Muffler modification

[WLS Ruby 93]

I am trying a muffler modification which is new territory for me and hopefully it will work out.
The premise is that if the mufflers are opened up, some internal changes made and then resealed that the exhaust gas flow will increase and hopefully give better performance and maybe even get a little more rumble from the system.
The attached pictures show what I have done so far.
Create a steady rest using two "Workmates".
http://www.corvetteactioncenter.com...aust-modification-picture2433-steady-rest.jpg



Outline drawn for the cutout on the bottom side of the mufflers.
http://www.corvetteactioncenter.com...aust-modification-picture2432-cut-outline.jpg



Using an angle grinder with a cutoff blade, cut the section outlined. Notice the support bands come free be sure to index them for the refit.
http://www.corvetteactioncenter.com...ust-modification-picture2434-band-removal.jpg



Drill out the spot welds which holds the wall to two baffles on the inside. Remove the cut panel.
http://www.corvetteactioncenter.com...fication-picture2435-drill-out-spot-welds.jpg



The inside revealed. what we have there is the inlet pipe on the right with perforations leading through two baffles but not a continuous pipe (notice the space between the baffles), into a chamber and two outlet pipes with perforations that are wrapped in steel wool. The mod is to cut two 2 inch holes on the solid baffle to allow the gasses to escape directly through the exit pipes from the large chamber.
http://www.corvetteactioncenter.com...modification-picture2436-muffler-interior.jpg



My next move is to reseal them by welding and give them a try. The only thing I couldn't do in my amateur work shop was to cut the holes in the baffle. I brought the mufflers to a local metal shop and for $38 the guys plasma cut the holes for me.
I will record the sound difference between the unmodified stock setup and the modified mufflers which some how I'll get posted so that others can hear the difference if any. Then I will be watching the performance and the gas mileage to see if there is any detectable difference.
This may take some time since Christmas is rapidly approaching and I have other things to do. This at least gives everyone a "Look/see" on the inside of C5 mufflers.
Also, this is a second set of mufflers to experiment with my stock set will remain of the car until the swap.
More pictures to follow, I hope these pictures work out OK.

Keep 'em rollin' :W
Bill

 

[WLS Ruby 93]

Modified mufflers final step

I need some guidance at this point.
I have the modified mufflers sealed up and pianted with high temp paint. Now for the removal of the unmodified stock mufflers so I can put in the mods.
I will be working on a four post lift so do I have to drop the rear anti-sway bar to remove/install the muffler sets?
If the rear bar has to be removed is it under tension when the car is sitting normally, (Not jacked up)? If needed any hints on sway bar removal will be appreciated.
I will post the final steps to the job when I finish.
Thanks for the help.

Keep 'em rollin' :W
Bill

 

[Hib Halverson]

You're going to find that the car probably will be annoying in it's sound quality and loudness with the mods to the stock mufflers.

If you wanted more "rumble" but without any annoying resonnance or unattractive sound, you should have simply bolted on an 01-04 Z06 exhaust or gone aftermarket, say...Flowmaster or CORSA.

As for the rear stabilizer bar, removal is straight forward and the instructions are in the Factory Service Manual. In short, you unbolt the links from the control arms then remove the u-brackets holding the mounts then pull off the bar.

 

[WLS Ruby 93]

Got it!

Hib,

Thanks for the reply.

I noticed that if I roll the car as far back as possible on the lift it leaves the tail end hanging over for easier access.

I also found a website, (Chevrolet Corvette C5 Round Outlets Photo), which said to unbolt the stabilizer bar brackets from the cross member and drop the bar out of the way which worked fine.

Then I just now swapped out the mufflers and started it up; I can't detect any difference in the sound tone or volume. As soon as I clean up the barn I will take her out for a spin and see if there is a detectable sound difference upon acceleration and at highway speeds.

Also, over the next few days if the weather is good I will see if there is a noticeable performance and/or gas mileage difference.

Bill

"Always be willing to learn something new"

 

[6 Shooter]

Interesting - I think when my next exhaust system will be the Corsa Extremes...

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C5 Corsa Extreme Exhaust System​

 

[6 Shooter]

Bill - When did ya sell your Ruby?

 

[WLS Ruby 93]

Ruby and Scarlett

Shooter,

I sold my Ruby during the first week of February 2009. I traded my 1988 Allante and the Ruby for a 1998 TRC Coupe, (AKA Scarlett).
The pictures of your Ruby are absolutely drop dead gorgeous they are beautiful cars.
I needed to get down to one hobby car plus I was looking ahead a few years concerning entry/exit issues of a Ruby. I made a deal with a used Corvette dealer here in VA. It wasn't quite an even trade but I laid out very little cash; he came and picked my cars and dropped off the Vette all in the same day. The one way trip to his dealership from my house is 105 miles so I was very happy.

Also, I just took the Vette out for a 40 mile run (Same as yesterday with stock mufflers for comparison), to hear/feel the difference in the modified mufflers today and I noticed a few things;
1. The car ran cooler 190-92 degrees instead of 194-196. The outside temp was the same both days.
2. Noticed a little more resonance at 65 mph than before but not annoying.
3. A little more rumble at idle and at rev-ing but not very noticeable.
4. MPG increased 1.5-2 miles for an average of 27.9 over 25-26 from yesterday. This could be unreliable so I will watch the mpg numbers closely over the next few weeks and report back.
5. I'm not sure if there was any real performance difference that I could detect.

This was a great winter project that I have been wanting to try.

Life's a highway enjoy the ride.
Keep 'em rollin' :W

Bill

 

[6 Shooter]

Bill - Here's another winter project for ya...

5. I'm not sure if there was any real performance difference that I could detect.

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C5 Supercharger - Tech Article Corvette Fever ​

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[WLS Ruby 93]

Gitty-up

Shooter,

Now that will kick it up a notch or two not to mention putting a big dent in my wallet.

Maybe I could out drag Jay Leno in his jet car with that pumper.

Yeeeee---HA!

Keep 'em rollin' :W
Bill

 

[Toms007]

The way I see it Bill, is you don't have much invested in your experiment, why not try? If you come up with something that works, it might save people some $$$$. Keep us posted. That huffer that D shows would definitely put a few more horses to the ground, and like you said and big dent in the wallet.

 

[Hib Halverson]

(snip)

2. Noticed a little more resonance at 65 mph than before but not annoying.
3. A little more rumble at idle and at rev-ing but not very noticeable.
4. MPG increased 1.5-2 miles for an average of 27.9 over 25-26 from yesterday. This could be unreliable so I will watch the mpg numbers closely over the next few weeks and report back.
5. I'm not sure if there was any real performance difference that I could detect.

"Annoying" is mainly a subjective term.

I think that "modified" stock mufflers often make an annoying resonance but, others may feel differently based on 1) their hearing, 2) what kind of exhaust sound they feel is "attractive" and 3) the specific changes made to the OE mufflers. For instance...it seems that "WLS Ruby 93's" changes to the C5 muffler internals might have not had as much an impact on resonance as I predicted but, in the "old days" many tried to modify the early C4, dual outlet mufflers by drilling out the blocked second tailpipe and were disappointed by the resonance and the nasty-sounding exhaust.

I maintain that the most economical exhaust upgrade for a stock or near-stock C5 with an LS1 is the 01-04 Z06 system. They are often seen on eBay or Craig's list as "takeoffs" for as little as 400 bucks. For that you get a little better sound, a little better performance and a decrease in weight.

 

[BigJimZ16]

"Annoying" is mainly a subjective term.

I think that "modified" stock mufflers often make an annoying resonance but, others may feel differently based on 1) their hearing, 2) what kind of exhaust sound they feel is "attractive" and 3) the specific changes made to the OE mufflers. For instance...it seems that "WLS Ruby 93's" changes to the C5 muffler internals might have not had as much an impact on resonance as I predicted but, in the "old days" many tried to modify the early C4, dual outlet mufflers by drilling out the blocked second tailpipe and were disappointed by the resonance and the nasty-sounding exhaust.

I maintain that the most economical exhaust upgrade for a stock or near-stock C5 with an LS1 is the 01-04 Z06 system. They are often seen on eBay or Craig's list as "takeoffs" for as little as 400 bucks. For that you get a little better sound, a little better performance and a decrease in weight.

I'm in total agreement with Hib... The Z06 exhaust system is real hard to beat from both a value and performance standpoint. Oh yah, a perfect (factory grade) fit!!

 

[WLS Ruby 93]

Mufflers

Jim,

If I get to "Corvettes at Carlisle" this August I might pick up a set of Z06 mufflers and give them a try if they are cheap enough.

Keep 'em rollin' :W

Bill

 

[WLS Ruby 93]

Modification complete

I'm not sure if these pictures will show but here goes.

Final pictures of the muffler modification;


View attachment 21714

View attachment 21715

View attachment 21716

Once the cutout sectiuon was welded back into place I sealed the seam with permatex muffler repair putty then let it cure for 24 hours and then I painted the muffler with high temperature BBQ grill paint. The paint dried 24 hours then I installed the mufflers and took the car out for a ride to cure the paint.

I would only reccommend this mod to anyone who wants an indoor winter project to do because from what you all have said it sounds like a set of Z06 mufflers would produce the same or very similar results.

I have driven about 80 miles over the last two days and mpg seems to be about the same so far.

At least now we all know what the inside of the C5 mufflers look like.

Keep 'em rollin' :W
Bill

 

[VETTEX2]

you can pick up Z06 Ti mufflers usually for 400 or less

 

[ernestD]

seems like a lot of work for not much result-stock c5's are much too quiet, i would think re-welded spots would rust.GM made them for a reason,just like the stock air box.I read somewhere ol Dave didn't like noise!Boo!Tons of beautiful polished units out there,why bother?

 

[Toms007]

Remember, 'ol Dave came from Cadillac........nuff said.

 

[WLS Ruby 93]

To know

Ernest,

Sometimes the need to know the answer to a "What if" out ways the practical and now we all know, I don't mind sharing.

Always be willing to learn something new.

Enjoy your ride.
Keep 'em rollin' :W

Bill

 

[ernestD]

I did not mean to knock you,it just seemed like a lot of work. i've looked a tpictures of the internals of mufflers and all that baffeling.Remember GM isn't going to give you a freebe,but if you can open something up-great! I have read a lot of good tips on this site.

 

[WLS Ruby 93]

To know

Ernest,

Not to worry, no offense taken.

This is a great web site and all of us are willing to share our projects and thoughts for the benefit of everyone.

Have fun and enjoy, spring is coming soon, (I hope).

Keep 'em rollin' :W
Bill