Bonez Cat Installation/Split Air Pipe
 

So I installed my Bonez HF Cat over the weekend. No problems with bolts/nuts!

Anyway, I ended up cutting the flange off of the split air pipe and used fuel line to attach it to the cat. Is that what everyone else has done? Any problems with melting the hose due to the heat of the cat?

No,
I cut the tube off my old Cat & welded it on the new Cat.

I just didnt hook it back up because i dont have an air pump.

What is the purpose of using the old flange with the Bonez? Is there a valve in there?

Yes, there is a flange that mates up with the end of the split air pipe from the air pump. You can see it in the service manual...

I just got my Bonez cat but haven't installed it yet. It came with a metal tube and a piece of hose to connect it to the cat. I was told this was all that was needed to install the unit and was a complete bolt up job using the factory flange. anyone else having problems? would like info before starting the job.
Thanks
Jeff

since were on subjucts on hi flows
 

I'm thinking of getting one also. My mods are dp, cat back and apexi ecu. Also i do have the newer pfc so that means my base map can handle these mods intake, intercooler, dp, hi flow, and cat back. anyone dissagree or should i just go with it and get the hi flow cat? I will get it tune but for now i want just to have the base map and modifications above.

I bought a kit from another forum member. Stock they come with a metal tube coming from the cat (as jeff_p mentions).

I also cut the split air pipe line (which includes a check valve) and used a piece of hose between it and the cat. Have had no problems with cracking/melting due to heat.

mine is in the shop right now getting a 2000 degree grey ice coating applied. my entire exhaust will be coated in this after putting on the cat. should look real nice under the car I'll post pixs when done

Jeff

There is a flange where the split air pipe connects to the stock cat. You will either need to cut the flange off of the split air pipe and connect a hose between the cat and the spit air pipe or cut the flange off of the stock cat and weld it to the HF cat.

Since I don't weld, I chose the 1st option.

Thanks. Extactly the answer I was looking for.

I didn't notice this when I replaced the Cat. I see it in the service manual and it shows it or it looks to be seperate from the Cat. Does Mazda sell these seperately?

If this is missing... Could it cause my car to fail smog?

Not quite. All that matters is that your car passes "visual", "functional", and "tailpipe". The only thing about the flange is that there is a one-way check valve that prevents exhaust gases from going back to the air pump. If that thing doesn't work... your air pump will be fighting the backpressure from the exhaust gases in the cat converter... you know? It would affect your tailpipe readings, but I'm not sure by how much. Make sure you get that taken care of to be safe.

Sorry for 'stealing' the thread but if you have no cat, can you just plug the air pump hole, where the split air pipe attaches? or should I just remove the air pump all together?

Get rid of it since its not doing anything.

Then you answered my question... It will affect smog. If the airpump has to fight this pressure, then the ammount of O2 getting into the exhaust would be less. This would explain my low O2 readings on my last test. They were 0.4% and 0.2%. As the RPM's went up the O2% dropped.

Looks like I know what my next project is..

Have you read on the air pump where it says "NEVER REMOVE AIR PUMP?" That's not entirely for emission reasons. The air from that pump goes not only to the cat converter, but also to the exhaust ports prior to the O2 sensor. If you take away the air, you de-calibrate the ECU's response to the O2 sensor (it will think the A/F mixture should be richer than it actually should).

FWIW, my '94 FD failed tailpipe testing in CA in 2002 with the stock converter. After replacing plugs, wires, oil, making sure the engine was really hot, etc, it failed again. So I bought a new Bonez converter. With the normal air injection and the new cat converter, the car failed worse than before! Eventually I had to buy an OEM converter, which passed with loads of margin. The car has also passed the 2004 and 2006 emissions tests with plenty of margin. My speculation is that the air injection into the Bonez is not handled correctly internally. The air needs to be distributed throughout the converter to burn the most HCs possible. I think the OEM cat is probably designed better for that, IMHO.

Hey I know this is raising something from the dead, but I tried this and the silicone tubing got greasy/melted and fell off the catalytic converter end. I'd recommend welding it for anyone else planning on buying this.

Deleted. See post #18 above. BTW, our car still passes CA smog (as of 2018 test) with the OEM cat installed in 2002.

Gmanpie,

I had this SAME issue twice with the Bonez cat. I lost my air tube twice at the track. I called Ari and he was SUPER helpful and sent me a new kit but we had the tube bead rolled on both ends. With the bead rolled tube, I didn’t lose the tube at the track and it’s held on MUCH better.

Ari is great with feedback. Call or send him an email. He’ll help you out.

Matt