CNT resonated testpipe review

kevin.z

Hello, this is the my first review I ever posted on this fourm. So if I did anything unnecessary, please correct me!Anyways, here is my review! PLEASE REP ME!

update: Smell has gone done considerably! The growl is also more prominent at 2k now instead of 2500rpm














ORDER AND DELIVERY: 10/10
I order mine CNT testpipes this monday on the CNT website. The ordering process is very easy. Just go online to order it with paypal. Price is 199 shipped. I believe that is the best price you can get now for resonated test pipes. Delivery is more incredible. I ordered it monday morning and it is shipped in the same afternoon. On wednesday, I received the testpipe.

PACKAGING AND CONTENTS: 8.5/10
When i received the box, There was a big hole torn on the box. You can actually see the test pipes through that hole. I dont think they bubble wrapped it enough for the abusive shipping of UPS. Also, I didnt get any CNT racing decals!

Quality: 6/10
I am no where near an expert when at looking at welds. So I can only comment on what I see, so don't quote me on my amateur comments. After comparing the weld quality of the amuse exhaust to these CNT test pipes, I have to say the CNT looks very rough and made-in-China (although i am Chinese) compare to the Amuse. The gaskets provided doest fit the stock y-pipe, so we have to use the stock gaskets again (The top gaskets does fit though).

Performance and sound: 9/10 NO cel
I just installed the test pipes, so I have yet felt a difference in power. Maybe I will feel more difference after the ecu and test pipes settles in. The sound is a bit on the quiet side. Keep in mind I still have the stock exhaust. lol But the sound is definitely more throaty. In fact, it is so throaty it sounds like a very aggressive G35 coupe. I don't know if you guys know the distinctive sound of g35 coupe. But it sounds like that times 5. You almost cant hear anything when it is below 2500 rpm. In fact, I think it is exactly the same as stock below 2500 rpm. But after 2500 rpm, the note becomes very distinct similar to G35 coupe. When it is at 4000 rpm or over, the car is very loud, definitely loud enough to get people's attention. However the exhaust note is not very deep. It is more like an enhancement to the stock note. More throaty, pronounced, louder(grammatically incorrect?) and high pitched. I haven't noticed too much rasp and I love the hissing! When you let off the gas pedal, a very cool hissing sound appears like a blow off valve. I really don't get why people didn't like the sound. It sounds special. Ohh, and the smell.

SMELL: LOL NO cel
MY car smell like cow crap now because of the test pipes. I was being told by my mechanic after the test pipes settle in and burn off the excess metal, the smell will go away. I just really hope that I don't get pulled over before the settling because everywhere I go now, the entire area smells like cow crap.

Overall value: 9/10
What I don't like is the lack of attention to detail in CNT resonated test pipes. The quality looks rough and the packaging doesn't look very assuring.
What I also don't like is the smell. The whole street smells after I drove by. I feel like everyone knows I installed test pipes.
However, if I were to do it all over again, I would still do the same thing. I only paid $200+160(labor) for a product that not only increase performance, but also sound. I was so tired of the stock sound and I definitely prefer the sound with test pipes. The car is definitely more aggressive and exciting to drive than before. For someone like me who can not afford the price of a full cat back exhaust, CNT test pipes is definitely a good value alternative, definitely. CNT resonated test pipes cost 200 shipped, F.I cost 375+ shipping, Berk is $350 and non-resonated.
Despite the roughness of the metalwork of CNT test pipes, I think test pipes is just test pipes, nothing more, nothing less. As long as it fits well and shows performance gains, I think the appearance of test pipes are not important. Would I recommend people to buy CNT test pipes? of course YES as long as people understand test pipes may smell and the metal work of CNT resonated test pipes looks rough.

If there is enough interest, I mite make a video comparing my current set up with Amuse R1000 y-back exhaust. PLEASE REP ME IF YOU FIND THIS REVIEW USEFUL.
Thanks
Kevin
Vancouver BC

W.O.W. 370Z

I got a CEL (P0420) after 50 miles with these. I think it's hit and miss with these test pipes.

Kastley85891

No probs with mine after 300 miles, fit good and ran good, I think an o2 extender would fix any issue, ^did you reset your ECU after initial install?

__________________

Boosted V8 hunter
2850 lbs and 375WHP

CBRich

I also got a CEL but don't find that to be an issue. I totally agree with the rest of the review. And if you do the labor yourself these are a huge value at $199.

kevin.z

No, no cel issues yet. I didnt even reset the ecu after the install. Sorry everyone computer is screw-up, wont link to my camera. Will upload pictures ASAP.

Just an update, SMELL WAS GONE! Although sometimes it stills smells a bit like lawn mowers at times, the cow crap smell is gone. Everything goes well!

SE

If you're installing any type of test pipes, you can expect a CEL to come on at some point or another. I got "lucky" and didn't have one appear until almost 300+ miles. The ECU only checks for function at certain parameters, but usually it pops up around ~50 miles. You can just clear the code with a scanner though if it bothers you. Usually a mechanical CEL fix will work, but it's not a guarantee. The two O2 sensors (post cat/pre cat) work together to verify that the catalytic converter is working. I switched over to FI longtubes and it's awesome that they were able to eliminate the CEL issues.

W.O.W. 370Z

Yes sir. I got lucky with my old 350z and had no CEL when I added the test pipes. I might add some non foulers (cel fix) to the test pipes, despite the fact that the test pipes already have them built in and they are pretty far out there.

Kastley85891

^ or wait for the ECU codes to be cracked fully to just turn off rear o2 CEL lol.

Weeee - you have just fitted a form of test pipe so if your logic is valid, you should expect a CEL at some point ;-) how did FI fix the CEL? they have the normal j bend anti fowler and the extension cabling for front o2 due to relocation on long tube, but I do not see anything more special then that?
I do not have a set in front of me, nor do I have a set installed so any info appreciated.

BTW - Hows are they? I looked at these early on but my mod fund is more limited these days. I do like the look of them, would love to see a set on a 4.5 or 4.8 stroker !!

__________________

Boosted V8 hunter
2850 lbs and 375WHP

SE

You know...to be honest I'm not 100% sure of the dynamics of how it works. Yes, there is a simply J-bend/anti-fouler, but it is for the pre-cat sensor. The post-cat sensor is just a normal bung with no anti-fouler. Most test pipes use an anti-fouler on the post-cat sensor since the other sensor is on the header. I have no idea how/why this works, but it does


Coming from someone who just changed from non-resonated test pipes, the F.I longtubes made a huge difference in low/mid-range power.

kevin.z

photos are up!

VancouverZ34

awesome, Kevin!

Jordo!

Two questions:

1. I know it comes with an O2 extender, but it might not be long enough. Has anyone tried this trick:

Use TWO 18mm spark plug defoulers (you can get these at Autozone).

Drill one out with a 1/2 inch bit and leave the other one stock, screw in one defouler into the other and the O2 sensor on the end of that; install whole assembly into bung.

The way the ECU determines cat efficiency, and why this trick (usually) works: The ECU monitors the rate of change in narrow band O2 voltage between first (precat) and second (post cat).

If the second and first change at the same rate, that tells the ECU the cat isn't working and sets the code.

The extender creates enough of a delay in exhaust gas reacting with the sensor tip (if it works that is) to fool the ECU into thinking the voltage values are varying at different rates.

You can also fool the sensor electronically -- I can dig up the info on that if anyone is interested in trying it.


2. Any difference in prevalence of the P0420 between '09 and '10? Might be slightly different logic in the newer ECU's.

CBRich

Someone did state that they used steel wool in the bung and haven't got another CEL for a few hundred miles. It's cheap and easy and seems to work.

STi 5

Already tried the defoulers, our O2 sensors are two big (the sensor itself) to fit in the drilled out defouler. I tried it myself, no dice, so I ordered ones from Strup (straight ones). They fit fine but I am still getting a cel after about 500 miles. I took one of the defoulers that I didn't drill out and filled it with steel wool and then screwed the Strup one into it, followed by installing it into the TP. Works for about 500 miles like I said earlier, but it (cel) still always comes on. I don't know if angled ones will work better, but that is what I tried.

Jordo!

The steel wool must act as a filter, further slowing down the rate the exhaust gasses reach the sensor.

Hmm. You have a 2010, does CBRich have a 2009? Could be different ECU logic for determining rate of voltage change.

I'd really like to figure this issue out... especially since this will probably be my first mod...

BTW, any significant difference in whp between TP and HFC or is this primarily an issue of price? Do the HFC's have the same CEL issue?

Anyone interested in details on a electroinic (possible) fix?