Oem y pipe with precat delete pipe




Precat and exhaust manifold off of my 2003 Nissan maxima (restrictive & has a different design from the obx after market y pipe and different design from 4th gen maxima y pipe. If you take your precat off a 5.5 gen maxima you’re going have to replace both manifold and precat with 4th gen manifold and use a flange pipe like mine to delete the precat or get a warp speed y pipe I heard it’s all put together)

Front precat delete pipe that comes with obx y pipe

OBX Y Pipe that deletes precats ooff 5.5 maxima. Fits good imo will update when installed.
I would like to show you guys my project. I have a 2003 Nissan maxima 3.5L. I already did my first mod BOP install. This is going to my 2nd mod when I install the full y pipe. So long story short my car was throwing a code for random misfire and precatalyst inefficiency. My car was running rich and I had definitely had a misfire in my 2nd cylinder caused by that Stupid fat precat in the front that’s restrictive. I’m guessing it’s blowback. So I took the front manifold pipe that replaces the pre cat off the y pipe I ordered from OBX racing. I then took my oem y pipe off my car and grinded the lip off that sticks out from the y pipe and bolted the pipe together with the oem y pipe and used some exhaust gasket maker. And for the last part ik your all wondering what about the headers well I decided to take a risk and get some 4th gen oem shorty headers off a 4th gen maxima since there less restrictive and installed it into my car and y pipe and it all fits nice. I didn’t bother the rear manifold for now but I plan on doing the rear one when I replace the whole y pipe. I plan on installing the y pipe at a friend so I can safely tilt the motor to get to the rear manifold This is my temporary fix because I did all of this in my parking lot at my apartment it only took me roughly 4 hours using a power drill deep sockets PB blaster!!! And a grinder no special tools needed. And 22mm wrench for those o2 sensors.
If you guys are thinking bout doing this don’t be scared and try it you’ll save some money and you’ll have fun doing it. Trust yourself and take your time and become comfortable with your car. I will be updating throughout build.

obx y pipe- https://www.walmart.com/ip/Stainless-Flex-Pipe-Fitment-For-95-thru-01-Nissan-Maxima-By-OBX-RS/1467687900?wmlspartner=wlpa&selectedSellerId=10119 4874&adid=222222222281467687900_101194874_14997124 4636_18620663426&wl0=&wl1=g&wl2=m&wl3=661038408860 &wl4=aud-2225087347867la-2081188045379&wl5=9011572&wl6=&wl7=&wl8=&wl9=pla&w l10=652721567&wl11=online&wl12=1467687900_10119487 4&veh=sem&gad_source=1&gbraid=0AAAAADmfBIqT3Aitv8S AzZtkLVfMzKSmg&gclid=Cj0KCQjw7ZO0BhDYARIsAFttkCgM-NcWwGteO52juA20uvfVQsOK9h1iaL6QqB_F4Xp3HJCTtAMkJLU aAnL2EALw_wcB

 

Nice find on that y pipe. Wish I knew about it when I threw some stock dek manifolds in my last 4th gen.

Where'd you get that front pipe?

 

It came with the y pipe that I ordered from Walmart online. It’s the obx y pipe it does not say it includes that piece of pipe but it Does come with the y pipe.

 

the front pipe comes with the obx y pipe

 

Welcome to the Maxima forums! Nice work with the pre-cat delete. I'll be installing the Magnaflow front and rear pre-cats soon on my 01 AE to pass the CA smog

 

damn i know those cost an arm and a leg.
Why you didn’t buy a y pipe instead and just drill an extra hole in the front pipe to fit an o2 sensor in. Could you still pass smog test if you would’ve did that? I only had to make one extra hole on my set up to have all my o2 sensors installed

 

Got a pretty good deal on the Magnaflow cats so I could not pass it up. My 2001 SE already has an aftermarket Y pipe with O2 anti foulers and it does not pass the visual inspection CA requires. Need to make the car compliant with CA smog requirements since I'll be keeping her for a while.

 

I’m glad I live in Florida no vehicle inspection here. That’s irritating though it has to pass a visual test too. Nice set up though I get to see the set up with high flow cats it looks crazy.

 

nice, switching the front exhaust manifold is a really good move, stock front exhaust manifold is really restrictive. I'm running 4th gen fed spec manifolds with Warpspeed 4th gen fed spec Y...

 

I’ve seen your set up and it gave me hope I appreciate your work. I wouldn’t have tried if I hadn’t looked on here looking for an alternative to fixing my precats. I plan on installing my y pipe soon and replacing the rear exhaust manifold and precat I’ve just been procrastinating because I see it is more involved to do. I got my Y pipe from Walmart online. It is OBX brand 95-01 Nissan maxima y pipe it looked identical to the warpspeed Y pipe that you have. In my opinion they are the same they both install the same way.

 

F


Front precat deleted
stock Y pipe and rear precat is still on
3.0 front exhaust manifold

 

Nice set up! It looks just like the Budget Y-pipe that I had on my Fed Spec 97 SE. The car sounded great with Frankencar intake and Y-pipe.

 

i was debating on doing frank take or getting the weapon r intake

 

I did a full write up on changing out both exhaust manifolds, the trickiest part was getting the rear mount bracket off the engine block.

https://maxima.org/forums/5th-genera...ated-info.html

I'm still running the stock air box but with a better snorkel

https://maxima.org/forums/5th-genera...k-air-box.html

 

would your intake be considered a cold air intake now that it’s under the car in the position it is in.
Another question do you have problems with driving through rain or wet conditions? I’ve heard of cold air intakes water locking the engine that’s why I was looking of going down the Short Ram hot air intake route to be safe because I live in Florida the weather is unpredictable.

 

I live in central Florida and so far it's been over 2 years since I started running that intake setup with no issues. I knew the car needed cooler air cause of the amount of power it would lose sitting in traffic on a hot day. my car didn't come with the stock snorkel so eventually I got one which helped, than a bit later I made the larger snorkel. I plan to cut a hole as shown in the diagram to sock air from behind the fog light which I will probably get rid of because I'm tired of replacing them when they crack.





also works well with 2nd gen swap

 

i never had foglights crack over 16 years. but always heard about em cracking

i have a full pair i will be selling for cheap soon, and 1 extra if interested shoot me a DM if you wanna keep fog lights haha

 

i had 2 lh lights crack within 6 months. for whatever reason rh has been fine. no evidence of why the lens cracked.

 

I actually have a set sitting in the garage that I'm going to put on once my car is back from getting painted. i also have some clear 3M headlight protector for it but it doesn't seem to stick to great.

 

Don't bother with any intake that sucks air from the engine bay.

 

yeah I believe ima try that snorkel set up uptownsamcv has or some sort of intake similar to his design. I like it it’s different

 

After installing 3.0 exhaust manifold I run into the problem of not having anywhere to put the o2 sensor that was in stock 3.5 exhaust manifold. The front exhaust manifold on the 3.0 does not have a o2 bung. So I guess ima have to take the manifold off (not hard) and drill a hole in it. Any of you guys run into this problem or heard of this problem I would like to hear other solutions.

 

my ECU is flashed to delete the secondary O2 sensors. it's best to add O2 bungs to the Y instead of the exhaust manifold.

if you haven't flashed your ECU yet it's a must. with the intake cam timing adjusted and other tweaks it makes a huge difference up top. the DE is just a choked and detuned base model Z engine. same heads, cams, and pistons.

the stock 2" exhaust really chokes down these cars to keep them quiet. I'm running 3" with super turbo muffler and it still gets me pulled over. I might go back to Thrush Hush and weld the seems so they don't blow again. I'm going to try a different resonator first..

I also removed the hood insulation to help with under hood temps

 

You need to keep the sensors that were closest to the engine. They are necessary. The O2 sensor that was in the manifold will go in the new Y extension. The O2 that was after/with the cat will need a new home. You can put it anywhere and do the spacer trick with it. The best place for it will be after a functioning cat. Do you have the rear most cat?

 

I HAVE one o2 sensor not connected. The precat o2 sensor is installed.
this sensor was in my old exhaust manifold and now has no home there is no bung on 3.0 exhaust manifold.
I have not bothered the rear o2 sensors or the y pipe o2 sensor

 

drill and weld a bung into the y-pipe after the manifold flange. i would recommend against drilling and tapping the cast manifold for an o2.

 

so I would weld another o2 bunge above the one I have now right under the manifold flange?

 

correct. above/below/next to. doesnt matter.

 

yes, add another O2 bung and use a spacer for the downstream 02 sensor..

one thing I discovered is that the 01-02 Pathfinder left side upstream O2 sensor has long wires if needed.

 

I will go to the junkyard and find that o2 sensor for the pathfinder. And I’m going to buy an o2 bung clamp that eliminates that use of welding just drill a hole and clamp the sleeve on. Thanks everyone for the advice. When I install the full y pipe I might try that ecu trick to delete that o2 sensors. I don’t want to send my ecu off I’ve heard mixed reviews so I might try and learn how to tune it myself with the vAFC or Safc. Whatever option seems easy for me to do

 

do it right or open yourself up for other problems.

vafc/safc/random piggyback wont tune your car.

 

never buy a used O2 sensor. a used OEM MAF sensor is the only thing I would buy used.

as for sending off the ECU, Darren at Nisformance knows what he's doing. exhaust and ECU flash really awakens the choked down DE

 

Went to the junkyard and all the pathfinder motors were pulled out or o2 sensors missing. Came back home and spliced the tape around the engine harness that comes up to the o2 sensor and spark plug connectors. It freed up a lot of slack. I’ll post a pic this afternoon. Will be installing aluminum radiator next week just ordered it. Won’t be posting in this thread no more until I do my rear manifold and y pipe install don’t want to get off topic from the the title of it.