95carrera

What can I expect the difference in sound to be? I don't want loud or annoying drone. I just changed out new magnaflow mufflers for three chamber turbo mufflers on my hot rod because I tired of noise at speed.

Adamant1971

It will be fine, I had the same set up on my S3. It's when you go with a RMB that things get loud.

alex70

Do you mean w/out cats and w/RMB?

I had cats on my '87 w/RMB and it was very drivable. No noise issues. Sounded nice too.

Don Carter

Do you have large or small resonators? I have X-pipe, no cats and RMB on my 86.5 with large resonators and it's a great sound. That said, it is somewhat loud to some people and it does drone some on the highway. I actually put the rear muffler back on for a couple of years because I got tired of the the sound, but it's back off again now and I'm enjoying the BWAAAAAA.

With small resonators it would probably be too loud for you without the rear muffler in place.

alex70

Small side note, there was a small tunnel in OC, CA 241 toll road SB out of Foothill Ranch I liked to juice it just to hear the exhaust note. It sounded good.

I need another 928 soon...

95carrera

All factory 85' just changing to x pipe and not replacing cats. Porken chip already installed.

Darien

Popo928 is across the river from you. His 86.5 has x-pipe, stock exhaust pipes and RMB. It sounds awesome and not too loud. You should PM him and get together for actual sound.

M. Requin

This is what I have now. I was worried about the drone, but Roger assured me that it wouldn't be a problem, and he was right. Really, not all that much difference in sound level, a little bit more sound, but not much, and certainly not unpleasant. OTOH, could be my aging ears!

hacker-pschorr

+1

I put an RMB on my 87, except for upper RPM WOT it's not much different than stock (with 87 mufflers & CATs). The twin shiny pipes do look a lot better than stock.

X-pipe next and different mufflers unless I can score a good deal on the smaller stock ones.

928S MN

This is what mine sounds like with the set-up you're asking about.

95carrera

That sounds much louder, burbley and raspier than what I expected. I can't reconcile this audio with other's statements that it doesn't change tone much.

95carrera

That sounds much louder, burbley and raspier than what I expected. I can't reconcile this audio with other's statements that it doesn't change tone much.

ptuomov

When the V8 sound is considered, people fall into two camps. The first camp finds the half engine order sounds sporty. The second camp finds the half engine order sounds just annoying. I'm in the second camp, but that doesn't make my camp the right camp. It's simply a matter of taste.

In my opinion, the best sport car sound is when the engine firing order frequencies dominate. For a V8, that's 4th engine order. In Hertz, that's 4*rpm/60. The noise at EO 2 and EO 2.5 is mostly just annoying to me. In Hertz, those are 2*rpm/60 and 2.5*rpm/60.

Furthermore, I've come to the conclusion that I want the car to be pretty quiet up to about 3000rpm. Above 3000rpm, with open throttle, it can and should scream. In the 3000-6750rpm range, the sound pressure and the dominant frequency should grow about linearly in rpm. Finally, I don't like sharp high frequency sounds.

What this amounts to is having a generous cross-over to make the 4th engine order dominant, a set of resonators that take out the 50-200Hz frequencies, and then a rear absorption muffler that takes out frequencies above 450Hz. The result is (by my theory anyway) a car that is relatively quiet up to 3000 rpm but progressively unleashes the fury after 3000rpm.

This is all theory, so caveat emptor. John's putting the first half of these theories in test as I write this and I hope to put the second half of them to test in the fall when the snow falls.

bureau13

Lol I have no idea what that means in terms of actual real-world sound...is the video above "half engine order" or something else? Whatever it is, I like it a lot...

The only thing I really don't prefer is a loud drone at highway cruising speeds. I have a bit of that now (S3 w/ MSDS headers, cats, no crossover or silencers, and a Borla muffler). Otherwise, I love the sound. I have an x-pipe to replace the cats but haven't done so yet. I need to get on that...

hacker-pschorr

My 79 - MSDS headers, Y pipe, 3" exhaust with no muffler.

Cruising down the highway or through town, 3k rpm or lower it's not any louder than my 87 with RMB.

Drop a gear and floor it, you wake the dead. If I really want to be quiet, close the valve and send the exhaust through a muffler.

All the work / trouble you are going through, why not make it adjustable? Todd's car is quieter than a stock Buick on the way to church on Sunday, when he wants it to be. His videos from the drag strip are wide open, still very quiet, even compared to some stock cars.