Why do people spend on aftermarket "high flow" cats when realistic its illegal to remove your cats. I only stress this point because I have been pulled over and the cop looked under my car. Now I dont have cats but I "faked" it by putting a fake straight through cat that the muffler shop did for $50.00 (not on my z other car) and the cop questioned it because it was welded so I got sent to a ref station. Gave me enough time to put my stock cat back on and I was fine. Here is the thing, removing your cats is illegal. You can't remove a working catalytic so by replacing it with a "high flow" your already comitting an illegal move. WHY spend $200.00-$600.00 on high flow cats when you can just get "fake" ones at muffler shops for a lot cheaper. Granted their are muffler shops that wont do that but most of the ones I seen do and you spend about 50-100 bucks and you get WAY MORE better performance. It just doesnt make sense. Your taking the stock cats out might as well do it the right way and just go all out. because either way your screwed....

 

a working cat will pass emissions. some people car about that and the atmosphere as well as performance. surprisingly, the difference in performance of a test pipe and high flow cat is negligable. it is ok to replace a damaged cat. i would imagine that places like performance nissan or whoever installs these cats will stand up for their customers if the are called into question.

 

Well, with my High Flow cat and test pipe their was a 11hp difference. And yes very noticiable. Of course a damaged cat is replaceable but lets face it, were not replacing damaged cats here But to each their own, I wouldn't spend $500.00 for a mod that can be done differently. And aobut passing emissions c-mon now? its not like you have to pass every year... Im still not convinced. And by the way, when I went to the Ref station I had "high" flow cats and he told me that it must be replaced with OEM.

 

I would put the Crawford hi flow cats on before I would do a straight pipe. It still will pass emissions, and there are no funny looking welds on it in case the cops pull you over to take a look at it. Unless he really knows the 350Z, which has 2 cats built in vs. 1, he won't give you a fix it ticket like the one you got.

 

My point is that there is a market for all sorts of different products. I used to have test pipes but didn't like the sound. A high flow cat will help with the sound, keep me legal, and reduce my emissions while giving me more than half of a test pipes gain, which I like. If I have to pay more for those benefits then I do. It's simple.

 

Some of us live in cities where we don't have the smog & emissions hitlers like Cali....it makes perfect sense to install the high-flow cats...speak for yourself.

 

i think your post contradicts itself but i can't tell for sure.

 

good luck to any cop trying to look under my car! im scraping as it is

 

Well I went over a nasty bump and it damaged my cats So I got new ones. They just happen to be hi-flow.

 

Here's something a cop might use to make inspection easier:
http://www.searchsystems.com/contraband.html

--
Jeff

 

Even with this thing I think it would be pretty hard to see the cat's the way Nissan stuffs them in the body....

 

How loud is straight through pipes? I'd get rid of my cats for 11HP without second thought. If I were sure it won't be too loud.

 

Straight pipes make the exhaust note really raspy. It will be noticeable.

As for that contraband do-hicky, something tells me your average cop will not have that thing in his trunk. It is meant for border crossings and customs mostly (oh, and maybe CARB shops).

Lets face it, if you do the following, you are breaking the law:
1. Remove a cat that is working with less than 50K miles
2. Deliberately damage a cat
3. Install high-flows in replacement of a working cat
4. Install test pipes for any reason for use on the street

Now, why would some of us choose to break the law but not go all the way and use test pipes? The answer is simple. First, some of us actual want clean air. Also, some of us do not want a raspy exhaust note. Even though high-flows are twice as expensive and may not free as much HP, they are still worth the money for the above two reasons.

 

Yeah good look trying to look under the car! Also, to get rid of the "raspy" sound you have to install an inline resonator. Problem solved and noise DB decreased

 

I hate to play the Z-tree hugger role but let's at least keep some form of cats in place. Spewing carbon monoxide and other nasties for a couple of hp's seems shortsided to me. Clean air is a shared commodity. Heck, you'll get the same traffic-light launching benefit by leaving the spare wheel in the garage. More so with 17" wheels instead of the 18 and 19's ;-)


breathing for a living

 

I already have 17". And I put away everythin I can including mats and spare tire. Still 11hp is 11hp!

 

Couple of HP?s Try about 40-80HP On a TT Supra im sure when I go boost on the Z their will be at least a 20-30HP Difference. And I will dyno to prove it Thats about .3-.5 of a difference in a 1/4 mile. Thanks for saving the trees but I dont drive my car enough to hurt the 0-Zone and it wouldnt be any different if I track used it. Have over 1 year with my Z and it only has 4Kmiles... And thats from long drives.. To me every HP is worth it and thats the difference between winning and losing a race drag or road race.

 

No emission test for 6 years. Cat's went off 26k miles ago and will stay off till I have to take the car back in 5 years to test lol. Definately to each his/her own, and I've enjoyed my choice since day one.

 

I would love to see that dyno between a high flow cat & straight pipes you are saying you can get a 30 hp difference. I don't think so.

 

I didn't mean from high flow to straight pipe 30hp.. I meant stock to straight pipe 30hp on (TURBO). I wouldnt waste my money on High Flow cats... Plus, I like to shoot fireballs from my exahaust... I love doing that on my other car something you can't do with cats..