Puppetmaster

iTrader: (48)

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: http://forums.maxima.org/5th-generat...01-maxima.html



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:

http://forums.maxima.org/all-motor/3...mt-6-7-eu.html

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:

http://forums.maxima.org/all-motor/3...-template.html
http://forums.maxima.org/all-motor/3...ng-advice.html

DandyMax’s EU threads:

http://forums.maxima.org/supercharge...up-inside.html
http://forums.maxima.org/supercharge...or-update.html
http://forums.maxima.org/supercharge...mate-here.html

UTEC:
http://forums.maxima.org/all-motor/5...highlight=UTEC

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:

http://forums.maxima.org/showthread.php?t=350787

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:

http://forums.maxima.org/all-motor/3...extension.html

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:

http://forums.maxima.org/all-motor/3...ru-s-step.html


Install Tips

*Link Needs to be Updated *


Product Specific Threads



Stillen thread
http://forums.maxima.org/5th-generat...r-threads.html

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:
http://forums.maxima.org/5th-generat...es-4-38mb.html
http://forums.maxima.org/5th-generat...6k-beware.html



Dyno Threads

Cattman (Generation I, no longer in production)

SR20DEN – 2002 6MT
http://forums.maxima.org/dyno-discus...cessories.html

vq356sp – 2002 6MT
http://forums.maxima.org/dyno-discus...xima-dyno.html

steven88 – 2003 6MT
http://forums.maxima.org/dyno-discus...spd-dynos.html

ynot411 – 2002 6MT
http://forums.maxima.org/dyno-discus...2-se-6smt.html

Nmexmax – 2003 4AT
http://forums.maxima.org/dyno-discus...q-03-auto.html
http://forums.maxima.org/dyno-discus...242-238-a.html

Fezzik – 2002 6MT
http://forums.maxima.org/5th-generat...vs-y-pipe.html

MaxBoost925 - 2000 5MT
http://forums.maxima.org/dyno-discus...bolt-dyno.html



Cattman (Generation II)

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

Puppetmaster - 2002 6MT
http://forums.maxima.org/dyno-discus...hp-237-tq.html

rbrown81 – 2003 6MT
http://forums.maxima.org/dyno-discus...take-look.html

Cattman (Gen III)

Merlyn - 2002 6MT
http://forums.maxima.org/dyno-discus...44-ft-lbs.html

knight_yyz - 2003 6MT
http://forums.maxima.org/dyno-discus...-lb-ft-na.html


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
http://forums.maxima.org/dyno-discus...gen-g37-s.html

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

iTrader: (22)

Attention *****..


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

iTrader: (15)

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

iTrader: (48)

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

iTrader: (48)

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

iTrader: (4)

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

AceofSpds

iTrader: (4)

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

iTrader: (15)

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

iTrader: (19)

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.

AceofSpds

iTrader: (4)

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

iTrader: (15)

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

iTrader: (15)

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

iTrader: (15)

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

iTrader: (28)

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

OOmaxSE

iTrader: (19)

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

iTrader: (48)

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

AceofSpds

iTrader: (4)

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

iTrader: (19)

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.

AceofSpds

iTrader: (4)

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

iTrader: (1)

So are you suggesting that there is no point in changing headers and y-pipe in a 5.5 or only y-pipe.. because i know that most aftermarket headers are matched to y-pipes.

Also, what type of effect does changing only a CAT have?

Based on all the info in this thread, and that I have an 03, I'm thinking of replacing my CAT with a high-flow CAT, along with the cattman cat-back, with my injen intake.. leaving my headers and y-pipe stock. How does this setup sound?

vq356sp

iTrader: (13)

The cat wont yield any gains so unless it is bad I would suggest save your money for headers. So based on the info in this thread you have decided NOT to get headers?

Puppetmaster

iTrader: (48)

I was referring to aftermarket y-pipes as the ones not being worth the trouble.

AceofSpds

iTrader: (4)

it depends on the gains, you get good gains on 00-01 and minimal on 02-03 because of the design of the exhaust manifolds were diffrent.

I dont think you really have to worry about 02 sensors, and if you do you can just get an O2 simulator

upstatemax

iTrader: (15)

Both... I need an EGR fitting and living in the NE, I should have SS. After factoring in the cost of putting on an EGR fitting it only made sense to me to do a total swap.

steven88

iTrader: (28)

http://forums.maxima.org/showthread.php?t=385360

clayman88

iTrader: (1)

I'm considering either the HS or Cattman headers right now. Theres a couple small things that concern me and I need to get cleared up before I pull the trigger.

I've heard alot of different years thrown around about EGR & no EGR, so I just want to make sure. How can I be sure that my 2001 does NOT have an EGR, so that I don't have to **** with that if I go with HS? Is the EGR easy to find in my engine? After hearing upstatemax's fiasco, I don't want to have to deal with that.

Also, I've heard a few folks mention that the AC compressor line gets in the way of the front manifold O2 sensor on the HS headers. I've searched around, but haven't been able to find the solution to this problem.

My experience working on cars isn't exactly extensive, so any info is appreciated. Thanks in advance!

upstatemax

iTrader: (15)

Chances are that you don't have one. The best way to find out, is to remove your entire air intake and reach under the throttle body and feel for a pipe going into your intake manifold (thats the guidetube). you could also, remove the throttle body and look into the intake plenum and you would be able to see the guidetube sticking up into the middle of the air path.

AceofSpds

iTrader: (4)

Cattman headers, they are the only choice now and you dont have to worry about EGR w/ them

Utsutsu

iTrader: (6)

I'm having my cattman headers installed at this moment at SGP, they are doing the headers install with the O2sim, VAFC install and dyno tune. I'm just so excited to get the car back.

I wish I could take pictures or record the dynos but I'm at work. I should have my car back tomorrow afternoon. Also I asked for the run files when I get them I will post it.

MaximumPower01

Im looking to do the same thing when tax returns come back...and Im considering having my mechanic install them, also...

If you dont mind me asking,

How much did they charge you for the entire installation, and what is the "guestimated" time, in which it took?


Ty in advance!

BlackBIRDVQ

iTrader: (15)

Install takes bout 2 hours. Took me 2 hours on the last 03 6spd, and 5 hours on the 5.5gen before that because I also did a clutch and ES motor mounts.

If I got a break on the headers from Cattman I would buy em, and test them out vs my HotShots..... BUT HotShot is now out of business so that is irrelevant.

HotshotVQ35

iTrader: (5)

there are no fitamet problems with the HS and the AC lines right? i keep hearing different stories...

MaxxBlack03TE

I don't think that the headers/y-pipe will be more than 5 whp more than the stock manifolds/y-pipe without some other mods, but with more tuning/mods then definitely they'd be worth a good 10+ hp.

Puppetmaster

iTrader: (48)

Got proof?

If you're talking about the Cattman or Hotshot headers for the VQ35 (and even DE-K for that matter), the dynos done by members of this forum over the past 2-3 years prove you wrong.

HotshotVQ35

iTrader: (5)

they are dyno proven for 20+WHP. mine are going on sunday, and a dyno the following saturday

MaxBoost925

iTrader: (33)

weee. header install was easy!

.....


....



after getting past the EGR issue, motor mount brackets, and the f'in A/C getting in the way of my bolts...

NmexMAX

iTrader: (22)

First off, what do you know about the 2002-2003 FWD (Front Wheel Drive) version of the A33B VQ35DE?

I don't care what you know about this that or the other engine, which one of your family members has this or that car, or how your 'shop' has tuned some hundreds of cars to 700 WHP.

The fact is, with what you posted, you haven't got a clue about this particular engine.

If you read the first post of this thread, you will see proof, proof, and a little bit more proof that quality(HS/CM) headers give gains that are a touch better than 5whp.

Read before trying to up your post count.

Max_Gator

Keep in mind that blackbird is an experienced mechanic with all the correct tools and A LIFT. If you think you can do them in the time it takes him - fugghedaboutit.

I have the Cattman and it took 2 of us most of the day to get everything off, get the damn things fitted up properly, and back on. There was of course a slight delay necessitated by some frozen bolts. We really could have used a higher torque impact wrench for sure.

And most of all, make sure you have ratcheting wrenches and universal extensions.

Utsutsu

iTrader: (6)

When I had my headers installed at the shop it took 9-10hrs for the whole installation.