Remove catalytic converter ? (2 Viewers)

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Flooded timber of Arkansas
In arkansas we don't require a smog test on vehicles. Would my lc run any better if i cut the cat converter off and had a pipe welded in? Or would this cause an O2 sensor to go into fault mode or something similar?

Always lookin for improvement!
 
Awesome. Maybe ill give her a go.!
 
Bad idea. The O2 sensors will not feed the ECU a good reading before and after, which will cause the ECU to try to compensate the air/fuel mix. Could lead to lean mix, rich mix and all the fun problems that are associated. You're driving a 3 ton truck that's made for longevity, not performance. If you want that, get a Ford and chip it.
 
Your front O2 sensors give the ECU the data it needs to alter the fuel/air ratio, the rears basically just tell you if the cats are working. If you remove the cats, you'll throw P0420 and P0430 codes (CEL will be on). You can 'trick' the ECU but modifying the readings coming off the rear O2 sensor, but in reality, you're simply better off leaving it alone.

Not sure what sort of improvement you're looking for, but I doubt this is going to noticeably alter performance - and if they ever do start inspecting, you'll have the joy of replacing both cats...
 
or if you sell it to a state that does have smog testing. IMO, having the check engine light on would drive me nuts.
 
Or just use the after-market high flow cat replacements that will give you more flow & power while helping a bit with fuel efficiency.
You may want to change the air filter to a K&N for increased input to match the new increased output...
 
All good responses... thanks
 
I have a straight pipe kit from EMS (no cats), which bolts directly to my Doug Thorley Headers. Cat's are eliminated (not needed in Alberta). Unfortunately EMS no longer makes these exhaust systems. They put in an extended neck on the O2 sensors, and I've not had any problems with the sensors.

You will reduce constricted flow without cats (or with high-flow replacements), which should give more power. Check out the dyno results that RobRed ran:

 
You can still order the Toyota factory bolt on CAT Delete, I think they're coming out of So Africa or Saudi Arabia now........ It was the First thing i did then we started to do SERIOUS OFF ROADING when we had our 1992 80 Series.

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I'd do it for the temp lowering on the s***ty manifolds!
I just replaced driver's side yesterday.
I wanna know who welds up the oem headers, the nerve of those people.
 
You can still order the Toyota factory bolt on CAT Delete, I think they're coming out of So Africa or Saudi Arabia now........ It was the First thing i did then we started to do SERIOUS OFF ROADING when we had our 1992 80 Series.

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Thats a start. My understanding is that you would get a cel and that your fuel / air mixture would be slightly imperfect without the cats. But i’m here to receive education not teach it.
 
I have a straight pipe kit from EMS (no cats), which bolts directly to my Doug Thorley Headers. Cat's are eliminated (not needed in Alberta). Unfortunately EMS no longer makes these exhaust systems. They put in an extended neck on the O2 sensors, and I've not had any problems with the sensors.

You will reduce constricted flow without cats (or with high-flow replacements), which should give more power. Check out the dyno results that RobRed ran:

I've got the whole system FS in the Fo Sale forums. Just sayin'
 
So the idea is that you would move the second O2 sensor slightly out of stream (by putting a spacer on it) and that would fool the O2 sensor in returning a signal similar to what would normally get with Cats?

I remember doing that with an older Honda Accord and it worked flawlessly.
 
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I won't work on vvti, I tried for a few weeks, seriously monitoring the rear o2 sensors. Even with the front wideband sensors on the vvti the rear narrowbands have a serious effect, the codes start stacking up. I Eventually bought the urd calibrator. Been a few weeks, no problems.
I bought the no cat cat pipes off partsouq for 120 each. Getting nice flanges like that is worth it.
 
I've got the whole system FS in the Fo Sale forums. Just sayin'
Can you semd me a link to your post please. I searched and couldn't find it
 
I won't work on vvti, I tried for a few weeks, seriously monitoring the rear o2 sensors. Even with the front wideband sensors on the vvti the rear narrowbands have a serious effect, the codes start stacking up. I Eventually bought the urd calibrator. Been a few weeks, no problems.
I bought the no cat cat pipes off partsouq for 120 each. Getting nice flanges like that is worth it.
Mine is a 98, does that mean I can just get the straight pipes from partsouq and use them in place of my cats?
Did you use any spacers to trick the downstream o2 sensors?
 
No spacers, I'm using the urd calibrator.
I can't say which pipes fit the early 100. I'm sure they exist though.
 
If you're doing other power mods, maybe worth it. If you're leaving the rest of the exhaust alone, I wouldn't bother. Cat-less engines stink and, IMO, sound terrible in most cases (unless we're talking straight-piped performance engines).
This hardly intended for power increase. My cays are roasting driver and passenger feet. I am suspecting the cats might be at the end of their life. Of that's the case I would prefer a less expensive option than buying new cats
 

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