Borla Cat-Back... What to do now.

[JimC]

Last year, I installed a Borla cat-back system on the '92 LT1 6spd. Now I'm struggling with two issues.

1. When using the stock hangers, the mufflers hang just about horizontal. This does not look that great as the car is black and the stainless mufflers are pretty noticable. I have to think that the folks who designed the system wanted it this way and I am a bit nervous about pulling the rear up closer to the body. I noticed member JEFNLSA's Magnaflow's follow the contour of the back of the car and look simply awesome. Has anyone modified the rear hangers for the Borla system to correct the mount angle?

2. The car sounds wonderful in almost all cases, but is unbearable at about 70mph. I can't take it anymore. Borla sent a couple of restrictors that one inserts into the system to increase back pressure a bit. Before I pull the sytem apart and start spot welding, has anyone tried the restricters and do they work? Should I toss the Borla mufflers and install Magnaflow mufflers and leave the muffler forward components from the Borla system intact?

Thanks in Advance.

 

[WNH]

Suggestion: Try putting sound deadener under the rear carpet area {Dynomat}.

It will take the sting out the resonance.

 

[JimC]

Wayne: Thanks for the cool suggestion. Tomorrow I'll investigate if the material can be added under the carpet without detracting from the appearance too much. I'm also going to look into modifying the Borla Mufflers to accept the stock LT1 tips. That may add the desired restriction to help with the resonance as well as improve the look without breaking the bank.

Regards, JC.

 

[P-ColaVette]

Another Ave of approach...

Hello Jim C

Welcome to the CAC ! If you can't get the resonance toned down to your liking with the Borla system, what I did on my '96 LT4 was run the stock exhaust piping, minus the factory resonator, and a set of DynoMax UltraFlow mufflers. There was no resonance at all with that set-up, and the sound was incredible. Just ask nyerngaII (Len) about the sound of my old C4. As far as performance, with that exhaust set-up, my car would run consistent 13.1's at 105mph in the 1/4.



Steve.

PS, I am running Borla on my C5, and I love it !

 

[JEFNLSA]

FYI...I had to bend the hanger brackets on a vise in order to get my mufflers to suck up under the car. That seemed to help alot although they still do not suck up like the originals did. I haven't seen any aftermarkets that do.

 

[JimC]

All super ideas. This weekend I'm going to install the Borla recommended flow restrictors and see if that changes the resonant dynamics of the exhaust system. I'll let you guys know what happends. It's best to give it a shot before pulling the system apart and changing components.

Jefnlsa,

I take it your talking about bending the brackets on the muffler? Good idea. I was simply going to weld over the existing bolt hole in the mount on each muffler and then punch a new one, lower, so that the muffler is pulled up a bit more when mounted.

Work and new baby are taking up most of my spare time these days, but will snap some photos and share as soon as possible.

Thanks for all the neat advice.

 

[JEFNLSA]

.

Jefnlsa,

I take it your talking about bending the brackets on the muffler? Good idea. I was simply going to weld over the existing bolt hole in the mount on each muffler and then punch a new one, lower, so that the muffler is pulled up a bit more when mounted.

Jim,
Actually I was referring to the new brackets that came w/ my Magnaflows that connect to the brackets on the mufflers. The part that slides into the frame. I 86'ed the OEM brackets and used the new ones from Magnaflow. First I snipped a bit off the end of the part that bolts to the muffler and then I bent the other end on a vise (so the hanger bracket was now curved) which in turn pulled the muffler up. Hope that makes it a little more clear.

Congrats on the "new addition" (baby ) to the family. As in my house...the Vette does not always come 1st.

Jeff

 

[PLRX]

Flowmaster drove me crazy, I put Dynomax, they are much better

 

[jssc4]

Where did the term "Cat-Back " come from.
Sorry for my ignorance,
jss

 

[PLRX]

A Cat-Back system bolts on after the catalysts, You may replace the factory exhaust system (after cats) with an aftermarket one (Borla, Corsa, Flowmaster, Magnaflow etc etc); they also sell aftermarket catalysts, they bolt to the manifold and; they also sell headers, the bolt on to the heads. A big happy Exhaust family I hope this helps you

 

[jssc4]

Thanks for the explanation.
jss

A Cat-Back system bolts on after the catalysts, You may replace the factory exhaust system (after cats) with an aftermarket one (Borla, Corsa, Flowmaster, Magnaflow etc etc); they also sell aftermarket catalysts, they bolt to the manifold and; they also sell headers, the bolt on to the heads. A big happy Exhaust family I hope this helps you

 

[WhalePirot]

Suggestion: Try putting sound deadener under the rear carpet area {Dynomat}.

I am just about to do this, but ordered FatMat (half the cost and deadening specs are comparable. Brown Bread is another (CDN) brand. All are quite thin layered slabs of foil and tar-paper-like stuff. I was told that 50 square feet will do the Vette, but I will double it in the rear. (Film at 11.) Weight will increase about 30#; similar to what I am losing in girth.

I like the sound and performance of my Flowmasters and found that the resonance only bothersome when the top is not stored in the car, which is quite rare.

CAT is short for catalytic converter. -back is downstream from it.

 

[JimC]

I called Borla yesterday and let them know that I was going to pay to have the flow restrictors installed and asked them if this was still the solution. They said to go for it, and that it was the solution, but not to expect too much. Well, I spent $60 for the install and there was no change in the resonance. Bummers.

WhalePirot: Good luck to you. Let us know how it turns out.

Here is a photo of the restrictors (venturies) that Borla sent. They are installed just rear of the mid-muffler.

 

[SSTibet]

CAT is short for catalytic converter. -back is downstream from it.

I read some where CATBACK is named after the back of an angry, growling cat because some of the pipes look like it. :L

Your explanation makes much more sense...

 

[WNH]

I am just about to do this, but ordered FatMat (half the cost and deadening specs are comparable. Brown Bread is another (CDN) brand. All are quite thin layered slabs of foil and tar-paper-like stuff. I was told that 50 square feet will do the Vette, but I will double it in the rear. (Film at 11.) Weight will increase about 30#; similar to what I am losing in girth.

I ordered FatMat too and sent it back because it stunk like tar.
This, despite their claims that its 'oderless'.

If yours smells like tar, do not install it, the smell will never go away, and once installed, its hard to remove.

 

[WhalePirot]

I ordered FatMat too and sent it back because it stunk like tar. This, despite their claims that its 'oderless'.

If yours smells like tar, do not install it, the smell will never go away, and once installed, its hard to remove.

Yikes. Thanks, I may refuse delivery tomorrow.