bigrob

I am thinking about redoing my exhaust from the cat back. I was going to go to a reputable performance shop & have them replace the primary muffler, with maybe a magnaflow-dual in & dual out, & then run 2 pipes out the back in the appropriate area. Does this sound OK or is there anything I need to know?

Thanks!

SMTCapeCod

Someone did that with my former '85. Sounded outstanding at idle, but WOT was a matter of taste. These cars are very loud compared with many others, I assume because perhaps the combustion chamber isn't as shrouded as some other V8s. Just make sure its a good shop, the stock path for the pipes is tricky particularly where it goes under the cross member. Some have routed pipes to opposite sides, but you can end up with disparate lengths then, not ideal. Be sure to check out your options for pre-made exhausts, 928 motorsports offers a new dual midpipe/muffler setup, might be apropose if you are already set up for dual-in. I assume you're already runnning an aftermarket pipe just aft of hte manifolds with a good crossover arrangement? That seems to be a key part of the equation.

IcemanG17

Rob
For that type of investment (custom exhaust)....an "X" pipe with stock or RMB would be a better investment....you would gain a solid 20+ hp and it would be far louder....at least with the RMB....

Jim bailey - 928 International

Since you have a EURO the BIG question is what kind of Cat do you have the Porsche cat was over $2,500 so MOST federalizing labs did NOT put on the correct cats ...often small restrictive cheap were used.

bigrob

My exhaust system is totally stock.........Looks like the cat was added later. Welds dont look too pro like! My cat is actually pretty big & long. Sounds like me Seriously, the cat is dual in & dual out. I am not looking for an awsome setup at this time, since I have so much other stuff that I want to address first. My secondary muffler hangs a little too low & looks sad. The 2 pipes between the primary & secondary mufflers are pretty pinched in the usual area, & are rusty. I dont want to spent alot of $ on it. Just clean it up a little & give it a little V8 rumble. The shop I use here in Vegas, Performance Muffler, is very good at custom work. I need to go & see what they can do & for how much. I realize the routing will be very important for clearance issues.

bcdavis

I loved the sound of my euro, with a flowmaster, and monza resonator tip.

http://www.thedeathknight.com/928/928_Test_Drive.wmv

http://www.thedeathknight.com/928/Fl...WindowOpen.MPG

http://www.thedeathknight.com/928/Fl...ndowClosed.MPG

Flowmaster alone was too loud.
And since you need some kind of tip anyhow, use one with a resonator.

It sounds like you may have the same cat I did, which is probably an s4 cat, grafted on...
They are long, dual cats...

tv

How can there be a correct cat for a car that was designed and built without one? Get some good spiral hi flow ss cats. Do a search on exhaust, more than you ever would want to know.

Jim bailey - 928 International

The 1985-1995 big "dual" cat is a direct bolt on and designed to work with 300+ HP. But the point was that the unknown added on cats are usually small and often very restrictive.

bigrob

That sounds pretty sweet! That way may be too loud after a while for me. I love loud, don't get me wrong, but there is no on off switch. You will be hearing the sound all the time & I dont want too much drone! I'llhave to see when I get to the shop. Right now I hear basically nothing, which is boring!

BTW, I have only one cat, but with dual outlets in & out. Or do you mean 1 cat after another? I may have that!

Thanks for the clips.......something to think about!!

bcdavis

Try a Flowmaster 50-series.
They are quieter than the 40 series, but still have that deep rumble.

And those clips are loud, because I am really on the gas.
Most of the time, for normal street driving, it was not too loud at all.

Richard S

I have an 84 Euro engine in my 1980 928. I tried an X-pipe into a single 3 inch then into 2 Borla's in series. Sounded HORRIBLE....unless you like it so loud you can't carry on a conversation with the passenger. At WOT it was vicious, at freeway cruising speeds it was unbearable due to the droning and resonance. So I ditched the X-pipe and installed a stock S-4 cat. Now it is perfect. So with X-pipe and Borlas = vicious snarl. With stock S-4 cat and Borlas = angry growl.

Also, with this set-up (S-4 cat + single pipe + Borlas) I gained over 20 RWHP vs. the stock 1980 small exhaust.

Rich

RDS928S

Rob,

check out this true 2.5 dual exhaust system I had fabricated for my early 86.
Includes two bullet style resonators and a final magnaflow muffler. Exhaust note is very exotic. Cost was
~1k.

Good Luck
Rich

Ed Hughes

Rob: Go look up the recent exhaust thread by Carl Fausett. He's developing/developed some new exhaust (catback) systems. I'm testing the pipes for the later version for him on my '91-we've got some fitment issues we're working thru, but he's got a version for older cars already tested that fits, and dyno'd well for him.

bigrob

Yo Rich, That is one sweeeeet setup!! It must be nice to have the resources available to do all that!! It looks like everyone is saying that just 1 muffler, where the primary is, will be too loud. That kinda throws my idea out the window!! I am not sure what I am gonna do. Threw a coat of wax on the old girl thinkin about it though Come to think of it, I just sold my '78. It had a hole in the primary so I had it cut out and only had the secondary rear muffler, & it sounded kind of nice a rumbley!

We'll see! Thanks all for the advice!! Always appreciated!

IcemanG17

Rob
With no cats & only 1 muffler that is gonna be very loud!!