Vortex Performance Exausts

[flipperthebushkangaroo 2]

Found a positive article about vortex performance exhausts in Augusts "Car Mechanics" and after a search found this topic

http://forum.205gtidrivers.com/index.php?s...9&hl=vortex

Lots of interesting opinions but no one had at the time tried one. So was wondering if anyone had tried them yet? as the origional posters said the performance and economy gains seem a quite optimistic but the magazine article seemed quite impressed with the cleanliness of exaust gasses.

 

So as i said any experiances?

Roddie

[Mad Professor 7]

When I used to work at the local garage / rolling road, we use to also make exhaust systems, and a number of cars where fitted with Vortex units.

 

I am talking about 2 to 3 years ago, since I left the firm, so I don't know what versions of vortex units are out now.

 

But I can say the Turbo'ed cars that we fitted Vortex to had much less turbo lag after, and also did gain bhp and torque.

 

I can't say much about the NA engines, and I never tested above and after fitting the vortex units.

[Batfink 201]

Without a comparison against competitors the results are pretty meaningless if you are trying to work out whether the technology works.

Looking at their site they have a nice diagram showing basically a straight through exhaust system so even they dont really help in matters.

Obviously bore size is critical to an exhaust system, but also whether the OE system is restrictive at high gas speeds makes a difference. The OE may be optimised for mid range and low down power, so will be too small for people chasing bhp.

I've just been developing a system for a VW Lupo GTI and we managed to get 9 bhp from an exhaust manifold (with a sports cat), but VW had managed to design a wierd but seemingly very efficient standard exhaust system that we could only make a couple of bhp up on. When the engine is further developed I'd expect results to swing in our favour but a flat minimum 10% gain on all standard cars is not going to be easy..especially normally aspirated.

I'd expect easy gains with turbo engines though as they respond very well to larger and straight through bore systems

[Cameron 16]

It's rubbish basically.

 

The effect of pressure, temperature and velocity of gases has been studied in great detail for a very long time, and it is a fundamental principle of engineering that the pressure, and velocity (forget temperature, it's irrelevant here) must be in balance in a system. What that means is for pressure to decrease, the velocity must increase in order for the flow rate of the system to remain constant. So yes, by speeding up the gases in the silencer they are lowering the pressure, BUT this does not mean the gases entering the silencer will be "sucked in", and furthermore as soon as the gases leave the silencer and slow down again the pressure will be equal to what it was before entering the silencer.

 

Creating a vortex also requires some energy, and since the silencer puts no energy into the system (it has no moving parts) and the fact that energy cannot be created or destroyed, this energy must come from the exhaust gases! I've seen the insides of a Vortex silencer while the guys at BTB were filling me in on how much bulls*it they are, and they're basically a bit like the inside of a jet engine in that the gases flow around a tapered core and are directed by curved vanes to create "da vortex!". But these curved vanes and the tapered channel act as a restriction, which saps energy.

 

The Vortex silencers get their performance gains by being more free-flowing than a baffled silencer, but they are not as free-flowing as a straight-through silencer. This is why NOBODY in motorsport (with the exception of a few morons who buy into their hype) uses these silencers, and everybody uses straight-through ones instead. Even DTM, which are basically closed-cockpit F1 cars, don't use this technology.

 

So yes, it's bulls*it. Everything they quote on their website goes against fundamental principles of engineering and physics. Don't buy one.

 

[Batfink 201]

By choosing the right bore you can help exhaust scavenging by keeping a high velocity. I guess this is the theory they are playing with

[Cameron 16]

The gas speed really has nothing to do with it as long as the system isn't causing a restriction, plus all of the tuning effects of an exhaust happen in the manifold, with the exception of V engines with separate headers. The tuning effect of an exhaust is an acoustic phenomenon, and is to do with the expansion of high pressure waves causing waves of negative pressure to be reflected. This all happens in the collector on the manifold, where the small diameter primary suddenly expands to the large diameter collector. Incidentally this is why 4-2-1 manifolds give a greater spread of torque, as you then have 2 instances where the manifold is "on tune" as opposed to a 4-1 where it only happens once. Once the system has expanded to it's final cross-section there is nothing more to be done other than ensuring the gases exit as freely as possible.

Edited August 23, 2010 by Cameron