test pipes or hollowing out the cats?

[medusa]

I'm just wondering which i should do. Should i hollow out the cats or just by the freaking test pipes. I was curious if anyone knows of any problems associated with hollowing out the cats other than smog related stuff. Also curious if anyone has passed smog without the cats?

 

[nsxtasy]

Originally posted by medusa:
I was curious if anyone knows of any problems associated with hollowing out the cats other than smog related stuff.

You mean, aside from the fact that they won't give most folks any performance benefit?

 

[medusa]

You mean, aside from the fact that they won't give most folks any performance benefit?

really? damn, just make my nsx louder? (laughs) i can live with that, but is that all? *reconsiders*

 

[hk4site]

Buy test pipes from dali and save the cats.

 

[burbel]

Yeah, that's it. Also, new cats are in the thousands of dollars (either 2 for 2k or 4k, either way, a lot) - just something to consider. I am in a different boat, I was doing headers + exhaust, and wanted to do the whole system, so I inquired as to new cats - not for that price!

 

[Gerard van Santen]

Originally posted by medusa:
I'm just wondering which i should do. Should i hollow out the cats or just by the freaking test pipes. I was curious if anyone knows of any problems associated with hollowing out the cats other than smog related stuff. Also curious if anyone has passed smog without the cats?

Hi Medusa,

I have a CTSC with Comptech headers, Remus exhaust and hollowed out cats and above all I passed the smog tests.

I don't know if I gained any hp, but I am still satisfied with my modified cats.

Gerard

 

[5inchfatlip]

I've heard different stories that is does help and it doesnt but for sure it does get LOUDER...what setup are you running too? it may get real loud with a full exhaust...

 

[nsxlover]

I bought test pipes from billetdesign.com They made the car sound better. For the $240 or so I would not hollow out the cats just for the reason of emissions and putting them back on for that.

Rob

 

[bill92nsx]

I bought test pipes and put them on my NSX. Even if you don't get an increase in power the engine will last longer without them. Don't gut them out they can get to be very expensive. Buy the test pipes and it takes about an hour to install. The car does get a little louder but for the better. It sort of loses that lawn mower sound everyone keeps talking about.

I passed my emissions without them. This engine is a very efficient engine and should pass the test. (only worry about the visual test-here in NY the emissions test is very strict but they dont do a visual). As for performance I do feel it alittle--the engine revs faster, but it could all be in my head. I know that when I took them out of my testarossa the car did gain about 28hp (dynoed). Then again on the TR there are four of them adn the funny thing is the car ran cleaner without the cats than with them. I saved my inspection summary, couldn't believe it.

 

[NSX 3.0]

Just buy the test pipes I have DC Headers Taitec By pass pipes and a RM Racing Exhaust it sounds unreal. As for HP I was hitting 115 mph in 3rd with just the RM I added the Headers and Taitecs now I'm touching 120 mph I can really notice it.


Steven 91 Blk/Ivory

 

[Periokid]

Originally posted by Steven Spanbauer:
Just buy the test pipes I have DC Headers Taitec By pass pipes and a RM Racing Exhaust it sounds unreal. As for HP I was hitting 115 mph in 3rd with just the RM I added the Headers and Taitecs now I'm touching 120 mph I can really notice it.


Steven 91 Blk/Ivory

I am confused on this one. Why would HP effect the max speed in third gear. Redline is redline. If horsepower was different at the same redline, the car is still going the same speed.

Am I missing something?



------------------
1991 NSX Red/Black

 

[DONYMO]

Won't Comptech's Catalytic Converter do the trick for $695? This is a far cry from $2,000 to $4,000!

 

[Saturn]

can you take out the cats and put test pipes in and still pass smog in CA?

has anyone tried this in CA?

 

[medusa]

thanks for the input guys! I feel like the engine should howl just a lil louder but that's just me. Me=type of guy that would install his exhaust on at 2:00am in the morning. I really think i am addicted to this car.

Now all i gotta do is buy this test pipes and wait for fed-ex, eh?

 

[NSX 3.0]

Originally posted by Periokid:
I am confused on this one. Why would HP effect the max speed in third gear. Redline is redline. If horsepower was different at the same redline, the car is still going the same speed.

Am I missing something?

Not sure what you dont get...Ever gone to a Drag Strip? A previous car I owned ran 14.1 1/4s at 99mph I added Headers,Exhaust and took of the Cats and it ran a 13.8 @102mph.
So I guess what my point is more HP=faster car.

Steven 91 Blk/Ivory

 

[nsxtasy]

Originally posted by Steven Spanbauer:
A previous car I owned ran 14.1 1/4s at 99mph I added Headers,Exhaust and took of the Cats and it ran a 13.8 @102mph.

And you think it was the cats that helped, not the header and exhaust?

 

[NSX 3.0]

Originally posted by nsxtasy:
And you think it was the cats that helped, not the header and exhaust?

No just all three

Steven 91 Blk/Ivory

 

[burbel]

As for the post about the Comptech cats, those still aren't street legal (off-road use only). To me, if you're going to break the law willingly, there is no difference between them and the cat bypass pipes, except the cat bypass pipes are a) cheaper, and b) lighter (I assume).

 

[DONYMO]

Originally posted by burbel:
As for the post about the Comptech cats, those still aren't street legal (off-road use only). To me, if you're going to break the law willingly, there is no difference between them and the cat bypass pipes, except the cat bypass pipes are a) cheaper, and b) lighter (I assume).

Wouldn't the difference be the ability to pass emissions? They may not be "street legal", but I would think that if they are cats, albeit not as effective as oem cats, they would have a better chance of getting a car past emissions...especially if the inspection place visually verifys the existence of the cats (which some appparently do).

- Don