Hi guys,

Need some help here. I have an 04 automatic g35 coupe, tossed on fujitsubo y-pipe, random tech cats, nismo intake and fujitsubo exhaust. Was pretty happy with the performance.

about 2 months ago, got some gashes from a dealer service in the flex areas of the y-pipe. needless to say, got worse overtime, sounded horrible, no backpressure and no power at all.

got the flex pipes cut out and welded with new ones on the y-pipe. the flex pipes are 1/4" bigger in diameter than the old ones. Car sounds normal now and I can't hear any leaking. However, it feels like I have no torque, doesn't push me back in my seat when I accelerate. In fact, feels slower than stock and when I put my hands in front of the exhaust tips in the back, it's very weak. It used to feel like a crazy blowdryer back there even at idle.

I've reset the ECU with the instructions from Technosquare and got the CEL light flashing correctly, that helped just a bit for shift responsiveness but power is still FUBAR'ed. Any ideas?

 

time for a new stock y-pipe?

 

If performance was fine with the Fuji Y-pipe in that combo, then the only real explanations are that you either still have a leak somewhere or that those larger flex-sections are the problem. I think that Fujitsubo would have used the biggest flex-sections they could without going too big.

If you were happy with your combo, just get a new aftermarket Y-pipe. They seem to be availalbe everywhere now and for pretty cheap. Or if you felt you had a loss of torque with that combo, over stock, then try an OEM Y-pipe and let us all know, once and for all, which combo works better on the street.

 

Somehow I recall an issue with the RT cats going south inside. If the dealer banged up your Y-Pipe, I bet they trashed the ceramic bits in the cats too. You might have some krap come loose in there and get wedged in sideways blocking the flow. Pull those suckers and take a look down the hole. I bet they are FUBAR. Get some resonated testpipes and be done with it.

 

Werd

 

if the cats were trashed inside, wouldn't you hear the **** inside rattling around?

 

thanks guys, the muffler shop is gonna be touching up some stuff on my y-pipe anyways so I'll get them to check the RT cats before.

This combo worked well for me before the y-pipe got trashed. felt much quicker and stronger than stock for sure. never really liked the RT cats b/c they rasped when they were new but the performance was definitely much better than stock cats.

I'm just reading up on the forum here about which pipes/cats to go with instead. Consensus is that crawford good but expensive, kinetix problems before but now new version, other one is something called spark plug fouler?

 

I got the Kinetix resonated with the no-foulers. No SES light anymore, but the Kinetix will still rasp a little. Word has it that the LaBree pipes are the best, but lots to choose from. Whatever you choose, the testpipes will make a noticable difference in power. Just make sure you still have your stock cats for when you need to get right with the law.

http://www.350z-tech.com/zwiki/Part:Test_Pipes

 

Maybe, but if that stuff broke loose and got wedged in sideways from the flow, it might not make a sound. Regardless, something is way wrong and a y-pipe shouldnt kill that much power. Plus his "crazy blowdryer" isnt working anymore. Sure sign, that one.

 

+1 on the cats... had the same problem on my TN kit.. cats got clogged and felt zero power

 

weird.......with all that you should have gained a little

 

Get a new Y pipe.

Try this one:



It has 60mm inlets and a 70mm outlet. Thats smaller then most y pipes so you should gain back some torque because of the smaller diameter.

Decent price too compared to other y pipes on the market:

http://www.istoreparts.com/tanabe-yp...e-p-13141.html

Most places will price match too.

 

Check the cats, after market regardless of who relabels and resells them, never have a long life.........just made to pass inspection one time maybe.

Please save your old parts as you maybe [by a lawsuit by buyer] made to bring the car back to oem in order to resell it! As is doen't apply to emission tampering!

 

well, they put in some slightly bigger ones that matched shape and size of my old flex pieces better and it's much better. However, still no torque now when I used to be able do donuts in a parking lot pretty easily.

I think I'm going to ask them to try the stock Y-pipe back on this weekend to try it out. Otherwise, I saw a Y-pipe made by a company named MEGAN Racing for decent price ($280 cdn), any feedback on that company? they also have some resonated test-pipes too...

 

Here are all the Y Pipes:

http://www.350z-tech.com/zwiki/Part:Y_Pipes

It is important to match pipe diameter of various exhaust components. A 3" y-pipe section dumping into a 2.5" rear exhaust section may cause undesireable sound (raspiness) and loss of power. However a 2.5" section dumping into a 3" section is ok. Some people have complained about ths sound when installing some of the Y-Pipes with the stock exhaust.

Looks like the Megan is ok to use since it has a 76mm outlet, thats the exact same diameter as the Fuji Exhaust.

I still like the design of the Tanabe more, and i think the smaller diameter of the Tanabe will improve torque. But hey, im no expert..