Exhaust Washer Mods

[Throckmorton]

I thought you were talking about cars. Now we're comparing motorcycle emissions to car emissions?

The engines are basically the same... except until recently motorcycles had no cats. Unless someone is willing to bypass their cats and do an experiment with a smog test machine, they are the best comparison

 

[Ferzerp]

The engines are basically the same... except until recently motorcycles had no cats. Unless someone is willing to bypass their cats and do an experiment with a smog test machine, they are the best comparison

You're close, but you're turning cats in to magical devices.

Motorcycles are what you get when you don't have stringent emissions requirements, but just throwing a cat on it doesn't magically fix that. There is a lot more to emissions than that one part.

 

[jlee]

The engines are basically the same... except until recently motorcycles had no cats. Unless someone is willing to bypass their cats and do an experiment with a smog test machine, they are the best comparison

A 2-4 cylinder motor that revs to12-16,000 RPM is not the same as a car engine.

You're making me want to go get my emissions test done sans cat just so I can show you how far off your numbers are.

 

[Gillbot]

You're close, but you're turning cats in to magical devices.

Motorcycles are what you get when you don't have stringent emissions requirements, but just throwing a cat on it doesn't magically fix that. There is a lot more to emissions than that one part.

That's been my whole issue with this argument from the beginning.

Plus if a car can pass an emissions test, it's still a gross polluter if it doesn't have a cat? They must be testing for the wrong things? Why bother testing them if they don't mean anything?

 

[xSkyDrAx]

:thumbsup::biggrin: I'm going to market that and start selling 'Speed Holes' on ebay.

I feel sorry for the man that has never heard of speed holes.

 

[Throckmorton]

You're close, but you're turning cats in to magical devices.

Motorcycles are what you get when you don't have stringent emissions requirements, but just throwing a cat on it doesn't magically fix that. There is a lot more to emissions than that one part.

Right, the cat also requires other equipment like the oxygen sensors and MAF to control fuel.

 

[Mark R]

Plus if a car can pass an emissions test, it's still a gross polluter if it doesn't have a cat? They must be testing for the wrong things? Why bother testing them if they don't mean anything?

That's quite possible - although it depends what you mean by "gross" polluter.
Tail pipe emissions testing necessarily has to be set quite slack, to avoid false failures. Similarly, OBD II doesn't necessarily mean terribly much, only that everything is working within design limits; which is not, in itself, proof that emissions are acceptable. It is a reasonable indicator, however.

For example, my local emissions testing regulations require test of tail-pipe emissions at idle and fast idle as follows:
CO: < =3.5%
Hydrocarbons: < 0.12%
If a cat is fitted, lambda must be between 0.997 and 1.003

It is possible to pass these emissions without a catalyst, and even possible to pass on a decatted car.

However, a car with a correctly functioning catalyst will almost always pass by a huge margin. I've kept all the emissions certificates for my cars. At every single tail-pipe test, the emissions have been measured as:
CO: Not detected (<0.003%)
HC: Not detected (<0.0001%)

 

[jlee]

Right, the cat also requires other equipment like the oxygen sensors and MAF to control fuel.

The ECU requires oxygen sensors and the MAF sensor (or AFM or MAP). The cat doesn't give a shit. It has no moving parts and just heats up and burns stuff.

 

[Throckmorton]

The ECU requires oxygen sensors and the MAF sensor (or AFM or MAP). The cat doesn't give a shit. It has no moving parts and just heats up and burns stuff.

Add I understand the cat requires the proper stoichiometric ratio or it well be damaged by carbon deposits

 

[JCH13]

Add I understand the cat requires the proper stoichiometric ratio or it well be damaged by carbon deposits

Those controls are in place to let the car run well, not so much to help out the catalyzer.

 

[TridenT]

The ECU requires oxygen sensors and the MAF sensor (or AFM or MAP). The cat doesn't give a shit. It has no moving parts and just heats up and burns stuff.

Mmm... I don't know about that. You make it sound like you can add a catalytic converter to any car like you could add any muffler.

From what I've read, that's not true at all.

 

[Gillbot]

Add I understand the cat requires the proper stoichiometric ratio or it well be damaged by carbon deposits

But you made it sound like tossing a cat on any car magically fixed it. Also, having a cat negated the fact that it could be a potential polluter after inappropriate mods were added.

Mmm... I don't know about that. You make it sound like you can add a catalytic converter to any car like you could add any muffler.

From what I've read, that's not true at all.

See above.

 

[JCH13]

Mmm... I don't know about that. You make it sound like you can add a catalytic converter to any car like you could add any muffler.

From what I've read, that's not true at all.

That is exactly what JLee did with his car, as a matter of fact. It is exactly what I've done to another MR2 as well.

 

[TridenT]

But you made it sound like tossing a cat on any car magically fixed it. Also, having a cat negated the fact that it could be a potential polluter after inappropriate mods were added.

See above.

That is exactly what JLee did with his car, as a matter of fact. It is exactly what I've done to another MR2 as well.

Contradicting statements here.

 

[Gillbot]

http://forums.anandtech.com/showpost.php?p=35412829&postcount=19

 

[jlee]

Mmm... I don't know about that. You make it sound like you can add a catalytic converter to any car like you could add any muffler.

From what I've read, that's not true at all.

You can. I passed emissions (tailpipe sniffer) just fine, too.

 

[FuzzyDunlop]

This thread makes my head hurt. I dont need cats or mufflers for my car where I live and THANK ALAH!

Trident is partially right, even though he may not know it... a poorly located over/under sized cat/muffler can have negative effects or next to no effects at all on emissions. SO therefore you cannot just throw ANY random cat/muffler combo on a car and expect better results. amirite?

Jlee installed appropriately sized and located cat/muffler (but of random brands) and made it work to pass emissions. He didnt need an MR2 specific cat/muffler combo.

how are these contradicting?


EDIT: back on topic. THis mod reminds me of the time my brother drilled holes in his catalytic converters on his 1980 Oldsmobile 88. It did help performance a lot, but it smelled and was LOUD.

 

[JCH13]

Contradicting statements here.

Not at all. Some minimum amount of though must be applied, but installing a CAT isn't some magical black art.

 

[AdamK47]

I have side pipes on one of my cars. 3" exhaust with 1-7/8" headers and no cats in the mid pipes. The aroma is pure decadence. I like to believe everyone I pull up next to in traffic feels the same way.

 

[Mark R]

Add I understand the cat requires the proper stoichiometric ratio or it well be damaged by carbon deposits

It's not so much that it's damaged by carbon deposits, but that it needs the correct balance of oxygen, NOx and HC to work optimally.

If the mixture is lean, there is insufficient unburned fuel to neutralise the NOx. As a result, NOx emissions tend to be excessive.

If the mixture is rich, there is insufficient O2 and NOx to neutralise the CO and HC.

This is why in sniffer tests, the tail-pipe lambda is usually checked, and must be within strict parameters; one of the problems with exhaust leaks, deliberate or not, is that they allow air into the tail-pipe mixture which will result in tail-sniffers reading excessive high lambda, resulting in an emissions fail.

Catalytic converters store oxygen from reduction of NO, so short term imbalances are allowed; e.g. for when short-term over-rich mixtures are used, such as hard acceleration. However, catalyst efficiency is impaired if over-rich mixtures are used for more than a few seconds at a time. However, the very latest emissions standards are getting very difficult, which is why some manufacturers are trying to push towards stoich at WOT; this is a major engineering challenge, requiring solutions such as water-cooled exhaust manifolds built as part of the head.

This oxygen storage is how the OBD test works. The ECU repeatedly sets the mixture slightly lean and slightly rich, and watches that the post-cat mixtures remains stable, indicating that the cat is absorbing and releasing oxygen in response.

 

[compman25]

Right, the cat also requires other equipment like the oxygen sensors and MAF to control fuel.

Tell that to my 78 F250 that had cats at one time. Pretty sure no o2 sensors or ecu or anything of the sort on it.

 

[Rallispec]

meh, haters gonna hate.

I ran the 'washer mod' on my 2005 Legacy GT for a year or so. I liked it, got a lot of compliments on how it sounded. I eventually upgraded to a full exhaust and actually felt like it droned more than the washers did.

great thing about the washer mod is that it's easy and cost 75 cents... You can try it and undo it at any time.

 

[AdamK47]

Muffler delete or this washer mod, it's going to sound like crap. This mod is akin to banging holes in your muffler with the screwdriver.

 

[exdeath]

I have side pipes on one of my cars. 3" exhaust with 1-7/8" headers and no cats in the mid pipes. The aroma is pure decadence. I like to believe everyone I pull up next to in traffic feels the same way.

Fuck yes.

 

[JCH13]

meh, haters gonna hate.

I ran the 'washer mod' on my 2005 Legacy GT for a year or so. I liked it, got a lot of compliments on how it sounded. I eventually upgraded to a full exhaust and actually felt like it droned more than the washers did.

great thing about the washer mod is that it's easy and cost 75 cents... You can try it and undo it at any time.

Meh, ricer's gonna rice.