No Cat=Bad mileage???

[LT1 Kayker]

I was in my shop class today and some kid told me that my trucks getting such bad mileage because is because I gutted the cat on it. He said something about the "hydrocarbons returning to the not burned fuel" or something. Didn't sound right to me, I always though that if its done right and you dont have the O2 sensors and crazy computer and all (old truck) that it would run better and have better mileage because of the less restriction in the exhaust system. Maybe I heard wrong, so im just curious on the hard facts here.

[4onFloor]

i've gutted a few catylitic converters and never lost any gas mileage. ask your shop teacher...

[Genopsyde]

he's confusing your cat with the egr i think.

[DaMoNe6969]

cat is for emissions only.. gutting it will only reduce backpressure.. I dont thik it'l affect fuel economy good or bad

[NINÅ]

Originally Posted by LT1 Kayker

I was in my shop class today and some kid told me that my trucks getting such bad mileage because is because I gutted the cat on it. He said something about the "hydrocarbons returning to the not burned fuel" or something. Didn't sound right to me, I always though that if its done right and you dont have the O2 sensors and crazy computer and all (old truck) that it would run better and have better mileage because of the less restriction in the exhaust system. Maybe I heard wrong, so im just curious on the hard facts here.

Modern engines are designed for optimal airflo / cam valve relationships with the cat in line. Removing the cat will hurt your off the line acceleration, and for the people that need to worry about it......... your gas mileage.

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[1992RS]

if your o2 sensor is before your cat then it shouldn't effect your gas mileage, if it's after then it probably will.

[BiggyD]

my cats have been taken off and I get about 22mpg (premium fuel and a couple cheap intake mods) in my 97 LT1

[lckycharm713]

i have no cat on my mustang with off road hpipe, my car sucks gas like you wouldnt beleive, worse then any v8, and it only a 6. be be honest with you, i been drive about an hours and half down to jersey to see my gf at college and for some reason it seem good one gas with me doing 75-85 the whole way. but i know around town it sucks, and yes your off the line sucks. i lost some much, im putting my y pipe with cat backs on witha cat back system as soon as i get cought up on my bills. hey sell high flow cats. i think i told you think b4. i may have been someone else, i dont remember. id leave there and dont worry about it. if you want to gain power, do other stuff. that little shit most ppl dont even bother. but it ups to you

[89IROC&RS]

wholly shit where did 92RS come from????

lol, but yeah, hes spot on, if you have a post cat 02 sensor and dont have a simulator on it, then the lack of a cat will cause the engine to run improperly, but then i would have assumed it would run leaner rather than ritcher, so your performance would suck, but you gas mileage should have been higher if anything. i woul start looking at other things, what kinda shape is your air filter in? last time you had a tune up? that kinda stuff.

[LT1 Kayker]

My sensors are before the cat. I just replaced the air and fuel filter less than a week ago. New plugs, cap, and rotor. And we tore it apart and put in new gaskets, pushrods, and fixed one of the springs that broke. The only thing I can think of is the timing, since we just threw the distributer back on when we were done and set it to whatever sounded right heh. I had a VERY bad gas and oil leak when I first baught it, but since I fixed the gas leak, and the oil leak isn't as bad as before, but still goes through a quart every few weeks. The timing isn't that bad, but would just that be the problem? I seriously go through $60+ a WEEK just going to school and work and back, hardley use it for anything else.

[89IROC&RS]

*smacks forhead with lead pipe* and you didnt mention that before why????? set your timing douche bag

[LT1 Kayker]

lol. I know the timing is off, but it runs fine for it not being right. It's not that far off, but even if it's off like 1 degree or something, that can really give you that bad of mileage? Anyways, I just heard him talking about cats and how they give you bad mileage if you gut them out with any car period. I was just wondering if it does or not haha.

[DaMoNe6969]

hahaha douche bag

[aaron7]

The only effect I had after I took the cat off is my exhaust makes your eyes water lol... Seriously though, you can tell if you are driving behind a car without one!

[LT1 Kayker]

I happen to enjoy that smell.