Slinger, I’m more familiar with eliminating the OBDII sensor altogether with a voltage clamp circuit, and haven’t seen this method used before. Does it require the sensor to still be reinstalled in the exhaust stream, or can it just hang in the air?

Also, since this hasn’t been brought up before, I’d like to point out that if you nix the 2nd O2 sensor and lose both cats, you could disconnect the EGR as well. This works well especially if you’re using a CAI.

Personally I’ve grown used to looking at “CEL” and “Service Engine Soon” lights. I only begin to worry when they go out!

 

well zues I do plan on getting a CAI as well but I would like to keep the CES light from constantly being on... Considering this P5 is less then 2 weeks old I would like to maintain the factory warranty for the duration of its 50k. I dont want to give any excuse to the service techs to not honor my warranty. I have already talked to the service guys at my local dealership and they said external bolt on upgrades will not void the warrenty unless it messes with something internal I.E. main computer. So I would like to tackle this problem without doing heavy modification to anything major. I am not even sure if the Mil-eliminator idea will fly with the mazda guys. Who knows... Might have to call up there today and ask.

Nick

 

I drew the schematic with EWB. This has worked for me fine. I did this mod to the Mirage I had and it is done to my Mustang now. The circuit keeps the voltage above the .5vdc so the computer thinks the cat efficiency is still there. With this mod, you leave the sensor in the exhaust. You can remove one or both cats. I just gutted mine so they would pass a visual. Works great for dealer visits too. The sensor is still there and the signals they pick up on their scan tool look completely normal.

Just takes a little sweat.

 

I called HP racing about the header. It will be available in the second week of May from NOPI and will be available in chrome and ceramic finishes. Now onto the important thing.....it will have both O2 sensor bungs accourding to the rep. He seemed knowledgeable to me. I have spoke with them since feb. or early march about this header. I will speak with NOPI and see if they have anything else regaurding it.

 

Great thanks for the info... Excellent News
So did they inform you whether or not it will give different readings for the 2 O2 sensors and if so how will they do it... Or will we have to opt for a type of Mil-eliminator set up?

Thanks again ULEV will be gone in no time!!!

Can anyone maybe estimate what the power gains will be with a INJEN CAI, HP header, and Bosal (federal) exhaust?

I know a dyno will have to be done to give a final ruling but estimates will at least keep my moral high for the wait... dreaming

 

Thanks Slinger, that’s what I thought. It’s a perfect fix for a state that has those kind of checks, and someone that still has a boss to screw the sensor into, neither of which is my case. But I will stash that info for potential future use, it’s good info.

In Florida there aren’t any inspections, none, nadda, zip. Even the wildest rides don’t get a look over by the law. The only thing they’ve hit me for, is having a bumper too high on a 4X4, but then shoulder high with 44’s may be a bit much for the road. So I swap wheels, drive to court with ridiculously low gearing, show them I fixed it, and they void the ticket. Is that cool or what? Oh, I guess I did get pulled for riding a bike with CCS numbers on it too. They said it was a race bike, duh, but I didn’t get a ticket.

I like your pic of the gutless cat from floor level, it shows good composition, or should I say DE-composition.

 

they didn't give me any information regaurding the readings that it would give. I just asked those questions specifically. I was under the usumption that gutting a cat can reduce flow somehow and is not a good idea....I have read that in many places including on this board and in Sport Compact Car....

 

Yeah I am not concerned about the Fl. regulations cause I know there pretty much arent any. I am only worried about the factory warrenty. This is more then likely the only mods I will do to it intil the 50k is up. Just a Injen CAI, HP header and Bosal exhaust. Think this will fly with the mazda guys???

Thanks again all for your info

Nick

 

Anyone convinced that the new header with 2 O2 sensors will fix the check engine light problem? I have a feeling the ECU will find the exact same reading and give an error.
Anyone else convinced that a mid-section with a new high-flow cat, and a bung after the new cat would fix the problem. i've been thinking about this for a while, and I cant come to a better solution.
The 1st o2 could be from the new header, and the 2nd o2 should be after a new high-flow cat. That or just get rid of the engine warning light.
Traveller has said that the problems with the stock parts are the restrictions in flange/pipe diameter. If we get rid of the honeycomb of the cats, this problem is not fixed. Only way is to replace the header/cats.

 

I see your point tester... but what would be the point of manufacturing a header with 2 02 sensor dungs if they would still produce an error in the main comp??? sounds like that would be a waste of materials and such to me. But who knows...

I still like your idea of the high flow cat but there isnt even a product like this on the drawing board yet (that we know of). The Hp racing header is a product near release so I would like to figure out a solution using products released or soon to be.

 

I have NO catalytic converter. I have BOTH sensors installed. I have modified the wiring on the second sensor just like the diagram shows. I have NO check engine light after almost 40,000 miles. It will work.

 

There are several manufacturers out there that make high flow cats. All we have to do is decide the physical dimensions we want and have space for under the car and then decide on the inlet/outlet diameter. Sure, they are going to just be cats without piping but a muffler shop could weld them in. I'm thinking of eventually going this route if I go turbo.

The primary cat is there for only one reason. To light off quicker to reduce emissions at start up and keep them down for the first few minutes of running until the secondary cat can come up to temp. ALL the new cars are fighting the new LEV laws and ULEV laws in certain urban areas. The best way to pass a visual inspection and still maintain good airflow through a cat is to cut the inlets and outlets off it and put a larger diameter pipe through it. ALL the way through it. weld it onto the pipe at both ends and it will look like there is a factory cat there. No flow restrictions as there is a solid pipe going from one end to the other. I used to do this on the 70's and 80's cars before the cats got better. You think they suck now? You should have seen them 20 years ago.

 

hehe I believed you slinger... I will more then likely go with this approach of the header doesnt already take care of it for me. But I still dont understand why they would release a product with 2 O2 sensor dungs if it would produce a Check Engine light. If it doesnt alter the gases then I will definately go about it with your approach. Either way I should be set :-D

Only thing I am worried about now is will the mazda dealership honor my warrenty even with these mods??? any info about this would be helpful...

Thanks
Nick

 

I'm not sure why they would put two bungs other than trying to keep the OEM fit. I guess they expect most people will be using some sort of MIL eliminator anyway. Is the header two piece? If it is, is the second bung on the second section of pipe?

FYI - I'll probably be going back to a high flow cat. I didn't notice a difference in performance removing it and the smell can get annoying sometimes.

 

What would be the point of having a high flow cat for me tho??? there are no restrictions on this where I live in Fl. Wouldnt it have better flow with no cat at all??? I would also like to avoid welding... So I think I will stick with just having the HP header and Bosal exhaust. I just dont see a need for a cat since I have found ways to avoid the check engine light. Any reason I should have one? besides emmisions since that isnt a factor for me?

Nick