My friend's recently purchased '85 euro 5-speed had seemed a bit slow to me, and when we changed out the exhaust system yesterday I found out why. The federalized exhaust was an oem Porsche y pipe (with cat) welded to the remaining rear exhaust, but there was no smog pump added and no O2 sensor either (pic #1). The piece connecting the cat to rear pipes looks restricting also (pic #2). I had thought his cat was clogged, and with no smog pump getting air into the cat it probably was.
The good news is that we mounted a complete Borla system from headers back (thanks to "Old&New). It is a free flowing system that has a muffler where the cat was, and a rear muffler as well. This thing hauls *** now, and runs great right through 6K rpms. It sounds great too. The exhaust is probably not much dirtier because the old cat was not getting hot enough to work right anyway. I will cut the cat open to see for myself.

 

You should also check the MAF (I think that's what it is). I friend here in the detroit area thought his Euro was sluggish. We found a restrictor ring (carboard doughnut) had been placed there during federalization. Good for a few more horses.

 

Please give details on how you mounted a muffler in the cat location. I currently have a gutted cat and I am not at all pleased with the rumbling under the cabin. This sounds like a geed solution.

 

That was a complete Borla stainless system. I forgot my camera yesterday so I will have to get pics some other day. The two pipes come down from the headers and stay separate through a muffler in the cat location and exit separately in two pipes that then enter and exit a muffler in the rear next to the battery location. The mufflers were open systems that flow right through. The whole set-up was used but still very good condition and mounted right up with a little work.

 

good job, now all you have to do it reinstall km odo, remove bumperettes, steel bars in the doors, side markers etc and it'll be a euro again....
jk good job guys... and another fine example of federalisation butchering

 

Without the air pump, the cat was undoubtably plugged.

I'm happy to hear that the system found it's way onto such a fine car - 85 Euro 5-sp with 27K miles... He's a lucky guy to have had you line him up!

 

Hey Carl -

Be carefull cutting open the old cat! The stuff inside is carcinogenic and nasty enough to prevent salvage yards from selling used converters - at least the last time I was shopping for one.

GW

 

The photo is an early cat and not the larger one which that 310 hp would have needed to be more happy. We have seen far worse on some cars.

 

I'm interested in the replacement of the entire exhaust system with the Borla exhaust. Does the cat, mufflers, and other restrictive items simply get cut out and tossed? This would seem to be the least restrictive system, assuming that the Borla was properly sized and tuned for the engine. Environmental concerns aside, it seems to me that having simple exhaust system without all the Jimmy Carter stuff in there is best for the Euro, anyway. Am I in the ballpark or is my interpretation of this modification wrong? TIA !

 

I also took my Euro's exhaust off. What I difference it made. Sounds even better. There's a pic of it if you do an exhaust search.

 

Here's a shot of it assembled in my driveway. I can't wait to see it on the car... nice work Carl!

 

It really works and sounds nice. That car sounds like some kind of animal now, and seat-of-the-pants says much faster. Thanks to "Old&New".