fredb

Is it a wife's tale that without a muffler you can damage your engine?
I'm thinking of removing the muffler in favor of the FABSPEED 911 Muffler Bypass Pipe. It's just a straight pipe.
Any truth that you can burn a valve or damage the engine without the proper back pressure created by a muffler?
My Cat is cleaned out. So I suspect it will be louder!!
Thanks for the info and advice!!

Chris M.

I run the Fabspeed bypass pipe but with a stock cat. It is loud but tolerable. Running the muffler bypass along with a cat bypass is VERY loud, as in earplugs required loud. I wouldn't recommend it for a street car. You'll be embarassed to take it out of your driveway.
As far as it damaging the engine, I've never heard of this. There are plenty of 911 race cars out there with open headers and little to no muffling.

84_Carrera

Fred, take a swing south this weekend if you like, join us in Sandwich MA for the Sandwich to P-Town cruise / lunch.

My 84 Cab w/ Fabspeed Cat Bypass & Fabspeed Muffler Bypass will be there wather permitting, and you can see / hear the setup 1st hand. It IS loud. A recent visit from a 997 owner compared it to the Miss Budweiser style hydroplane racers.

Or, if you can't make it that far south, meet me somewhere between uh, maybe the MA Pike & NH Line. I'm always up for a reason to drive.

fredb

Ok here it is!!
Without a CAT, the FABSPEED bypass pipe is tooooooooo loud.
My wife thought there explosion in the garage!!!
Anyone want to buy it?? Half price?

old man neri

You selling the muffler bypass or the cat bypass?

fredb

I'm too busy, but thanks for the offer.
I drive a 1988 930 on the street!!!
The 1984 is track only and will be at NHIS this up coming Wednesday (21st) with NER PCA.
Have a good ride!!

spence88mph

save it for trackdays, it wont sound half as loud in an open area and add a few more hp and drop a few pounds.

fredb

I paid $60 plus shipping.
To Canada, $40 total
paypal fredb@remax.net

84_Carrera

Fred, from experience, NHIS & Lime Rock will black flag you with that setup unless you've got a rare unmuffled day. You can try with the turn-down tip they usually include with the dump tip, but not likely to help much.

I run an M&K 1-in / 1-out muffler normally, but annually I get the bug to run the dump tip for awhile.

old man neri

Done!

fredb

Would never meet NHIS, Lime or Calabogie!!
If the Candian sends me money, it is his.
I suspect with turn down on it and a CAT in place it might meet DB.
But, I run Control for NCR PCA and don't need the aggravation.

old man neri

Ya, the Canadian had PM'd you.....

Money in your account regardless.

KeithC2Turto

YES, YOU CAN DAMMAGE YOUR MOTOR!

Modifing the muffler increases air flow. The stock Air-Flow-Meter runs out of fidelity just after 5k rpms. Thus, it is possable to run to lean above 5K RPMs.

A few run ups around town it likely to not hurt the motor.

With (or without) any mods, concider having you car dyno's to check the Air/Fuel ratios. Have them, unplug your and remove your O2. Then put there wide band in its place.

If you should maintain at least 13/1 to near red-line. If not, you can try using the Fuel quality switch on the CPU to get it in line. Or, have a custom chip burned.

Stock chips usally have enough fuel for some mods but varitions in components like the fuel presure reg, calabration of the AFM, dirty fuel filter etc creats potental for problems.

If one is going to track a 3.2, haveing the A/F's checked is cheep insurance
($125).

I was just at a shop I used and they recently had such a failure.

fredb

make sense, thank you.
The straight pipe was too loud, so stock is on.
Thank You

Ed Hughes

I'd say that most of those muffler bypasses that Fabspeed sells as new, immediately end up being sold as used by the buyers.