Impulse Emission Vapouriser Muffler

[rmay635703]

At first I was reminded of that exhaust heated intake side cat that reacts the gasoline upstream of being injected so it burns more completely.

[cfg83]

California98Civic -

Originally Posted by California98Civic

I noticed the NOx omission too in some of their results too. On another part of the site, IIRC, they showed that their muffler has little or no benefit with that pollutant, I think. But they posted video (edited video) of a comparative test between just a CAT and the CAT plus their "EV8" ... it shows what it alleges are sceenshots of the toyota's emissions:
...

It may be that the NOx is not part of Australian emissions testing. We need to find out what their emissions laws are.

CarloSW2

[niky]

It's easy to see from the readout that the "After" runs have the engine running much leaner, which explains the lower HC and CO readings and the much higher O2 readings.

I'm not sure how a muffler would cause an engine to run leaner unless it drastically changed the O2 sensor readings... but yes, those numbers would indicate that NOx levels will be correspondingly higher. I'd like to see EGTs for that.

This is the first time I've heard of a hotter exhaust causing lean running instead of the other way around...

EDIT: Mazda uses exhaust pulse tuning to enable their SkyActiv engines to do ultra-lean burn... and I've seen really good flowing headers cause lean-running, but this is different, obviously, from a down-stream muffler that looks more restrictive than a straight through... I'd like to see if and how this creates pulses that enable better scavenging for myself before passing judgment.

[Ladogaboy]

I don't know about whether this applies universally, but if I reduce the back pressure on my car's exhaust, the engine will run leaner. I'm not sure of the exact reason, but it is something that tuners take into account.

Regardless, I'm sure that the NOx has to have increased significantly. If anything, these results look similar to the results I've seen for "high-flow" aftermarket CATs. Usually 100 to 300 cpsi (as opposed to the 600+ for OEM, ceramic CATs).

[niky]

But these are mufflers that go onto the exhaust of a car already running catless. Why would mufflers with inner (capillary?) tubes cause less backpressure? Is it because some resonance tuning causes better scavenging? Or is there something to the hot exhaust idea (supposedly hot enough to melt cats...)? And how does it heat up the exhaust?

[Ladogaboy]

I'm not sure why the mufflers themselves would lean out the AFR, but that seems to be the result. In regards to back pressure, most OEM mufflers are baffled and cause the exhaust to change direction (slowing it down and causing back pressure). These mufflers are a straight-through design, so the exhaust gasses should be faster and less impeded.

[jakobnev]

Originally Posted by Ladogaboy

I'm not sure why the mufflers themselves would lean out the AFR, but that seems to be the result.

I think what we are suspecting here is that the Emissions Fairy turned the mixture screw om the Camry between tests..

[cfg83]

jakobnev -

Originally Posted by jakobnev

I think what we are suspecting here is that the Emissions Fairy turned the mixture screw om the Camry between tests..

Hmmmm, good point. Is my table consistent with that hypothesis?

CarloSW2

[jakobnev]

cfg83 -

The table screams it.

[mort]

Originally Posted by jakobnev

cfg83 -

The table screams it.

At the start of the video a slide says "no tuning or modifications" I just don't see how any muffler can increase A/F from 15.1 to 17.1. At 17.1 that Toyota would have been barely able to keep running.

If I may speculate, there is an open fitting on the Vapouriser and by venturi effect, air is drawn into the exhaust system, diluting the emissions and adding oxygen some of which improves converter action. Many problems with this theory, like any back pressure...

More likely Emissions Fairy.

-mort