H.F.B.

Could you post a photo of the resonator plate as mentioned in posting #16

I'm interested in a bit louder exhaust as well. If this resonator plate thing seems promising, so I will give it a try. Either remove it or drill some holes in it. Will see.

pete968/928

I would say raspy. I will try to post a clip on the weekend.

Spokayman

The B&B cat back system I bought weighs 32.8 lbs out of the box and the stock system weighed 48.4 lbs, for a weight savings of 15.6 lbs by my scales.

jsheiry

Inquired with Hanksville Hotrods about the down pipe and cat delete pipe and here was his response: You could also get your own more efficient free flowing cat if you do not want complete delete.

Merged Y-pipe: $475
Cat delete pipe with the square 4-bolt flange on the end: $395


Pricing includes shipping to the contiguous/lower 48 US.


For the 968, we use a 3" exits at the end of the Y-pipe and use 3" tube for the cat delete. Tubes and bends are made from 304SS and all welds are TIG-welded. Please let me know if you have any questions. If you would like to order, I can add a special listing or feel free to call. Thanks again! -Hank

J1NX3D

I've thrown together all the info in this thread and on google into a spreadsheet

Yogii

Great, thanks.

Now we need SOUND VISION. Love to hear what they sound like.

You should add what OEM is just for comparison sake.

-Yogii
AKA 968 Novice

H.F.B.

Ok. Some facebook research and I came across this photo.


Opened 968 resonator

Today I looked into my 968 resonator and I didn't like the idea, that the engine has to press the exhaust gas through the perforated tube and those two small oval holes.


968 resonator

So I opened the oval holes a bit and cut out some of the perforated tube.



Result: Better flow, better sound, happy PO

odurandina

you should just put a single straight through cheese grater pipe.
inside the oem triangular canister, fill it with steel wool,
Then run a big Magnaflow out the back.

H.F.B.

I don't want a raspy Fiat 131 sound. For now it's ok. My 968 is a convertible, so a moderate tone is fine.

odurandina

It won't just be LOUD & raspy...... it will be loud & howl a good bit too.
Seems we can't get much power from an inline 4 n/a without facing this conundrum.
A flowmaster in place of the Magnaflow might be a decent compromise.

.

sm

What about putting in a Y section so the large inlet can smoothly distribute air into the two smaller pipes?

H.F.B.

That's what the Facebook guy did. But I assume, this way the OEM resonator's function of sound absorption is more or less eliminated. I don't think, that the remaining perforated tube acts very much as a muffler.
In my case above, the idea was to remove most of the perforated tube, so that the exhaust gas can find its way through the enlarged oval and the triangular holes into the two small pipes. That alone should eliminate most of the former backpressure and you improve the exhaust sound too. Removing the perforated tube is a piece of cake. You just need a Dremel.

sm

I’d like to know how loud that is because it effectively is a straight pipe through the resonator. Any droning etc (I know this is a Facebook post you are referencing)?

H.F.B.

I don't know how loud it is. On my 944 I installed a straight through pipe and kept only the muffler. Result, a louder and raspy and a bit droning exhaust note.

Porsche advertised the Porsche 968 intake and exhaust system as follows: ...Fine tuning encompassed "streamlining" the engine's "internal aerodynamics" from the air intake in the new nose all the way to the new tailpipes....
..No component was overlooked in Porsche's drive to minimize power-depleting back pressure. It meant developing a new muffler and a state-of-the-art metal monolith catalytic converter, while preserving a satisfying exhaust note....

If I recall correctly, the ID of both small pipes is around 1.77inch each. The orifice of the resonator is at least 2 1/2inch. So I assume the two small pipes shouldn't be a restricton, apart from this strange perforated tube in front of this two holed plate.
The more a muffler flows, the better. But once all the flow and therefore potential (restricted) engine power is unlocked, further exhaust flow won't produce any benefits in power. But if not good for power, it may be good for more noise.

odurandina

i would part ways with the resonator/968 cat back exhaust altogether.
It's heavy, albeit quiet. But mostly it's restrictive junk.
DId i mention heavy?
*The very-heavy 968 exhaust is there to handle the earthquake-like
vibrations caused by the huge crank and worn down motor mounts.
To anyone who hasn't beheld a complete 968 exhaust in their arms:
just wait til you have one out of the car.

There are wonderful 4 inch resonators out there. Or go even bigger
w/ a long, 5 inch circular resonator as well.
One or even (two) slightly shorter resonators in series is also good,
as i am doing with my V8: two resonators, & the big Magnaflow out the back.

i had given to TPC-Texas, 2 big Borla resonators to install up in there,
with ample room to be able to do so.
i had thought to bang them into "triangularish" forms, then forgot to do it.
but they mysteriously [disappeared], and 2 smaller cheapo ones
appeared in their place.
i had been thinking to reorder the same 2 larger Borla units, and run them.

but i found these nice, straight through "968-style" triangular's
https://cortekexhaust.com/pages/mufflers

i may eventually get one of these in 3 1/2" X 22"
to make the V8 sound even quieter & cleaner.


edit to clarify previous post: