Cats or no cats
#1
Cats or no cats
I am considering long tube headers and exhaust on my l98. It is registered as a classic car and will not need emissions tested.
My question is are there any negative effects of removing the cats? Smell? Rideability? Durability?
Thx
My question is are there any negative effects of removing the cats? Smell? Rideability? Durability?
Thx
#4
Race Director
You'll be fine with no cats, i took mine off way back and if you have a decent cat back, you'll get some seat of the pants improvement too
Magnaflows are good, i had them for a while but now i have Pypes true dual's and I love them
Magnaflow
Magnaflows are good, i had them for a while but now i have Pypes true dual's and I love them
Magnaflow
Last edited by LD85; 06-01-2013 at 04:55 PM.
#5
You'll be fine with no cats, i took mine off way back and if you have a decent cat back, you'll get some seat of the pants improvement too
Magnaflows are good, i had them for a while but now i have Pypes true dual's and I love them
Magnaflowhttp://youtu.be/UPJnw2PrWjA
Magnaflows are good, i had them for a while but now i have Pypes true dual's and I love them
Magnaflowhttp://youtu.be/UPJnw2PrWjA
#6
Team Owner
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Magnaflows are good, i had them for a while but now i have Pypes true dual's and I love them
I had Magnaflow cat-back with OEM headers, hi-flow Y & cat and, though it sounded "mean" at WOT, the drone was a bit much...
#7
Race Director
Yes I have headers, 1 3/4"
I did not have drone with Pypes true dual.
Magnaflow Y system had a slight throne in a specific narrow RPM on the interstate
I did not have drone with Pypes true dual.
Magnaflow Y system had a slight throne in a specific narrow RPM on the interstate
#9
Le Mans Master
With no cats you lose low end torque, but gain upper RPM horsepower. Personally, I say leave them be unless it's a track car.
#10
Race Director
I don't remember anyone without cats not complaining about smell (even eye-burning). LD85: Didn't you complain about that too?
#11
Le Mans Master
I actually JUST saw before and after dyno results. I believe on a LS-1 Corvette. I'll have to try to hunt down that article. Was on facebook, so I'll probably never find it again.
#12
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Removing cats won't change the torque on an L98 motor, the stockers are very restrictive.
I initially had more drone with a straight pipe instead of the main cat with the TPIS headers. Going to true duals helped some of the drone, but its strongly dependent on the muffler you are using. My 88 has the same exhaust as the 86 - TPIS into duals- but the mufflers made a big difference.
I initially had more drone with a straight pipe instead of the main cat with the TPIS headers. Going to true duals helped some of the drone, but its strongly dependent on the muffler you are using. My 88 has the same exhaust as the 86 - TPIS into duals- but the mufflers made a big difference.
#14
Le Mans Master
#15
just a little tight on cash. If I can remove the precats and install a magna flow exhaust with the secondary cat in the Y it will be a lot less. The only stock part would be the exhaust manifold.
magna flow $599
magna flow $599
Last edited by Racod; 06-03-2013 at 01:06 PM.
#16
Team Owner
My '87 is primarily an autocross and track day car. I removed all of the original exhaust and went with true duals, an X-pipe, and DynoMax Ultra Flo mufflers. I stayed with the stock 2-1/4" pipe.
One caution with removing the stock exhaust (classic car plates or not) is that mufflers shops may not want to do the work. Removing a working cat from a car could result in a 5-figure fine from the EPA if they get caught. What you can do is to remove the plates, remove the exhaust yourself, then trailer the car to a muffler shop and tell them you are building an "off-road" car that won't see street use.
The Dynomax mufflers are very quiet at city and highway cruise speeds. At WOT they are loud. But there is very little interior resonance at cruise which I found surprising as all of the carpeting/padding has been removed. Members that have installed Flowmasters reported lots of resonance especially with the 40 or 44 series.
One caution with removing the stock exhaust (classic car plates or not) is that mufflers shops may not want to do the work. Removing a working cat from a car could result in a 5-figure fine from the EPA if they get caught. What you can do is to remove the plates, remove the exhaust yourself, then trailer the car to a muffler shop and tell them you are building an "off-road" car that won't see street use.
The Dynomax mufflers are very quiet at city and highway cruise speeds. At WOT they are loud. But there is very little interior resonance at cruise which I found surprising as all of the carpeting/padding has been removed. Members that have installed Flowmasters reported lots of resonance especially with the 40 or 44 series.
#19
For the folks whose cars are not registered as classic cars: In Texas, cats are not required on vehicles 25 years or older. Even if factory equiped. Check with the DMV in your state.
Last edited by mixalive; 06-04-2013 at 02:11 PM.
#20
Race Director
What's reality and what's law can be two different things. Internet search of Texas converter law seems to indicate the need to maintain existing factory converters. It's also been repeatedly posted that EPA regulations outweigh state law in this area.
But, local inspection is the bottom-line and what you have to answer for.
I would also add that your eyes and nose will have to answer too!
But, local inspection is the bottom-line and what you have to answer for.
I would also add that your eyes and nose will have to answer too!