Cats or no cats? That is the question.
03-27-2015, 09:13 AM
#101
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St. Jude Donor '15
03-27-2015, 07:08 PM
#102
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What about windows down / going down the interstate? Any smell?
I don't expect there to be zero smell at idle while sitting still with the windows down or anything.. just when going down the interstate it seems no matter what I did, it smelled so bad it literally was making me sick, which can't be normal. No way anyone puts up with that for long periods of time or they would literally be sick after an hour or two of driving.
I noticed one nut missing on the joint connecting the [gutted] catalytic converter to H pipe, so based on that I'm guessing that's where the leak is coming from. I'll probably put new gaskets / nuts on this weekend and tighten everything down really well and see what I get. Hopefully that makes it bearable!
I don't expect there to be zero smell at idle while sitting still with the windows down or anything.. just when going down the interstate it seems no matter what I did, it smelled so bad it literally was making me sick, which can't be normal. No way anyone puts up with that for long periods of time or they would literally be sick after an hour or two of driving.
I noticed one nut missing on the joint connecting the [gutted] catalytic converter to H pipe, so based on that I'm guessing that's where the leak is coming from. I'll probably put new gaskets / nuts on this weekend and tighten everything down really well and see what I get. Hopefully that makes it bearable!
03-27-2015, 09:14 PM
#103
I'm running catless and dont notice the exhaust smell unless i have the windows down and stopped. However I do have a vented catch can from moroso that sits right infront of the cabin air inlet so I get some fumes when I get on it. Keeping the A/C on recirculate helps a lot, but its not good for the A/C system.
03-27-2015, 09:59 PM
#104
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St. Jude Donor '15
Cats or no cats? That is the question.
Originally Posted by MikeJr72
no fumes at all while cruising...sounds like you had a leak that was forcing fumes into the car. I only notice it if I am at a stop/idle.
Originally Posted by J504
I'm running catless and dont notice the exhaust smell unless i have the windows down and stopped. However I do have a vented catch can from moroso that sits right infront of the cabin air inlet so I get some fumes when I get on it. Keeping the A/C on recirculate helps a lot, but its not good for the A/C system.
03-28-2015, 11:01 AM
#106
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03-28-2015, 12:09 PM
#107
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St. Jude Donor '15
Cats or no cats? That is the question.
I wonder if running the cats further back would help in keeping them alive
03-29-2015, 09:26 PM
#108
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St. Jude Donor '15
Fixed exhaust leak. Nut was missing on one of the flanges where the cats meet the H pipe. Gaping hole just after gutted cats probably wasn't helping the in cabin smell
03-29-2015, 09:33 PM
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03-29-2015, 09:41 PM
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St. Jude Donor '15
03-30-2015, 09:11 PM
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St. Jude Donor '15
No smell when going down the interstate now. Noticed some when sitting still a while, but I think that's probably normal.
03-31-2015, 03:23 PM
#112
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Anyone ever used cats from HJS? They supposedly have some that will survive high HP applications, up to 400HP per cat. They aren't cheap though. Like $750 a piece not cheap. They also aren't small.. over 5" in diameter for the higher HP ones, so I'm not sure they'd even fit
03-31-2015, 04:36 PM
#113
We always recommend that you keep your cats. Adding a supercharger and water/methanol injection shouldn't affect your catalytic converters unless your tune is off. If it's too lean, your EGT's will spike and you'll melt the substrate in the cat. Too rich and unburned fuel can ruin the cat. Typically modern cars run better with a cat, plus that catless raw fuel smell is no fun. Also, cats shouldn't be looked at as being barriers to making power. Look at the Hellcat for example. That's a factory car, legal in 50 states, with a warranty and cats and it makes a conservative 707hp. Just some food for thought!
03-31-2015, 04:38 PM
#114
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St. Jude Donor '15
We always recommend that you keep your cats. Adding a supercharger and water/methanol injection shouldn't affect your catalytic converters unless your tune is off. If it's too lean, your EGT's will spike and you'll melt the substrate in the cat. Too rich and unburned fuel can ruin the cat. Typically modern cars run better with a cat, plus that catless raw fuel smell is no fun. Also, cats shouldn't be looked at as being barriers to making power. Look at the Hellcat for example. That's a factory car, legal in 50 states, with a warranty and cats and it makes a conservative 707hp. Just some food for thought!
I'm still tweaking to try to reduce the smell, but may give cats another try at some point. It is nothing when going down the road, but it's still a bit annoying when I stop, and when I'm in reverse.. barf
Is there a particular type I should be looking for. i.e., metal vs. ceramic, a certain density, etc.?
04-06-2015, 01:34 PM
#115
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So whats the verdict on the highflow Kooks cats that comes with their header setup?
I will be doing the ECS1500/meth setup in two weeks trying to decide if I should just gut them before bringing it to ECS.
I will be doing the ECS1500/meth setup in two weeks trying to decide if I should just gut them before bringing it to ECS.
04-06-2015, 01:45 PM
#116
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I read something the other day that said the mistake a lot of people make is going too rich + too little timing. The problem with that is the richer you go the slower the flame travels.. then add on top of that delaying ignition, and you end up with a LOT of heat going out the exhaust and right to the cats. There is an AFR timing correction table helps with this, but most people zero it out.
Anyways. ECS has as much experience as anyone with that type of setup, so I'd call them and ask them. My guess is it depends heavily on how high you're wanting to go HP wise and how you drive the car though. Making a few "spirited" runs on the street every now and then is a lot different than full on top speed passes on a runway.
04-06-2015, 01:51 PM
#117
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I've read every answer you can imagine on this. What RWHP are you going for? I know everyone keeps saying gut them, but I would try to keep cats if you can. I would go with whatever ECS recommends. The smell isn't unbearable, but I'd still much rather avoid it altogether if possible.
I read something the other day that said the mistake a lot of people make is going too rich + too little timing. The problem with that is the richer you go the slower the flame travels.. then add on top of that delaying ignition, and you end up with a LOT of heat going out the exhaust and right to the cats. There is an AFR timing correction table helps with this, but most people zero it out.
Anyways. ECS has as much experience as anyone with that type of setup, so I'd call them and ask them. My guess is it depends heavily on how high you're wanting to go HP wise and how you drive the car though. Making a few "spirited" runs on the street every now and then is a lot different than full on top speed passes on a runway.
I read something the other day that said the mistake a lot of people make is going too rich + too little timing. The problem with that is the richer you go the slower the flame travels.. then add on top of that delaying ignition, and you end up with a LOT of heat going out the exhaust and right to the cats. There is an AFR timing correction table helps with this, but most people zero it out.
Anyways. ECS has as much experience as anyone with that type of setup, so I'd call them and ask them. My guess is it depends heavily on how high you're wanting to go HP wise and how you drive the car though. Making a few "spirited" runs on the street every now and then is a lot different than full on top speed passes on a runway.
I have owned F-bodies with huge cams/no cats before im not worried about the smell. The idea of having a 650-700rwhp car full emissions legal sounded like a good time. However my concern is the cats blow out somewhere down the line and need to get it retuned they're not exactly around the corner.
I'm going to ask them about it when I go down there.
04-06-2015, 01:53 PM
#118
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St. Jude Donor '15
Whatever it makes on 11-12psi with a M6 transmission
I have owned F-bodies with huge cams/no cats before im not worried about the smell. The idea of having a 650-700rwhp car full emissions legal sounded like a good time. However my concern is the cats blow out somewhere down the line and need to get it retuned they're not exactly around the corner.
I'm going to ask them about it when I go down there.
I have owned F-bodies with huge cams/no cats before im not worried about the smell. The idea of having a 650-700rwhp car full emissions legal sounded like a good time. However my concern is the cats blow out somewhere down the line and need to get it retuned they're not exactly around the corner.
I'm going to ask them about it when I go down there.
They'll know though.. one thing I read said the stock ceramic substrate cats tend to handle heat better than the metal substrate ones that are common with aftermarket headers, but who knows. It is the internet, after all
04-06-2015, 01:56 PM
#119
Instructor
I've read every answer you can imagine on this. What RWHP are you going for? I know everyone keeps saying gut them, but I would try to keep cats if you can. I would go with whatever ECS recommends. The smell isn't unbearable, but I'd still much rather avoid it altogether if possible.
I read something the other day that said the mistake a lot of people make is going too rich + too little timing. The problem with that is the richer you go the slower the flame travels.. then add on top of that delaying ignition, and you end up with a LOT of heat going out the exhaust and right to the cats. There is an AFR timing correction table helps with this, but most people zero it out.
Anyways. ECS has as much experience as anyone with that type of setup, so I'd call them and ask them. My guess is it depends heavily on how high you're wanting to go HP wise and how you drive the car though. Making a few "spirited" runs on the street every now and then is a lot different than full on top speed passes on a runway.
I read something the other day that said the mistake a lot of people make is going too rich + too little timing. The problem with that is the richer you go the slower the flame travels.. then add on top of that delaying ignition, and you end up with a LOT of heat going out the exhaust and right to the cats. There is an AFR timing correction table helps with this, but most people zero it out.
Anyways. ECS has as much experience as anyone with that type of setup, so I'd call them and ask them. My guess is it depends heavily on how high you're wanting to go HP wise and how you drive the car though. Making a few "spirited" runs on the street every now and then is a lot different than full on top speed passes on a runway.
Gotcha..yeah, that would be nice, but not sure it's going to happen on 11-12psi. That's a pretty healthy amount of boost for sure
They'll know though.. one thing I read said the stock ceramic substrate cats tend to handle heat better than the metal substrate ones that are common with aftermarket headers, but who knows. It is the internet, after all
They'll know though.. one thing I read said the stock ceramic substrate cats tend to handle heat better than the metal substrate ones that are common with aftermarket headers, but who knows. It is the internet, after all
04-06-2015, 02:04 PM
#120
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St. Jude Donor '15
