How many have cat bypass and muffler bypass together?

[84_Carrera]

I go between the Fabspeed Pre-Muffler w/ Muffler Bypass dump tip, and the Pre-Muffler with the M&K 1-in / 1-out. It's NOTICEABLY louder than the pre-muffler with a normal Bursch as well.

I love the TONE of the bypass/bypass, but not the volume of the sound - it's a bit loud when leaving the house before 8am. Harley guys do respect you though...

[3.2 CAB]

When I had the factory, stock muffler off of my car, when I was doing some testing and development of some new tensioner replacement tools, I had to run the engine with the chain covers removed, but the oil lines connected, and I also had two different exhaust systems that I had made up for the testing. One was just a correctly bent exhaust pipe that was connected directly to the CAT and extended just below and past the rear roll pan and bumper. The other was very similar, except the exhaust went through a muffler. Even when running the engine with just the "straight" pipe, the exhaust was not as loud as I had thought it would be. It actually made less noise that some of the ricer fart pipes do. The tone was also pleasant, not harsh. The testing with the "test muffler" seemed just like having the stock muffler on it. A standard 2-1/2" header collector adapter fits the stock 3.2 CAT perfectly, which would lend itself to be fitted with various exhaust test pipes/muffler combinations, till you find just the right sound you are looking for. Just my $0.03

[glewis80SC]

I run that setup on my 80SC mostly for the track. It is loud but i LOVE the way it sounds, especially around 4800-5200rpm.
Driving around the streets could get annoying after a bit, the switch back to the stock muffler takes about 15 minutes. I don't have any concrete numbers on power difference but the car has more torque with the bypass, plus the weight savings is great for the track.
This is it rounding turn 1 at Willow Springs you can here the car accelerate into turn two.

[SCWDP911]

Originally Posted by glewis80SC

This is it rounding turn 1 at Willow Springs you can here the car accelerate into turn two>

Sounds great!

[oregonmon]

I wouldn't mind you living near me just so I could listen to you driving around. But I just gotta laugh because it does sound so loud.

Originally Posted by glewis80SC

I run that setup on my 80SC mostly for the track. It is loud but i LOVE the way it sounds, especially around 4800-5200rpm.
Driving around the streets could get annoying after a bit, the switch back to the stock muffler takes about 15 minutes. I don't have any concrete numbers on power difference but the car has more torque with the bypass, plus the weight savings is great for the track.
This is it rounding turn 1 at Willow Springs you can here the car accelerate into turn two.

[grobious911]

Originally Posted by oregonmon

Grobius911, how long have you had that setup and also do you have any clips of it so we can hear?

Ive been running that setup since last october, I dont have any sound clips though sorry

[oregonmon]

Well I'm about 1 1/2 hours north of you in Silverton. Maybe I have heard you.
So your saying it's not too loud, huh? What did you drive before, a semi?

[oregonmon]

Wait grobios! I read that you were running stock cat and muffler bypass right? I think that clip is cat and muffler bypass.
Am I getting this clear or not.

[grobious911]

Originally Posted by oregonmon

Wait grobios! I read that you were running stock cat and muffler bypass right? I think that clip is cat and muffler bypass.
Am I getting this clear or not.

Yeah Im running the stock cat and the fabspeed muffler bypass, and its just perfect as far as loudness goes

[84_Carrera]

Yep, I ran the Fabspeed Bypass / Bypass setup at an unmuffled track day at Lime Rock (does NOT make it under the 95db limit of most of the tracks I frequent), and all of the Vette guys in my run group were approaching me after the runs telling me how AWESOME the car sounded out there (as they blew by me on the straights).

[gtc]

Call me crazy, but I think my M&K 1-in 2-out is louder with the cat still on the car. When I paired it with the fabspeed cat bypass, the noise seemed to smooth out a bit.

[rtoms]

i have catbypas and muff bypass, loud but i love it, heck its a 911 your gonna get noticed
http://youtube.com/watch?v=nl9rleur9nA dont mind brakelight out

[Gator]

I thought I needed a little more noise so I installed the muffler bypass and left the cat on. Took it off and installed the muffler again in about three days. OMG it was loud!!! I have flowmaster super 50's on my pickup and have had glass packs on my 64 vette (440hp) those were quiet compared to this. It might be great for the track but too loud for a daily driver for me.

[oregonmon]

Originally Posted by grobious911

Ive been running that setup since last october, I dont have any sound clips though sorry

Get any sound clips yet of your muffler delete?

[Won]

Take off your muffler and drive it to see what it sounds like. I drove for a day without the muffler after 2 months of downtime due to suspension rebuild. The heat wouldn't hurt anything in such a short time and probably ok in the long run as well, unless the car is stationary and idling for a long time.

The "****s and giggles" factor is high on this one. Everyone will give you a look if that's what you want. I can't imagine driving past any LEO without getting too much attention, especially if you live in places where they have even the slightest bit of concern towards "modified" cars. I was laughing my butt off for the first 10 minutes or so, then I decided to roll up the windows and put the top back on - did not make a slightest bit of difference.

For a track car it might work (if there's no noise limit at the track) but otherwise you'll want the muffler back on after a while. Even if you can "mentally" tolerate it, the sound levels should be up there borderlining long term hearing damage, physically. I play the drums in a loud band so my hearing's already half gone but boy that bit of drive without the muffler really made my ears hurt

Just try it and you'll see .

[KFC911]

I always get compliments on how my car sounds from almost everyone, from the LEO who wrote me up a couple of years ago , the early hot rod 911 guys, and just folks in general. I have a GHL 1in/1out (the REAL source of my sound), and when I replaced the cat with a Fabspeed euro premuffler (not the same the as a straight pipe/cat bypass), I didn't notice any change whatsoever in the sound, but that swap was for the performance gains. M&Ks weren't available back when I purchased my GHL, but that's probably the route I would go today...Fabspeed euro premuffler and M&K 1/1.

[charleskieffner]

oregonmon you have beat this subject to death and lost out on a hell of a deal on my ghl bypass/w/O2 sensor that was one year old.(SOLD).

heres the drill.........again.

if you have to pass emissions then your only choice is a bypass and a O2 sensor. list is 298.10 GHL from pelican and bosch sensor 144.25.

if you want heat which i would recommend in oregon let alone az then its headers w/heater boxes. or SSI's.

if yer gonna track it all the time then headers and anyones exhaust that passes decibel meters at the tracks you go to.


this is really a no brainer. and there is no way around the cost of SSI's and a new exhaust.

if you ever sell it it must pass emissions period.

in my case i do not have to go to emissions ever again in this state since its a collectible car. i do track it on occasion but most of its life its burning canyons on a public highway. i live one and half hours from flagstaff which gets lots of snow. i live at 2500 elevation and it gets colder than hell here so the heat stays for me.

i went with GHL's cuz their local, i know them personally, lifetime warranty no questions asked and their quality and the size of the pipes ID. i make more power, than BandB(quality issues) or SSI's.


sound hell i have a cab...........if any type hears it all the time its a cab. top up top down. best comparison over stock......bypass and 1in/1out GHL i had to turn my alpine up about 2 clicks to hear it better over stock..when i went w/headers/heater boxes i had to turn alpine up about 5 clicks to hear it.

at redline............well its just music.

buy a bypass from ghl their closer to oregon ie. freight. buy my 1in/1out ghl im closer freight and save a few bucks.

or break down and get the SSI's which will satisfy the concours nuts.

p.s. the amount of weight over stock or SSI's saved by me going to GHL w/heater boxes was quite abit.

dont try to install on your back at home. put it on a lift and buy the correct tools or your in for a cluster fuch like you have never experienced and you will be crying in your beer for weeks if you break a stud off. PBR blast the hell out of those nuts and barrel nuts for a week before you attempt install. even then its a HUGE CRAPSHOOT and the odds are anyones guess if they all come off in one piece !

[charleskieffner]

heres another point to ponder................

since bucks seems to be a problemo..................going with SSI's you get the value added fun of buying new oil lines to fit and the excruciating fun of replacing oil lines without spilling a drop. good luck???

my suggestion when you do this:

plan on buying also new valve cover gaskets,new nuts,new washers, and feeler gauges w/extra tips. loctite lil screw on feelers so you dont loose them(more crying in beer i assure you).

adjust your valves. why???? because its a hell of alot(did i say a hell of alot easier) to adjust your valves while exhaust system removed.

GHL system you dont need new oil lines. less bucks.

now should you go w/anyone elses ideas plan on having a tube bender, oxy/acetylene, tig welder, and a slew of other goodies to FAB a system. ie. have a full service shop in yer pocket.

looks real simple...........especially if you have ever played with V-8 headers. but truth be told.........one of the biggest pain in the ass jobs yer gonna do to your car. even if the car were new off the line from der fabriken, it would be a PITA.

also if you were to poll this goofy group of p-car owners as to FIT AND FINISH of their respective exhaust systems i would wadger my paycheck the MAJORITY did not have a trouble free experience in either removing or installing their system. angle of dangles as to bends/flanges fitting perfect all go by the day/week/employee/employee hangover rate/employee wife/g/friend relationship etc. as to QC(quality control)

remember these aint ISO 9000 speced aerospace parts.

my right flange from header to exhaust didnt mat up to muffler flange hence a nasty leak that pissed me off to no end. LIKE REALLY PISSED ME OFF!

solution.........back on lift, cut flange, and re-tig flange at correct angle, new bolts, new gaskets etc.

have BIG FUN WITH THIS! been there doned dat and glad its off my ass and given a zip code to the out basket!

[dfink]

Ooohhhh Yeahhhh.... Fabspeed bypass with 3" straight exhaust. Just got a friendly your getting close warning at the solo midiv divisionals. Came in at 92dB not really all that loud but the have a fairly low 95 dB sound restriction. I gaurantee it was the best sounding car there........

[oregonmon]

Thanks Charles for the long list of info. I am going to start a thread on my low budget temporary or deaf first exhaust change. I installed Bursch cat bypass today and should be installing Fabspeed muffler bypass Friday or Monday, whenever it's delivered.
The homeowner's association will love me! Not to worry our house is for sale anyway.