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Old 01-12-2005, 01:00 PM   #1
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Default Remove cat convertor

How much HP do you think i can gain on my LG3 vin 3 after removal of the cat convertor? It'* not on there right now it'* just straight pipe? 15 hp u think?
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Old 01-12-2005, 03:36 PM   #2
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Not much unless was clogged, exhaust back pressure is not a real issue & limiting factor is usually the rear exhaust manifold cut-out.
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Old 01-12-2005, 03:54 PM   #3
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15hp maybe with an 18 year old cat + muffler, and replacement of both of those with high flow, performance units. If you have a straight pipe now, you will only lose power [in theory] adding a cat [even a high flow unit].


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Old 01-12-2005, 09:50 PM   #4
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Well it'* already taken off, and i'm NOT spending money on another convertor. There is no emissions testing in minnesota and i like the way it sounds better.
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Old 01-13-2005, 02:51 AM   #5
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Actually, these engines like a little bit of backpressure anyway. I won't go into why right here, but it has to do with the valve timing overlap, and the density of the fresh air/fuel mixture. Having too free flowing an exhaust system on these cars will actually hurt performance.

I know the things are expensive, but I had a major leak in front of the cat for about a week, and got really sick of smelling like exhaust all the time. The seat of the pants felt the lack of power too, although I'm sure it wouldn't be so bad with at least the rest of the exhaust there.
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Old 01-13-2005, 02:33 PM   #6
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Then I would expect you need to change your mixture to compensate for the loss of charge dilution resulting from the cat.

Seriously, I doubt that there is going to be much difference, as I said, the exhaust restriction at the headpipe is probably more than anything downstream.
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Old 01-13-2005, 09:21 PM   #7
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Quote:
Originally Posted by alec_b
Well it'* already taken off, and i'm NOT spending money on another convertor. There is no emissions testing in minnesota and i like the way it sounds better.
Even though we have no emmissions in MN anymore....You still have to have a cat legally....you know that I could report you to the EPA for a quick $250?????
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Old 01-13-2005, 09:46 PM   #8
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Hey Lakeville, got a number or URL I can visit? jokes..


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Old 01-13-2005, 10:39 PM   #9
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Sure i spose u could but it was off when i got the car so it'* not my problem. Lol It'd be the previous owners.
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Old 01-13-2005, 11:10 PM   #10
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Yeah, but your name is on the pink slip. Put on a cat. I'd rather pay $25 for a basic one, then who knows how much in fines. Mind you, I have a cat, the original one, that is clogged like hell. And, maybe if I didn't know the consequences I would just put on a straight pipe to replace it. But, you know the consequences, and I think I speak for everyone, I would recommend putting on a Cat.


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