5th Gen / 5.5 Gen Header Thread

[Puppetmaster]

Questions about headers come up very often, so it's about time to consolidate as much of it as possible.

This is all the info I could think of at one sitting, so please post more especially if I've missed important pieces of info relating to headers or have gotten anything wrong. Thanks.

Remember, this isn't all the information out there, but just whatever I've bookmarked that has helped me in the past.



General Header Information

Good aftermarket headers for the Maxima typically include the exhaust manifolds (headers) for both banks, as well as a y-pipe type piece that is unique to the set of headers. This means that you cannot use your stock y-pipe or any other aftermarket y-pipe with them. The Cattman and Hotshots sets have the best design in terms of having long tubes and equal length collectors.

There are sets out there that are cheaper and have more interchangeable y-pipes, but those do not give you the same sort of power as the ones with the long tubes and equal length collectors. They are mostly of the same shorty header design as the stock manifolds, and while they do not have pre-cats either, exhaust flow isn’t greatly increased and they are not worth the hassle since replacing the manifolds isn’t worth the little gains these give. Some of these brands are OBX, SS Autochrome, Stone Mountain Racing, and Stillen.

And no, they are not street legal, although many of us have passed emissions testing in various states with them.


Headers on 00-01s (Courtesy of BlackbirdVQ)

HotShots fit just fine on a 3.0L, with the exception of the 02 sensor on the front manifold primaries- where it hits the AC line RIGHT at the compressor. 01 Cali specs have it eassy, no EGR so nothing to worry bout. 00s are screwed cause of the EGR, so for them Cattmans (if they acutally fit) are the only way to go as they are designed with the intention of working on eighter VQ. HotShots are designed with no provissions for EGR, one could be welded in- but it will require lots of customization to get it right.

See also: 5Zigen MK6 for my I35



Air Fuel Tuning

Since most VQs tend to run rich with headers, people typically get some sort of piggyback A/F controller to correct that. The APEX’i S-AFC-II and V-AFC-II are two of the more popular and affordable units (the V-AFC-II is preferred mainly because it has more tuning points than the S-AFC-II). For more advanced piggybacks (but also with more capabilities), look into the GReddy Emanage Blue and Ultimate, as well as the SMT6/7.

Typically, a few dyno runs with A/F readings is the best way to tell if you’re running rich or lean. It’s recommended to get dynoed before spending the money on a piggyback unit.

For more general information about AF adjustment and headers + AF adjustments:

Thread to consolidate info about SAFC/VAFC, SMT-6/7 and EU
Hotshot Headers on a 2K2 SE

Vipervadim's Ultimate Header Thread:

http://forums.nycmaximas.org/showthread.php?t=20592

SAFC-II/VAFC-II wiring diagram and other info:

http://forums.maxima.org/showthread.php?t=347604
http://forums.maxima.org/showthread.php?t=345841
http://forums.maxima.org/showthread.php?t=349285

DandyMax’s EU thread:

http://forums.maxima.org/showthread.php?t=348546



Oxygen Sensors

All 01-03s have four O2 sensors (CALI spec), two are primary (upstream or before the pre-cats) and two are secondary (downstream or after the pre-cats).

The primaries MUST remain connected (there will be bungs on the headers). They provide feedback to the ECU to adjust the air/fuel mix.

Since aftermarket headers remove all pre-cats on the 00-03s, something has to be done about the secondary O2s since they now have nothing to monitor and will cause the ECU to throw a CEL to indicate that the pre-cats aren't working right (because they aren't there anymore). The DTCs will be P0430 (front bank or Bank 2 precat) and P0420 (rear bank or Bank 1 precat).

The secondaries can be simulated using a dual output O2 sim, but you need to keep the sensors plugged into the harnesses because the ECU needs to read voltage from the heater wires. These heater wire signals are not simulated by the O2 sim. You can find resistors to simulate these and do away with your secondaries altogether.

For an O2 sim write-up:

O2 Simulator Installation

For purchasing dual output O2 sims:

www.o2sim.com

Alternatively, you can extend the secondaries and bung them behind the main cat, so that the feedback to the ECU shows a "working pre-cat" since the secondaries are reading exhaust fumes that have already gone through the main cat.

More opinions on using the O2 sim vs extending the secondaries here:

O2 Simulators or O2 Sensor Extension?

You need to keep all your O2 sensors unless you can find a resistor to simulate the heater signals as well. More info on that here:

Completely Removing Secondary Oxygen Sensors – Guru’s step in..


Install Tips

*Link Needs to be Updated *


Product Specific Threads


Stillen thread

http://forums.maxima.org/showthread....31#post2790131


Cattman threads

http://forums.maxima.org/showthread.php?t=455513

http://forums.maxima.org/showthread.php?t=505235

http://forums.maxima.org/showthread.php?t=505075


And these 2 Hotshot threads:

http://forums.maxima.org/showthread.php?t=450524

http://forums.maxima.org/showthread.php?t=435912



Dyno Threads

Cattman (Generation I, no longer in production)

SR20DEN – 2002 6MT
http://forums.maxima.org/showthread.php?t=475914

vq356sp – 2002 6MT
http://forums.maxima.org/showthread.php?t=471519

steven88 – 2003 6MT
http://forums.maxima.org/showthread.php?t=460022

ynot411 – 2002 6MT
http://forums.maxima.org/showthread.php?t=451001

Nmexmax – 2003 4AT
http://forums.maxima.org/showthread.php?t=411340

Fezzik – 2002 6MT
aftermarket fog: has install bolt in center, max has no hole. help?

MaxBoost925 - 2000 5MT

http://forums.maxima.org/showthread.php?t=511321



Cattman (Generation II)

6spd_hayes – 2002 6MT
http://forums.maxima.org/showthread.php?t=473771

rbrown81 – 2003 6MT
http://forums.maxima.org/showthread.php?t=437492



Hotshot

NISMAX03 – 2003 6MT
http://forums.maxima.org/showthread.php?t=462984

dlee275 – 2002 6MT
http://forums.maxima.org/showthread.php?t=482832

jay_pee99 – 2002 6MT
http://forums.maxima.org/showthread.php?t=469549

inspiredbykev – 2002 6MT
http://forums.maxima.org/showthread.php?t=466771

jimmycapp – 2003 6MT
http://forums.maxima.org/showthread.php?t=433516



Where to buy them

http://www.hotshot.com/

http://www.cattman.com/



And some pictures of Cattman headers:


Gen I:


Gen II:


Gen III:

[NmexMAX]

Attention whore..


VERY informative thread, this should help cut down (or not) on posts.


My primaries aren't connected.. ...

The FSM states if the primaries are dead or d/c'd, and the secondaries are connected, the ECU will monitor these(2ndaries) and use their signal as primaries for A/F adjustments. Though this doesn't have any affect @ wot (such as on the dyno/racing)

[BlackBIRDVQ]

HotShots fit just fine on a 3.0L, with the exception of the 02 sensor on the front manifold primaries- where it hits the AC line RIGHT at the compressor. 01 Cali specs have it eassy, no EGR so nothing to worry bout. 00s are screwed cause of the EGR, so for them Cattmans (if they acutally fit) are the only way to go as they are designed with the intention of working on eighter VQ. HotShots are designed with no provissions for EGR, one could be welded in- but it will require lots of customization to get it right.

[Puppetmaster]

Okay guys, please keep the posts to only header related topics, and no more "Nice thread", "Good info", etc, comments. That's nice and all, but its getting too cluttered, so back to headers and what other info can be added to the original post. Thanks.

[Puppetmaster]

Originally Posted by momo80

All 5.5 gens for the dyno links. I wonder how much the 3.0 would gain from a header, y pipe and air fuel tuning upgrade?

There are more than a few people with VQ30s who have headers, just don't come across their dynos that much. I'll see if I can find some actual links. If anyone else has VQ30 header dynos, please post em.

[ope2k4]

Originally Posted by BlackBIRDVQ

01 Cali specs have it eassy, no EGR so nothing to worry bout. 00s are screwed cause of the EGR, so for them Cattmans (if they acutally fit) are the only way to go .

So what about 00 Maxima cali specs? Do they have EGRs? Will the Hotshot fit?

[chopstix2nrz]

Originally Posted by ope2k4

So what about 00 Maxima cali specs? Do they have EGRs? Will the Hotshot fit?

yes an 2k cali has an EGR... because mine has one

all 2000 maxima's have egr's.... So what blackbird posted applys to you also.

[upstatemax]

For the 2000 guys with EGRs; after dealing with this damn EGR for almost a year now I can safely say if I could do it all over again I would have gone with the Cattmans if they were available...

It is going to cost me roughly $300 to connect my EGR since I cannot get the light to turn off for it. Add it up:

HS Headers $560shipped+ $300 EGR+ $80 sensor relocation = $940

And the Cattmans are Stainless Steel.

I would think that welding the EGR on while the headers are off the car is MUCH cheaper, but I had no choice but to deal with it after the headers were on (I was told 00' Cali's had no EGR's), not to mention, when I was in the market for headers Cattman was no longer making the first Gens and the second Gens were no where in sight...


Anyone want to buy a set of HotShots!

[OOmaxSE]

That's true, what upstatemax said. I have a 2000 cali spec and I relocated the o2 sensor and had to precisely customize the location of the EGR on the rear manifold. Let me tell you, PITA! Unless you know somebody with a shop and correct tools, I wouldn't touch the hotshot on 00 cali spec.

[chopstix2nrz]

I read somewhere that the 01 cali/ae's gain more hp because theirs dont have EGR's... I mean do we really need them? All it does is put exhaust gases into the intake so the motor warms up faster right?

[upstatemax]

Don't really need them, but good luck getting rid of the CEL when you disable them...

I have not been able to "simulate" it, a 2001 ECU without an EGR will not work, and you cannot send out your current ECU to get reprogrammed to get rid of your EGR. So you can say that we are stuck with it.

[upstatemax]

Originally Posted by steven88

what exactly is this?

$300 EGR+ $80 sensor relocation

The HotShot headers have no provision for an EGR, so to drill and weld on an EGR fitting cost about $300 for the HotShots. The $80 to have the front O2 Sensor relocated to the front collector because it does not fit thanks to the AC Compressor ( drill and weld a new O2 sensor bung).

[upstatemax]

Originally Posted by steven88

couldnt u just plug up the EGR...and pocket that $300? since u gonna get an SES either way?

Noooooo...

The $300 is so I can reconnect the EGR to get rid of my SES. The only reason I have an SES is because my EGR IS plugged off.

I am getting an EGR flow code since the computer monitors how much exhaust is being put into your engine. SO when it is plugged off, the computer realizes that no air is flowing through. The computer also monitors how hot the air is that is comming in so I cannot just let it suck in fresh air.

[steven88]

so bottom line is, you will get an SES no matter what?

[OOmaxSE]

Originally Posted by steven88

so bottom line is, you will get an SES no matter what?

Only way you won't have any codes (EGR code) when installing hotshots would be if you plug the EGR in. And basically, EGR is wicked hard to correctly match with stock location. Reason for that is because the tubing is metal and a biitch to screw in.

[Puppetmaster]

FYI, there is an EGR/No EGR discussion going on here:

http://forums.maxima.org/showthread.php?t=479773

[momo80]

I'm planning to do the y-pipe soon but would like to know if doing headers with a y-pipe would have worthy gains over just simply the y-pipe.

If it's something like 5whp over the y-pipe only I don't think it'd be worth the hassle with all this EGR business. If it's over 10whp with the potential for more by Air Fuel tuning down the road I think I'd consider it.

Also, if there is more info on noise increase due to headers and Y-pipe it would be greatly appreciated. I read the exhaust sticky but it's hard to tell with all the other mods people have done. Basically I would like to know if the header/y-pipe mod will increase the exhaust note a lot more than simply a y-pipe mod.

Thanks

[chopstix2nrz]

Originally Posted by momo80

I'm planning to do the y-pipe soon but would like to know if doing headers with a y-pipe would have worthy gains over just simply the y-pipe.

If it's something like 5whp over the y-pipe only I don't think it'd be worth the hassle with all this EGR business. If it's over 10whp with the potential for more by Air Fuel tuning down the road I think I'd consider it.

Also, if there is more info on noise increase due to headers and Y-pipe it would be greatly appreciated. I read the exhaust sticky but it's hard to tell with all the other mods people have done. Basically I would like to know if the header/y-pipe mod will increase the exhaust note a lot more than simply a y-pipe mod.

Thanks

Ok If you are gettin real headers like hotshots or cattman's then its a full headerset meaning its headers and ypipe put together, A cattman y or any other y will not work with a good real set of headers. There are crappy headers out there like OBX... dont buy em! You have an 01 AE and from what i have read all the AE's are Cali specs, so you dont have an EGR. If you have stock exhaust there wont be much of a difference if any difference. Ive heard that people w/ headers or y pipe have a little tone difference while having stock exhaust exept for aftermarket rear section. I have a y-pipe and test pipe and stock exhaust for the rest and i have a small difference in sound. Hope this helps. Scince you have a cali spec i would reccomend getting headers instead of a y pipe because the headers will eliminate all the precats, where as with the cali y pipe it only eliminates one of the precats.

[OOmaxSE]

Originally Posted by chopstix2nrz

Ok If you are gettin real headers like hotshots or cattman's then its a full headerset meaning its headers and ypipe put together, A cattman y or any other y will not work with a good real set of headers. There are crappy headers out there like OBX... dont buy em! You have an 01 AE and from what i have read all the AE's are Cali specs, so you dont have an EGR. If you have stock exhaust there wont be much of a difference if any difference. Ive heard that people w/ headers or y pipe have a little tone difference while having stock exhaust exept for aftermarket rear section. I have a y-pipe and test pipe and stock exhaust for the rest and i have a small difference in sound. Hope this helps. Scince you have a cali spec i would reccomend getting headers instead of a y pipe because the headers will eliminate all the precats, where as with the cali y pipe it only eliminates one of the precats.

I'd like to point out that MY cali spec has an EGR. And I believe upstatemax has a cali spec w/ EGR. I feel like they stopped the EGR during late stages of '00 max's with cali spec. Reason I say that is because IIRC, somebody on here has a '00 max cali spec without EGR.

[chopstix2nrz]

Originally Posted by OOmaxSE

I'd like to point out that MY cali spec has an EGR. And I believe upstatemax has a cali spec w/ EGR. I feel like they stopped the EGR during late stages of '00 max's with cali spec. Reason I say that is because IIRC, somebody on here has a '00 max cali spec without EGR.

I have an 2000 Cali also, mine has an EGR also, mine was made in 1999 Dec, so yeah id go w/ that theory.

But momo80 has an AE max from what it says in his info... so he doesnt have EGR

[BaDMaNDUNK]

Originally Posted by Puppetmaster