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Old 04-11-2004, 03:02 AM   #1
dokswon
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Default gains from ditching the cat

i want to ditch my catalytic converter, but i want to know if its worth it. does any one know how much hp is gained running a straight pipe?
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Old 04-11-2004, 12:36 PM   #2
Ru fan
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Just one or two. Not worth. Be responsible and keep them on.

Later,
Seth E.
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Old 04-11-2004, 12:50 PM   #3
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take them off. i noticed a big difference.
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Old 04-11-2004, 01:38 PM   #4
Matt Monson
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Let see, 2-3hp or a $10,000 fine if pulled over running catless? It is your call...
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Old 04-11-2004, 02:33 PM   #5
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just run a highflow, it's legal and the hp difference is almost nothing, nothing your butt would ever notice.
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Old 04-11-2004, 02:35 PM   #6
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Plus the car will stink running catless...my friend is running catless in her msp and the smell will get to you after a while. It'll also get a ton louder, not a little but a ton. It'll also make alot of popping/backfiring noises too. It'll turn your car into a cop magnet really.
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Old 04-11-2004, 03:47 PM   #7
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I ran a highflow last year and it made a difference. I will be looking to get the Stromong catless track pipe for track days.
The highflow helped out a bunch and probably more with no cats but I only recommend it for the track as like tapper said, it's will make you car much louder. I ended up run a quicker 1/4 mile with the high flow. I got down to a 15.1
I would bet with no cats it would go quicker. Just keep your exhaust at about 2 1/4".
My engine mods when I ran a 15.1 were custom intake, Borla header, UDP, highflow cat and custom 2 1/4" catback.
I do want to see about getting a reprogramed stock ECU for a higher redline and maybe some help in the power department. I am back with my stock cats as I am back running Solo2 STS class.
You will need to invest in a CEL fix as some highflow cats will give you CELs.
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Old 04-13-2004, 02:00 PM   #8
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Take them off. I noticed a big difference.
And its not THAT loud.
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Old 04-13-2004, 08:19 PM   #9
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thats what i said!
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Old 04-13-2004, 09:11 PM   #10
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keep your cats, there's a reason we have them...
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Old 04-13-2004, 10:26 PM   #11
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I plan on getting the Stromung Catless pipe too for the track in the next couple of weeks. Not to sound like a huge jerk but going catless in a subaru at a track for a few hours would pollute about 200% less than a '76 GM driving a few miles to the local gas station, etc. Just trying to make a valid point as I love the outdoors as much as anybody... I'm from Colorado ya know.
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Old 04-13-2004, 10:56 PM   #12
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Quote:
Originally posted by D-Speed 2.5
Not to sound like a huge jerk but going catless in a subaru at a track for a few hours would pollute about 200% less than a '76 GM driving a few miles to the local gas station, etc. Just trying to make a valid point as I love the outdoors as much as anybody... I'm from Colorado ya know.
this thread wasn't track specific, otherwise I'd agree
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Old 04-13-2004, 11:21 PM   #13
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Quote:
Originally posted by Machine Age Victim
this thread wasn't track specific, otherwise I'd agree
Then I guess he just wants the extra power for show and not to take it too the drag strip, SoloII or DE at a road course.
Get a highflow cat for every day and if you don't track the car and if you wanted. Get a catless pipe for the track if you deside too. Heck we don't have inspections in Oklahoma. Heck, If I was running SoloII DSP, I wouldn't be running one.
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Old 04-13-2004, 11:45 PM   #14
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I'm running catless, only b/c it was cheaper. If I had known it would've taken 5-6 weeks to get my headers, I would've just ordered it with the cat. You should def get the cat if you're daily drivin' it. You don't wanna get f'd over by cops or inspection. Plus running catless smells like a mo'fo.
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Old 04-14-2004, 12:43 AM   #15
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Quote:
Originally posted by ttboy19
I'm running catless, only b/c it was cheaper. If I had known it would've taken 5-6 weeks to get my headers, I would've just ordered it with the cat. You should def get the cat if you're daily drivin' it. You don't wanna get f'd over by cops or inspection. Plus running catless smells like a mo'fo.
Post whore, your name was all the way down the right side of the forum index.
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Old 04-14-2004, 10:58 AM   #16
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Quote:
Originally posted by Top_Dog
I ran a highflow last year and it made a difference. I will be looking to get the Stromong catless track pipe for track days.
Quote:
Originally posted by Opie
Actually going cat-less will reduce HP compared to running a stock or High-flow cat on a computer controlled car. Few reasons why; not enough back pressure, ECU "correcting fuel and air mixtures to try and compensate, etc.

I did a year of testing on this subject back in 1996 for the comapny I worked for; Gordon-Darby. We had consistent dyno test results that computer-controlled cars saw a reduction in their HP readings and mileage after removing the cat compared to the stock cat. We also tested a few high-flow cats at the time and saw that those, depending on brand/style, provided minimal HP gains yet still reduced mileage all with acceptable emission levels. Without re-programming a car's ECU to compensate for the removal of a cat, those that are claiming gains from doing this are making these claims via "butt-dyno" testing, not and repeatable or consistent testing method such as a dyno.
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Old 04-14-2004, 11:55 AM   #17
Patrick L
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I don't agree with Opie. with the high flows and no cats. Itcomes down to the size of the exhaust piping that make the difference.
He said:
Quote:
We also tested a few high-flow cats at the time and saw that those, depending on brand/style, provided minimal HP gains yet still reduced mileage all with acceptable emission levels........these claims via "butt-dyno" testing, not and repeatable or consistent testing method such as a dyno.
Well my mileage never changed. I was still running about 29-31 mpg on the highway and I didn't need to use my butt dyno. With the highflow, I went from a 15.5 1/4 mile to a 15.1 with just the high flow. Top end on the car was much better. The only draw back is the CEL coming on once in a while for Catalyst System Efficiency Below Threshold and the CEL fix would get rid of that. I might get a chance to test both the highflow and no cat at a dyno later this year.
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Old 04-14-2004, 12:23 PM   #18
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For daily driving use the only responsible option is a high flow cat.

For NA engines we are not going to gain that much with a track pipe. Turbo cars are a whole other story, they can have pretty substantial gains with no cats compared to high flow.
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Old 04-14-2004, 01:24 PM   #19
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I'll be responsible the day detroit quits selling 10mpg road hog suv's that even with cats damage the enviroment more than my catless 4 banger.

F big brother.
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Old 04-14-2004, 03:02 PM   #20
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I run a stromung track pipe. Sounds awsome and its not too loud compared to other cars on the road(stock mustang gt's are louder than me). And it gives great top end and my mpg is the same if not better(275-300 a tank). I got video clips if you'd like to hear what it sounds like.
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Old 04-15-2004, 09:47 AM   #21
Zen
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If you go catless.. you'll get sick of it. Having a super loud car just to get low 15's is NOT worth it.
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Old 04-15-2004, 10:28 AM   #22
Matt Monson
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Quote:
Originally posted by CSM101
I'll be responsible the day detroit quits selling 10mpg road hog suv's that even with cats damage the enviroment more than my catless 4 banger.

F big brother.
What a BS attitude. I'll do the right thing when everyone else does? You guys running catless on a daily basis suck arse. I curse you all to get pulled over and have to sell your cars to pay the $10,000 fine for tampering with emissions equipment. That is a Federal offense, BTW, so you guys that claim no local emissions better not get popped out of state...

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Old 04-15-2004, 11:20 AM   #23
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Quote:
Originally posted by Zen
If you go catless.. you'll get sick of it. Having a super loud car just to get low 15's is NOT worth it.
There's nothing to get sick of. It sounds nice and isn't too loud unless you get on it(just like a cobb intake).
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Old 04-15-2004, 12:19 PM   #24
Patrick L
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Quote:
Originally posted by Zen
If you go catless.. you'll get sick of it. Having a super loud car just to get low 15's is NOT worth it.
I'd be looking for the 14's with a new ECU.
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Old 04-15-2004, 12:28 PM   #25
Patrick L
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Quote:
Originally posted by Matt Monson
What a BS attitude. I'll do the right thing when everyone else does? You guys running catless on a daily basis suck arse. I curse you all to get pulled over and have to sell your cars to pay the $10,000 fine for tampering with emissions equipment. That is a Federal offense, BTW, so you guys that claim no local emissions better not get popped out of state...

Your an idiot. Even if the local police pulled him over for no cats he could not give him a ticket for that fine. Plus the only ticket someone here in OK would get is for loud exhaust and that doesn't cost much and make you put the cats back on. We don't have state inspection. Heck, if I or anyones around here got that then they would have to pull over almost every drag racing Mustang or Camaro owner around here to for no cats and there are alot. I see it happen all the time cause some of them run race gas which is leaded.

IMO, I would run highflows on the street and get a track pipe for the track. People running no cats happen all the time and I don't think I have even seen anyone get a fine for it. Beleive me I seen alot of them in autocrossing and see them on the street.
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