Should I re install my cat?

As an experiment I put a test pipe on my 84 QV. The only difference I notice is the car is considerably louder and the smell of gas is quite a bit stronger. It may run a tad cooler, although It might be my imagination. I've had it on for a few weeks and I am debating about just re installing my old cat. I don't feel like spending $$$ for a new high flow cat unless they are actually better than the original. The original appears to be in good condition. Just confused, any suggestions from those who may have had a similar experience would be appreciated. If I knew what I know now I probably would have just kept the original cat on.

 

Get a Hyperflow.

That gas smell can't get pretty bad. In your clothes and everything.

 

if you can smog it(if you need to do this in your state)without the cat, I would remove it permanently.
save it of course

 

Zero advantage to buying a high flow cat. 308 with the large single cat gains about 1 hp with a straight pipe. How much better do you think an expensive aftermarket cat will be?

If it smells bad without the cat it is probably out of tune. Fix that and you'll get more HP than any new parts will get you.

 

We talk a lot about hp around here and all the little tweaks etc. but exactly how much hp is needed before we see and feel a difference?

10? 15? 20? I mean, unless what you are bolting on isn't at least up in that area, it is for all practical purposes a waste of money, correct?

 

sometimes getting 10 hp, and more direct throttle response can have a big difference.

 

The only advantage to removing the cat is lowering the fire threat. Since my SLOW DOWN ecu is toast, and there's no replacements available, I reduced that threat long ago. It does stink a bit, but so be it.

 

Running non-ethanol fuel in it will reduce the smell factor. The ethanol makes it smell acrid.

My catless 3.2 Mondial smells like a '60's muscle car now that I am running non-ethanol, even my Wife has stopped complaining about the "stink."
Alden

 

What does your dog think?

 

Give that man a cigar.

 

And most people don't even know what they need. They ask for HP when in reality they want to feel the torque. Years ago a guy had a Camaro and wanted to modify his engine to get more power. I asked him what he was doing with the car and with his answer instead told him to change the diff ratio.

He came back and had a large smile on his face, cheap and easy. I'm sure if I would have done the job myself and painted the engine and put some chrome valve covers and other stuff he would have believed he had a new modified engine.

 

Personally, I'd add it back. If straight pipes aren't giving you any significant power boost, result in a strong gas smell, and further pollute the environment to boot, there just doesn't seem to be much reason to run catless.

 

+1

Answer seems pretty obvious, no?

 

Think you- I was trying to think of a response-

 

I actually have a spare Magna Flow cat at home. I have one on the 308, then a spare one and then the OEM. No clue what the p.o. was trying to do, but I have a spare. LMK if you are interested. I dont even know what its worth... I think you get the best of both worlds. My 308 sounds fantastic over stock, but it has the benefits of the cat...no gas smell and not obnoxious loud.

 

Sorry, but you guys Beyotching about 'smell' make me giggle.

If you don't LOVE the smell of oil, rubber and gas, I GOT TO QUESTION your 'Car Guy' card.

Bet you don't like the smell of JP8 and 'Wolf Puzzy' either.

 

I haven't had my cat on my 84 US for 6 years now. I did adjust the fuel air mixture to the leaner side and now you can't hardly smell any richness it runs cool and smooth.

 

Yes I was wondering if I might be running a bit rich. I will try to lean it out and see if that helps the smell. If not I'll probably just install the old cat. I am also not sure if I like the droning. I drive this car a lot and its a little loud and on longer drives it gets a little obnoxious. Thanks for all the advice.

 

Last time I checked Ricambi's site, the slow down/cat ECUs were still listed as being available, albeit expensive. Are those now unavailable?

 

+2...no real advantage w/o it.

 

It's just louder, if you want that sort of thing. I have a Tubi and when I didn't have the cat on it - it was a big difference in sound. The Hyperflow took about half of that away.

 

Mike - we still need to meet some day. Are you putting the cat back on every 2 years, or you haven't needed to?

 

Can anyone with an original TWC tell me what are the highest temps you see on the outer surface after running the car hard?

I have what I think is a bad thermocouple or "A-12305" controller, causing intermittent SLOW DOWN light (sometimes in hard turns, sometimes over a bump, at odd other times, and often not during the times I'm running the car hard...).

I bought and IR temp gun and have been reading the surface temp of the cat right after driving. Hottest I've seen after running hard up the Snake (LA canyons) on a warm day was ~900° F. Typically in the 800°'s and cooling quickly to the 500-600° range within the first minute after shutting down.

Basically, I'm trying to correlate exterior temp to interior temp to see if I'm in fact anywhere near 1600° or 1700° F.

 

Hi Beau! No, I don't need to put the cat back the cat anymore. And yes, we need to meet one of this days.