Curious what catalytic converter people are running on cars without the air pump.

I have the bonez one on mine but after about 5k miles I'm still getting the same chemically smell I got when I first installed it.

 

Running Bonez but I also have an air pump.

 

I run the Vibrant GESI UHO-Series Catalytic Converter, 3" Inlet/Outlet x 4.5" O.D. x 7" Overall Length (rated for 500-850HP) OBD2 metal cat. It is welded into my midpipe. No smell at idle with a idle AFR of around 13.2. Little backpressure since its a racing cat.
Mike

 

I ran the Bonez cat for awhile and then switch back to stock. Never had any funky smells with the Bonez even right after the install. Passed smog no problem. Is the smell your getting coming out the tailpipe??

 

Yea. I can really smell it when i come to a stop light after getting on it or when I'm reversing.

 

 

I have had three different cats over the last 15 years. I am twin still with no emissions and old twin pipe 'RSR cat back. No major changes during those times.(recent rebuild not counted)
Bonez brick-type cat=smell
100 cell SMB metal cat=smell
New Vibrant 300 cell metal cat= no smell

The higher end 300 cell cat made the difference for me.
Mike

 

 

FWIW, my Bonez with an air pump stinks. Stinks is really a subjective term though

 

Glad to see I'm not the only one who experienced this.

 

With no airpump, it's though to eleminate the smell. The higher end, and higher cpi (300 or more) metal cats should work well, especially after warmup. Cold starts will always smell.

I have a bonez type cat with an airpump and a ported motor. There's no smell at all. Maybe a bit at startup in the garage. I can drive the car for hours and not have my cloths smell, etc. I also believe that most racing cats (200cpi metal core) will work well with an air pump. If I were to switch I'd go with the vibrant 300 cpi metal core cat (their more expensive one) plus airpump.

A lot of people remove the air pump because of the ACV... I removed the ACV and routed the AP directly to the cat. Still "simplified sequential". No smell, and close to 400whp (bnrs).

 

Same. Bonez cat. When I disconnect air pump to tune the car it stinks. When I reconnect the pump there's no smell at all except cold starts.

 

hmm might look into the vibrant cats, been looking for something to tone the car down just a tad, and make it smell a bit better, with out much of a performance hit

 

3 inch hollow pipe...

 

Just another point about metal cats. Many of them use metal alloys with lower melting points, OK for pistons but not good for our higher heat rotary exhaust. I partially melted my previous 100 cell SMB cat. My new Vibrant is still in great shape (I had it off during my recent rebuild and inspected it with a snake camera) and uses a higher melting point metal alloy more suited for racing-type engines. Ideal for our rotaries. IMO, best metal cat for our cars if you choose the high end one with either the 3" or 3.5" pipe depending on your exhaust diameter.
Mike

 

Seems like I might need this vibrant car in my future. Has anyone tried one of the maganflow ones? I picked up the magnaflow 59959 some months back, curious how it is on our cars.

 

I got the car with an HKS hi flo cat. not sure about the smell you're talking about but maybe i'm just used to it.

 

Pettit hiflow here. What I thought was just the "burning in" smell is still there. Not sure how many miles I have on it. I would estimate 500. I get an exhaust smell at lights (which I like) and still get a chemical type smell (which I dont like). Chem smell is what I thought was the burn in process. No airpump.

 

I get this same exact thing with my bonez cat

 

Would a cat like the Bonez or Vibrant unit be a true OEM replacement in terms of flow? I'm on the stock ECU with no plans of upgrading and want to avoid anything which would require boost or air/fuel control.

My car makes boost completely to spec but fades to 7-8 PSI from 6500 to redline, so hoping a fresh cat could possibly alleviate that before diving deeper into it.

 

Bonez would be the most similar to stock, but it certainly flows more. Do you have any other mods?

 

My Vibrant is on a significantly modified twin car with a PowerFC. I would be a little hesitant on a stock car since the Vibrant will provide less back pressure and therefore you risk boost creep.
Mike

 

HKS downpipe and RE Amemiya cat-back. Otherwise bone stock, which is why I'm cautious.

 

Anyone know what size the rubber hose is that runs to the cat from the air pump closest to the air pump? Debating putting on the bonez and don't want to cut stuff up.

 

It's possible that you'll boost a bit higher, maybe 11 psi or so. Would recommend a pfc or a boost controller (electronic or manual) if your going to add more mods.

Magna flow makes a direct fit cat as well. Seems similar to stock. It's a 2.5" midpipe with a ceramic cat . I would go with that if I wanted to stay as close to stock as possible, but have a fresh cat. I wouldn't expect that to cause any significance boost increases.