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Catalytic Converter replacement - looking for clarification?


Markus

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From NASA TT rules 6.4.1 Modifications and Point Assessments:

31) Removal, upgrade or modification of catalytic converter(s) +1

 

6.5 OEM Definition:

For the purpose of NASA TT points assessments, the term OEM will be defined as follows: Any part that is identical in size, shape, and functional characteristics compared to the part that originally came on the vehicle, from the manufacturer, as a standard feature of the base model as it is listed in section 6.3.2 Base Classifications or is listed as a standard replacement part by the OEM manufacturer.

 

My situation - I have a 1991 Miata. When the OEM cat went bad I replaced it with a straight pipe and took the +1 point. I still daily drive the car in the summer and feel a little environmentally guilty, also I'm not sure the minimal gains from removing the cat are worth the +1 point anyway.

 

So - what counts as an "OEM replacement"? If I go to the dealer and ask for an OEM replacement it's several hundred $$. Can I buy an aftermarket equivalent as long as it is not marketed as a high-flow cat and be in compliance with the rules?

 

What I am looking at specifically: Catco replacement catalytic converter at Summit Racing for $108

(http://store.summitracing.com/partdetail.asp?autofilter=1&part=CTO%2D4529&N=700+400320+4294907824+4294907590+115&autoview=sku)

- Note it is same size in/out as OEM, marketed as "direct replacement" and "maintain vehicle's performance level"

 

I know there are several high-flow cat converters on the market for Miatas (Jackson Racing and Flyin' Miata for example) but they are all marketed as such and usually carry a stiffer price tag ($250 range) as well.

 

So - if I go with the Catco am I meeting the intent of the rules and will this stand up to protest?

 

- Mark

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I would assume the ruling would be the same as it is for shocks. Non-OEM or direct replacement part number (from vehicle manufacturer) equals +1

 

Tho' maybe there's a little more wiggle room in Pep-Boys converters than there is in shocks...

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Change the cat, run new dyno and weight and resubmit to GG for official base classification.

 

You know...I am curious to see if I can borrow a direct OEM replacement cat as well as the Catco cat, then go to Backstreet with my straight pipe and dyno compare them all...

 

But - don't see how this would really change the weight of the car OR my base classification? Either the Catco is an OEM equivalent replacement (+0) or it's not (+1).

 

And - looking at the big picture - I'm bringing this up because alot of other people are probably in the same boat? Look at any 7-10+ year old car in Time Trials and tell me - is the cat legal or not? Seems to me like this would be a useful place to have some clarification.

 

- Mark

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Markus,

 

I have a Mazda factory cat with 40k on it that I pulled of my 1991 to install the mazda test pipe. You are certainly welcome to borrow it if you get some dyno time.

 

I would give it to you, but I am considering putting it back on as I also drive the car on the street and he test pipe with the SM exhaust is #%#^% loud.

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Some converters have steel air tubes with perforated holes to help distribute the airflow evenly, without robbing power

 

This is a grey area--getting a replacement at Pep Boys maybe---getting a replacement from Summit RACING--probably not. "Direct Fit" does not mean OEM equivalent replacement. So +1.

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Some converters have steel air tubes with perforated holes to help distribute the airflow evenly, without robbing power

 

This is a grey area--getting a replacement at Pep Boys maybe---getting a replacement from Summit RACING--probably not. "Direct Fit" does not mean OEM equivalent replacement. So +1.

 

Greg, not to add anything to this, but a catco is available many places. I searched "catco", and found a list of cats for a miata at this site.

 

They state it as:

 

1991 Mazda Miata

Catalytic Converter

Brand: Catco

 

Note: Direct Fit, Original Replacement Catalytic Converter, Stainless Steel Piping

 

[link removed]

 

What im saying, is pepboys may actually sell the exact same convertor. Then it's down to where he purchased it, rather than what the gains are.

 

my 0.02.

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Greg, not to add anything to this, but a catco is available many places. I searched "catco", and found a list of cats for a miata at this site.

 

They state it as:

 

1991 Mazda Miata

Catalytic Converter

Brand: Catco

 

Note: Direct Fit, Original Replacement Catalytic Converter, Stainless Steel Piping

 

[link removed]

 

What im saying, is pepboys may actually sell the exact same convertor. Then it's down to where he purchased it, rather than what the gains are.

 

my 0.02.

 

Here's another place listing it as a direct replacement - Car Parts Wholesale:

http://www.carpartswholesale.com/cpw_store/buy.php?make_text=mazda&model_text=miata&ml=mia--001&year=1991&part_name=catalytic_converter&brand_name=catco&make_code=MA

 

Unfortunately, it doesn't look like you can search Autozone or Advance Auto online for cats but I can go by their store if it would make you feel better?

 

Only reason I brought up Summit - I work 1 mile away from their warehouse here in Ohio (lucky me). In addition to performance parts they sell alot of OEM replacement parts and maintenance items.

 

I can run by Summit and buy a Catco on my lunch break, or I can order it from carpartswholesale without leaving my desk - just let me know which one is the +0 option, thanks.

 

- Mark

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From Greg's post:

 

Some converters have steel air tubes with perforated holes to help distribute the airflow evenly, without robbing power

 

Note this says without robbing power, which would seem to mean reducing it from OEM level. It says nothing about adding power.

 

Also, from the exhaust replacement section of the TT rules:

 

Note: Replacement of a failing OEM exhaust system with a similar new system with the same size diameter, length, and positioning of the piping, and similar size, function, and number of resonators and/or mufflers is not assessed any points.

 

So maybe the catalytic converter section needs to read something like:

 

Note: Replacement of a failing OEM catalytic converter with a OEM or OEM equivalent converter with the same size diameter, length, and positioning and similar size and function is not assessed any points.

 

Seems like similar function would allow the use of commonly available OEM replacement units like Catco while ruling out specialty high-flow units (not similar function)?

 

- Mark

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Seems like similar function would allow the use of commonly available OEM replacement units like Catco while ruling out specialty high-flow units (not similar function)?

 

- Mark

 

 

Hmmm. No matter, can I phone in my protest for your next event?

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Mark,

Just drop thew tree hugging and keep the cat you have!

 

 

if he does that, he wont have anyone to hold him. DOH!

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Ok, it seems that Catco makes both the OEM replacement catalytic converter and high flow catalytic converters. Since the one in question for Mark's Miata is a direct fit (same size, shape, and functional characteristics), and not a high flow cat. it would seem to fit the description of an acceptable OEM replacement without a points assessment.

 

Mark, make sure that there is some way for an inspector to be able to verify that you have the OEM replacement and not the high flow replacement.

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  • 1 month later...

If a cat DELETE is worth a point, why should high flow cat worth any points? If anything it should be worth 1/2 a point.

 

For instance...billy bob's car gains 5hp for a cat delete, and only gains 2hp by going to a high flow, why would both be given the same point assignment?

 

 

BTW...props for putting your cat on.....

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