PreCat/Cat/Exhaust ?'s
Thread Starter
3rd Gear
Joined: Dec 2014
Posts: 3
Likes: 0
From: San Antonio TX
PreCat/Cat/Exhaust ?'s
I recently purchased my 1986 with low miles, but with low miles comes a lot of sitting around time, my pre cats are rusting out and need to be replaced, if im replacing them I might as well do the whole cat/exhaust ssytem
Main question is if the car will not be in CA or NY do I need to run the pre cats or can I run straight pipes to catalytic converter. The car will be in Texas which does an emmission test
Planning on running Magna Flow mufflers, any pros or cons or other options appreciated
Thanx
Main question is if the car will not be in CA or NY do I need to run the pre cats or can I run straight pipes to catalytic converter. The car will be in Texas which does an emmission test
Planning on running Magna Flow mufflers, any pros or cons or other options appreciated
Thanx
Team Owner
Joined: Dec 1999
Posts: 34,873
Likes: 487
From: Lacey WA RVN 68-69
NCM Sinkhole Donor
The thing to do is to check with the TX DMV for all of the rules regarding emissions requirements for your year of car. If you have to have the car tested, you will need to know what's involved. Is there a visual inspection? Or just a sniffer test?
I would think the pre-cats do some cleaning of the exhaust gasses before going thru the main cat. It may be hard to tell if the main cat alone will be enough to meet the test minimums.
If a car fails emissions in TX, is there a free re-try? Or do you have to spend some amount of money for fixing emissions before another test? What you may try is to cut the pre-cats out and replace them with exhaust pipe. Then get the car tested to see if it passes with just the main cat.
Also, you may find that most muffler shops will not remove working cats to replace then with straight pipe. That's a violation of federal law and if they get caught, it can be a 5-figure fine
I would think the pre-cats do some cleaning of the exhaust gasses before going thru the main cat. It may be hard to tell if the main cat alone will be enough to meet the test minimums.
If a car fails emissions in TX, is there a free re-try? Or do you have to spend some amount of money for fixing emissions before another test? What you may try is to cut the pre-cats out and replace them with exhaust pipe. Then get the car tested to see if it passes with just the main cat.
Also, you may find that most muffler shops will not remove working cats to replace then with straight pipe. That's a violation of federal law and if they get caught, it can be a 5-figure fine
Drifting
Joined: Jul 2009
Posts: 1,258
Likes: 98
From: Ashland PA
2021 C4 of the Year - Modified Finalist
If you dont need precats you can get this y pipe included.
http://www.ebay.com/itm/Flowmaster-2010028-Catalytic-Converter-3-IN-OUT-for-86-91-Chevy-Corvette-V8-/141286165442?pt=Motors_Car_Truck_Parts_Accessories&fits=Year%3A1990%7CModel%3ACorvette&hash=item20e54fcbc2&vxp=mtr
http://www.ebay.com/itm/Flowmaster-2010028-Catalytic-Converter-3-IN-OUT-for-86-91-Chevy-Corvette-V8-/141286165442?pt=Motors_Car_Truck_Parts_Accessories&fits=Year%3A1990%7CModel%3ACorvette&hash=item20e54fcbc2&vxp=mtr
Race Director
Joined: Nov 2003
Posts: 12,221
Likes: 446
From: Overland Park Kansas
2020 Corvette of the Year Finalist (appearance mods)
C4 of Year Winner (appearance mods) 2019
Technically, Federal law says you're supposed to maintain the original configuration of emissions control systems (and/all of them). As pointed out, age may change (lower) the requirement -- though it's likely in regard to testing.
You will even find that individual shops vary of the interpretation and strictness of what they'll do. I'm saying some shops will modify while others will only replace as it sits.
The 3rd piece to understand is the consolidation of converter technology. When your car was made, the pre-cats removed NOX and the main removed carbon monoxide. (NOX is a by-product of running engines at higher times -- to lower carbon monoxide levels via more complete burn. And, the EGR valve makes sure it doesn't get TOO hot and create too many NOX fumes.) That said, modern converters perform both functions in a single unit. If/when measured, you should expect a single converter to pass -- assuming all other components are operating "in spec".
With Magnaflow mufflers, I think you'd avoid exhaust "drone" which usually becomes prevalent when altering L98 exhaust systems -- and making them louder. So, again, I think you'd be fine with a new center converter sans pre-cats. (By "fine", I'm referring to sound quality.)
Magnaflow sells some inexpensive ($65ish) ceramic bullet converters that would fit/work well if you choose to replace what you've got. I think they'd pass even in CA....which means you'd still be "50-state legal".
The bottom-line comes down to the shop you find, the use for the car, and personal preference. Federal oversight to check configuration of your converts is too costly to be added to the EPA. So, it's kind like that commercial.... All FORDs are equal, it's the dealer that makes the difference!
Except we are talking about a much better Chevy! And, the cool-factor Mazda advertises with "Vrooom, Vrooom".
I think you should try the Magnaflows with a new center converter. If you like the sound, you're done. If not, add the pre-converters back in. The ultimate cost will not be affected doing it in two steps.
You will even find that individual shops vary of the interpretation and strictness of what they'll do. I'm saying some shops will modify while others will only replace as it sits.
The 3rd piece to understand is the consolidation of converter technology. When your car was made, the pre-cats removed NOX and the main removed carbon monoxide. (NOX is a by-product of running engines at higher times -- to lower carbon monoxide levels via more complete burn. And, the EGR valve makes sure it doesn't get TOO hot and create too many NOX fumes.) That said, modern converters perform both functions in a single unit. If/when measured, you should expect a single converter to pass -- assuming all other components are operating "in spec".
With Magnaflow mufflers, I think you'd avoid exhaust "drone" which usually becomes prevalent when altering L98 exhaust systems -- and making them louder. So, again, I think you'd be fine with a new center converter sans pre-cats. (By "fine", I'm referring to sound quality.)
Magnaflow sells some inexpensive ($65ish) ceramic bullet converters that would fit/work well if you choose to replace what you've got. I think they'd pass even in CA....which means you'd still be "50-state legal".
The bottom-line comes down to the shop you find, the use for the car, and personal preference. Federal oversight to check configuration of your converts is too costly to be added to the EPA. So, it's kind like that commercial.... All FORDs are equal, it's the dealer that makes the difference!
Except we are talking about a much better Chevy! And, the cool-factor Mazda advertises with "Vrooom, Vrooom".
I think you should try the Magnaflows with a new center converter. If you like the sound, you're done. If not, add the pre-converters back in. The ultimate cost will not be affected doing it in two steps.
Thread Starter
3rd Gear
Joined: Dec 2014
Posts: 3
Likes: 0
From: San Antonio TX
Technically, Federal law says you're supposed to maintain the original configuration of emissions control systems (and/all of them). As pointed out, age may change (lower) the requirement -- though it's likely in regard to testing.
You will even find that individual shops vary of the interpretation and strictness of what they'll do. I'm saying some shops will modify while others will only replace as it sits.
The 3rd piece to understand is the consolidation of converter technology. When your car was made, the pre-cats removed NOX and the main removed carbon monoxide. (NOX is a by-product of running engines at higher times -- to lower carbon monoxide levels via more complete burn. And, the EGR valve makes sure it doesn't get TOO hot and create too many NOX fumes.) That said, modern converters perform both functions in a single unit. If/when measured, you should expect a single converter to pass -- assuming all other components are operating "in spec".
With Magnaflow mufflers, I think you'd avoid exhaust "drone" which usually becomes prevalent when altering L98 exhaust systems -- and making them louder. So, again, I think you'd be fine with a new center converter sans pre-cats. (By "fine", I'm referring to sound quality.)
Magnaflow sells some inexpensive ($65ish) ceramic bullet converters that would fit/work well if you choose to replace what you've got. I think they'd pass even in CA....which means you'd still be "50-state legal".
The bottom-line comes down to the shop you find, the use for the car, and personal preference. Federal oversight to check configuration of your converts is too costly to be added to the EPA. So, it's kind like that commercial.... All FORDs are equal, it's the dealer that makes the difference!
Except we are talking about a much better Chevy! And, the cool-factor Mazda advertises with "Vrooom, Vrooom".
I think you should try the Magnaflows with a new center converter. If you like the sound, you're done. If not, add the pre-converters back in. The ultimate cost will not be affected doing it in two steps.
You will even find that individual shops vary of the interpretation and strictness of what they'll do. I'm saying some shops will modify while others will only replace as it sits.
The 3rd piece to understand is the consolidation of converter technology. When your car was made, the pre-cats removed NOX and the main removed carbon monoxide. (NOX is a by-product of running engines at higher times -- to lower carbon monoxide levels via more complete burn. And, the EGR valve makes sure it doesn't get TOO hot and create too many NOX fumes.) That said, modern converters perform both functions in a single unit. If/when measured, you should expect a single converter to pass -- assuming all other components are operating "in spec".
With Magnaflow mufflers, I think you'd avoid exhaust "drone" which usually becomes prevalent when altering L98 exhaust systems -- and making them louder. So, again, I think you'd be fine with a new center converter sans pre-cats. (By "fine", I'm referring to sound quality.)
Magnaflow sells some inexpensive ($65ish) ceramic bullet converters that would fit/work well if you choose to replace what you've got. I think they'd pass even in CA....which means you'd still be "50-state legal".
The bottom-line comes down to the shop you find, the use for the car, and personal preference. Federal oversight to check configuration of your converts is too costly to be added to the EPA. So, it's kind like that commercial.... All FORDs are equal, it's the dealer that makes the difference!
Except we are talking about a much better Chevy! And, the cool-factor Mazda advertises with "Vrooom, Vrooom".
I think you should try the Magnaflows with a new center converter. If you like the sound, you're done. If not, add the pre-converters back in. The ultimate cost will not be affected doing it in two steps.
My other toy is a 60s Dodge w/440 running Magna Flows and I like the sounds, started off with Flowmasters and they were just to harsh
