Catalytic Converters
08-10-2004, 03:47 PM
#1
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Catalytic Converters
Im looking at getting the Helix uppipe and Downpipe. Im debating wether buying the Helix with the cat in it, or the catless. I will also be replacing the "intermediate" pipe that is between the dp and the rear exhaust section. ( i have blitz axle back right now) My main curiosity would be is it worth ptting a high flow cat in the intermediate pipe? or is that money not well spent? hopefully ill be able to get a lot of input from you all on this matter. i want to consider sound levels, smell of exhaust and also emission, knowing that the catted dp is emissions legal. Thanks everyone
08-10-2004, 05:32 PM
#2
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Getting a helix up pipe with a cat is really up to you. I know that in California a high flow cat will not pass smog. The only reason I would get a high flow cat would be to keep cops off my back. IMO, I would not get a high flow cat on my up pipe and down pipe, only on the mid section.
08-10-2004, 05:42 PM
#3
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A high flow cat is still not technically emissions legal, as it is a federal violation to remove a working catalytic converter from any vehicle with less than a certain amount of mileage (may be 50K, not sure). In some cases you may be able to pass a sniffer test in your state with such a setup, but it's not 100% legal by any means.
08-10-2004, 10:20 PM
#6
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Originally Posted by jdepould
A cat (hi flow or not) shouldn't noticably effect sound levels
edit:
Its highly dependent on the make of the cat though some are like a few pieces of chicken wire in a bottle others are more dense.
08-10-2004, 10:38 PM
#7
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I wouldn't worry too much about the smell. This was something that worried me before I went catless, but afterwards the only time I notice it is if I roll the windows down, idle for a few seconds, and then drive in reverse. I never smell anything at stop lights, etc.
08-11-2004, 08:49 AM
#8
I have a hi flow on an n/a car, and the only thing that's different is occasionally I'll get crackling sound when I rev it (kinda like an old muscle car), the rest of the sound is a function of the muffler (Magnaflow cat and muffler).
08-11-2004, 12:25 PM
#9
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not true, a highflow cat will indeed PASS the first portion of california emmisions, but keep in mind you will fail the visual.....
as long as you keep the position of the cats on the stock locations it will do its job, therefore passing, onething to keep in mind is that it will only work efficently if the hi-flow cat is closer to the turbo.
a few exhaust that come in mind which work great are the mad-dad high-flow twin dump dp+ mad-dad 3ce pipe mated to the catback of your choice, this is the most stealthy option available and will pass ca emissions.... carb eo = dont think about it like i said visual will be your enemy..... but with a quick glane this is the best!
btw having a highflow will not take much power off, so dont worry you will not see an effect in power until you reach much higher hp levels greater then 400-500bhp....
as long as you keep the position of the cats on the stock locations it will do its job, therefore passing, onething to keep in mind is that it will only work efficently if the hi-flow cat is closer to the turbo.
a few exhaust that come in mind which work great are the mad-dad high-flow twin dump dp+ mad-dad 3ce pipe mated to the catback of your choice, this is the most stealthy option available and will pass ca emissions.... carb eo = dont think about it like i said visual will be your enemy..... but with a quick glane this is the best!
btw having a highflow will not take much power off, so dont worry you will not see an effect in power until you reach much higher hp levels greater then 400-500bhp....
08-11-2004, 12:31 PM
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Originally Posted by hyp36rmax
not true, a highflow cat will indeed PASS the first portion of california emmisions, but keep in mind you will fail the visual.....
08-11-2004, 01:23 PM
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Littleboyblue,
There is a thread on NASIOC BAIC about a member who had a high-flow-catted MRT turboback and passed the sniffer with flying colors. I'm too lazy to search for it. "MRT smog" in that forum will find it.
-=eric
There is a thread on NASIOC BAIC about a member who had a high-flow-catted MRT turboback and passed the sniffer with flying colors. I'm too lazy to search for it. "MRT smog" in that forum will find it.
-=eric
08-11-2004, 08:18 PM
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Originally Posted by mexicanpizza
Littleboyblue,
There is a thread on NASIOC BAIC about a member who had a high-flow-catted MRT turboback and passed the sniffer with flying colors. I'm too lazy to search for it. "MRT smog" in that forum will find it.
-=eric
There is a thread on NASIOC BAIC about a member who had a high-flow-catted MRT turboback and passed the sniffer with flying colors. I'm too lazy to search for it. "MRT smog" in that forum will find it.
-=eric
08-11-2004, 10:17 PM
#13
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Originally Posted by Littleboyblue
Sorry, but a higlow cat will fail. Personal experience. Had a hiflow cat on a car, failed smog bad. Put the stock cats back on and they passed with flying colors. A friend of mine had the same problems. Until I see someone pass with a hiflow cat, I will not believe that they pass.
what kind of cat was it? ceramic or metal substrate? and where did you have it placed? i will gaurantee you that it may have been a bad cat, or possibly the placement, it is really more effective only if it is near the turbo....
contact gruppe-s in regards to their helix dp with high-flow, there is also a proff of it, again it will not pass visual though....
08-11-2004, 10:24 PM
#14
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Originally Posted by Littleboyblue
Interesting. I bet that they will pass the sniffer, but not the dyno.