FAQ: The Exhaust Thread

Corey painted his silver: rivperformance.editboard.com/t9257p60-cleaned-up-the-exhaust-a-bit

I think somewhere someone said they're painted black from the factory. That mothers polish will work, but you'll be under there once a month keeping them nice.

Look at my showroom thread. Should be the first/second page I "mexi-chromed" them. Looks great and has stood up to all kinds of weather hell since summer

AA wrote:

I've heard when you're using a turbo, you throw all the theoretical stuff out the window... there is no scavenging effect because the turbo blocks the exhaust pulses from the engine. The idea is to just open up the system. I'll buy that

You could be right (probably are), but I can't help but think about these theories before I make cuts and welds. With a blower the idea is similar to turbo, so opening things up as much as possible could be best. I can see how boost would force the exhaust gas out, so maybe you needn't be concerned with scavenging. But unlike turbo, the blower is on the intake side, so exhaust plumbing is connected directly to the engine. Perhaps its design (tuning) still has some effect?

When I research exhaust design, it's usually divided between N/A and turbo and applications. There is very little conclusive info specifically for blown engines that I've found. The only thing so far is Thrasher's tests, which didn't show much improvement from increasing exhaust tube diameter.

I spoke with Steve at ZZP today and he told me that back pressure is not an issue with SCed 3800. Open that pipe up all day all day. Does that mean 3" all the way to the split is the way? Cody, is this what you did on your Turtle?

I've come to agree that opening up the exhaust will make power with SC application - if you have an engine that takes advantage of the plumbing. I don't think many among us do. I also believe it makes a lot more noise than actual power gain. Since I'm not maxing the limits of my exhaust system yet, stock it will stay from headers back.

llamalor2112 wrote:

Look at my showroom thread. Should be the first/second page I "mexi-chromed" them. Looks great and has stood up to all kinds of weather hell since summer

\

Looks good. Can't decide if I want to nurture my chrome or murder it all.

AA wrote:

I've come to agree that opening up the exhaust will make power with SC application - if you have an engine that takes advantage of the plumbing. I don't think many among us do. I also believe it makes a lot more noise than actual power gain. Since I'm not maxing the limits of my exhaust system yet, stock it will stay from headers back.

Word.
I said to Steve, I said, Steve, do I really want to open my pipes up with a only a 3.6" spinnin'? Will I have enough juice to get out the back and still keep back pressure at satisfactory levels? Steve laughs and says, brother, you will only make horse power if you open that pipe up. Your supercharged 3800 is not affected by back pressure like an N/A engine is. Please note, we were talking about a 3" downpipe not catback. Anyways, someone help me out in the downpipe thread!

Is the pipe from the resonator back 2.5"?

2 and 1/4" and then splits into two 1and 7/8" pipes

69GSColorado wrote:

2 and 1/4" and then splits into two 1and 7/8" pipes

I plan on doing 3" down to a 2.5" resonator then OEM 2.25" back. Am I missing anything? I heard the 2.25" stock piping is able to put up to ~500whp until it needs an upgrade consideration? So yeah, I should be good with the 2.25" then, right?

I have SLP headers in my car and I went 3" all the way back to the Y, where it splits into two 2.5" pipes. If you're going to go ahead and spend money to open up the down pipe and the exhaust up to the resonator, it doesn't make much sense to choke it down right afterwards. At least leave it 3" to the Y, then you can go with two 2.25" pipes if you want.

I thought about going 3" to the Y but I was under the impression that a smaller diameter pipe would increase temperature and velocity? I was thinking about leaving the OEM pipe in place after the resonator to make sure the exhaust stays hot and moves fast.

What is everyone else doing? 3" all the way back or 3" to 2.25"? If you do go down to 2.25" in what part of the exhaust system are you reducing?

Thanks for your help, everyone!

The real issue hear is drone, rasp and general 3800 V-6 exhaust tone. If you want to hear it then increase the diameter of the exhaust after the cat, eliminate/change resonators, swap mufflers, etc. If you don't want the noise, keep the exhaust stock. OEM is all SS, lasts forever except for cat, will support up to 400 crank HP, and keeps the car sounding quiet and stock on the inside.

The idea that you gain HP by increasing exhaust diameter works, but with a penalty, and there are other ways to let the engine breath. Like INTENSE did with the 8-ball Bonneville, if I were building a monster 3800 FWD race car, I'd save the exhaust upgrade until very last, unless you want the sound. That's what's really gained, more so than actual power.

I'm not trying to do catback exhaust right now. Just a down pipe and resonator. Should I get a 3" resonator or 2.5"? I plan on using the 2.25" OEM exhaust piping after the rez.

i cant wait to instal a walker resonator. it sounded fine and dandy in the begining,the rumbly exhaust,but if you like to listen to tunes, a rez and cat delete wont care if you do! i shoud have done what i did to my Legend and instal a high flow cat.that really upped the torque and gave a little burble but kept it relatively quiet in the cab.
i would recomend a high flow cat for the Riv.keep the oem rez.you wont regret it.

Quote :

I'm not trying to do catback exhaust right now. Just a down pipe and resonator. Should I get a 3" resonator or 2.5"? I plan on using the 2.25" OEM exhaust piping after the rez.

Resonator is after (beyond) the cat, so that's what I meant about changing anything cat-back. If you swap the resonator, you change the sound of the system with little HP gain.

AA wrote:

Quote :

I'm not trying to do catback exhaust right now. Just a down pipe and resonator. Should I get a 3" resonator or 2.5"? I plan on using the 2.25" OEM exhaust piping after the rez.

Resonator is after (beyond) the cat, so that's what I meant about changing anything cat-back. If you swap the resonator, you change the sound of the system with little HP gain.

Right, but should I go 3" down to a 3" rez and then down to 2.25". Or, 3" down to a 2.5" rez then down to a 2.25"? Cat is getting cut.

If you want it louder, go 3". If you want it to sound close to stock, keep the stock res.

2.5" aftermarket res is probably going to land somewhere in between.

I've got 3" exhaust and its unbelievably quiet. In my opinion, the brand and style of mufflers affect the sound more than pipe diameter.

I've got a magnaflow resonator and Borla XS Pro mufflers. There is no droan, and I know it's a lot quiter than the 2.5" set ups I've heard on here.

If Jordon's set-up is as quiet as he says, maybe that's the winning combo. This would be the first 3" Riviera exhaust I heard described as "unbelievably quiet" with no drone.

yup. a 3" exhaust has a deep rumble.its the rumble that makes my system livable.if it had a shrill note i would shoot it.
ill be swaping out the thrush turbo muff for a borla and a walker rez. asap.love my music.

Check this out. ZZP's DP comes with a 2.5" reducer welded in at the end. (this is not optional) I really think a 2.5" rez and then down to 2.25" out will be fine. I've read enough about what our exhaust is capable of handling before it needs to be repiped completely. I would do 3" all the way with fresh catback everything. But aint nobody got time for that!
The ZZP badge is worth at least 5HP, right?

The majority of my noise comes from the thin tube headers. I hear more noise from the front of the car than the back.

Don't get me wrong, my car is not as quiet as stock, but it's super quiet for a car with a performance exhaust. There is slight drone at fourth and low climbing a hill, but even then it's still not even as loud as my dad's Regal GSX with a 3" DP and a 2.5" catback with Magnaflow mufflers at regular cruising speeds.

At 60 mph and above you don't even hear my exhaust. That's what I love because I do a lot of highway driving. However, when you floor it, it's a different story

It's definitely a very low tone with absolutely no rasp. I believe the bigger piping helps reduce rasp.

69GSColorado wrote:

The majority of my noise comes from the thin tube headers. I hear more noise from the front of the car than the back.

Don't get me wrong, my car is not as quiet as stock, but it's super quiet for a car with a performance exhaust. There is slight drone at fourth and low climbing a hill, but even then it's still not even as loud as my dad's Regal GSX with a 3" DP and a 2.5" catback with Magnaflow mufflers at regular cruising speeds.

At 60 mph and above you don't even hear my exhaust. That's what I love because I do a lot of highway driving. However, when you floor it, it's a different story

It's definitely a very low tone with absolutely no rasp. I believe the bigger piping helps reduce rasp.

you dont have a sound bite do ya?

There is one issue with my car that I cannot seem to figure out. I still get a very slight ticking sound from my exhaust at about half-throttle or when I'm in overdrive climbing a hill at low rpm.

I know the SLP headers have been known to "tick," but I followed AA's header wrap write-up and covered the entire flex-joint. There are no gasket leaks or other exhaust leaks, as I've checked the entire system and replaced all the clamps with welds.

AA, do you still have a slight tick or did the wrap take care of yours?

robotennis61 wrote:

69GSColorado wrote:

The majority of my noise comes from the thin tube headers. I hear more noise from the front of the car than the back.

Don't get me wrong, my car is not as quiet as stock, but it's super quiet for a car with a performance exhaust. There is slight drone at fourth and low climbing a hill, but even then it's still not even as loud as my dad's Regal GSX with a 3" DP and a 2.5" catback with Magnaflow mufflers at regular cruising speeds.

At 60 mph and above you don't even hear my exhaust. That's what I love because I do a lot of highway driving. However, when you floor it, it's a different story

It's definitely a very low tone with absolutely no rasp. I believe the bigger piping helps reduce rasp.

you dont have a sound bite do ya?

No unfortunately I don't at the moment but I could easily get one in a couple weeks when I get my car back. It's back at home with my Dad's shop. I just had a dual guage pod installed and fastened to my A pillar. After re-upholstery, I'm installing a boost guage and fuel pressure guage. It's going to be awesome!