Installed a cat bypass - LOUD

Took a couple hours this aft to install the cat bypass that's been sitting in the garage. The car is a stock 79 SC with a Flowmaster 1 in 2 out. Initial impression is that it is now quite a bit louder (it was borderline too loud before), but the old butt dyno says there's more go fast there. It may just my my perception that it's faster, but I'll test run it some more this week. Did I mentin that it is LOUD?

[Joe Bob]

Did I mention that it is LOUD?
>>>>>>>>>>>>>>>>>>>>

Is that a BAD thing?

Replace the muffler if it is to loud or consider a Supertrapp, they have replaceable discs, or consider a sporterized banana muffler that allows for capping one or two of the three outlet ports....

[rstoll]

You'll get used to it. Enjoy!

[Adam]

Are cat-bypasses noticably louder than a Euro-premuffler?

[nostatic]

I'm sorry, did you say something? I couldn't hear...

[Jeff Alton]

What brand cat by-pass did you install?

Jeff

[ckelly]

Yes, cat-bypasses are A LOT louder than the premuffler. I initially had the stock cat, installed a Bursch by-pass and OMG, too loud. I have a Dansk single in-dual out as well, and it was just too much, I thought I was in high school again. I ordered a "euro-premuffler" from Fabspeed and it didn't fit right at all, so I returned that and ordered a Dansk Pre-Silencer (euro-premuffler). Not only is the fit perfect, but the sound is almost identical to the stock cat, maybe a little louder, but not much at all. I get a lot of compliments at DE's and other events on how nice my car sounds. I'd highly recommend the Dansk, a couple bucks more, but as I found out, much better and cheaper in the long run.

PS, Pelican can get the Dansk for you too.

Loud isn't normally bad, but I just stuck a new Eclipse/Focal system in it - now I gotta get an amp and sub to hear John Lee.

Catca, don't know what brand. It was used.

[jriera]

Mark, looking forward to 'hear' the new sounds..

Who needs a CD player!

[JavaBrewer]

To be honest I haven't noticed increased noise from my 86 with the bypass (straight pipe) but did pickup a nicer exhaust note. Not louder just better sounding. Increased performance? Maybe it's like the playing cards in your bicycle spokes...?

[Rick Lee]

My test pipe gave the car little more of a low-end growl and it's bit louder too. But I swear my stock muffler sounds so sweet, I just can't justify the expense of relacing it. Yesterday I took a middle-aged lady visitor from Germany for a spirited drive in my car and she immediately commented on how nice the exhaust note sounded. It's a little loud for long drives when you need tunes, but it's so nice on spirited fun runs.

[silverc4s]

My 73 3.2 Carrera powered Targa has a pair of bullet shaped glaspacs folded a la bursch type, and was always fairly loud in this configuration, including the stock 87 cat converter. Last weekend, I replaced the cat with a bursch bypass pipe, including the oxygen sensor. It is now really loud!!!
I know what you mean about being back in high school, ckelley...

I am not sure if it is any faster...butt dyno says yes, but the sound misleads, most likely...

[Mike Feinstein]

Clay,

Regarding your pre-muff/dual out Dansk setup...is there any resonance in the cabin (typically between 2500 and 3000, especially when accelerating)? How does it sound at high rpm under hard acceleration? How is performance overall with this setup compared to stock?

I have the Fabspeed premuffler (mine fit, fortunately), but sold my Fabspeed dual out muffler as it was just too loud for my taste.

Thanks,

Well, I just got back from lunch. Took a co-worker who had ridden in the car last week. She asked, "Is this thing louder than last time." It was loud enough that conversation was difficult.

The cat is going back on next weekend.

[jhoagg]

My experience seems similar to Dave M. and Richard L. Replacing the cat with a straight bypass pipe didn't make my 85 Euro with a stock muffler much louder (if at all). But the engine does seem to rev a bit more freely, and the exhaust note is better with a bit more growl.

[ckelly]

Mike, I don't notice any resonance at all in the car, at any rpm. Hard acceleration sounds really sweet. My DE instructor, a long time racer, also commented on how nice it sounds. As I said, I got more than a few comments at the track about how nice it sounds. To me it's the perfect balance, keeps that sweet "Porsche sound", not droney like a turbo muffler, doesn't cackle(sp) like a glass pack, and not ricey like those Honda kablaawy pipes.

As far as performance goes, my butt told me there was more low end torque than with the stock cat. Powerband seems wider too. I can sometimes bust the 275's loose coming out of corners, NEVER did that with the cat installed. I've never dyno'd the car at all, so not sure of the actual gain. I just know it makes me

[efhughes3]

Another used part for the market....

Too bad, I would have liked to hear your car with an even louder voice.

[Mike Feinstein]

Clay,

Do you have the Dansk stainless "sport" muffler, or the OEM "equivalent"? And one last question...is it any lighter than the stock muffler?

Thanks,

[ckelly]

Yes, I have the sport, polished stainless dual 80 something out, single in. I don't know on the weight factor, I would say about the same, but I didn't weigh either of them.

[Glasgow 911SC]

"Replace the muffler if it is to loud or consider a Supertrapp"

Mike
How does the supertrapp bolt up? Possible with standard H/Es?
I've only ever seen them on motorbikes.