FAQ: The Exhaust Thread

I was coming up with some pretty retarded ideas for how to temporarily connect and seal a muffler to the end of the v-band going to my downpipe (like i have any more of those laying around - I can't even buy on from the people that make the stupid headers) The intake boot off the L26 worked perfect. Fit the lip of my vband and the muffler pipe like a condom!

Fellas,

After a couple of months of trying to put the right pieces togther, this is what I have come up with...

3" downpipe
http://shop.zzperformance.com/store/p/249-ZZP-Downpipes.aspx

That goes to a 3" high-perf Magnaflow catalytic
http://shop.zzperformance.com/store/p/164-Catalytic-Converters.aspx

From there, it will go to a 3" Magnaflow resonator
http://shop.zzperformance.com/store/p/521-Magnaflow-Resonators.aspx

After the resonator, the pipes will drop down to 2.5". I will have a shop mandrel bend the Y-pipe to bring it out to the 2.5" DynoMax Super Turbo mufflers.

Finish it off with 2" x 8" rectangular tips
http://www.summitracing.com/parts/PYE-EVT37/

What do you think? Will this reduce the restriction i nherent w/ the factory pipes and preserve back-pressure while keeping the scavenging effect? Also looking for a deep, low rumble at idle and a nice howl at WOT - do not want drone in the cabin but do want people to take note when the hammer goes down.

Your thoughts and feedback is welcome!

Thanks.

thank you!

Ron's Rocket Riv wrote:

Your thoughts and feedback is welcome!

It's going to be pretty quiet with the super turbos and resonator: very quiet at idle, not very loud at WOT either. Drone shouldn't be an issue. I'd go for the longest resonator you can get.

What about no resonators. and do Two Chery Bombs at the rear!
J/K ! thought a laugh would be good

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.

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

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.

Okay fellow Riv owners, I'm in need of your advice. After reading almost 50 pages in the exhaust and muffler threads, It's finally time to build my exhaust.

I have brand new SLP ceramic coated headers with the integrated 3" downpipe, as well an SLP high flow catalytic converter with a 3" inlet and outlet. Like so many other Riv owners are concerned about, I don't want a lot of droan because I do a lot of highway driving back and forth to college, but at the same time I don't want it to be as quiet as stock. A nice drone and rasp-free tone is everyone's dream, and I'm trying my best to accomplish that.

I plan on running 3" pipe after the cat along with a resonator up to the Y split. This is where I've run into problems. I'm trying to find a nice quiet, yet non-restrictive resonator. I've looked at many different resonators and have yet to find the perfect one. I was thinking of going with SLP Loud Mouth II Bullet type resonator, but the name itself suggests that it might be too loud. The ZZP whisper resonator was discontinued and after hearing horror stories from this board as well as many others, I'm not sure I want to go that route. ZZP now sells the magnaflow resonators. These come in two different sizes: 5X14 with a 3" inlet/outlet and 4X18 with a 2.5" inlet/outlet. Assuming I go with the Magnaflows, If I'm running 3" pipe, should I continue with a 3" in/out 14" resonator or should I opt for the longer 18" 2.5" in/out resonator and get the required reducing spacers? Of course I'm not limited to just these, I'm just having trouble finding any resonators. I've looked at all the big shops, but for some reason haven't been able to really find any.

Now we are to the Y-split. I'm debating on whether to go with 2.25" pipes and mufflers after the split or 2.5" pipes and mufflers. Again, I don't want it to be loud, but I wan't to preserve back-pressure and also let it be non-restrictive. The mufflers I've chosen are the Borla ProXS mufflers made of T-304 Stainless steel. They are 14" overall in length, and are among the best flowing mufflers yet also produce some of the quietest sound decibels. They come with both 2.25" and 2.5" in/out., but that of course depends on the piping I decide to run after the Y. I'd really appreciate your suggestions. Thank you

If you eliminate the stock rez yer gonna have drone.no matter what you use.I dont know for sure if anyone here has the magnaflow rez,but I hear it's the best you can get in terms of sound dampening.
Get the longest rez possible.The bigger outside dia has a better bass than the 2.5.
if you open her up wide at the down pipe and taper her off after the cat to 2.5,you will maintain back pressure for the lower engine revs.if you maintain 3" all the way through to the 2.5 muff,you will give the Riv longer legs at high speeds but will lose a little grunt in the mid range.
after cutting off and cutting open the stock rez,Ive determined that the stocker aint as restrictive as many think.Its pretty free flowing and I would try to work with it with some reducers to make the rest of your exhaust mod work the way you plan.
This is based on my exhaust odysey and my deep regret of having thrown away a perfectly good stock rez.
My system is a 18" cherry bomb in place of the stock rez along with a single 2.5 Thrush turbo muff.I posted a sound clip where I'm revving the nuts of her,but it dont do the system justice.It's really not that loud.but drone is bearable to the point where with the stereo on I can live with it.With the stereo off,I find myself letting off the throttle more often.Not such a bad thing.Like anything,ya gotta do to do it!
Post sound clips when done

Robotenis, so you're saying I should run 2.5" pipe after the 3" high flow cat, not 3" piping to the Y? Also, you think it would be best to use the magnaflow resonator 4X18 with the 2.5" inlet and outlet instead of the 5X14 with the 3 inch outlet?

Then after the Y, should I go with 2.5 inch pipes and 2.5 inch mufflers or 2.25 inch pipes and 2.25 inch mufflers... I still want low end torque, but at the same time I'm aware that changing to a smaller super charger pulley will increase torque..

Which is best?

1. 3" cat, 3" piping and res: with 2.5" pipes and mufflers after the Y

2. 3" cat, 3" piping and res: with 2.25" pipes and mufflers after the Y

3. 3" cat, 2.5" piping and res: withe 2.5" pipes and mufflers after the Y

4. 3" cat, 2.5" piping and res; with 2.25" pipes and mufflers after the Y

Thank you and I would appreciate everyones imput.. Its a lot of money I'm about to spend and I want to make sure I get it right.

If possible, see of you can fit the cat converter behind the stock resonator and keep using the stock res. Use a tapered venturi cone to adapt the 3" down to 2.5" before the resonator. Keep everything stock from the resonator back.

Broken record starting to play... Opening the exhaust after the cat converter serves one real purpose: create rasp, noise, and drone - at least until you're making 400 HP+. If you want more sound (some folks do), go 3" all the way back, change the Y pipe, mufflers, resonator, etc. But if you only want the exhaust to flow better, remember you have a blower up front pushing air through the engine. And you've taken care of the biggest restriction by adding headers. There is a lot more you can do to the engine to improve its breathing that doesn't require increased noise level. Since it seems noise is a concern for you, focusing on the exhaust at this point is not where I'd recommend spending your time. Just my .02!

I hear what you are saying, but the stock exhaust is too quiet for me. I want a little tone, but I don't want a lot of rasp and drone.

I'm aware that modifying the exhaust and changing mufflers isn't going to net me major horsepower gains. That's not why I'm doing it. I want it to sound good, but also take into account backpressure, free and easy flow, and sound dampening to minimize or eliminate rasp and drone.

I've heard a lot of V6s with the Borla Pro XS mufflers on them, and I'm really impressed with the sound. Alot of the people on here that complain about droan on here are running 3" piping all the way back with cat deletes and resonator deletes and are running loud mufflers.. Some are only running one muffler and a single pipe, which contributess to the droan.

I've tried to take all this into account, by searching for the quietest resonator, suggesting smaller pipes

And I've found some of the quietest, best performing mufflers money can buy. What exactly am I doing wrong?

I don't think anybody else has tried to build an exhaust this quiet, and was hoping for suggestions as to which of my setups would provide the least amount of droan and rasp, but also factoring in performance and the appropriate balance between low end and top end power. I'm not at all trying to be rude and write off your suggestion to keep the system stock, but I'm just honestly searching for some ideas and answers.

youre looking for a definitive answer.no one has one.you have to experiment and figure it all out through experience like most of us.If you go through all the exhaust threads you will find experimentation to be the norm in finding a setup that works for you.it dont mean it would work for me or anyone else.

Very true Robo. For my set up I have the ZZP shorty 3" down pipe going down to 2.5". With Magniflow cat and 2 Flowmaster 50 Series Delta Flow Mufflers. I do not have a resinator. I'm still debating that one. It has a nice tone to it and I'm used to it now. Before it was factory and of course very quite. It took me months of reading on here and making an ultimate decision on the way I wanted to go with my exhaust.

Quote :

And I've found some of the quietest, best performing mufflers money can buy. What exactly am I doing wrong?

I don't think anybody else has tried to build an exhaust this quiet, and was hoping for suggestions as to which of my setups would provide the least amount of droan and rasp, but also factoring in performance and the appropriate balance between low end and top end power.

It has been tried. I think albertj gave it a shot. Results have been semi-successful by DIYers; the reason I favor the stock design, the Buick engineers tried exactly what you're suggesting, and succeeded. It works because it's tuned correctly, something very difficult for you and I to do. Basically it's trial & error method, unless you can calculate the tuning frequency of the entire system, including the pipes themselves. It's a lot like tuning a reflex speaker enclosure - the box, driver, and duct all play equal roles on the output.

I installed headers with a high flow cat and used the stock resonator back. It sounded a little bit louder than stock but the quietest I've heard. I don't think the 3800 sounds good when the exhaust is opened up any more. I ran a 13.8 in the 1/4 on my stock resonator back, so until you are running low 13s your stock setup is fine. You want louder? Change to headers and a HF Cat instead. Just my opinion. Don't have any video of my car like that. All you can hear is the supercharger anyway

Okay well I'm nowhere close to the 13's. And since I haven't heard any exhaust set-ups that sound decent on the riviera, maybe I should just be realistic and face the fact that I'm probably not going to strike gold and somehow put together the perfect exhaust system.

The money would probably be spent better elsewhere. With that said, at the very least I'm going to swap out the stock mufflers. Do you think I could get that nice distinctive tone I'm looking for by just installing the Borla Pro XS mufflers and leaving all the stock piping and resonators alone? That wouldn't create too much rasp or drone would it?

It's hard to know what the nice distinctive tone you're looking for actually is. It is something you think you want? Can it actually be achieved? I don't know, but my gut says odds are it won't happen. But like robo said, you never know unless you try. Imo, the resonator does a lot to mute the drone. Lots of opinions on mufflers here:

https://rivperformance.editboard.com/t370-faq-mufflers

I agree with you there Aaron, but I was able to get close to what I was going for. I may have just gotten lucky there and I still may put a resinator in.

Chris, for your set-up are you running a high-flow cat? Also, are you running 2.5" pipes after the cat and also 2.5" pipes after the Y? What size is the inlet and outlet on your mufflers?

I hear these cars don't sound terrible if you just replace the manifolds with headers and remove the cat. If you wanted even more sound deadening, you could leave the cat on or put in a high-flow one. Other than that, I wouldn't bother.

My Regal sounds good, I think. But it seems to be quite loud after being used to the cushy noise-less Riv. Regal has headers, magnaflow cat, bullet res and dual dynomax ultraflos. If you delete any of those components, that high end rasp comes in and it sounds like complete garbage.

after the 3" downpipe it's all 2.5". The cat I'm using is a highflow cat.

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?