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**Puppetmaster** · 07-27-2006, 08:59 PM

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: How to- HS headers 01 Maxima.

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

See also All Motor forum and Dyno forum.

Vipervadim's Ultimate Header Thread:

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

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

VAFC-II setup template
VAFCII Questions + Tuning Advice

DandyMax’s EU threads:

Finally it's done - my EU writeup inside
My Emanage Ultimate is here! -Part 2- *MAJOR UPDATE*
My Emanage Ultimate is here!

UTEC:
UTEC is in..........

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
!!!!!!!!MOTHER OF ALL Stillen Header Threads!!!!!!!!!!

Cattman threads
http://forums.maxima.org/oldthread?t=455513
http://forums.maxima.org/oldthread?t=505235
http://forums.maxima.org/oldthread?t=505075

And these 2 Hotshot threads:
My Hotshot header install experience (20 pictures, 4.38mb)
Pics after Hotshot header install 56k beware

Dyno Threads

Cattman (Generation I, no longer in production)

SR20DEN – 2002 6MT
265whp 255wtq NA - all accessories

vq356sp – 2002 6MT
2002 6speed Maxima dyno

steven88 – 2003 6MT
Two Nissan Max 6spd dynos!

ynot411 – 2002 6MT
239.12 hp - 245.25 tq - '02 SE 6SMT

Nmexmax – 2003 4AT
233 whp / 231 wtq 03 Auto
242/238

Fezzik – 2002 6MT
2k2 Dyno: Cattman's Headers vs Y-pipe

MaxBoost925 - 2000 5MT
2k VQ30DE-K bolt on dyno.

Cattman (Generation II)

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

Puppetmaster - 2002 6MT
2002 6MT Best Run - 241 WHP 237 TQ

rbrown81 – 2003 6MT
Cattmans 2nd Generation headers - Take a look

Cattman (Gen III)

Merlyn - 2002 6MT
2k2 SE 6-Speed I/H/E 250 HP / 244 ft-lbs

knight_yyz - 2003 6MT
new numbers. 253.75 fwhp and 249.75 lb/ft NA

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
New 4thgen, 5.5gen, and G37 #'s

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:

07-27-2006, 08:59 PM	#1
Puppetmaster Super Moderator 2002 Maxima Join Date: Apr 2004 Location: Fairfax, VA iTrader: (41) Posts: 16,012	5th Gen / 5.5 Gen Header Thread 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: How to- HS headers 01 Maxima. 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 See also All Motor forum and Dyno forum. Vipervadim's Ultimate Header Thread: http://forums.nycmaximas.org/showthread.php?t=20592 SAFC-II/VAFC-II wiring diagram and other info: VAFC-II setup template VAFCII Questions + Tuning Advice DandyMax’s EU threads: Finally it's done - my EU writeup inside My Emanage Ultimate is here! -Part 2- MAJOR UPDATE My Emanage Ultimate is here! UTEC: UTEC is in.......... 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 !!!!!!!!MOTHER OF ALL Stillen Header Threads!!!!!!!!!! Cattman threads http://forums.maxima.org/oldthread?t=455513 http://forums.maxima.org/oldthread?t=505235 http://forums.maxima.org/oldthread?t=505075 And these 2 Hotshot threads: My Hotshot header install experience (20 pictures, 4.38mb) Pics after Hotshot header install 56k beware Dyno Threads Cattman (Generation I, no longer in production) SR20DEN – 2002 6MT 265whp 255wtq NA - all accessories vq356sp – 2002 6MT 2002 6speed Maxima dyno steven88 – 2003 6MT Two Nissan Max 6spd dynos! ynot411 – 2002 6MT 239.12 hp - 245.25 tq - '02 SE 6SMT Nmexmax – 2003 4AT 233 whp / 231 wtq 03 Auto 242/238 Fezzik – 2002 6MT 2k2 Dyno: Cattman's Headers vs Y-pipe MaxBoost925 - 2000 5MT 2k VQ30DE-K bolt on dyno. *Cattman (Generation II)* 6spd_hayes – 2002 6MT http://forums.maxima.org/showthread.php?t=473771 Puppetmaster - 2002 6MT 2002 6MT Best Run - 241 WHP 237 TQ rbrown81 – 2003 6MT Cattmans 2nd Generation headers - Take a look Cattman (Gen III) Merlyn - 2002 6MT 2k2 SE 6-Speed I/H/E 250 HP / 244 ft-lbs knight_yyz - 2003 6MT new numbers. 253.75 fwhp and 249.75 lb/ft NA 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 New 4thgen, 5.5gen, and G37 #'s 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: Last edited by Puppetmaster; 03-24-2009 at 11:41 PM.