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FFCobra Craftsman
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Discussion Starter #1
Ok, just saying less offensive exhaust might be offensive to some who think the louder the better.
I have the FFR 4 into 4's and my sidepipes are uncoated. My main concern is spending the money ceramic coating the stock sidepipes with the glasspacks that will blow out in 4000-5000 miles. From what I have found there are a few solutions...Vortex cones, Car Chemistry inserts and the Lobaks. Someone posted about a homemade solution a few months back but I haven't seen any follow up.
Quieting pipes, a different fix
Has anyone actually compared these 3 approaches as far as quieting down the exhaust noise? For those of you using these could you post your thoughts and tell me about the difficulty or ease of installation. Can the Car Chemistry 3 disk be installed from the end without cutting the pipes? Thanks for any help you can offer.
 

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The Lobaks are probably your best choice. There's nothing to burn out. They're 24" long instead of 18". Someone on this forum also used Vortex cones along with Lobaks with good results. Don't know what the loss of HP was, but with all the power adders available, it would'nt take much to get a few ponies back. If your build is strictly for performance, let the glasspacks burn out and then wear ear plugs. JMHO Mike
 

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FFCobra Craftsman
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This is an idea I had a while back. Modeled it in Autocad.
First I need to finish my beast and get her on the road. Then I plan on making these up. Quiet and respectable, then pull the cable flipping the door, and you hear the animal roar. Nice to have a choice. What do you think? I've been thinking I might make them for others too.
 

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FFCobra Craftsman
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I see you have the 4 into 4s. I have shorties, and the j-pipe arrangement, so I am going to make it fit in place of the j-pipes. Obviously it won't be configured as a straight square, in and out set-up, but I can't imagine why I couldn't fit in a similar design in that space. I like the idea of starting the car and driving out of the neighborhood quietly, then when the mood hits me, let it snort. Roll into the gas station, nice sound. Oh, theres a cop. Pull the levers and back to a nice quiet old guys car.
 

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Mitch, you didn't include the chambered pipe as was used on the 63-67 Vettes. I've seen them advertised in different lengths and diameters. Not sure how quiet you're trying to get but it's another option, not to mention they're the best sounding of the lot IMHO throughout the RPM range.
Frank
 

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FFCobra Craftsman
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Discussion Starter #8
Frank, I'm not sure what Corvette fix you are talking about. Has it been discussed here?
 

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Grover,

Jim Doak is having an under car exhaust built by Dr. Gas in Salt Lake City. It looks promising. His will exit out the back and include an X pipe. It will only fit that way with the 4-link rear. Others have exited in front of the rear tires. Do a search for Doak and you will find some discussion. He will post results when it is done.

Craig
 

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had the Car Chemistry inserts and didnt like them. actually made it harder to pass sound at my racing events because it raised the pitch. also sounded wheezy. i just wear earplugs.

james
 

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Mitch,
This is what I was talking about. Chambered Exhaust Again, I don't know if this will work for you or how quiet you're trying to go but it is an alternative. Look around the site as there's a lot of good info as well as some .wav files, so you can hear what they sound like.
Frank
 

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Grover the best comparison that I could give is with the 6 different setups that I've had on my car.
Cats: mello cruise and accleration fairly quiet idle.
jpipes louder than cats esp on acceleration crisper sound.
CC 3 disc inserts in the Jpipes about as loud as cats but wheezier
4X4 loud and a real nice sound definate ear pain on accleration under boost.
4X4 with my home made inserts that you refered to above. not too loud nice sound just below the pain threshold on boost but maybe some loss of power.
CC inserts in the end of the glass packs. sounded like the car had asthma.
I tend to go between my inserts and just the open pipes mainly because I'm a power hog. I hope to get the car on the dyno in the spring with the inserts in and out to see if its losing power or I just think it is because it's quiter.
 

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Glen,

I have been thinking about something like that too. I saw an advertisement for drag dropouts that are reverse to this. The flow is normally through the mufflers, with a gate that would allow you to 'dropout' the muffler at the dragstrip.

I havent even started collecting parts yet, but thought that this would be nice for my neighbors. They already 'remind' me to mow the lawn on Sunday, if it isn't done on Saturday--not sure what they would do hearing a 400hp engine with 4 into 4 pipes every morning at 7am.

Where do you invision this box fitting? Under the car somewhere? In the engine compartment? I would like to keep as stealth as possible, but would obviously have to make some concessions.

Thanks, Trent
 

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Trent - tell them it is the lawnmower :D

I am running J pipes and plain but old side pipes. They are pretty loud, but I can get out of the neighborhood without setting off the car alarms. It took me a couple of months to get it down pat.
 

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FFCobra Craftsman
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I am going to try to make up something like I had drawn to fit in place of where my j-pipes will go. My donor had BBK shorty headers. The j-pipes are maybe 16?" long and there is actually quite a bit of room in front of the footboxes. It may be square or oval, but the main idea will be the same. Straight thru and out thru the sidepipes, and a cable pulled damper diverting the exhaust thru a baffled chamber then thru the side pipes. Should work ;) . We'll see
. Glen
 

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Larry Johnson recently converted to the Vortex/Lobak combo and is very happy with it.

Larry...mind chiming in here?
 

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No, I don't mind at all.

I have a bone stock 1995 5.0 Cobra engine, EFI.
Had the ceramic sidepipes from FFR with J-Pipes, also ceramic.

It pops on decelleration like all EFI's; "roars" on accelleration. At first it was ok; nice healthy sound. After about 3000 miles and it is getting louder, especially higher revs, I am thinking "too loud".

Then we see a solution that has promise: John Husdon Installs Lobaks. John says it is quieter, including the Vortex cones ahead of the Lobak in the collector part of the sidepipe. I think..."yes".

So we do the exact same thing. Not cheap because of the ceramic redo, welding by a pro, etc....but done, never-the-less.

Question "How is it?" The car has a healthy, tough sound..."don't mess"...ok...that is not gone. But, when the revs go up, you can still carry on a conversation with the passenger. So, there is a definate reduction in db's. How much? No idea, some guess 6.

Whatever the reduction is, I really like the sound. Not too loud; not too quiet. And it will not change because there is no glass inside to wear out.

Power? Seems the same to me so far. We'll see at PIR this year if the timeslips change.

There was a Forum discussion of this installation at Lobak Mod Done

Hope this helps.
 

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IM sorry but the whole idea of making a cobra quieter "less offensive" is like saying the mona lisa should have a smaller smile or the grand canyon is too big......its just wrong. I have a used hyundai I can sell ya, low miles good on gas and its not too "loud"
 

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IM sorry but the whole idea of making a cobra quieter "less offensive" is like saying the mona lisa should have a smaller smile or the grand canyon is too big......its just wrong.

Of course 'back-in-the-day', the vast majority of original Cobras, both small and big block had no sidepipes, only the comp cars did. So saying that a Cobra's not a Cobra unless it sets off alarms, scares dogs and children and burns your ankles (fun as that may be :D ) strikes me as simple preference, not gospel.
As far as safety, yes it's nice to be heard, it's also nice to be able to hear other cars. Driving around getting your ears blasted, or worse yet, wearing ear plugs strikes me as least as dangerous as driving a quiet car. And finally, those of us who've already damaged their hearing (anybody else enjoy Tinnitus?) don't wish to add any more ruination to them than necessary.
 
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