Are there any performance differences between Resonated vs Non-Resonated?

[Eddie Man]

Reason for the question is that when I had my B7/S4 from day one, I modded directly to Milltek Non-Resonated & DPs w/HFC...

The sound was great but I grew tired of the constant roar in the cabin. After a month, I went the Resonated route...
Still the great sound, but muted in the cabin. It's actually very "dandy" now in the cabin by I want some bite.
I only wish I had the sound somewhere in between the Rez & the nonRez.

Now if there really is no performance differences between the two, would I be completely Off-My-Rocker to even think to only have one of the CatBack Pipes be Resonated and the other CatBack Pipes be Non-Resonated.
Hypothetically, then the sound would be, like I said somewhere in between.
Would back pressure be affected and hence have an imbalance in the V8 banks?

Has anyone done this?
Thoughts?

[Meradin]

If the resonator is after the h-pipe then back pressure shouldn't be a problem. I don't know how it would sound but I would guess the same as you.

[craiglieberman]

Assuming the resonator has the same inlet/outlet size as your piping and is not necked down inside, there should be minimal impact on performance, but there will be noticeable difference in the drone.

The bigger the resonator you install, the more drone you'll remove...but the more likely it'll be that you'll affect your hp.

This is one of the significant disadvantages of building a custom exhaust at a muffler shop, or to using a system built by tuners who insist on oversizing pipes in the hopes of making the system as "free flowing" as possible.

I'm not saying that your exhaust builder did that, I'm just saying that we see similar results in the above scenarios.

[RE5PECT]

Originally posted by craiglieberman
Assuming the resonator has the same inlet/outlet size as your piping and is not necked down inside, there should be minimal impact on performance, but there will be noticeable difference in the drone.

The bigger the resonator you install, the more drone you'll remove...but the more likely it'll be that you'll affect your hp.

This is one of the significant disadvantages of building a custom exhaust at a muffler shop, or to using a system built by tuners who insist on oversizing pipes in the hopes of making the system as "free flowing" as possible.

I'm not saying that your exhaust builder did that, I'm just saying that we see similar results in the above scenarios.

craig, arent you rollin a magnaflow RS4 nowadays?

[craiglieberman]

Originally posted by RE5PECT
craig, arent you rollin a magnaflow RS4 nowadays?

On and off...we still have the car, although it's been idle mostly as we wait to show it at SEMA.

I ordered a Sprint Blue one in July and just found out today that the car arrives at my dealer Monday...loved the car so much I had to get one of my own!

[RE5PECT]

Originally posted by craiglieberman
On and off...we still have the car, although it's been idle mostly as we wait to show it at SEMA.

I ordered a Sprint Blue one in July and just found out today that the car arrives at my dealer Monday...loved the car so much I had to get one of my own!

nice well congrats on that... i dont know if you remember but we met a while ago with jeremy nagelburg...anyways...your UBER M3 is kickin some ass out on EP east coast crew... but that car was aswome

but as far as the RS4, yeah our shop built a sprint blue one already, its amazing color. im gonna order me a balloon white one here in the next few months and that should be a fun car.

anyways, post up pix when y ou get it...

[Eddie Man]

Originally posted by craiglieberman
Assuming the resonator has the same inlet/outlet size as your piping and is not necked down inside, there should be minimal impact on performance, but there will be noticeable difference in the drone.

The bigger the resonator you install, the more drone you'll remove...but the more likely it'll be that you'll affect your hp.

This is one of the significant disadvantages of building a custom exhaust at a muffler shop, or to using a system built by tuners who insist on oversizing pipes in the hopes of making the system as "free flowing" as possible.

I'm not saying that your exhaust builder did that, I'm just saying that we see similar results in the above scenarios.

So what you are saying is that if the inlet and outlet diameter of the pipe are the same (no necking up or down in size in any area before and after) there should be NO performance difference (sound/drone excluded) to that of a straight pipe???

On that understanding and in your opinion; Would there be any Ill-Effects of one V8 bank vs. the other V8 Bank, long term wise?

Any light you can shed on this would be appreciated.
Thanks.

[craiglieberman]

There would be a slight difference in power, but probably not anything you could feel seat of the pants.

It's difficult to explain in short terms, but basically, opening up the exhaust to a larger size and having no resonator will produce a distinct sound and a unique power curve.

Adding a resonator will change the sound, and might alter the power curve at certain points. Would the peak power be higher or lower? Would there be more power at all points on the curve? The answer is: it depends on the parts you use, their sizing and their construction.

It would not be wise to put a resonator only on the pipe from one bank of your V8. It could cause enough of a difference in flow to trigger a CEL but if nothing else, would probably affect things like EGT temps which in turn could cause the computer to compensate in strange ways. Not recommended.

The short answer is, unless you're going to dyno a bunch of configurations, your best bet is to by a dyn tested cat back for your vehicle...otherwise, you may be trading sound for power.

[Eddie Man]

Thanks for the informed feedback, Craig :)

[NWEuropean]

to the original poster -- Maybe the AWE exhaust system could meet your needs? They offer that mix and match cetner section so you can run 0, 2, or 4 resonators to mix/match for sound.

Just tossing it out there for you.

[Eddie Man]

Originally posted by NWEuropean
to the original poster -- Maybe the AWE exhaust system could meet your needs? They offer that mix and match cetner section so you can run 0, 2, or 4 resonators to mix/match for sound.

Just tossing it out there for you.

Thanks, I think I'll give them a call to see if I can maybe use a tad smaller resonator (same inlet/outlet dia, though) in place of the stock milltek resonators.