Which Cat ByPass would you choose from these 3?

[seafood10]

So my 87 Targa is running SO well now that I had Steve Wong repair the idle circuit on my DME and I also installed a new ICV so am now looking for a cat bypass to match up with his chip that I purchased from him as well.,
I have to say that working with Steve is a real treat, he wiill spend the time explaining everything and never once tried to hurry me off the phone, great guy with a solid product.

Back to the issue at hand, I wanted to get some feedback regarding these 3 different test pipes that range in price from $279 to $675.

I'm a weekend warrior and don't need the latest and the greatest, just a solid pipe that may eek out a couple of HP if possible and sound great at the same time.

I punched out the cat from my 84 years ago and haven't tried it because I just feel that the gasses would get 'confused' in there and feel it may hamper performance, feedback is welcome.

Here are the 3, they start at the Racing Dynamics pipe for $279 then the Dansk for $425 and finally the Fabspeed Euro for $675.

Here are the links respectively and look forward to hearing any feedback regarding not only these pipes but any others out there, maybe you have one for sale?

Appreciate it!!

https://www.racdyn-usa.com/PROD/911+08+00+200.html

https://www.pelicanparts.com/More_Info/991012256.htm?pn=99-1012-256-M350&SVSVSI=591&DID=17924

https://www.vividracing.com/fabspeed-european-premuffler-race-pipe-with-gaskets-porsche-911-carrera-19761989-p-25299.html

[darrin]

I'd personally go for a premuffler (similar to what Porsche did on euro models), like this one https://mkexhaust.com/pre-muffler/ - or if you want to eek out a few more HP and sound even better, an active premuffler -- https://mkexhaust.com/active-exhaust-with-pre-muffler/
.

[proporsche]

or you can just use rosepassion same thing not shiny for 225 or less bucks here is the number P71282
Ivan

[mike sampsel]

I prefer the active sport cat, lot less smelly, and maybe just as much oomph, as it starts to bypass the muffler at full throttle.

Look up Brian, Crotchety Old "guy" he sells them, likely a lot more costly than the ones you listed.
Oh well ...

https://mkexhaust.com/Active-Exhaust-with-Sport-Cat/

[FA-18C]

I just pulled the trigger on the stainless Dansk - euro version built to same spec from RP. Figured for the price of stainless over painted it is a wash since I would have had is media blasted and cerokoted.

[josephvman]

I went with an M&K cat bypass pipe and their sport muffler, and Steve Wong matched his chip tune to this setup. Sounds great and a noticeable improvement in performance.

[Cevan]

I have the M&K cat bypass and muffler. They are extremely well made and sound good. And way lighter than stock.

[seafood10]

I wanted to thank everyone for their feedback, going to look at the additional options that you provided me and see how they may work out for me.

[Antomero]

Scart premuffler and supersound exhaust)

[RarlyL8]

Here's a promo ad we put together for Excellence a few years back. It highlights the unique attributes of our M60 Bypass family of products.



The Active Exhaust and Sport Muffler combo is great if you want to squeeze out every last HP while using the OE exchangers.

[famoroso]

I accidentally posted this in the Oil Cooled Engine for sale thread yesterday. D'oh! Anywho...

]I've run quite a few different versions over the years, including very positive dyno tune results with a hollow factory cat.

They're all pretty good and they all improve sound and breathing. The factory pre-muffler offers a beefy flange, perfect fitment and stealthy factory appearance.

The Dansk pre-muffler is essentially an aftermarket copy thereof (available in mild steel or SS) and is easier to source. I was super happy with Dansk SS pre-muffler and 84mm SS Dansk Sport muffler on my '88.

The M&K stuff is exceedingly well built and, as a bonus, lighter weight. The valved M&K active unit is unique in that it allows for sound & flow variability depending on load / vacuum / throttle position.

Unless you're trying to eeke out the last 0.5hp, they'll all flow better than a cat and they'll definitely flow better than a damaged cat...
https://youtu.be/CNDkAZcb8AE

Below: SS Dansk, Factory, Hollow, Hollow, Stock '89 cat (less than 1k miles), M&K Active...

[/QUOTE]

[proporsche]

Nice collection Amoroso..mine is none of the above just a solid strait pipe...it makes nice deep sound..

Ivan

[Tinkerer]

Originally Posted by proporsche

Nice collection Amoroso..mine is none of the above just a solid strait pipe...it makes nice deep sound..

Ivan

Straight pipe to a factory muffler?

[darrin]

Originally Posted by Tinkerer

Straight pipe to a factory muffler?

That's why they call(ed) them "test pipes" -- one would buy it it to "test" whether a catalytic converter was "clogged" (wink wink)

[Tinkerer]

Originally Posted by darrin

That's why they call(ed) them "test pipes" -- one would buy it it to "test" whether a catalytic converter was "clogged" (wink wink)

Asking about using the factory muffler with a straight bypass. I’m ready to install the Dansk unit and have read that a straight pipe will blow out the muffler and didn’t plan for that.

[dutchcrunch]

A pre-muffler is nice. motor runs a lot cooler. not that much louder at all .


now for the unsaid, the cat cleans up the fumes quite well, so without the fumes can be a little much in bumper to bumper traffic. just saying.

I have a Scart, i love it, its a premuffler not a test pipe. if i did not get a sweet deal on my Scart, i would have got the M&K premuffler. plus if you buy it and resell it for a little loss you can sell it real fast, they dont last when reselling.

when i had the factory cat that was in good condition and i would shut the engine off it would make that tick sound like when something is hot and its cooling. but when the premuffler is on it never does that. I think a cat does not belong on an air cooled engine.

[proporsche]

Originally Posted by Tinkerer

Straight pipe to a factory muffler?

Yes..
Ivan