FAQ: The Exhaust Thread

Ok thanks Chris. Did you notice a change in the amount of low-end torque or high end horsepower with your exhaust change? Is there a lot of rasp or drone at any particular rpm zone or at highway speeds?

69GSColorado wrote:

Rick, why does it have to be so hard to get these Rivieras to sound good? Your Regal set-up sounds pretty similar to what I want, but for some reason it's been tried over and over with poor results. What type of "bullet" resonator are you using? I've heard a bunch of fantastic sounding Regals, and with the same engine, why can't the same results be achieved with the Rivera?

think of the exhaust as an organ pipe. Many of the same tuning constraints apply. So the regal's pipe is a different length. If you figure out how to duplicate (precisely) the Regal exhaust then you can duplicate (approximately) the Regal sound.

And there the headache begins.

I'll give you a hint: the Regal has a **bigger** resonator.

Albertj

I probably get most of my droan I'm thinking around 2000-2500 rpm. Which is kind of why I'm tinking about a resinator, but it's not that bad either. I haven't noticed any change either way in performance.

Karma wrote:

Ron's Rocket Riv wrote:

Hmmm... Wonder about doing it without the resonator... Just a 3" pipe from the cat down to the dual Super Turbo mufflers...

Or

Keep the resonator and replace the Super Turbo mufflers with something more aggressive, something like the DynoMax VT series or the DynoMax UltraFlow SS.

The tough thing is that I have NO idea what this is going to sound like; I only know what kind of sound/tone I like and I hope to hit with these components.

I like my DynoMax VTs. Sounds very good at WOT, subtle rumble at idle. And they mean it when they say its a drone free muffler.

Thanks for the info, Andrew! Are you running with or without a resonator? With or without a cat?
How big are your pipes?

Thanks again! Maybe I will go for the VT series...

J. Chris Davis wrote:

This link has audio clips taken by members of how their exhaust systems sound. Maybe that will help some.

https://rivperformance.editboard.com/t6854-riviera-pro-exhaust-sound-clips-by-members?highlight=exhaust+clip

Thanks, Chris. I will definitely check this out tonight!

Another option you might like to try is keep the stock resonator and put a single 2.5" muffler on the back. Then you can play with different muffler loudness but not have a lot of drone.

69GSColorado wrote:

Rick, why does it have to be so hard to get these Rivieras to sound good? Your Regal set-up sounds pretty similar to what I want, but for some reason it's been tried over and over with poor results. What type of "bullet" resonator are you using? I've heard a bunch of fantastic sounding Regals, and with the same engine, why can't the same results be achieved with the Rivera?

The Riv will sound very similar to the Regal. I don't know why it wouldn't. There are a couple of differences between the two in the way the catback looks but it wouldn't affect the sound that much.

The whole thing is that the transversely mounted 3800 sound like crap no matter what.

I have a carsound cat that goes into an 18" dynomax bullet resonator before the mufflers. It is pretty damn loud but the sound is a lower pitch than most 3800s you hear. People have asked me to get a vid but my camera sucks at life. I'll try to get one up if I can get the proper equipment.

Sorry to chime in here, but; what are the effects of a cat delete? A cat delete is just chopping the thing out and replacing with pipe, right? What exactly does that achieve or do?

It increases CO levels, mainly. Decreases some restriction, and very little noise increase. The cat is not intended to act as a sound supressor. More on cat delete:

https://rivperformance.editboard.com/t3299-catalytic-converter-delete

It might be different because it was a w-body but my Regal was quite a bit louder without a cat. The cabin rattled and it was annoyingly loud so I decided to weld the high-flow cat back in. Again... this was with the dynomax mufflers and bullet resonator. I'm guessing the stock components on the Riv exhaust wouldn't allow it to be as loud.

1) was the exhaust fully welded up with the cat converter removed?

2) what happened to the sound level when you welded in the high-flow cat?

It was welded in. I had to cut the pipe again and have the cat welded in.

The sound went down pretty considerably with the cat installed. The car is still loud but nowhere near what it was without one.

The OEM resonator and mufflers must be even better at filtering noise than I thought. Not even the slightest bit of increased exhaust drone or tone inside, with headers and deleted cat. A little noise from the thin wall headers, that's it.

Enrique (Oldsman) told me to never cut the resonator off these cars because it is that good at mellowing the noise and tone. He was the one that said to just slap headers on/delete cat and call it a day.

I cut my cat and my resonator off when I put my headers on and its sounds pretty good. No drone or anything inside the car. I will have to get a video of idle and a little gas or something. matter of fact, I'll be right back.

Bowersk wrote:

I cut my cat and my resonator off when I put my headers on and its sounds pretty good. No drone or anything inside the car. I will have to get a video of idle and a little gas or something. matter of fact, I'll be right back.

...do you drive at cruise on the highway for more than 30 miles at a time? Do tell.

Doing cat back exhaust on 95 riv what should I use was going with bosal but it is n/a now... So I was thinking manaflow performance cat but what should I do after that? Cut or keep res? What muffler should I use? I want a low agressive idle but throtty on throtle... Help me please and Im trying not to get major droin while cruising

Pipes wrote:

Doing cat back exhaust on 95 riv what should I use was going with bosal but it is n/a now... So I was thinking manaflow performance cat but what should I do after that? Cut or keep res? What muffler should I use? I want a low agressive idle but throtty on throtle... Help me please and Im trying not to get major droin while cruising

Keep the res (keep the cat too if it's not abused it isn't' restrictive worth beans) and consider putting a couple of Hooker "Maximum Flow" mufflers on.

Albertj

I agree with Albert. How loud you want this beast?

I miss my rez

albertj wrote:

Bowersk wrote:

I cut my cat and my resonator off when I put my headers on and its sounds pretty good. No drone or anything inside the car. I will have to get a video of idle and a little gas or something. matter of fact, I'll be right back.

...do you drive at cruise on the highway for more than 30 miles at a time? Do tell.

Sorry didnt end up getting a vid yesterday but yes, 30 mile back and forth trips routinely to pickup and drop off my kids and its quiet as can be inside. The videos I did get don't accurately illustrate the sound as they make it seem louder than it really is. Now I go from downpipe back to the stock y-pipe with 3" exhaust....so once I get rid of that restriction it will probably be louder than I want but I'll cross that bridge when I get there.

Bowersk wrote:

The videos I did get don't accurately illustrate the sound as they make it seem louder than it really is.

Hmm. Are you saying the video makes it sound louder, like there's drone in the car? Or is it just road noise?

I just took a video of outside of the car and it makes the exhaust sound way louder. I can get a video next time im on the highway though.

Again, that's 3" pipe connected to the downpipe all the way back to where its SMASHED into the y-pipe to stock mufflers. When I get a chance to remove that restriction, it will probably be intolerable so I may be putting the cat or the res back on at that time.

Sounds tough as nails, but I don't think I could live with that every day! I have a 34 mile (each way) ride to work... that would wear on me!

I took my Rivie to a local shop that does a LOT of custom exhaust work (that's what they are known for). The guy that owns the place told me that the best bet for me (since I am not sure how loud I want it) would be to remove the stock mufflers and replace them with straight pipes out... lleave the stock cat and stock rez there to absorb the sound.

In a way, the approach my local guy is suggesting I take is the opposite of what you did (removing the stock cat and rez and leaving the stock mufflers).

I will probably go this route and have the stock mufflers removed and just add a couple of 2.5" pipes out from the Y. When I do, I will get some video/sound for you all to hear. Might be doing this within the next 1-2 weeks, so stay tuned.

Oh, and yes... I am doing this purely for the sound. I know if I want to squeeze a few more ponies from the car, I need to replace the down pipe w/ a 3" pipe - I will get there, but not any time soon... In all honesty, she feels plenty fast for me right now - I just want to hear some sweet mechanical music when I lay into the throttle!

I LOVE this thread!!!