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Old 06-21-2013, 05:09 PM   #1
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HP Gains From Getting Rid of Cats on N/A Motor?

Been awhile since I posted on here last, but title pretty much says it all. I live somewhere where there are effectively no emissions laws and was wondering what HP gains can reasonably be expected with removing my cats on a car that already has intake and exhaust. (ECU tuning is out of the question for now) Thanks!
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Old 06-21-2013, 05:23 PM   #2
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If you won't be tuning the car do not remove them.
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Old 06-21-2013, 05:33 PM   #3
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if you pull them I dont think you will see any gains, also, if you pull them and dont tune the ecu to delete the rear o2 sensors your check engine light will light up.
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Old 06-21-2013, 05:34 PM   #4
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Swap them for Hi-Flows 10-20whp'ish... and if you decide to go with nocats at all, yea youll gain a little, it will be bit more raspy and you will probably smell fuel out the backside...You will need a tune to get rid of the CEL though.
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Old 06-21-2013, 06:11 PM   #5
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as brim said. there is a gain from stock cats to no cats or hfc. and a good gain at that
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Old 06-21-2013, 07:54 PM   #6
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If tuning is out of the question then you will need the Solo high flow cats. Those do give a good gain and don't throw a CEL or require a tune. I think I read that there is a way to use the JBA high flow cats to where you don't have to tune and wont get a CEL but someone else will have to chime in on that one as I don't know for sure.
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Old 06-21-2013, 11:08 PM   #7
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So would about 20 hp be expected as a reasonable gain? With a few little things to deal with of course, thanks for the tips guys.
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Old 06-22-2013, 08:26 AM   #8
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So would about 20 hp be expected as a reasonable gain? With a few little things to deal with of course, thanks for the tips guys.
20 is way high. At most you'll get 10 hp. The factory cats are restrictive but not that restrictive. As already stated, unless you get a tune, don't bother doing it.
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Old 06-22-2013, 10:30 AM   #9
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Oh alright, probably won't bother unless I go for tune, thanks.
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Old 06-22-2013, 02:31 PM   #10
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20 is way high. At most you'll get 10 hp. The factory cats are restrictive but not that restrictive. As already stated, unless you get a tune, don't bother doing it.
I respectfully disagree. 20 is attainable, 10-15 is avg.
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Old 06-22-2013, 04:18 PM   #11
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I respectfully disagree. 20 is attainable, 10-15 is avg.
I agree as well and if you do the Solo high flow cats you wont need a tune. No cats would be out of the question with out a tune.
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Old 06-22-2013, 04:38 PM   #12
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I respectfully disagree. 20 is attainable, 10-15 is avg.
1000% 10 is very low. those cats from factory suck for hp.
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Old 06-22-2013, 04:49 PM   #13
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Well then lets just agree to disagree but I've seen a car dynoed, get hi-flos and a cat back installed, then redynoed and gain just a little over 10 hp with no tune.
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Old 06-22-2013, 04:59 PM   #14
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Well then lets just agree to disagree but I've seen a car dynoed, get hi-flos and a cat back installed, then redynoed and gain just a little over 10 hp with no tune.
First, anytime there is a change you should allow for a re-learn period......Second, every dyno is different as is every car and the conditions in which they are dyno'd. And third, I have seen 3 cars personally in my club (TBC) who have put on HFC's who have made over 15whp. 10 is on the lowside. But as you said...agree to disagree.
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