Kurttama

I have a 93 RSA, want to do a 2nd muff bypass. Any recommendations on which brand to get. Fabspeed is $375 there's others for much less. Appreciate any recommendations.

Peteinjp

Check Dansk. I think it’s a much lower price on it. We typically call it a “secondary bypass” so you might use those search terms to look for it.

Pete

911PERVY

Search "G Pipe"

911Jetta

I’ve had both. One car with a primary bypass for the more traditional cup car sound, and another with a secondary like you are interested in.

Be aware there are different secondary bypass. They differ in length, and that effects the sound/tone. Originally, I wasn’t attracted to the sound of my friend’s cars with the shorter “g-pipe”, too low, woofy (sp?), Harley sounding... then my second car came with a secondary installed... but it sounded different?? Turns out the length has a large effect on the sound. I have what’s called a swan’s neck or “j-pipe”. It has that deep sound, but not Harley or Subi at all. Now I prefer this 100% over a g pipe and has a much better, meaner sound than a primary, which I used to love, but sounds weaker, and tinny in comparison. J pipe all the way. Sounds so good on cold start up, it mean really good for a 964, then really trashes in the cabin at 3,000, gruff at 4000, and starts roaring at 5000, then screams at 6000.

adding a fab speed design cat bypass makes everything 10% louder, but so, so much more mechanical sounding (also gets rid of the heat shield which holds back a lot on mechanical lifter music).

Then drill you air box ($0), for extra sound at 4,000+ and WOT. Checkout some of my posts on it where I explain things better... (on phone now).

The best, cheapest way to get all the sound out of a 964.

Fabspeed Motorsport

Happy to give you our Rennlist discount!

Feel free to use code: John5 at checkout

911Jetta

John,
Thank you for chiming in, helps having an expert join the conversation. Takes these forum threads to the next level!

Can you speak to my comment and experience above regarding the length of the G-pipe vrs. J-pipe. Forum member have often mentioned their preferences in different threads, but usually is a personal preference, and most people aren't aware that there are secondary options. People default to the G pipe without really knowing why other than they chose that option over a primary bypass, but that's another decision all together.

Why is there a a difference in sound/tone and even volume? Some of that might be obvious, but a more technical explanation would be helpful.
Has Fabspeed tested different variations and came to a conclusion that a G pipe is best?
Was simplicity and cost the final determinate? As, a J pipe construction and the supporting brackets definitely create a more complex product?
Would Fabspeedbe interested in creating a version of a J pipe?

Thanks in advance for answering these questions.

BTW, your cat bypass is very well made and looks like a lot of design/performance consideration went into that, verses just copying a standard design. I've put 3 on various cars over the years.

Fabspeed Motorsport

Happy to help you out!

Might need a little more clarity on your terminology.

G Pipe = Secondary Muffler Bypass?
J Pipe = Primary Muffler Bypass?

Providing the assumption above is correct - Primary and Secondary mufflers BOTH offer sound attenuation. The Primary is larger and offers more muffling, whereas the Secondary is smaller and muffles less. So by replacing those sections with straight pipe, you can alter the sound accordingly - Primary Muffler Bypass being a more considerable departure from stock than Secondary Muffler Delete.

Let me know if this helps!

Cheers, John

Sirenty

g-pipe is right.

J pipe is usually this. Also called long g-pipe. Or maybe medium since I think a longer g-pipe has been posted that goes all the way back to the bracket.

Fabspeed Motorsport

So the JPipe you're referring to is also just a longer version of the G-pipe aka Secondary muffler bypass?

Want to make sure I give you the highest quality recommendation!

911PERVY

G pipe is 2nd muffler bypass short, its the shape of a G

J pipe is 2nd muffler bypass long, its in the shape of a J

Kinda thought a specialist might have known this.........................

Fabspeed Motorsport

The terminology you are using for that specific product is only really being used by one of our many competitors, I apologize for seeking clarity so that I may better assist you.

There is no real change between those two bypass pipes, they will have the same effect. I agree that it is most likely all personal preference as there is no real engineering change. We have never had a car equipped with the FVD setup, if you have one and are in the area, I encourage you to come by so we can put it on the dyno.

Furthermore, We refer to our Primary muffler bypass as a 'J' Pipe, hence my prior response regarding the differences.

Would love to hear your take on the variability!

mperez

there is also the "Swan's Neck" secondary muffler bypass pipe, no affiliation.



PORSCHE 964 Col de Cygne - Swan's neck SCART - Bing video

911PERVY

Thats what is known as a J pipe version

JohnK964

I have the swans neck it has the bracket that mounts where the back of secondary mounted. I’ve never heard it out side the car but inside the car pretty quite at low rpm as the revs climb she starts to reall howl. I like it 😎👍

mperez

isn't the cat bypass pipe is what you call the j pipe?