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Catalytic converter to cure fumes?


280Z Turbo

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I'm running one with my L28 turbo and it made a world of difference! You may still be breathing exhaust, but it's a lot less toxic. I don't notice any exhaust odor anymore other than the occasional faint whiff of a rotten egg smell when backing off the gas after a full throttle run.

 

Based on my experience, two of my friends with NA L28's have added cats and they too are very pleased with the results. The converters are so cheap these days, and the power loss is insignificant if any, so it's hard to find a reason not to do it. Mind you, this is not a solution for a badly tuned engine!

 

Oh yeah, and it's better for the environment too, so it's a win-win solution all around!

 

Nigel

'73 240ZT

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A converter won't change infiltration.

 

1% Carbon Monoxide is considered fatal. It's also orderless. You can pick up an inexpensive disposable CO 'indicator' at most any small aircraft renter.

Edited by RTz
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A converter won't change infiltration.

 

1% Carbon Monoxide is considered fatal. It's also orderless. You can pick up an inexpensive disposable CO 'indicator' at most any small aircraft renter.

 

Exactly! All the better a reason to have a converter...

 

Nigel

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As I understand it, a converter primarily addresses hydrocarbons.

 

Modern three way converters split nitrogen oxides into nitrogen and oxygen, oxidize carbon monoxide to form carbon dioxide, and oxidize hydrocarbons to also form carbon dioxide and water. With a closed loop system, you can get close to 100% conversion of all three.

 

Nigel

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I'm probably going to get this one:

 

http://www.summitracing.com/parts/MPE-59959/

 

GRM tested a cat just like this on their Miata and the dyno showed no difference between it and a test pipe.

 

That's the one one of my friends is using. It's a nice compact unit. I wish it'd had been available 6 years ago when I installed a converter in my Z.

 

Nigel

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its funny, I have about 36" of exhaust off my turbo and I dont think its that bad inside. And I dont even have a hatch seel lol.

 

Maybe you're used to it? Smokers don't seem to notice how much cigarette smoke smells or how sick it's making them either. BTW, I'm not trying to imply that YOU are a smoker. I've no idea if you are or not. I'm just trying to make a point.

 

Nigel

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Many times the fume problem is caused by people running a tailpipe that is TOO SHORT relative to the OEM fittment.

 

If you don't have that tailpipe in the right portion of the airstream (see aero forum) the gasses boil up around the back of the car and jus sit there. With a window open, you create a vacuum in the car, and just draw fumes in like crazy. Have a short enough pipe, and they can acually be brought in through the drain plugs in the spare tire well, radio antenna drain tube, etc...

 

If the chassis was originally designed with a Catalyst in mind (proper floor clearances and heat shielding) there is nothing wrong with putting one on there, jsut realize most of the aftermarket stuff is worth what you pay for it---which isn't much. It's not uncommon for these to be dead after working a year.

 

Plus, three-way catalysts usually require additional air be provided (it's why new GM's have Air Pumps again...) The catalysts on the earlier cars were not three way.

 

I'd look where your tailpipe exits. I've solved more 'fume problems' by simply putting a chrome tailpipe extension onto the car.

 

Also, realize if your getting a 5% CO reading (threshold point where just about everybody finds it objectionable to smell the exhaust fumes), likely you have ANOTHER problem with your fueling. Putting a catalyst on it is merely masking the real issue. These cars should really be just as clean without a catalyst as with one. The Federal and CA specs for 76 aren't that different. One with Catalyst, one without. It's there for times when you are out of the closed loop situation (WOT, Over 80mph, Over 3500 rpms) and the engine is making full rich power, and needs scrubbing of the exhaust. Other times, you are in closed-loop at 14.7:1 simply to keep enough HC and O2 in the exhaust to keep the converter operating. Really, you can clean up the car at cruise to 83 California Catalyzed Levels (save for NOx...it will be high...) by leaning the mix out to the point of impinging on lean misfire. The EFI (or SU's for that matter) will run EXTREMELY clean on HC and CO at that point. My 73 with SU's and AIR injection passed the tailpipe test to 83 Catalyzed standards when tested!

 

Remember they have to keep the catalyst hot to work on transients, so for that to happen Stochiometric gives enough O2 and HC to keep it hot and ready to roll. Emissions of HC and CO will drop on the lean side of Stoich under cruise, NOx will rise. Someone has a chart to post, I'm sure...

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I put similar bullet cats on mine and "smell wise" it made a total transformation. The wife stopped complaining about the car stinking up the garage and in general the exhaust smell went away. OK, I may have lost a few HP, but it was well worth it.

 

Jody

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A converter is not a cure all for a poorly running engine and a missing hatch seal. And yes, a well tuned engine can pass 26 year old emissions standards without one (I’ve seen it done too). But if you can significantly reduce those emissions even further with minimal cost and no performance loss as part of an overall strategy to reduce exhaust fumes by incorporating a converter, then it makes sense to me to take advantage of that.

 

No, a converter is not going to be 100% efficient 100% of the time. But neither is an engine going to be 100% tuned and running in the ideal state to minimize emissions 100% of the time. And you could drive yourself crazy obsessing over every little pinhole leak in your car.

 

Try one out. For $100, it’s not much of a gamble. I’ve had mine in my Z for 6 years and 20,000 miles, and I’ve done track days and probably 200 drag runs and it’s holding up fine so far. If it crapped out tomorrow, I’d gladly shell out another $100 for a replacement. Everyone that I’ve come across who’s tried one has been happy with the results.

 

Nigel

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Nigel,

 

Any info or a Toronto connection of where to buy?

 

I've been thinking of tossing one on my car...

 

I can't remember if I ordered mine from Canadian Tire or bought it on-line from driverfx.ca (prices in Canadian $). Driverfx.ca has some really competative prices and a hugh manufacturers list. But the weird thing about driverfx.ca is that you have to call them if you want to place an order over $200. If you try to submit the order on-line for anything above $200 you get this vague message that there was "a problem" processing your order. Nowhere does it tell you about the $200 cap on the website! So, when you're ready to submit your order on-line, you have to call them and they will temproarily raise the limit. Really stupid. There's also performanceparts.com, which has free shipping in Canada. But there's ~$17US handling fee, and even if the website says they have stock, they may not have stock on the item in Canada and they won't ship it from a US warehouse unless you call them and ask them to send it USPS from the California warehouse. Apparently the California warehouse is the only one that can ship USPS!

 

Other than that, your best bet is just to call around to some local performance shops and see what you can find.

 

Nigel

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