Helmholtz Exhaust 2012

[Tommy Cookers]

The subject of the thread is an exhaust system that has a blind pipe branch with no neck

the effect of this depends on where it is, the likely goals here are synthecising an ideal overall system length or/and geometry that are unattainable otherwise, this has been known in the performance field for 60+ years


The Helmholtz device is a chamber with a neck, not really the same thing

Who decided to call the blind pipe Helmholtz ??
Have Ferrari got Wikipedia-itis ??

[cheapracer]

The subject of the thread is an exhaust system that has a blind pipe branch with no neck

The Helmholtz device is a chamber with a neck, not really the same thing

Meh, semantics, in this case the chamber happens to be the same diameter as the neck.

Anyway, didn't come back to post that, thought just occured to me that it's probably illegal under the engine freeze agreement.

[strad]

Just shopping for for a new exhaust for the Stang and guess what MBRP Exhaust has?,,,Tuning tubes ..ie Helmholtz chambers.

[hardingfv32]

Went to MBRP Exhaust and could not find it. Can use post a reference.

Brian

[strad]

Brian...been looking back and can't find it....Maybe it wasn't MBRA,,they had two chambers on either side of a new Camaros driveline. I'll keep lookijng but I'm begining to question my sanity,.

[n smikle]

The subject of the thread is an exhaust system that has a blind pipe branch with no neck

the effect of this depends on where it is, the likely goals here are synthecising an ideal overall system length or/and geometry that are unattainable otherwise, this has been known in the performance field for 60+ years


The Helmholtz device is a chamber with a neck, not really the same thing

Who decided to call the blind pipe Helmholtz ??
Have Ferrari got Wikipedia-itis ??

where does it say it needs a neck? The f1 tuning cannot be the same as a 6000rpm road car.

[hardingfv32]

The Helmholtz device is a chamber with a neck, not really the same thing

Yes, the correct name should be 'Side Branch Resonator'. So what is the function in this application? Are they trying to mask the sound of off throttle blowing?

Brian

[Holm86]

Many standard cars has these chambers. Just not on the exhaust but on the intake. There they work as to reduce resonance and sound from the induction.

[strad]

In the exhaust syestem for road cars , I'm still trying to refind, uses it to combat drone.
AND in said looking about I found that the stock mufflers for an LS3 Chevy engine,,in a 2010 Camero I believe. have a pipe and chamber that could well be called a Helmholtz device .

[Cam]

Some nice reading here from our friends at NASA: Fluid Mechancial Model of the Helmholtz Resonator.

The introduction, about 6 pages in, pretty much explains in explicit detail what is, what is does and you can see why it's of particular use in F1 engines talking about intense sound fields. Full of equations, experiments and detailed info. Enjoy.

http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19770025891_1977025891.pdf

Below image is a sample of one of the graphs.

[aussiegman]

The Helmholtz device is a chamber with a neck, not really the same thing

Yes, the correct name should be 'Side Branch Resonator'. So what is the function in this application? Are they trying to mask the sound of off throttle blowing?

Brian

Why would they when the ECU mapping would show exactly what they were trying to hide, that being off throttle blowing of the diffuser similar to that which was seen by the FIA review of RBR in Germany.

[hardingfv32]

Why would they when the ECU mapping would show exactly what they were trying to hide, that being off throttle blowing of the diffuser similar to that which was seen by the FIA review of RBR in Germany.

A bit of sarcasm, as these resonators are usually used for drone elimination on the street.

On a serious note, keeping a development stealth is half the fight. What RB did could just as easily been viewed favorably by Buaer and no statements made about what was going on. If the car does not exhibit telltale sounds, why is the competition going to complain? Off throttle blowing is not against the rules if accomplished with in the rule set.

Brian