NSX/MR2
Suspended
I am going straight-pipe and is thinking bout removing the cat. How do i do this? Any special tools needed?
Thanks,
De
Thanks,
De
Taking out the cat?
- Thread starter NSX/MR2
- Start date
You know that it's not going to give you any greater performance unless you have forced induction, right?
NSX/MR2
Suspended
I an installing a straight-pipe.
Yellow Rose
Suspended
- Joined
- 22 November 2001
- Messages
- 2,256
I am going straight-pipe and thinking about removing the cats. How do I do this? Any special tools needed?
Each cat has two pairs of bolts for a total of eight threaded fastener assemblies. The weirdest thing on my cats. You would think that the hex of the nut and the hex of the bolt are the same. Not on my car! To remove my cars I have to use various combinations of 12mm, 13mm and 14mm wrenches / sockets.
I don't recall if early year NSXs have the O2 sensor in the cat or in the piping. If in the cat, you'll also need a 21mm O2 socket. This is a special socket with one of the six sides notched out so it will slip over the wires. I would not try to get by with a conventional two-sided open-end wrench. All it takes is accidentally rounding off the "shoulders" of the O2 sensor hex, and your day is done.
Each cat has two pairs of bolts for a total of eight threaded fastener assemblies. The weirdest thing on my cats. You would think that the hex of the nut and the hex of the bolt are the same. Not on my car! To remove my cars I have to use various combinations of 12mm, 13mm and 14mm wrenches / sockets.
I don't recall if early year NSXs have the O2 sensor in the cat or in the piping. If in the cat, you'll also need a 21mm O2 socket. This is a special socket with one of the six sides notched out so it will slip over the wires. I would not try to get by with a conventional two-sided open-end wrench. All it takes is accidentally rounding off the "shoulders" of the O2 sensor hex, and your day is done.
I am sure he is doing it for weight reduction... not increased HP.
NSX/MR2 said:
You are going to need patients, strength, 6 point sockets, extensions, breaker bar, new gaskets, PB blaster or something similar. I had to take off my front cat and front pipe when I replaced my oil pan. Twisted off 2 of the 6 studs on the cat, not a big deal because they are replaceable. Also put anti-seize compound on the studs to facilitate disassembly in the future when you will have to put the cats back on to emission test.
Since I haven't figured out how to get by without breathing this removing the cats thing kind of bugs me on cars that will be operated on the street, but then again I remember how the air was in LA back in the 60s. I think a lot of the people pulling their cats off probably don't. Oh well.
leave it on pleaseeeee!!!! I am choking..De, the man says it is NOT going to help unless you have forced induction 
nsxtasy said:
Sure it will - though performance gains are relative. Dyno'd rwhp gains will typically be 5-6hp. But the real advantage is in the reduction of weight of 17-18lbs. To some, like me, they are well worth the cost.
The legality of the purchase and install is up to the owner. And in the state I reside in, they are perfectly legal.
The legality of the purchase and install is up to the owner. And in the state I reside in, they are perfectly legal.
nsxtasy said:
So if you do have forced induction, it helps?
Can you explain?
DONYMO said:
Any force induction setup will greatly benefit from a free flowing exhaust. The exhaust gas exiting combustion chamber faster will allow cleaner Intake stroke of the combustion cycle.
Super charger and turbo charger can benefit from a free flow exhaust.
SC- better intake stroke - allow more charged air with a lot less exhaust gas left in chamber.
Turbo - Above + quicker spool response and better peak boost if your engine is tuned for it.
Although a cold air (side draft ramair ) intake + Header + AEM EMS + Catless straigth thru exhaust may still give you good gain.
To be Enviromentally friendly. You can go after market Cat from Random technology or Magnaflow. They will only restrict 1-2 hp in testing. In NSX you will use two of them. The key to free flow Cat is to have bigger frontal surface area design = less restriction. Cat will keep also your bumper cleaner too.
Ponyboy said:
WHaaaaaaa???
I thought emissions control devices on automobiles were federally mandated. How could it possibly be legal to remove them and then continue to use the car on the street? Just because in some states they don't test every year doesn't mean its legal. Nate
NSX/MR2
Suspended
Don't you know that the NSX has one of the smog-friendly system there is? Something about a high performance V-tec engine. My brother runs a smog shop and every NSXes passed through it with flying color. Given the same mileage between the NSX and the MR2, the NSX is a better conditioned vehicle by far.
Ponyboy, my last NSX was originally from Lawton, Oklahoma. I know how easy it is with the smogging system over there.
Ponyboy, my last NSX was originally from Lawton, Oklahoma. I know how easy it is with the smogging system over there.
Went to inspection last friday. By Saturday 10am the cats were gone.
No one mentioned that the car now sounds like a nasty screaming bitch. I love it.
I think the performance gain is noticeable.
No one mentioned that the car now sounds like a nasty screaming bitch. I love it.
I think the performance gain is noticeable.
I have never seen or heard of such gains on an N/A NSX. Most of the dyno reports I have seen have shown at most an increase of 1-2 hp, and some of them have shown a loss of hp.Ponyboy said:
17-18 pounds is not a huge amount of weight, and won't make a huge performance difference. (We're talking about differences in 0-60 and 1/4 mile times of less than three hundredths of a second, which is about what you would get from an increase of 3 hp.) And the substantial increase in pollution - this isn't just a measurement; you can smell the difference yourself - is not worth it.Ponyboy said:
The catalytic converter is one of the most important innovations in automotive technology. You can read about how it works here. It has noticeably reduced air pollution throughout most of the country, and this has benefitted everyone who breathes air.
I think the willingness of some owners of street-driven NSXs to increase the pollution of their environment for such an insignificant and imperceptible performance improvement is a shameful travesty and reflects extreme selfishness and lack of consideration by those involved.
So you have commited fraud - which is not only unethical, but illegal. I'm sure your parents are very proud of you.hondaholic said:
You can also get the same noticeable performance gain from getting one of those low-restriction, Placebo brand catalytic converters instead, but without the increase in pollution.hondaholic said:
Last edited:
NSX/MR2
Suspended
fkong777 said:
How can I get my hands on these cats? Need some info., please.
nsxtasy said:
So you have commited fraud - which is not only unethical, but illegal. I'm sure your parents are very proud of you.
Most of you track your cars (where no cats are legal) more miles/year than I drive mine on the street. The first milisecond of a lame IRL or CART race polutes more than a year of miles in my car.
NSX/MR2
Suspended
Like I said, the NSX is one of the most smoq-friendly vehicle around. Even eithout the cat, i think it will be better than my MR2, which has the same mileage, but already blows smog when it is cold.
NSX/MR2
Suspended
I've decided against this idea after hearing about the $2000 fine and tow-away for a while.
NSX/MR2 said:
Uhhh.... the NSX is a car, with an internal combustion engine, like any other car it needs its emissions controls to run clean. If you take the cat(s) off of any car it is going to be a HUGE polluter. And despite what you say, NO car will pass an inspection without cats.
Nate
NSX/MR2
Suspended
Big_nate said:
Uhh, i didn't say it will, but I said that the NSX is one of the cleanest running vehicle around. Also, I know that it will not pass the test, you don't need to educate me, I have an ok head on my shoulder as my degree would have suggest. And did you also read my last post? As it is, I am more concerned about the fine and the car-impound than about the polluting.
Last edited:
hondaholic said:
So someone on the board has met my ex-wife
Similar threads
