Which Cat Bypass Pipe?
 

I am getting ready to buy a bypass pipe for my 3.2 and was wondering if there was any reason to go with a more expensive brand over OBX.

Any thoughts?

OBX CAT DELETE 75-89 PORSCHE 911 2.7L 3.0L 3.2L | eBay

I was looking for something quiet. I went with the M&K pre muffler because it does have some "muffling" properties. Along with my stock exhaust I've got a pretty quiet, low-key car.

also interested in thoughts on this

The OBX stuff usually doesn't look so nice from the inside. Their collectors/junctions are poorly made. My fabspeed was much nicer, and the M&Ks I've seen look great as well (the M&K was not available when I bought the Fabspeed). A lot of people gripe about the Fabspeed taking the O2 signal from only one cylinder bank, but I don't think it's really that big of a deal. Mine worked fine.

My previous 3.2 had a Dansk sport one in two out.

If I ran a bypass (as opposed to a premuffler) and a stock one in one out exhaust how do you think the two would compare?

I think the cat + dansk sport would be louder than a bypass + stock muffler.

I suppose it depends. I know some of the older OBX stuff wasn't as nice, but their recent stuff is quite good. And the price is more than fair. I've handled one of those OBX pipes and the quality seemed perfectly fine.

I'd personally run an OBX on my car without worry.

I have the M&K Bypass from our host, nicely made and not very expensive. My car is louder, would probably have gone with the pre-muffler if chance to do again. Ben at M&K said both were similar loudness wise so ?? why does he sell both. I went with the less expensive option.
Went in easy.

This was my preference also with a M&K one in/two out muffler. Before I had a gutted cat that sounded metallic and loud to the level that I capped the drivers side exhaust. Now run both sides open with the pre muffler, not too loud but still sporty.

I like the factory Euro premuffler.

+1

This in addition to my Flo-Pro 1in/1out muffler makes great sounds.:D

I also have an M&K per muffler with an M&K oNe-in two-out GT3 exhaust. Pretty loud but I love the rumble

M&K pre muffler and stock muffler on the 88. A little rumble and nice sound. Not too loud. But I'm an old guy and don't like loud noises anymore. And I never listen to the radio in the Porsches.

Obx
 

I bought an OBX last year and it fit with no problems and was nicely polished.
Cost $89.00. Installed a new O2 sensor.
If it doesnt last I'll re-weld it.
Hooked to a Bursch muffler and all sounds great.
I'm well pleased considering the price difference.

IHMO for what it's worth.

All this talk about bypass's - I decided I'd buy one. I then worked out I should get a proper jack support and while I'm at it a new 02....$$.

After buying all the goods and removing the Cat - I discovered the guts had been removed anyway. So the job came down to cosmetics and a fun hour tinkering with the car.

The package was wonderfully boxed - thanks PP

Some tips:
1. The Fab Speed bypass comes with gaskets and bolts/nuts - the bolts are a different hardness to OEM - not sure it matters but the length of the bolts do and 3 to 4 thread lengths to short (I'll replace the bolts when I fix the rocker gaskets/leak).
2. Remove the wheel (LR) - I didn't to start with and by the time I mucked around maneuvering myself to get a swing at some of the bolts....I simply came to the conclusion to remove the wheel anyway.
3. Consider an oil change (and rocker gasket) while your at it, with the cat out of the way things are easy to get to.

I have the following pictures.

http://forums.pelicanparts.com/uploa...1342696251.jpg
http://forums.pelicanparts.com/uploa...1342696303.jpg
http://forums.pelicanparts.com/uploa...1342696348.jpg
http://forums.pelicanparts.com/uploa...1342696386.jpg
http://forums.pelicanparts.com/uploa...1342696425.jpg
http://forums.pelicanparts.com/uploa...1342696459.jpg
http://forums.pelicanparts.com/uploa...1342696490.jpghttp://forums.pelicanparts.com/uploa...1342696580.jpg

dansk pre-muffler, stock muffler. sounds a little beefier under 2k, above it sounds like normal.

http://i15.photobucket.com/albums/a3...e/IMG_0319.jpg

The one thing I can tell you for sure is only wish We could sell our bypasses and premufflers in the $89 range. We run off of a $60 an hour scale which is way light by todays fab standards and it takes waay longer then an hour to produce a part but thats what you get when you build them by hand and TIG weld them versus stamped and MIG welded.

Same setup on mine, except my pre-muffler is an M&K. Pretty subtle sound, IMO. In fact, maybe too subtle. I'm still thinking about what might replace my stock muffler that might improve the sound but not be too loud for the neighbors and wife.

Pulling the old cat and knocking out the catalyst is a lot cheaper option. It always amazes me how much people pay for 'Porsche' exhaust systems.

A pre-muffler or bypass has the advantage of being reversible, should that ever be desired.

The cat most likely will have over 100K on it and not functioning up to standards.....I don't see a downside.

I bought OBX and am very happy with it!

I have the M&K version and it fits and it doesn't add noise. The interior is smooth and flows nicely. I had it ceramic coated to reduce heat and improve flow (same with CAT). M&K makes quality parts so you don't have to worry about fit or longevity.

Dunno, I'd consider the thread linked here to be a downside if it were me...

Borrow a cat?

heat shield????
 

I made an aluminum heat shield that mounted to the one of the flange nuts and blocks heat transfer between the bottom tube and the Bilstein.

Took maybe an hour.

Picture?

I know this has probably been covered at one point or another, but what if any difference is there in volume or quality of the sound between a euro pre-muffler and a cat bypass?

In my specific situation, I have one of Ben's 1 in, 1 out mufflers. I assume I have a euro pre-muff as my car is a European RoW car. It sounds pretty decent as it is now. Sometimes it would be nice to have a bit more volume, but idle had a nice throaty rumble. It's so difficult to tell how it sounds when you're driving though. Gotta let someone else take it for a spin and sit on the sidewalk to listen to tell for sure - not that likely... :)

from what i found most pre-mufflers have some sort of small baffles in them, i know my dansk does, vs the straight pipe of a bypass.

Which manufacturer's product you choose has to do with what you want to compromise on.
We use the best materials, best welding methods, and pay US craftsmen a decent wage to make a great product. No stamped crap, thin welds, or uneven transitions. Yes a Walmart bypass pipe will work just fine but a Porsche deserves better. And so do the US workers.
They both appreciate your support.

I got an OBX from ebay as well, looks nice, stainless, im going to install soon