How to tell diff between a 2 & 3 way cat.
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Visually there is no difference. Internally, the 3-way cat has a separate bed in the front that reduces NOx emissions during slightly rich emissions. During slightly lean mixture, it stores O2 in the substrate material, for release into the Oxidation bed to convert HC and CO to CO2 and H2O.
Visually there is no difference
Hay Joe:
Well...when ordering, how can we tell that the guy behind the (PepBoys, Kragen, you name it) counter is "really" ordering a 3-way?
Am I right that a 3-way is more smog effective, & will help pass a car that otherwise may borderline passing tech?
Thanks...appreciate your constant vigilance this site.
...Ray
Hay Joe:
Well...when ordering, how can we tell that the guy behind the (PepBoys, Kragen, you name it) counter is "really" ordering a 3-way?
Am I right that a 3-way is more smog effective, & will help pass a car that otherwise may borderline passing tech?
Thanks...appreciate your constant vigilance this site.
...Ray
- Joined
- Jul 20, 2001
- Messages
- 2,205
The part number is the only way to determine 3-way or 2-way. Then you'll have to cross reference the part number to the parts catalog. USEPA regulations requires the part number of the cat to be visible on the outer shell.
3-Way Cat
Thanks. I remarked that, because a while I ago I mentioned about 3-way cat to counter person & he didn't know what I meant, that gives me impression we can be receiving a 2-way or 3-way & not know difference. Is there a particular description, etc., than can be used to ensure that a 3-way is being purchased?
Also, will it help smog check in a case where car is borderline?
My GN has always been ok with smog, but will need new cat with next check up, so may a well get a 3-way. I'm sure that is same for many owners.
Appreciate the info......Ray
Thanks. I remarked that, because a while I ago I mentioned about 3-way cat to counter person & he didn't know what I meant, that gives me impression we can be receiving a 2-way or 3-way & not know difference. Is there a particular description, etc., than can be used to ensure that a 3-way is being purchased?
Also, will it help smog check in a case where car is borderline?
My GN has always been ok with smog, but will need new cat with next check up, so may a well get a 3-way. I'm sure that is same for many owners.
Appreciate the info......Ray
- Joined
- Jul 20, 2001
- Messages
- 2,205
Used to be that a 3 way cat had an air tube mid bed to inject air (from an air injection system) to assist with oxidation and the forward bed was used for reduction. But these days, ther is really no way to tell. So if you're unsure, ask the counter person to let you see the parts catalog (to confirm).
- Joined
- Jul 20, 2001
- Messages
- 2,205
#1HotRod said:Thanks Joe.
How's your GN coming? Doing anything new with Chevy?
Some of us down here will be going up to Sacto dragstrip for Hang Over Nationals (Jan 1). You interested? Would be great to meet ya.
On the GN I just installed clear park lenses and they look great. I just purchased a set of window sweeps and will replace them this weekend, plus some maintenance work. I was at Good Guys last weekend and may have a buyer for the Chevelle carcass. I'm still looking for a 2 door 64 chevelle. I'm interested in Jan 1 at Sac raceway. Keep me posted.
Cool on the GN progress & interest in Jan 1 meet.
Just put new MT Drag Radials on GN & would be great to know it's timing, never had it at a strip. Fairly stock & peg-leg, but runs great with little mods it has (thanks to 60 pounders, Eric's chip & Lou's finess), I would hope low 13's. I'm sure I'll bring the 442 but wld be cool to also have the GN. Come on down & drive it up for me & I'll let ya run it (it would only be about 800 miles for the 4 trips!). Or, a funny sight would be the GN pulling 442 on a trailer. If the weather sucks the Fresno crowd could all gather in your garage & eat all your food & drinks :biggrin:
Will keep ya in mind as gets close to 1/1/06. Adios....Ray
Just put new MT Drag Radials on GN & would be great to know it's timing, never had it at a strip. Fairly stock & peg-leg, but runs great with little mods it has (thanks to 60 pounders, Eric's chip & Lou's finess), I would hope low 13's. I'm sure I'll bring the 442 but wld be cool to also have the GN. Come on down & drive it up for me & I'll let ya run it (it would only be about 800 miles for the 4 trips!). Or, a funny sight would be the GN pulling 442 on a trailer. If the weather sucks the Fresno crowd could all gather in your garage & eat all your food & drinks :biggrin:
Will keep ya in mind as gets close to 1/1/06. Adios....Ray
