[Ben2009GT]

Sub frames work big time.

[morpheousssv]

Sub frames work big time.

Ben what did you notice differently about how the car performs by fitting the sub frames ????

[JimmyJazz]

On my G8, I noticed it made the sunroof stop creaking going up or down off camber inclines.

[G8 GT V8]

On my G8, I noticed it made the sunroof stop creaking going up or down off camber inclines.
It stopped creaking with or without the brace or are you talking about subframe connectors?

[JimmyJazz]

Sorry about that. When I put my subframe connectors on the sunroof quit creaking. I have always used the cross brace, but I did add 1/4" of spacers on using the stock brace after the Kooks setup was installed. I just cut some 1/8'' x 1/2'' strap aluminum and used 2 pieces on each side.

[Ben2009GT]

The subframes connecters make the car stiffer and that help with handling also.

[texn884]

Are the subframe connectors easy to put on?

[Ben2009GT]

Yes they are no problem at all, They come with every thing you need maybe less than 1 hr to install.

[texn884]

Thanks Ben I think I am going to order this for the Rat