Hey all,

Been looking to get some high flow cats installed. I don't see any other than Velocity AP but they are $1300 for a 200 cell car and down pipes.

Universal cats run $200 - $500 so I was thinking of that option instead. My guy said that universal high flow cats can be installed if the outlet and inlet tubes on both ends are made to fit which can be done.

Anyone have any recommendations for this?

 

No doubt many universal 200 cell cats can be welded on in place of the OEM cats but the big problem might be the O2 sensors especially the mid-cat sensor.
On the F-Type there are six O2 sensors, one pre-cat one post-cat and one mid-cat on each side.
The mid-cat sensor is exactly that, slotted between the two elements/bricks of each cat, so I can't see how a normal after-market cat is going to get around that.
I don't know what that mid-cat sensor measures or reports, I asked about it on here years ago but never got an answer, maybe it can be deleted with no ill effects such as a CEL but maybe that would require a new tune? If anyone would know VAP would.

 

Hmm okay, wouldn't that mean the Velocity AP 200-cell cats throw an engine code too or do they have a special mechanism that works with the OEM O2 sensors?

 

Sort of.
On the VAP page here: https://www.velocityap.com/product/j...-and-downpipe/
Down the bottom of that page it says, quote: *MAY RESULT IN EMISSIONS WARNING LIGHTS UNLESS ECU IS REPROGRAMMED*.
Also note that in the pics on that VAP page I can see two O2 sensor bungs in each pipe, one pre-cat and one post-cat, but I can't see any "mid-cat" bung.
The blurb also says "....these catalysts replace the cumbersome OEM catalyst units which contain a 600 cell secondary ceramic catalyst...".
So pretty much confirms two things - the mid-cat O2 sensor becomes surplus to requirements and as a result it's odds-on you will need an ECU tune as well to avoid errors codes and a CEL.

 

Buyer beware information;

1. please do your due diligence before spending your money on any sport cat product. Many are actually made in Asia, China. You should conclusively confirm who actually made the item, you seek to purchase.

2. The inside honey comb chamber contains precious metals to convert the CO2 into harmless vapor to exit from the exhaust muffler. Think about it, how much precious metals would be inside a $200 - $500 "universal" sport cat.
Most resellers have these sport cats at a low cost, to make the product appeal to the potential customer's wallet, being in a cost effective price range. A proper sport cat must have very dense amounts/quantity of precious metals in order to do its job efficiently. Otherwise, the low priced sport cat is essentially, as if you are doing "running" straight pipes from the exhaust manifold to the exhaust muffler.

If you have any particular questions, feel free to reach out to me. I will help in any way I can.
Thank you.
Respectfully,
Roberto.

 

The post above is accurate. It is almost impossible to determine whether an aftermarket catalytic converter contains sufficient precious metals. My old S2000 came with an aftermarket metal matrix cat, and I'm 100% sure it was nothing more than a decoration. One thing is certain, aftermarket cats often won't pass emission tests, so be very careful with what you use if you need to pass the test.

I've noticed that some aftermarket cats will state that they can prevent most "check engine" lights. This is a roundabout way to say that "this one is more effective". Those tend to cost about $600-$700 per cat. Kooks Headers sells a "green cat" that might meet some requirements.

 

You obvious are educated in the reality of aftermarket sport cats. The majority are a "PLACEBO" for the car owner and actually WORSE off than having the factory OEM Cats. A complete waist of money.
We at SuperSprint are proud to be partnered with HJS of Germany. HJS makes our sport cats, being a proprietary design. Here is their link;
https://hjs-motorsport.de/en/product...rsal-catalysts
Thank you.
Roberto

 

Thanks Roberto, that is something I didn't know as I don't know much about the process in general. I think I will have to stick with VAP to avoid it unless I find a good universal cat for around $700-$800. Considering I will need an ECU tune which I'm also unfamiliar with, would I have to stick with VAP or can I go to an independent shop that specializes in ECU tunes? Would that type of shop be able to work on the check engine light? I wonder if the cost would be the same since it seems like I can just buy the VAP ECU tune and flash it myself at home.

 

We do have emissions test unfortunately in Chicago but I can't really determine whether or not these 200 cell cats will pass the test or not. I've read they do but I'm not 100% sure how accurate that is since I believe different states run different states and have different thresholds to pass their emissions tests.

 

Attn: Ojeii
as I stated in previous message, please make sure you positively know where was the sport cat built/manufactured. Ask the vendor, are the sport cats built "in-house" ? Ask the vendor if they outsource the building of the product and if this in fact the situation, ask who makes the sport cats, where is it manufactured, which country.
Stay away from China made product, as they are worthless.
Roberto

 

Summit Racing stock a wide range of after-market cat converters, see here: https://www.summitracing.com/int/sea...rder=Ascending
Known reputable brands such as Magnaflow, Flowmaster and Kooks so unlikely they would sell defective Chinese made parts.
I bought a Magnaflow 200 cell stainless steel cat from them many years ago and it was a top quality product although I can't vouch for the efficiency of the cat in removing pollutants as we don't have emissions tests here in South Oz.

 

I agree....
these two you mention are reputable companies ( Magnaflow, Flowmaster ) I am not familiar with the third name brand. I believe the two names here have their own fabrication department. They are not considered to be a small company. It's the small businesses that outsource to have their products made.

 

It's pretty simple. The higher the number of passageways in a cat, the more surface area it has, and the more rare metals it requires to be fully coated. The more surface area the cat has to react with the exhaust, the better it works. Choosing a 200 cat means it has some compromises. Believe it or not, restriction in a cat is not beneficial with regard to effectiveness. Effectiveness is related to surface area exposed to exhaust and the amount of catalyst. A 100 cell cat has large passageways, and much of the exhaust gas moves through without ever touching the catalyst.