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R60 Aftermarket Catless DP or just delete cat

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Old 03-21-2017, 03:30 PM
97nicolaus
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Aftermarket Catless DP or just delete cat

If I'm planning on getting my ECU tuned, would deleting the cat gives out the same power increase as replacing the downpipe with an aftermarket catless one?
 
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Old 03-21-2017, 08:04 PM
yesti
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Delete = catless. Or am I missing something here?
 
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Old 03-22-2017, 01:37 AM
97nicolaus
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Originally Posted by yesti View Post
Delete = catless. Or am I missing something here?
oh pardon me, what i meant by delete is having an exhaust shop replace the cat with a straight piece of steel pipe, instead of purchasing an aftermarket catless dp and swap em out...
 
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Old 03-22-2017, 06:39 AM
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i believe the aftermarket downpipes are a larger diam and don't neck down by the flange at the bottom. which then would be the next restriction over the cat. so a catless DP would flow better than a cut up stock DP
 
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Old 03-22-2017, 07:34 AM
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Originally Posted by Saltysalt View Post
i believe the aftermarket downpipes are a larger diam and don't neck down by the flange at the bottom. which then would be the next restriction over the cat. so a catless DP would flow better than a cut up stock DP
Thanks for the explanations Saltysalt! But do you think cutting up the stock cat would still yield better power out of the car compared to having the cat still on? Would cutting up the stock cat fulfills the stage 2 requirement of having catless downpipe on the car?
 
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Old 03-22-2017, 07:42 AM
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Originally Posted by 97nicolaus View Post
oh pardon me, what i meant by delete is having an exhaust shop replace the cat with a straight piece of steel pipe, instead of purchasing an aftermarket catless dp and swap em out...
This isn't really practical. The factory downpipe with the cat is stamped out and welded together to form the cat chamber. You'll really better off buying a premade catless downpipe.
 
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Old 03-22-2017, 07:59 AM
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This:

Originally Posted by cerenkov View Post
This isn't really practical. The factory downpipe with the cat is stamped out and welded together to form the cat chamber. You'll really better off buying a premade catless downpipe.
I would think even one of the cheap ebay versions would be better than a hacked up stock pipe.
 
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Old 03-22-2017, 11:37 AM
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Originally Posted by 97nicolaus View Post
Thanks for the explanations Saltysalt! But do you think cutting up the stock cat would still yield better power out of the car compared to having the cat still on? Would cutting up the stock cat fulfills the stage 2 requirement of having catless downpipe on the car?

while yes if the DP was catless it would flow more, but for manic stage 2 I believe the 2nd cat has to go as well. all said in done all the work and effort putting into the stock down pipe, I think the CNT catless DP would be easier and known to improve power
 
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Old 03-23-2017, 08:19 PM
yesti
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Stage 2 doesn't specify removing the 2nd cat, not sure how much power (and noise) would increase. Hacking up the stock unit sounds like a headache that'll probably be more trouble than its worth but if you got talent, go for it and let us know how it turned out.
 
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Old 03-24-2017, 09:02 AM
Sall4Ken
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I asked the same question previously its not necessary to remove the second cat. Mario gives some numbers below.

Quote:
Originally Posted by Sall4Ken View Post
Mario sorry just need some clarification. I am at an impass here. I have a catless downpipe on the way and im looking at exhausts that remove the secondary cat only because of the restiction and the requirements for Manic stage 2 (but honestly would rather keep the stock and exhaust and stay relatively quite). Are you saying i would still have a pretty good increase and remain somewhat under the radar sound wise if I was to keep the stock exhaust from the downpipe back (keeping secondary cat and resonator) and lets say order a FMIC and get a Manic tune (i already have an air intake). Would that be considered stage 2?
That would be stage 2, you can remove the second cat with a small piece of straight pipe and it will get you maybe 10hp at the top of the RPM range. You could also leave the second cat in. Many of my customers run stock exhaust on a stage 2. I ran a stock exhaust on my GP with stage 4 and JCW Countryman with Stage 3.
Make sure you change the plugs to a colder plugs and tighter gapping

mQubed Motorsport, Manic Tuning Dealer
 
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