Don in Texas

iTrader: (-2)

Where do I begin?

Last Friday night I started to remove the OEM manifolds and replace them with the "new & improved" manifolds. If you remember pics I posted earlier, these manifolds were opend up BIGTIME, ported and polished. (I was talking with Dman in Dallas yesterday, and he reminded me to weigh them to see what was removed) ONE POUND OF MATERIAL WAS REMOVED FROM EACH ONE OF THESE MANIFOLDS to give you an idea of how much they were opened up.

REMOVAL
The initial removal took about 10 hours (wasting time, trying to figure the best way to remove, lunch, etc). Drew (BigTexan) worked with me until 3am on Saturday night, until we had both manifolds removed. In a nutshell, they both came off pretty easy, removing them and getting to the bolts was the time-consumer. The front manifold came off after removing the A/C compressor and moving it to the side (all for one bolt). The rear was a little more complex. the rear will not come out from below, but most of the bolts can be accessed from below. The manifold will only come out from the top. You must first remove the upper plenum, TB, EGR work (attached to rear manifold) and to get it our, you have to remove the rear valvecover. 3am---DONE!

INSTALLATION
Drew & I finished about 3pm today (May 10)Putting them back on was very easy, no problems there. While putting it all back together, I cleaned the TB, the EGR system, the upper plenum, etc.. Re-install took about 3-4 solid hours.

RESULTS
The car started immediately, and we just backed it out and let all the grease,etc burn off for about 30 minutes. We drove around the block, re-checked everything, and decided there was enough time to take it to Carboy (here in Houston) and get some feedback.

The dyno results proved an average gain of .5 hp and .1 ft lb of torque THIS IS NOT A MISPRINT.

WHY?
We knew the results would be more significant on a forced-induction (S/C) car....But we didn't have a base to run with. Here's the theory:

The Nissan motor is pretty efficient as a stocker. More efficient airflow will always increase performance. The only explaination is that the OEM manifolds were the most efficient they could have been from the factory, even with the increased flow of a CAI (minimal gain).

In the event of forced induction, more (maximum gain), an enormous amount of air is forced into the engine, and the new, improved manifolds will start to show the results of the porting. How much will it gain on a S/C car? Don't know. but I'm sure as hell not pulling these off for that test. I will when I do my motor swap.

SYNOPSIS
Exhaust is efficient for small increases in air intake. Benefits will be gained thru the use of forced-induction simply because of the additional air the exhaust will have to process.

BOTTOM LINE
You gotta break a few eggs to make an omlette. It was a good test. I don't think at this point a header design (that wasn't equal length ;header/y-pipe combined) would be of benefit to a N/A car.

HEADERS GOING FORWARD?
Not sure. I will continue to work with the info I have, but unless I can get a design that will increase on a N/A car, you might be outta luck unless you are Supercharged. Stay tuned!!

Don

dmbmaxima2k2

iTrader: (1)

So you are saying that headers for our car would only produce about as much gain as a high-flow cat. DAMN, no wonder no one makes these for our car, sob....

MardiGrasMax

iTrader: (14)

Thanks Don, great info. I hear ya on the headers fo a NA set up.

BEJAY1

iTrader: (19)

Appreciate all your efforts on behalf of everybody. Guess Nissan did it right when they created one of the best V6 engines around.

Just heard a rumor last weekend that Finish Line Performance here in IL did a custom header for a Max recently. I haven't gotten a hold of them yet for details but I'll let you know if it's true.

Nismo87SE

Even though the average gain was less than 1hp, was there any changes at all to the shape of the power/torque curve? I'm sure it had to smoothen out or reduce a dip somewhere. Maybe you could dyno that manifold on nitrous .

Don in Texas

iTrader: (-2)

The power and torque curves are almost IDENTICAL, there is absolutely no changes anywhere to speak of.

Its almost like I never put them on.......or did I?

Dave B

Don-

I had always wondered about this and you've answered my questions. Your ideas make complete sense. I think hardly anyone in here will want to pull their intake manifolds and such to install headers. I'm sure headers could improve performance, but not like many have anticipated. The headers will improve performance simply because of the longer and equal length tubing vs the manifolds, however, the gains would most likely be in the 3-4hp range. I think a y-pipe is plenty good enough for the rest of us. If you've got forced induction, then port your manifolds. Forced induction likes big ports and piping.


Dave

bigtexan7

Yeah, getting the original manifolds off was a pain in the butt. We were both baffled at the dyno-plotted curves--identical. Since such extensive porting was done, and no power realized, it follows that getting more air INTO the engine would reveal gains...hello superchargers! These manifolds were opened up so much that they shoud really be able to flow some air out probably increasing directly proportional to the amount of boost being made.

SleeperSE

- Well guys, we owe you all big time. Your work raises some serious questions...

*** - You all worked on the exhaust manifolds... Do you think that freeing up the actual heads might help more? ***

- My concern is that the engine was originally developed for a German Touring Car Championship series, meaning that it had high-revs in the plans. When Nissan stuck it in our beloved mid-size sedan, they cut the power somehow and now it doesn't even make power past 5 grand. I was under the impression that they clogged up the heads... Choking the breathing makes the most sense because the power dies at 5,000rpm and because the cams seem fairly aggressive already (since there is no strong pull below 3,000 rpm).
- However, what about the 5th gen's? They are virtually the same as the 4th's configuration. I think that Nissan only changed the exhaust because I saw a parts diagram at a dealership and the 2001's with 222hp use the same intake manifold as a 1999 California Edition car. I mean, the '99 CA was the most choked up car that they offered!!! It's got to be something in the breathing if Nissan could just swap a few parts around and gain 32 quiet, reliable horses.

- Thus, I think that we should all look further into clearing out the intake manifold and the actual heads. Also, why not raise the compression to 11:1 with new pistons and rods. I mean, build the engine for serious N/A duty. I really want to have a Max that pulls strongly to 7,000rpm and that is tuned to at least 90hp/L.

RussMaxManiac

What about using 2000+ Maxima Exhaust Manifolds? There supose to be equal length and gives more hp?

Maximamike

Buy a VE powered Max then..

Jambo

Great information. Thanks for the experiment and the information.

Y2KevSE

iTrader: (13)

I bet you want me to FAQ this, huh?

Dave B

Okay, there is a huge difference between the 5th gen intake manifold and 4th gen manifold. The 5th gen manifold incorporates two lengths of intake runners. One set is short and set is long. Short runners make topend hp and long runners make good torque. The 5th gen intake manifold uses a set of butterflies to open the short runners after 4500rpms very much like the systems used on the Yamaha 3.0 SHO V6, DOHC 4.6 Cobra motor, GS400, BMW Vanos motors, etc. The 4th gen intake manifold uses a long runner design only. The 4th gen VQ does make power to 5700rpms (at least my car does as does lots of other dynos I've seen). Simply put, the 4th gen VQ is limited by it's runner design. The only way you will make more past 5700 is either by adding forced induction or shortening the runners. An intake, chip, y-pipe, etc WILL NOT improve power past the limits of runners. Forced induction gets around this simply because it makes it's own atmosphere.

The manifold gaskets of the 99 and 00 Maxima are the same, but not the intake manifolds. The 5th gen intake manifold is really the only part that makes the 5th gen perform so well after 5800rpms. The heads are the same and the manifolds and cams are basically the same. I am looking into seeing if the 5th gen intake manifold will truely bolt up to the 4th gen. If it does, I think I can figure out how to make the butterflies open at any given rpm.

Making for a 11:1 compression ratio would require some serious work. You would have to mill the head, use thinner head gaskets, and possibly use a new high compression type (domed-style) piston. Plus you would have to reprogram the ECU to understand that when the car gets hot, lots more timing will have to be pulled out because of detonation. You would also have to run 94+ octane which isn't readily available in the States. A 11:1 compression ratio alone, could net around a 10-15hp gain. The only street car I know of that run a 11:1 ratio is the Type R.


Dave

Nismo87SE

Basically now we know that header's won't make such a difference like anticpated. That means the only other way to get more power while from NA aside from higher compression or headwork is with the intake manifold swap or more agressive cams. Right JWT is way too busy to prototype cams for the VQ30DE. The only other way is to buy new cores from nissan and have them ground. The cost of this type of work is around $150-300, but you have add the cost of the new cams themselves (probably around $125-200 a cam). Not to mention lots of time in R&D will be needed to find a good combination of midrange-toppend power increase without losing much lowend power or getting MIL lights. The 00+ intake manifold will no doubt be harder to come by, I don't believe many junkyard would just sell the intake manifold and not a perfectly working motor as a whole. Now I'm sure with some research someone can find out if the JDM VQ30DE has more agressive cams or not. If the JDM VQ's do have more agressive cams, then a dealer should be able to order them. Hell the OBD-I intake cams from the 91-93 SR20DE's give a 5-8fwhp gain in the 94-00 SR20DE's. While 5-8fwhp might not seem like much but there would probably be alot better gains above 5000rpm. Not as much as the 00+ intake manifold, but enough to drop that ET .

Asian_N02

wow! i was looking at getting a new intake manifold and exhaust manifold for my engine, but if i don't have a s/c then i guess my results will not be very noticable...? Thanks for the experimentation and results.

Nam

Maximamike

Haha.. Yeah, ok. If you went into a normal Nissan dealership and went, "I'd like to order some cams from the Japanese version VQ engine." They'd probably look at you like you had 10 heads, shake their head, and go back to work. Want factory shipped JDM ****? Email me..

vmok

Thanks for all the work. I've been wondering myself as to the gains from porting and stuff.

Also, same question as Russ2k, is it confirmed that the 2000+ has equal length exhaust manifold already? If so, those should bolt onto the Gen 4 right because spacing would theoreticalliy be the same?

Has anybody take out the intake manifold on a gen 4 and seen if it could be cleaned up any or is it already pretty clean?

-V

DaEnigma

I am really interested in the 00+ intake manifold... If it does work (Bolt on to 4th Gen) and they can be had for a reasonable price... Then I may be looking into doing this... Bad part is I do have a CA/NLEV which will make this that much harder...

Don in Texas

iTrader: (-2)

I'm not sure who actually READ my original post, or is just throwing sentences out there hoping to get a rise out of someone. Reading these comments, I think people are confusing INTAKE MANIFOLDS (air going in) with EXHAUST MANIFOLDS (spent air going out).

The 00+ EXHAUST manifolds? Not sure. Never looked. If they are longer than the 4th Gens, they probably won't fit. But the only way to do it for sure, it to get after it.

The Intake manifolds on the 4th GEN are pretty clean (minus a little cast flashing, extrude hone would be good on these, but not worth the hp-per-$$ ratio.

OFF TOPIC
You know....every day, I see people with ideas about swaps for this or that, wondering if they will work. Why do we keep wondering? Whats the hold up? What are you waiting for? do the research, get the parts (or have them made), open up your car, and get dirty (it washes off, I promise).

I see paragraph after paragraph on theory, what-ifs, Nissans design flaws, etc, but very few actually taking these ideas to heart and rolling with it. I don't get it.

I don't mind doing what I do and passing on results to people here (I didn't do that for 2-3 years, ask Russ) and was the ONLY CAR running 13's. I haven't raced in almost a year, and there are more and more cars that are hitting the 13 sec mark and faster.

The new generation of Maxima performance is coming...its not cheap, parts do not exist, you can't "buy it on line" yet...its all unchartered territory. Its the stuff you DON'T read about that is defining the sport

Maximamike

Word..

maximaisokay

Umm You have a girlfriend?

John

Maximamike

Why, are you interested?

emax02

iTrader: (1)

I'm telling you maxima.org needs a dating forum to keep these horndogs at bay, LOL.


Don, Good work! I can't wait until you get your new engine in and all.

Don in Texas

iTrader: (-2)

Yep, I've got a GF....sorry to break it to you this way

Don

mAdD MAX

Where do you get the money to do all this research and experimenting??

Most people would try to put their theory to practice, but that costs money..which some of us don't have to follow out our theories.

But we can always keep dreaming right?

SleeperSE

***DISCLAIMER***
- The following is a summary of information that I have compiled through mechanics, friends, and fellow Maxima.org members. While I have not personally had the opportunity to work on the internals of my Maxima, the information is, to the best of my knowledge, correct.
- Yes, some of what I write is theoretical. I do not have the resources to tear my engine apart constantly, so I rely upon others for information. That is, after all, one of the reasons we all come to this forum, is it not?
- The use of the word, "we," refers to other Maxima owners (typically 4th generation vehicles) who seek to gain knowledge on this subject. The use of the word, "we," is not intended to insult "Don in Texas" in any way.


1. INTAKE MANIFOLDS
- The 5th generation Maxima's have a dual-stage intake runner system on their intake manifolds. The long runner is for long-end torque and the short runners are for top-end horsepower. Since the 4th generation cars only have the long, torquey runners, they can't make much power past about 5500 rpm. Nor will they benefit (that much) from a super free-flowing engine. They will always be a held back by the lack of top-end efficiency from the intake manifold. Fortunately, the gasket for the 5th gen intake manifold is the same as a '99, which means that there is a possibility that the better manifold will bolt onto a 4th gen. (It is unconfirmed whether all 4th gen cars used the same gasket as the '99, since Nissan voluntarily restricted the '99's to meet future emmissions requirements. ie - it might not fit on pre-'99 4th gen cars.) The ECU might also need to be reprogrammed to operate the stage-shifting manifold - or it might just work through the physics of it all.


2. EXHAUST MANIFOLDS
- Thanks to the work from our somewhat friendly Texans, we've now learned that porting and polishing the exhaust manifolds for better flow won't help that much. Don gained only .5 hp (yes, that is a decimal) and 1 lb-ft of torque. This means that the OEM Nissan parts were free-flowing already. While the extra space afforded by this work could help a forced induction car, it won't do squat for a N/A car.
- Don mentioned that he removed a pound of material per exhaust manifold, which I am now corrected on, is a substantial amount.
- So far there are no aftermarket headers available for the Maxima (possibly because the car doesn't gain enough power to justify the purchase). Someone mentioned that a company was currently developing such a product. No word yet on prices or power gain. For now, stick with the Y-Pipes.
- As a side-note, I would like to add that "Headers" are NOT the same as "Exhaust Manifolds." Manifolds are cast pieces that are quieter and more solid than headers, which are typically thin aftermarket parts that are often freer-flowing and lighter.


3. HEADS
- As of now, we know that the stock intake manifold and the exhuast manifolds are all reasonably free-flowing (the first step towards glorious horsepower), but it is unconfirmed whether the actual heads are as clean. It is possible that the car could benefit from a port and polish job to the actual heads. The gain depends on how freed up the engine already is. I have heard that 5 liter Mustangs who port and polish their heads, intake, and exhaust manifolds gain upwards of 100hp (since they come so detuned in stock form), whereas Acura Integra's with the same work gain only 5-10hp. The power gain depends upon how the engine comes straight from the factory.
- Don't forget that the VQ30DE was originally developed for a German Touring Car Championship, meaning that a high-horsepower motor was probably intended right from the start. Theoretically, a 4th generation Maxima should be able to ditch all this torque crap and gain what a 4th generation Maxima owner should want (according to the author, not Don). Horsepower. How a 4th generation Maxima owner could go about this is what the author is trying to find out.


4. CAMS
- According to the author, who claims no liability for his words, most 4th generation Maxima owner know that more aggressive cams will supply more top-end horsepower, while sacrificing some bottom-end torque. Obviously, a person seeking hotter cams can't get too aggressive or they will lose daily driveability. Also, revving very highly, especially on a N/A car, puts added strain on the engine.
- Unfortunately, it appears that JWT is too busy right now to finish devlopment on a set of cams for the VQ30DE engine. JWT already has two sets available for the 3rd gen VG engine, one so aggressive that it's not even recommended for cars with automatic transmissions, so 4th and 5th generation Maxima owners can only hope and wait for their turn (according to the author, who claims no liability for his words).
- Since the Maxima is a Japanese car, it should be safe to raise the redline to 7000rpm if a set of cams is installed. There should not be too much of a risk of throwing a rod, since most Japanese cars are designed and built to handle high-rpm stresses.
- One could also have custom cams ground from Nissan "blanks." (Yes, you can get them from most car manufacturers.) However, no one knows exactly what the proper design should be for decent mid-high rpm punch. Nor do we ("we," in this case, referring to a 4th or 5th generation Maxima owner) know how large the powerband will be. For now, most seem content to let JWT do the research. However, keep in mind that the JWT set of 4 cams (twin-cam = two intake, two exhaust) will run you about $3000, whereas a custom set will cost about $1600. Maybe we (those who do not have cam-grinding facilities in their back-yard) should just pool our money, but a JWT set, and then have a machine shop copy them. ;-)
- There was talk of throwing in a set of "Japanese Spec" cams, but I don't think that they even exist. I had the opportunity to pour through the January 2000 issue of Britain's CAR Magazine (great publication, by the way) and I learned a lot about the Maxima through their performance index. It turns out that the Maxima and the Infiniti I30 are basically combined into one car (as most already know). There are, I believe, three engine choices, with the VQ30DE being the top-of-the-line motor. Unfortunately, since gas is so expensive, and since the VQ is quite thirsty when you push it, most sales come from the mid-range V-6 (~160hp/135lb-ft). This engine, which isn't sold in the US, is more fuel-efficient and packs enough punch to sell. Since Britain and Japan usually get the same spec cars (similar fuel prices and right-hand drive), I doubt that a Japanese Spec cam exists. Besides the Euro-spec VQ30DE is tuned exaclty the same as ours (minus a catalytic converter, which results in ~195hp for England).


5. COMPRESSION
- The Maxima already operates at a fairly high compression ratio of 10:1. (This is why we are required to fuel up with Premium. Otherwise, we will experience harmful "knocking" or detonation, which will later result in lost compression and lost performance.) There are ways to increase compression, namely by "shaving the heads" and by swapping pistons for a higher compression version (possibly domed-style).
- Shaving the heads is a process in which a minute amount of metal is shaved from the bottom of the heads, so that it sits a little bit closer to the block. This raises compression since there is less of a gap between the block and the heads.
- Shaving the heads on a V-Shaped engine is always difficult because, in addition to shaving the heads, you must also shave the intake manifold so that it can still sit above the heads properly. The mathematics of this are complicated and no one (that the author knows of) wants to risk their entire engine for 2-7 horsepower.
- Usually, in addition to shaving the heads (and intake manifold), pistons are swapped out for higher compression parts. It would be possible to raise the compression ratio to 11:1, gaining an estimated 15-25 horsepower in the process.
- Usually, when one raises the compressio ratio, it is recommended that you upgrade to higher octane gas (to avoid knocking). Unfortunately, 4th and 5th generation Maxima owners are already buying premium. Luckily, a bump in compression shouldn't require anything higher. Remember that the Toyota Celica GTS operates at 11:1 and that the Honda S2000 operates at a startospheric (for a street car) 11.7:1 compression ratio. (Honda gets away with it due to a very efficient combustion chamber design. FYI, 12:1 is race-fuel territory.) Thus, the Maxima should be fine at 11:1. If a 4th generation Maxima owner were performing all of this work, I would personally recommend porting and polishing everything, having a full intake and exhaust set-up, and maybe even having the rods "shot-peened" (sorry, I forgot the correct spelling). Shot-peening strengthens the rods so that they can handle the rigors of high-rpm life. Although Don mentioned that OEM rods are shot-peened from the factory, the mechanics and engine-builders who I have spoken with say that the rods are still not as strong as they can be.


MY TWO CENTS
- Frankly, I'm horrified that the 4th gen cars have so much torque and so little horsepower. Since the Bore and Stroke of the engine are virtually square, it shouldn't be a problem getting the revs up, so long as the breathing can be improved upon.
- So far it seems to me that the best thing to do for more power is try to retro-fit a 5th gen Intake Manifold onto a 4th gen car. If anyone knows whether you need to reprogram the ECU or if the dual-stage system operates physically, please post something.
**** - Also, if you reply to this post, please don't let the whole thing sit above your reply. Please eliminate anything that you don't need and please be specific to what you are replying to. ****

Don in Texas

iTrader: (-2)

"However, there are a few problems with Don's work. First, only a pound of material was removed from each header. While this may seem like a lot, keep in mind that my friend with the Miata installed headers on his car that weighed 11 pounds less than stock! The lost weight could be in the costruction of each component or it could mean that a lot more could be removed from the stock units."

****WRONG. The OEM IRON (IRON, not steel) VQ30 manifolds weigh 8 pounds from the factory, I removed a pound from each one. Unless your Miata friend bought an IRON header (which he didn't) this is a BS remark. I promise there is nothing more to take from that manifold, the test only PROVED (not theorized) that the OEM exhaust manifold is efficient for the maximum amount of air that can be sucked in a N/A car....Gains will POSITIVELY be realized on forced induction....you may wanna show us your handy work on the next set , mkay?..........next?


"Theoretically, we should be able to ditch all this torque crap and gain what we really want: horsepower. How we do this is what we are trying to find out."

**** Who the hell is "we"? again with the theories...no actual work.

"So far, it seems like the best thing we can do is try to retro-fit a 5th gen Intake Manifold onto a 4th gen car. If anyone knows whether you need to reprogram the ECU or if the dual-stage system operates physically, please post something.

**** Again, who is "we"?

"If you're doing all this work, I would personally recommend porting and polishing everything, having a full intake and exhaust set-up, and maybe even having the rods "shot-peened" (sorry, I forgot the correct spelling). Shot-peening strengthens the rods so that they can handle the rigors of high-rpm life."

**** OEM Nissan rods are shot-peened already.


No one is picking on me, on the other hand, if they were, I don't see how they could justify their remarks, simply because they added a post.

Again.....WAAAAAYYYYYYY to many Theories, guesses, and what ifs....Get after it!!! I don't have any problem backing up my work, cause its not just typing


Money for R&D? its called "elbow grease". I rub a little on before I go into the garage, and wipe it off and put it in a jar after I'm done...

SleeperSE

- Two words: College Student. I have absolutely bupkus in terms of money. I'm working 50+ hours a week to gather enough funds to get me through the upcoming school year and to get my suspension set-up (Maxima's can turn too, you know). I had hoped that you would appreciate the time that I spent on my post because it will save YOU from a bunch of stupid Newbie questions later on. My intent was to save time and keep us focused on engines so that we can all learn.
- I have no mechanical experience, no tools while I'm at school, and not enough money to do anything substantial (yet). I just like cars and I'm trying to (slowly) turn my vehicle into a quick driver's car. I have attended a track day to improve upon my driving (my next one is coming up in early June) and I insist on doing all of my own work - I think that I might have busted my brake booster as a result of that philosophy. But that's fine with me since I got some great experience out of it. (BTW, if anyone knows where I can get a used brake booster from a scrapped car, or something, please e-mail me.)

- All of my "we" comments were written to gather a sense of online community and to hint to others that it is possible to tune our cars beyond headlight bulbs and shift-*****. Would you have preferred that I write "Don could do this with his car, but the rest of us can't or won't bother?"
- I really do appreciate all of your work and I would like you to know that your posts are some of the only ones that I read. I value your integrity, your knowledge, and your passion. Perhaps, you're just getting a bit too passionate this time...

- I have gone and done my "homework," which is the best that I can do for now. Although it's not actual grime-time stuff, I still spoke with as many qualified people as I could and got as much information as possible. That research was my first forray into engine internals. I didn't even know that intake manifolds had runners in them before I started asking around!!! I thought that it was just a pipe that went to each cylinder, for crying out loud! Some people just don't grow up taking apart carbs. I'm doing my best to catch up now.

- I feel that I must also defend my Miata-driving friend. Ian has NEVER been wrong about anything to do with his car. He and his dad rebuilt the entire engine themselves, I might add. If Ian says that his aftermarket headers weighed 11 pounds less, than they weighed 11 pounds less.
- I think that they were, in fact, iron - which would explain the heavy weight. Besides, Captain Logic, 8 pounds (our weight for 3 cylinder, as you posted) divided by 3, multiplied by four (to adjust for a 4-banger) = 10.667 pounds. That would be Ian's weight in aluminum if the construction was similar to a Maxima's. So, if it's iron, his headers should have been around 22-25 pounds. ALSO - he has real headers. Ours are like mini-headers plus a Y-pipe. His "Y-pipe" is included in the package. An iron OEM unit versus an aluminum aftermarket header would most certainly account for an 11 pound drop in weight.
- Don't be so nit-picky and bitter. I try not to post what I don't know. That is why I include key phrases, like "should work" and "this has the potential to..." I admit, through my verbage, when I do and when I do not have the answers.

- Look, Don, I respect you a lot. I would absolutely love to be able to do some of the amazing things that you do. If you were "Don in Florida," I would probably be over at your garage every weekend getting dirty too. For now, I would just like to know what you think, based upon your experience with the Maxima, about some of the questions that I posted.
- Thanks again for your willingness to share with the rest of us,

Matt

Dave B

Matt-

Headers and manifolds are completely different. Manifolds are cast iron pieces that are made for strength, ease of construction, low cost, and low on noise. Headers are tubular pipes that are made out of thin gauge metal. Headers are loud due to their thin walls, headers can get VERY hot, and headers are usually less restrictive. Cast iron molded manifolds are much heavier than a set of tubular headers. Your buddies header isn't made out of cast iron, I'm sure of it. As far as I know, you can't bend castings because they are......cast.

Hope this helps.


Dave

RussMaxManiac

I can tell you one thing man. Don is not a NEWBIE, he has been here for many years, probably 5 yrs. He was the first, maxima to every hit the 13s, and the 12s. He knows his stuff when he talks about cars. Also, headers and manifold is completely different part. You seem to not have the knowledge to discuss this issue and you might want to stop this arguement before you blow your way out the door with non-sense newbie talk should I say. 1 lb of those manifolds are ALOT, since there NOT THAT BIG compared to headers.

SleeperSE

- OK, I just want to close up some things and then I would really like to get back to engines.

- First, I never accused Don of being a Newbie. I did write that the purpose of my reference guide post was to save him from the typically uneducated questions that Newbies ask. I was merely trying to help out.

- I would like to thank you guys for telling me the difference between headers and exhaust manifolds. Obviously, I didn't know the difference before, so I went back and edited my post.

- Look, I've admitted time and time again that I don't know engines or mechanicals that well (as evidenced by the header incident). I could give you 0-60 times, engine displacement numbers, top speeds, even gas mileage for just about any modern car, but I couldn't tell you what the intake manifold runners do. With my post, I was merely trying to help stop Newbie questions and test my own theories. I would really like to get back to the Maxima questions that this thread was posing so that I can know more about my car and what I can do to improve upon it.

- As I asked before, what do you all think would be involved if performing the swap on a 4th gen car to a 5th gen intake manifold? Does the newer manifold require ECU input to work, or is it based on the physics of the engine?
- Thanks again for your help, guys.


Matt

Don in Texas

iTrader: (-2)

"As I asked before, what do you all think would be involved if performing the swap on a 4th gen car to a 5th gen intake manifold? Does the newer manifold require ECU input to work, or is it based on the physics of the engine?
- Thanks again for your help, guys. "

I think it would be a LOT of work/$$$$ for the amount of power gain you would get. It would be better to use the work/$$$$ and get the gains elsewhere.

I do appreciate your comments, just not the question on the work I did on the headers. I still don't think you get the difference.

I never questioned your friend. If the aftermarket headers are 11 pounds lighter than a CAST IRON manifold, I don't doubt it. But you can't compare the weight of an aftermarket header to an OEM manifold.

I don't care if you are newbie or not. There is a lot to be learned from most people on this board, and I don't have the physics knowledge to figure out the theories myself, but I'm old-school, its all come from doing, not guessing. The only problem I have is someone tearing my work apart, and at the same time, never have done this type of stuff himself.

This board is a very powerful tool, but in the old-school, you have to back up your smack. People tend to be more bold on the internet, where 5-10 years ago they would have thought twice about the things they say.

Don

bigtexan7

the manifold swap would be way too hard to rig, Matt...just my 2 cents. ......although I do dream about it at least 4 nights a week.

Kenneth

iTrader: (8)

yeah man... you stained my bed... thanks

Keven97SE

Bud, you totally asked for this one...

Exactly what was bigtexan7 doing in your bed?

Ba da boom ba da bing

brianw

iTrader: (3)

Hmm... ouch. Less than 1hp/1lb-ft of torque?

The curves are almost identical to stock? OUCH!!!

I would say something, but given the complete lack of positive or negative results (no gains, but no losses either) makes it difficult to say. Sounds like if someone wants to research headers, they're on their own and may not make any power anyway...

Kenneth

iTrader: (8)

i slept in the guest room. punk

deezo

iTrader: (3)

After reading a lot of the post here, I figured I wouldn't get into the amount of engine mods that some people have gotten into. It seems when people did some mods like cold air(Brian V and others), they weren't happy with the test results or they expected more from the tests. I was starting to feel like the engine could be in the best position for performance so I cut my plans for Pop Chargers and Cold Air. I, however, would like to go with full exhaust because that is probably a more promising way to get more performance from the VQ.

When Cheston gets the 97 ECU results from Japan, I will think about upgrading. Don thanks for your efforts because I think this will save people money and time on trying to get the most from these engines.

Daniel B. Martin

Shaved or not, the heads always sit the same distance from the block. That distance is equal to the thickness of the head gasket. The real reason shaving the heads increases the compression ratio is because it reduces the volume of the combustion chamber.

The term "square" means the bore and stroke are equal. The 4Gen VQ30DE engine has a bore of 93mm and a stroke of 73.3mm, which makes it decidedly oversquare.