i cut my cats off last night, it got loud as hell. i got so caught up in the sound i didn't really care about how it ran. well, today i decided to run my 0-60 time just to see what it did, and i picked up an average of .42 seconds on three runs. it's just a friend sitting in the passenger seat with a stop watch, so there's lots of room for variables, but on an average of three runs? has anyone else noticed a drop in power after they took the cats out?

 

I dont notice any difference either way......which is why i run cats.

 

a friend with a TBSS gutted his and thought it slowed a little..


someone said it works but only when its tuned for them . :shrugs:

 

if your engines not modded and not tuned for it you'll lose too much back pressure and lose torque. it will feel slower

 

Tune!

 

kinda what he said, in a way. Not backpressure I don't think, but something to do with scavenging, you now have less, cause the exhaust is moving faster, makes less vacuum that way, same as you have less engine vacuum at higher rpms. I don't know if tuning takes it out or not, if they say it does, I guess it does. You will ultimately make more HP most likely, but less tourqe, and on the street that is what you feel, unless you are passing someone or something.
A different grind cam is probably the biggest bang per buck.

Torque gets you going and out of the hole, unless you have a high stall and you are stalled up to higher hp, HP keeps you going.

Converters are so advanced now, they really aren't that much restriction unless they are messed up, or you are making quite a bit more power. Honestly if the cats are ok, your muffler is probably a bigger restriction. I don't have flow numbers to back it up, so may be talking out my butt, maybe someone does.

 

well, i was looking to make it louder. where my muffler used to sit there's an SLP Loudmouth 1, so there isn't much i could do in that area. i couldn't find any information on gaining or loosing performance with out cats, so i decided to try it. i like the sound at higher rpm's, it rasps alot about 1500-2500 rpm, but i'm getting used to that. if you guys think a tune will help, then i'll give that a shot when i get the money. it might be a month or two before i get the money for a tune, but i'll let you guys know how it goes.

thanks for all the responses

 

When my truck was pretty stock, intake and a tune was all i had. I gutted the cats and ran a pipe through them so it was just like they werent there, i went from runnin 9.81s to 9.69-9.71 at the drag strip. It was a consistent gain too, maybe mine were just old and had a some **** built up in them though who knows? Damn that was a long time ago though, im pretty close to a full second faster than that now and have maybe 3 foot total of exhaust now of 3in duals. Mufflers i would think make enough back pressure as long its just not a strait through muffler.

Jon

 

1/8 or 1/4 though. If you have the right stall and gears for it, ya, less exhaust is usually always better, in the higher rpm ranges you don't get much scavenging anyway, the higher rpms are all about hp though, and not tourqe, that is really the debate in this thread. If he is wanting sotp he probably would like tourqe better, so bigger free flowing exhaust won't help him.

I reread, obviously you are talking 1/8 with those times..

 

1/8th mile, **** i wish the 1/4 mile. That was with 3.42 gears no stall, and a sweet flowmaster. The sound to me was worth it, made it sound like a whole new animal.