Cat Delete vs. Hi-Flow Cats?

[JBW1997]

Other than meeting emissions, why would someone install hi-flow cats instead of simply removing the cats altogether? For one thing, the heat that gets generated on the side sills is incredible. Does deleting the cats have a big impact on the sound of the car?

 

[plumcrazy]

much louder, a decent amount of unburnt fuel smell. but ice cold sills and more power is worth it

 

[JBW1997]

Plum, could the unburnt (rich) exhaust smell be tuned out with a programmer?

 

[RTED]

I have the Roe system (hi-flow cats / mufflers) on my Gen I.......VERY LOUD - sounds great! Glad I did not delete the cats entirely, it would have been ridiculously loud. Keep in mind that the sound is exiting on the sides versus on rear for Gen II.

 

[plumcrazy]

Plum, could the unburnt (rich) exhaust smell be tuned out with a programmer?

on my second trip to DLM , i had him tune out some. but not all.

 

[GTS Bruce]

No cats is great in a GTS. BUT WAY TOO LOUD IF YOU HAVE A SIDE PIPE CAR. GTS Bruce

 

[happy]

i got no cats and love it!!!!!!!!!

 

[AZTVR]

No cats plus Corsa is loud on the street and wonderful on the track. However, the exhaust smell in the car is obnoxious and not worth it to me (windows open.) I'm going to hi-flows.

 

[Makara]

For just a few hp difference if any, why not just use good high flow cats and put a less pollution in the air?

 

[DrumrBoy]

The volume goes way up and the sill temps go way down. A trade off that I went for in a heartbeat.....actually it wasn't a tradeoff, I like the volume at WOT.

 

[Chrissss]

I first deleted the cats altogether. The sound was unbelievable (not in a good way in my opinion)so I went with the Roe high flow cats. Great low end rumble, still good sound but not out of control. I also found the heat was not so much with the cats as it was with the crossover design in my 06.

 

[Chuck 98 RT/10]

No cats with a good muffler sounds awesome.

 

[happy]

ya i have borla exhaust with no cats its loud but thats allright i only drove the car for a few days before it went in storage, and never once smelled fumes... maby if i was standing behind it and had some one reving it right hard, but ya no fumes. but my check engine light did go on the moring i was putting it into storage i would have to say there being no cats caused this.

 

[plumcrazy]

this will fix the check engine light from coming back on when you remove the cats......allegedly !

Dorman 42009 - Dorman Spark Plug Non-Foulers - Overview - SummitRacing.com

 

[happy]

very nice sir thanks alot!! So you just wind out the 02 sensors wind these in where they were then wind ur 02 sensors into it thats it??? Our cars just have 2 sensors or 4?? i never thought to look something tells me 4..

 

[Bluvenm97]

If you drive your car much on the street, don't do it, you will hate it (unless you're a freak )..

I have a side exhaust conversion with headers and run random tech high flow cats, and the sills are only slightly warm after a run.. Even the summer heat hasn't caused any problems, and I have some Hushpower mufflers in there too. The sound is awesome, but barely at the tolerable decibel level in my opinion at certain RPM's with the windows down.

I've had a catless 5.0 Mustang, and the smell was horrible in traffic or at a stop. On the other hand, if you have a track car only, then anything goes I guess, unless you run into some track noise restrictions..

I say keep some cats on...

 

[AZTVR]

very nice sir thanks alot!! So you just wind out the 02 sensors wind these in where they were then wind ur 02 sensors into it thats it???.

$5 o2 cheater/non fouler how-to - evolutionm.net

Some have just used one of these per sensor instead of two and that worked for them. My check engine light never came on ( 2002 GTS ) ; so, I needed none.

Our cars just have 2 sensors or 4?? i never thought to look something tells me 4..

Our cars have 4 sensors; but, you just do this on the rears.

 

[happy]

ya thats what i thought lol!! Ya mine was doing good for a few days w/o putting on the check engine light too, i never checked the code but everything worked still perfect so im guessing thats the problem!

 

[SquadX]

on my second trip to DLM , i had him tune out some. but not all.

Iam having DC Perf. tune mine out some as well. Should give me a tad bit more power as well. The gas smell is a bi#ch and the wife hates it.
Also, most tuners will not run stock or hi flows on a super charged built, could blow your motor as some here can attest too.
I think Plum once stated if you CAN NOT feel the exhaust pressure three feet from your exhaust, your cats maybe clogging up and should be replaced.

I personally feel safer running no cats to save my motor.

 

[plumcrazy]

yeah, been there, done that...

any high HP, boosted car should be sans cats IMO and others as well.

 

[CitySnake]

If you drive your car much on the street, don't do it, you will hate it (unless you're a freak )..

any high HP, boosted car should be sans cats IMO and others as well.

Shoe fits?

 

[sniper1]

I've had a cat delete system for over a year now with a 3" Borla exhaust system and E/B ceramic headers and LOVE the sound most of the time and the nice cool sills, but not the smell. So I popped in some Bellanger HF cats this last week and so far I love the sound and less smell. I disconnected the O2 elims and re-connected the O2s. So far so good and still nice cool sills. I have to admit, I miss the LOUD decel exhaust sound sometimes... Car seems to run better, throttle wise.

 

[happy]

i dont know about some of you guys but my car gets driven not parked in a garage worring about fumes or smell or noise lol If i we wanted a quiet clean car we would have bought a smart car not something with a v-10!! I think the free flow adds just a little more smell for that chevy or ford or what not that is behind ya trying there hardest to get in front of ya!!!!!!!!!!!!

 

[Sweet Ride]

If you drive your car much on the street, don't do it, you will hate it (unless you're a freak )..

Count me a freak then! DD with no cats and I love it!

Dumping the cats made mine louder for sure. I don't notice the smell anymore but anytime a guest is in my car, its the first thing they ask about.

 

[Fatboy 18]

Anybody got stock headers, and Belanger Cat back exhaust?

That's my set up at the moment, and I cant make up my mind weather to go for Hi flow cats or No cats? I have a feeling that if I go for no cats, the system will be VERY LOUD!

I can't afford headers so there out for at least 18 months

Any advice?
Cheers Mark.
2000 GTS

 

[JBW1997]

My question to all of you is:
Are the catless ones that are having fuel smell and noise issues all side pipe cars? And those that don't mind all rear exhaust cars?

 

[sniper1]

My question to all of you is:
Are the catless ones that are having fuel smell and noise issues all side pipe cars? And those that don't mind all rear exhaust cars?

Nope! Mine is a 96' with rear exit exhaust. I will probably go back to a cat delete system once I find a good tuner to give this thing more fuel for the AF ratio. The noticable air sucking sound is gone at the air inlets too. I'm thinking the cat delete is better for more HP but you need to be able to add/tune in more fuel to match the really good air flow.

 

[plumcrazy]

rear exit exhaust here

 

[Limit]

Anybody ever get a ticket for a CAT delete? How much?

 

[plumcrazy]

personally i dont worry about non point tickets.