Cal Club Autocross Forums

Hey Jason,

Are you making the inlet/outlet size (modding a 2" cat) not recommended as it will damage the cat or stating that changing the inlet/outlet size of a replacement cat illegal?

I asked online and Andy Hollis had this to say:

Andy Bettencourt:

Jon Lugod:
does "sizing" also apply with the ID/OD of the cat? so going from a stock 2" cat to a 2.25" is not legal?

I don't read ANY sizing restrictions. Just TYPE and LOCATION.

Taking this a step farther for clarity (hopefully)...there are two sets of things going on. The first are the objective things spelled out in the rules which include quantity, type and location. The second set of things are what happens behind the scenes in the way that cat manufacturers approve a specific cat for a specific application. There are direct-fit cats which have a unique cat fitment for a location, with stamped EPA labeling for such. Then there are "universal" cats which each have a range of applications that they are approved for. That range is typically spec'd by engine size, vehicle weight, and cat type. Those cats are approved only for applications which meet those parameters.

So tube size is not referenced directly by the rules, and practically-speaking is only a factor in having large enough tubing to flow enough for the engine/vehicle size it is approved for.

Hope that helps,

--Andy

This was a year ago when i was in search of a new cat as my stock one had gone bad. The cat meets oem requirements and is 2.25"in/out.

So according to him, I would be able to replace my stock cat with a replacement cat that's range is spec'd by engine size, vehicle weight, and cat type... So as long as my 2.25"in/out catalytic converter applies to those requirements, it is legal. yes?

jonlugod: To be blunt. Is a Magnaflow Spun Cat in 2.25" diameter LEGAL for an ST Civic accordingly to the rules set for 2009.

Yes.

--Andy

Can open, worms everywhere...

Jon, this is how I interpret things-
Take a legal cat for your car - it has an inlet diameter and and exit diameter. The stock Civic piece is a little under 2", most of the aftermarket pieces are 2", but some are even more, like the 2.25" piece you found. It's conceivable there are 2.5" or 3" diameter cats out there too, but the point here is that there are no hard-and-fast rules around that dimension.

Now, in the case of the universal cats, you're going to have a section of straight pipe at its provided inlet diameter, then at some point the piping will "neck out" to its maximum diameter, to accommodate the cat substrate. After the cat's guts, it will neck back down to its exit diameter. What I am suggesting a person NOT do, is to cut into the section of the cat where it's necking up or down, at a diameter greater than its provided inlet or outlet. I have seen the neck-down area on a 2" exit cat cut when it was about 2.5" to accommodate a 2.5" cat-back. That wasn't entirely kosher IMO but I tend to be conservative on these matters.

The good news is with the new rules one should be able to find a high-enough flowing cat that such gray-area mods aren't even necessary to avoid cat-induced power loss.

Picture below.

Andy sees it one way, Jason another, I see it another. The really cool part is our opinions don't really matter unless one of us has the honor (dishonor?) of protesting what you did...

...with all these worms, we can do some good fishin'...

ok kool. Thats what i thought you meant.

After reading this, I can't fathom how you guys can afford to build a non-stock ST legal (if there is such a thing) exhaust for these cars. The exhaust system will cost more then the car's worth.

John Coffey wrote:The exhaust system will cost more then the car's worth.

Ding Ding Ding we have a winner!!!!!

As do just about everything else they do to these cars

Speaking of ST aka spec civic

Shocks cost more
Wheels cost more
Tires cost the same as some of the cars in the class
Blueprinted engine costs more
And yes exhaust costs more

But that's better than a class where the car costs $35K and then you spend the money on mods on top.
Think of how much more expensive STU and STR are in comparison to ST to go similar times.
And man, what does it cost to run ASP?

And in ST the cars are fairly inexpensive in comparison to maintain and keep in fresh rubber.


It should also be pointed out than in ST, the low hanging fruit is quite accessible and gets you most of the way there. The old school Koni Yellow's Cawthorne had on my car worked pretty darn well and were dirt cheap. Even the shortened Koni SPSS's are under a grand new and you can win on those. Nationals keeps getting won on 195 tires so a much cheaper 15x7 wheel can probably work. The "old" setup package that is affordable still works. Its just a hypercompetitive class and people are pushing the envelope and spending a lot of money for tiny gains. That's racing.

Craig Naylor wrote:

John Coffey wrote:The exhaust system will cost more then the car's worth.

Ding Ding Ding we have a winner!!!!!

As do just about everything else they do to these cars

And the reason why our "development" has gone so far, and why the other ST classes are still playing catch up. Not everyone in the other classes are willing to go with Poly bushings, custom exhausts/header, custom ECU tune (not reflashes) - dyno time, weight reductions, Tire Testing, High End Suspension shocks/struts, Suspension Testing/Dialing, corner balancing, aggressive alignments...etc

it goes a whole lot further than bolting parts within the allowances of the class.

*NEW CALIFORNIA
CATALYTIC CONVERTER LAW
Effective January 1, 2009

* NEW LAW DATE: Effective January 1st, 2009
* LAW CODE: California Vehicle Code Section 27156 & 38391
* WHO THE NEW LAWS EFFECT?: Manufacturers, Installers and Resellers of New Aftermarket Catalytic Converters.



General Guidelines:

CALIFORNIA VEHICLE APPLICATION CATALOG INSTRUCTIONS - For California Application look-up it will no longer be based upon G.V.W. (Gross Vehicle Weight) and engine size. Catalytic Converter Application look-up for California ONLY is the only approved method for determining the correct part number. It is illegal in California to select a catalytic converter for installation based solely on vehicle weight, engine size, physical shape, size, configuration or pipe diameter.

For California non-OBD-II vehicles, the application list will identify the vehicle based on the categories below:

(PC-1): Passenger cars with single or dual exhaust systems with one catalytic converter per exhaust bank.
(View Diagram)
(T-1): Light-duty or medium-duty trucks with single or dual exhaust systems with one catalytic converter per exhaust bank.
(View Diagram)
(PC-2): Passenger cars with single or dual exhaust systems with two or more catalytic converters per exhaust bank.
(View Diagram)
(T-2): Light-duty or medium-duty trucks with single or dual exhaust systems with two or more catalytic converters per exhaust bank.
(View Diagram)


DETERMINING SINGLE AND DUAL CONFIGURATIONS - A single configuration refers to vehicles with an OEM catalytic converter configuration consisting of a single catalytic converter per bank.



A dual configuration refers to vehicles with an OEM catalytic converter configuration with two or more catalytic converters inline per bank.



IDENTIFYING A NEW CALIFORNIA AFTERMARKET CATALYTIC CONVERTERS - As of January 1st, 2009, what you need to look for to ensure you are selling, buying or installing California LEGAL catalytic converters:

The body should be clearly labeled with the following:
# A.R.B.- EO Number: (example: D-193-88)
# Part Number: (example: 34015)
# Date Code: (example: 0109)
# Directional Flow Arrow
# 1/2" Tall Numbers
# Must Be Visible From 5ft. Away


New California Aftermarket Catalytic Converters
As of January 1st, 2009, What You Can and What You Cannot Sell/Required:

(A) The vehicle is specifically included in the vehicle application list for which the new aftermarket catalytic converter has been exempted;

(B) The vehicle is more than 7 years old or has more than 70,000 miles on its odometer;

(C) The vehicle is beyond the coverage of the OEM catalyst warranty period (which can vary from 7 years or 70,000 miles to as high as 15 years or 150,000 miles).2 Installers may reference the vehicle owner’s manual/warranty booklet or contact the vehicle manufacturer or its representative to verify the applicable OEM catalyst warranty;

(D) The vehicle has a legitimate need for replacement of the existing converter that has been established and documented by the installer on the repair invoice. If the OEM converter is present, the installer must make a determination that it is not functioning properly before acting to replace it;

(E) The exempted new aftermarket catalytic converter is installed in the same location as the OEM catalytic converter it is designed to replace. The front face of the installed catalytic converter shall be no more than three inches further upstream or downstream in the exhaust from where the front face of the OEM catalytic converter was located. The installation may not alter the location, position, or orientation of oxygen sensors upstream and downstream of the catalytic converter(s);

(F) The exempted new aftermarket catalytic converter is installed on a one-for one catalytic converter (not substrate) basis;

(G) The exempted new aftermarket catalytic converter is installed with all other required catalytic converters (no consolidation of catalytic converters, nor addition of extra catalytic converters is allowed); and

(H) A warranty card has been filled out by the installer, signed by the customer, attached to the repair invoice, and a copy returned to the manufacturer.

(I) Installers shall keep documentation regarding the installation of the new aftermarket catalytic converters including all of the above information. This documentation shall be made available to ARB or its representative as provided for in title 13, section 2222(b)(8). All such records shall be maintained for four years from the date of sale or installation of the catalytic converter.




RELATED LINKS:

* California ARB website
* California Catalytic Converter Pre-OBDII & OBDII Vehicle Product Search

California legality is completely irrelevant for ST cat legality.

Though it may get your car impounded for those who drive on the street with their competition vehicle.

Jonathan Lugod wrote:

Craig Naylor wrote:

John Coffey wrote:The exhaust system will cost more then the car's worth.

Ding Ding Ding we have a winner!!!!!

As do just about everything else they do to these cars

And the reason why our "development" has gone so far, and why the other ST classes are still playing catch up. Not everyone in the other classes are willing to go with Poly bushings, custom exhausts/header, custom ECU tune (not reflashes) - dyno time, weight reductions, Tire Testing, High End Suspension shocks/struts, Suspension Testing/Dialing, corner balancing, aggressive alignments...etc

it goes a whole lot further than bolting parts within the allowances of the class.

I just had a flashback to all of the lapdances Whitehead and I wasted just in what we spent in 6 weeks in the summer of 2005...

Curt Luther wrote: I just had a flashback to all of the lapdances Whitehead and I wasted just in what we spent in 6 weeks in the summer of 2005...

We did quite a few lapdances that September anyway....