APS Camaro. Hp loss from single cutout over dual cutouts? Cats?
08-12-2008, 02:39 AM
#1
APS Camaro. Hp loss from single cutout over dual cutouts? Cats? Short thread:
For money reasons, I would like to run a y-pipe normally to a single cutout to a single cat in the I-pipe. I just wonder if one cutout will flow half as much or if it will flow like 80% of the duals. More is not always better. Same thing with cats. Will two cats be better than one or will one get rid of 80% of the fuel smell as two. If two is only a little bit better than one then theres no point.
Long thread:
I'm running a stock Z28 catback because I want the option of having it dead quiet. I was thinking about running catalytic convertor(s) to get rid of the fuel smell. I was originally going to run dual cutouts right off the downpipes and then dual cats right after the cutouts but I don't think that can all fit before it reaches the intermediate pipe. Plus it would be VERY expensive.
Then I thought about running dual cutouts off the downpipes and then a single cat in the intermediate pipe.
Then a single cutout to a single cat in the I-pipe.
Questions:
If I do a single cutout it will be after both 3" merge into a single 3". How much worse will it flow compared to the duals?
Cats are usually right after the exhaust manifolds. Does it have anything to do with the exhaust having more raw gas right after the manifolds? Will a single cat do anything all the way back in the I-pipe to help with fuel? What if I ran two in a row in the I-pipe?
For money reasons, I would like to run a y-pipe normally to a single cutout to a single cat in the I-pipe. I just wonder if one cutout will flow half as much or if it will flow like 80% of the duals. More is not always better. Same thing with cats. Will two cats be better than one or will one get rid of 80% of the fuel smell as two. If two is only a little bit better than one then theres no point.
Long thread:
I'm running a stock Z28 catback because I want the option of having it dead quiet. I was thinking about running catalytic convertor(s) to get rid of the fuel smell. I was originally going to run dual cutouts right off the downpipes and then dual cats right after the cutouts but I don't think that can all fit before it reaches the intermediate pipe. Plus it would be VERY expensive.
Then I thought about running dual cutouts off the downpipes and then a single cat in the intermediate pipe.
Then a single cutout to a single cat in the I-pipe.
Questions:
If I do a single cutout it will be after both 3" merge into a single 3". How much worse will it flow compared to the duals?
Cats are usually right after the exhaust manifolds. Does it have anything to do with the exhaust having more raw gas right after the manifolds? Will a single cat do anything all the way back in the I-pipe to help with fuel? What if I ran two in a row in the I-pipe?
08-13-2008, 01:56 AM
#3
Ohhh, good to know... didn't even consider that. What codes would it throw exactly? This would apply to MAF and SD tunes?? I considered the fact that it would be more rich when the cutouts were open when cruising but I would only run WOT with the cutouts open. Does this change anything? And your experience with this is with highflow cats?
08-13-2008, 10:15 PM
#4
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My experience with this is that cats and turbos don't work well together. Especially when you've got the hammer down quite a bit and parts of the brick starting flying out the back of your car.
You'd throw codes because the O2 sensors after the cats would show an improper reading. Just ditch the cats and tune out the rear O2's.
You'd throw codes because the O2 sensors after the cats would show an improper reading. Just ditch the cats and tune out the rear O2's.
08-13-2008, 11:34 PM
#5
I just want to run cats to get rid of the fuel smell. There wouldn't be any rear o2 sensors. I just have two in the front in the manifolds and I might even take those out with this speed density tune so I can run leaded race gas. Like I said, I just want to kill the fuel smell when I'm cruising so my g/f will ride in the car again. I expect it to smell like fuel when I'm dumping out of the cutouts but I'm hoping to get rid of most of it or at least a majority of it by closing the cutout and running it through the cat. conv. and stock muffler. Between the cat and pushing it out the back instead of dumping it under the seats, I would think it would take care of quite a bit of the smell inside the cabin.
So there shouldn't be a problem with throwing codes since I will have no rear o2 sensors. It will be manifolds, to downpipes, to cutouts, merged into the I-pipe, to a single cat in the I-pipe just before the axle, to a stock Z28 muffler and out the back. And I wouldn't be pushing the ceramic out of the cat because I would never get on it with the cutout closed. It would be WAY to rich with the cutout closed anyway. It wouldn't even pull through the run most likely.
Cutout closed = throught the cat and muffler for quiet and cruise only.
Cutouts open = for molesting unsuspecting competition!
So there shouldn't be a problem with throwing codes since I will have no rear o2 sensors. It will be manifolds, to downpipes, to cutouts, merged into the I-pipe, to a single cat in the I-pipe just before the axle, to a stock Z28 muffler and out the back. And I wouldn't be pushing the ceramic out of the cat because I would never get on it with the cutout closed. It would be WAY to rich with the cutout closed anyway. It wouldn't even pull through the run most likely.
Cutout closed = throught the cat and muffler for quiet and cruise only.
Cutouts open = for molesting unsuspecting competition!
