Exhaust for max performance.

[HAWAIIZR-1]

Originally Posted by Corbusa

Craig , are you going to use the factory pipes? either way Please take some pictures..

No, I have had the 3" B & B triflo cat back system as long as I can remember. I think my factory exhaust came off a few weeks after I bought the Z in 2003. I'll be sure to take photos and video, just not sure when and it may be another month or so depending on how long to tune for emssions retesting.

[-=Jeff=-]

Originally Posted by sammy

very nice sounding car. love a car with a good cam in it . what did it sound like inside the car cruizing on the freeway ?????

Not as loud as the B&B it had, but was still noticeable

Originally Posted by HAWAIIZR-1

Thanks Jeff. That sounds great and it looks like it was a nice car too.

Not sure how different the LT5 w/SGC Stage I cams will sound with 2.00" SW headers, no cats, SW x-pipe, pair of 17220s and Pypes tips. I hope the it eliminates or reduces drone.......ha, ha! Like Pete said, I don't want no old geezer exhaust and this should help keep me awake as well as no need for stereo (how much weight can I save by pulling all of that out? just kidding, but I never turn on my stereo anyway).

Craig

craig,

yes they will reduce drone, but not completely eliminate it..

[HAWAIIZR-1]

Originally Posted by -=Jeff=-

craig,

yes they will reduce drone, but not completely eliminate it..

Thanks Jeff, I did not think so but was not exactly sure what causes the drone. Its not really that bad and it never bothered me like to does others. I'm curious to know how it will sound once the resonator is off and straight through mufflers, but I can imagine similar to Dom's or your 89.

[sammy]

2 things i found that really contribute to the drone . 1) if the pipes that go under the rear end don't have at least 10-12 mm of clearance 2) the tips if they are tucked up to close the the valance and don't go at least 3-4 in past the end of the valance . i know they don't look as good that way but it does make things tons quieter inside the car while cruising . i found this out while finding the best exhaust for my car .jmho

[RHanselman]

I have B&B's on the stock car, Borla's on the 368 and just CAT's and turbo's on the 91'

The only one of the car's with the resonance is the B&B. The Borla and Turbo Car have no resonance and they both sound great.

Here's a clip of the Turbo car and the 368 Borla car.

http://s1132.photobucket.com/albums/...urbo1Small.mp4

http://s1132.photobucket.com/albums/...=Ruby099_1.mp4

So I'm thinking the Trubo Exhaust is actually the best exhaust for max performance!

[ZR1dogan]

Well folks, I’m bringing back an old thread – Wow what a wealth of information!! I am looking to update my exhaust and this has me looking at the DynoMax route but I am looking for a little clarification.

How much difference does the flapper make? I am surprised that it would make a really significant difference in noise/drone, since it is only covering up one of the two exhaust ports and the other is still wide open. Certainly the single port left open on the DynoMax is still less restrictive than the B&B, which is known for drone. If the single flapper is truly effective – then can anyone explain why?? Noise cancelling / standing wave effect maybe??

Has anyone run the DynoMax 17228 without the flapper? How is that noise/drone compared to the B&B or a Power Effects?

I have a B&B system. How do I tell what generation the mufflers are, and which generation do I want them to be? Is there a source for a flapper if I decide to use the B&B Tips on a DynoMax?

Lastly, DynoMax has a new muffler with a flapper inside. The 17963 Specs show the same CFM, however the muffler casing is 20” long (vs 14" for the 17228). Has anyone tried or considered these? Are they just too long?


Thanks for all the info and thoughts.

Robin
94 Dark Red – Almost Stock
94 Adm Blue – Not stock

[Pete]

Dominic,can you post up some sound clips of your exhaust?

Also can you tell us what you think of the sound, i.e. too loud,does it rattle your brain,can you hear yourself think etc,.

I was in Doms Z very nice and quiet at cruise,we can talk normal and hear each other but at WOT it's a different story.
I thought my B&B's w/flappers was quiet after getting in Doms Z his sounds like a stocker compared to mine.

Dom, please post up some thoughts on your exhaust system.

Pete

[Paul Workman]

Originally Posted by sammy

How much difference does the flapper make? I am surprised that it would make a really significant difference in noise/drone, since it is only covering up one of the two exhaust ports and the other is still wide open. Certainly the single port left open on the DynoMax is still less restrictive than the B&B, which is known for drone. If the single flapper is truly effective – then can anyone explain why?? Noise cancelling / standing wave effect maybe??

"Standing wave"... You obviously know a bit about impedance matching, and the phenomenon of energy reflecting back when a change of impedance is encountered, yes?

Reflected (sound) energy will either add (if in phase) or cancel (out of phase) with the arriving energy. The math gets a bit involved, but by experimenting with different (exhaust pipe length in this case) the gist of it is it is possible to cancel certain frequencies by intentionally causing (sound) energy to be reflected and be at the opposite phase with relation to the arriving sound pulse ... and thus cancel eachother out. The flapper is that impedance altering device in the line, and when closed, the sound pulses reflected by it will (at certain frequencies) if not completely cancel the arriving sound pulses, at least diminish it significantly.

Baffles in mufflers and chambered exhausts have been around since the internal combustion engine. But the really exciting thing about this "flapper" thing is the ability to turn it off and on, depending on power demands. I used to have a motorcycle with a manually controlled flapper at the tip of the pipes. They were like a washer, rather than a "on-off" gate, and man were they ever effective! So, when I first saw the flappers used on a car, it was like a palm slap to the forehead...Dayam!! Why didn't I think of that!!!

I agree w/ Pete n Bob G n Dom that the vacuum actuated gates (flappers) are the way to go. They automatically respond to "right foot demands". However, those aren't lying around everywhere which has me looking at electric gates at a reasonable price. I may have found some. Just last week I saw some really nicely built 'lectrics for $99 a copy at a local speed shop. The size was bigger than I wanted for blocking one of the exhaust ports, but they said other sizes are available.

Interesting stuff, this having one's cake and eating it too!

P.

[XfireZ51]

Originally Posted by Pete

Dominic,can you post up some sound clips of your exhaust?

Also can you tell us what you think of the sound, i.e. too loud,does it rattle your brain,can you hear yourself think etc,.

I was in Doms Z very nice and quiet at cruise,we can talk normal and hear each other but at WOT it's a different story.
I thought my B&B's w/flappers was quiet after getting in Doms Z his sounds like a stocker compared to mine.

Dom, please post up some thoughts on your exhaust system.

Pete

Pete,

At the FBI, we have a few flavors of the Z06 flapper system. Al and Pete are using the valves with B+B tips, while BobG and myself also have the Z06 tips. Al and Pete have driven in our cars (Bob/mine) and have noted how the Z06 tips may also contribute to the lower noise level. The B+B tips are straight wall design from entrance to exit while the Z06 tips are a funnel. Going along w Paul's point, the horn shape may disrupt the creation of a standing wave in the tip and so limiting drone. JMO but its interesting that the Z06 tips mimic the Corsa tips and that both Pete and Al have noticed a audible difference even w using the flapper valve. Frankly, I have noticed a mellowing of the exhaust note as the Dynomaxs have broken in. At steady throttle cruise, the exhaust is no louder than my Magnaflow w the resonator. And w the addition of the 3.73, its really pleasant to drive.
Here's a vid at idle from today and as you can see the outer tip is closed so the exhaust is coming from the inner tip which also shows more coloring from the exhaust. As I step back, it really is fairly quiet. BTW, no resonator and using an SW Xpipe w 3" pipe.

[Hib Halverson]

As an owner of both a '12 Z06 and a '95 ZR1, I've found the adaptation of the C6 Z's bypass valves to a C4 Z exhaust system a very interesting idea.

A couple of questions, however, which maybe the more experienced Zroners here like "Pete," who one person posting here termed a "god," and others who are using the bypass valves in a 2G ZR1 exhaust might be able to answer...

The bypass system used on 3G ZR1s, Z06es and Grand Sports with NPP was intended to use a muffler with two "paths". One is virtually a straight through path, which operates when the bypasses are commanded open and the other path is a "circuitous" route, typical of a quiet, reverse flow muffler, which is active when the bypasses are commanded closed. Do the aftermarket mufflers you guys are using support that sort of arrangement or do the mufflers you choose simply have two outlets and you're using the bypass to close one, thus, increasing restriction but not necessarily changing the route exhaust flow takes.

Second question in re: the Flowmaster muffler...it was said in an earlier post that...

"Exhaust for max performance" and Flowmaster do not belong in the same sentence. I have a set of Flowmasters on one of my cars, so I'm not really a hater, but they just don't belong on a Vette, especially an LT5 car.

What I missed is why that is true. No one posted any explanation, facts or test data to support that statement or elaborate on it.

I'm looking to become better informed so, please, help me out here.