tchuck's custom intake

[Tko512iFX]

Have you thought about upgrading the plenum to the Kinetix SSV maybe? I dunno if its worth the money (I think about $600) but everyone says its really good for FI setups and gives around a 20+hp gain. More than anything else its defenently an engine dresser w/ the custom carbon engine cover. I dunno just though i'd throw it out there lol

---------- Post added at 08:15 PM ---------- Previous post was at 08:12 PM ----------

EDIT: It says it adds 30.5hp and its closer to $700

---------- Post added at 08:16 PM ---------- Previous post was at 08:15 PM ----------

http://www.kinetixracing.com/enginecoverforthessv-350zg35.aspx

http://www.kinetixracing.com/new-ssvextremeflowkinetixmanifold350zg3503-06.aspx

 

[turbocad6]

theres more to tuning an intake manifold than just airflow. there are also pulse waves & pressure waves that really come into play, both negative & positive. these pulse waves are caused by valve overlap & the velocity of the stack of air in the runners moving at a high rate of speed & then sudenly crashing into a dead end when the valve closes. this causes a reverse wave that travels backward back into the plenum at the speed of sound.. there are many many pressure waves & pulses going all through the intake, just as there are pulses in the exhaust. Nissan knows about these pulses & part of the intake manifold design is to harness these pulses & pressure waves in a way that benefits velocity through the runners. there are resonant cavities & calculated resistances & port tuning to specific frequencies, with enough engineering it is possible to harness these pulses & resonating & use it to boost & increase the velocity at the valve in such a way that by design they can create situations that can have a positive pressure at the valve over ambient, up to 10psi over atmospheric pressure in some cases just by tuning the intake. it's not just about airflow. well in the end it is just about air flow, but it takes more than just airflow to calculate airflow...

you can be sure that the manifold just the way it is is tuned to a level that is just not readily achievable without the amount of resources that Nissan can throw at it, Nissan can throw a ton of tuning into the mix because they are sharing the cost across many many vehicles, the cost of doing all this for one or even a few would never ever be worth it, & just winging it without doing all the computer modeling & flow bench work & mock-ups & testing can never get as good results, & you can also be sure that the whole upper plenum as it is is part of there overall tuning

there are a lot of hotrodders & enthusiasts & yes, even "pro's" that may not fully realize all of the science involved, & there are many cases of "pro's" building there own manifold & having worse results than even the factory manifold. when you just think about it as airflow you think you can see the obvious improvements, but it is so much more than just airflow too, joe hotrodder can get the flow really nice but joe hotrodder canot harness the pulses & resonating frequencies & use them to there advantage like nissan can for the most part. theres a reason why today they can extract more power from a tiny little 4 cylinder than the old big block v8's of yesteryear & it is in the science & precision of design. unless you fully understand the design you can not have any Hope of improving upon it.

in the end I think your attacking something that is not a real bottleneck for you, you want more power there are better ways to go about it than building a Frankenstein manifold. now everything before the manifold & TB I'll agree that I think you yourself can make an improvement over even what the aftermarket has done, but the manifold itself, the only way I think you can improve it yourself would be to replace it, & even then it can be a bit questionable weather it really is an improvement or not because it not only has to be better in flow but also better in a match to the VE of the engine as it exists... I think there is so much room elsewere before you should even have to worry about the intake manifold itself.

 

[tchuck]

... If it were, tuner communities would have already done this beyond what we have seen in the Kinetix, APS & Cosworth examples - which by forum consensus have mixed results - certainly nothing worth the $1200 that Cosworth wants.

I could continue to argue my point and cite almost every modern high performance V6 (excepting the VQ35DE), V8, V10, and V12 engine that has a symmetrical intake plenum but it's obviously doing no good. All I can say is that I disagree.

VQ has been around for a long time and an intake plenum is no simple geometry. You're making a lot of assumptions as to why the plenum was designed a certain way (I certainly don't know why it's designed like that) and thinking a front feed would be "better" based on what - notional theory?

First, I'm only modifying the upper plenum. The complicated parts of it are not the important parts. The simple fact that a plenum spacer improves overall performance proves this.
Also, the front feed idea is a secondary goal to symmetry. Technically the main chamber is going to be fed from the top anyway. Actually, I may rotate the upper feed tube now that I think about it... See, this is a perfect example of the benefit of constructive criticism.

The push-back you feel might just be the community saying, "been there, tried that, fell back on what is out there because it's still better than OEM, watching yet another attempt and are hopeful you'll come up with something ground breaking but not holding our breath".

I wish the feedback were that positive and direct...

As an engineer, I'd be interested in what tools you would be using to calculate flow. Some sort of finite element analysis would be the way to go - or software specific to engine development applications. If you don't have specialized tools or software and are using artistic intuition with no real objective calculations, I find it difficult to know where to start, "helping". Your concept looks cool but how anybody could improve on it without working with a prototype and a flow bench is where I lose touch with this thread.

I'm a tiny little bit insulted by your baseless assumptions. You could just ask me about my software, tools, or qualifications directly. In fact I have stated in this very thread which software I am using. All that aside...
As a Certified Solidworks Expert with over 8 years experience in structural and mechanical engineering I will be using Solidworks 2008 for the 3D modeling and FEA, and Floworks (a Solidworks add-in) for the fluid analysis. Considering this was sufficient for my 4+ years of work as a subcontractor for Lockheed-Martin (contracted by the Department of Defense) on several multi-million dollar projects on multiple SLC sites at Vandenburg AFB and CCAFS, I think it should be ok for this project. I also own a hammer.

I really value your opinions and ideas Jumbo, more than most in fact. But with all due respect, I'm not begging for your input. If you don't have anything positive to contribute or don't know where to begin helping, then by all means wait until you do. No harm done. We can still be cyber-friends in the meantime. If it makes you feel any better, this forum is not my only source of information pertaining to this project. Perhaps the fact that I only pose my vehicle-specific questions here is somewhat misleading.

It's late and I just got home from a kick-ass rock and roll show. Forgive me if any of that sounds abrupt or insulting; I don't mean it that way.

---------- Post added at 02:04 AM ---------- Previous post was at 01:56 AM ----------

I always wondered if you could stick a maxima or 3.5 altima manifold in our engines. that would give you a different angle for sure.

the other problems I see relocating the TB is all the cables and wiring that needs to be moved.

I think the maxima plenum would probably fit considering it has the VQ35DE, but it's not just the angle I'm looking to improve. I don't know about the 3.5 Altima...

Very true. I haven't even addressed the TB relocation yet, though it is definitely going to have to happen. That part seems pretty straight forward though, hopefully it won't be too painful.

---------- Post added at 02:07 AM ---------- Previous post was at 02:04 AM ----------

Have you thought about upgrading the plenum to the Kinetix SSV maybe? I dunno if its worth the money (I think about $600) but everyone says its really good for FI setups and gives around a 20+hp gain. More than anything else its defenently an engine dresser w/ the custom carbon engine cover. I dunno just though i'd throw it out there lol

---------- Post added at 08:15 PM ---------- Previous post was at 08:12 PM ----------

EDIT: It says it adds 30.5hp and its closer to $700

---------- Post added at 08:16 PM ---------- Previous post was at 08:15 PM ----------

http://www.kinetixracing.com/enginecoverforthessv-350zg35.aspx

http://www.kinetixracing.com/new-ssvextremeflowkinetixmanifold350zg3503-06.aspx

I'm pretty set on making my own upper plenum. If it ends up not working, I'll probably end up doing the HR manifold swap with dual TB's.

---------- Post added at 02:14 AM ---------- Previous post was at 02:07 AM ----------

Reply added below...

---------- Post added at 11:14 AM ---------- Previous post was at 02:14 AM ----------

theres more to tuning an intake manifold than just airflow. there are also pulse waves & pressure waves that really come into play, both negative & positive. these pulse waves are caused by valve overlap & the velocity of the stack of air in the runners moving at a high rate of speed & then sudenly crashing into a dead end when the valve closes...
. it's not just about airflow. well in the end it is just about air flow, but it takes more than just airflow to calculate airflow...

I think we have some of the same books...
I know about the pulses, but from what I read addressing them is done mainly at the manifold (as you said) and somewhat by altering the overall length of the intake tube. I will not be touching the intake manifold, but will be creating an upper plenum with the same internal volume as the stock plenum with a 3/8" spacer. Speaking of the spacer, doesn't the fact that the addition of a spacer can have a positive effect on performance pretty well prove my theory? As a logical person, think about the "ideal" intake. Regardless of specific dimensions, the manifold runners would be equal length, straight as an arrow, the plenum would provide perfectly equal flow to all cylinders, the intake tube after the TB would be straight, and the filter would be large enough to provide unrestricted airflow into the system. Now think about why the OEM DE plenum strays from this philosophy. It's because the whole system had to fit under the hood of a 350z. In regard to the Hemholtz resonators ("resonant cavities"), most of them in this application are for sound mitigation and are removed by the use of the "z-tube". There is also a large one under the stock air box, which I'm sure most people remove when they install any kind of aftermarket intake.

you can be sure that the manifold just the way it is is tuned to a level that is just not readily achievable without the amount of resources that Nissan can throw at it, Nissan can throw a ton of tuning into the mix because they are sharing the cost across many many vehicles, the cost of doing all this for one or even a few would never ever be worth it, & just winging it without doing all the computer modeling & flow bench work & mock-ups & testing can never get as good results, & you can also be sure that the whole upper plenum as it is is part of there overall tuning

I'm ok with the fact that I may need a tune afterward, I am doing computer modeling, and I am using top notch fluid dynamics software. At this point I agree that it seems like I'm winging it, but I assure you that I am very familiar with the product development process. As far as the prototypes and real world testing; When I build it, they will come.

there are a lot of hotrodders & enthusiasts & yes, even "pro's" that may not fully realize all of the science involved, & there are many cases of "pro's" building there own manifold & having worse results than even the factory manifold. when you just think about it as airflow you think you can see the obvious improvements, but it is so much more than just airflow too, joe hotrodder can get the flow really nice but joe hotrodder canot harness the pulses & resonating frequencies & use them to there advantage like nissan can for the most part. theres a reason why today they can extract more power from a tiny little 4 cylinder than the old big block v8's of yesteryear & it is in the science & precision of design. unless you fully understand the design you can not have any Hope of improving upon it.

I think you are overestimating the value and necessity of the intake pulses. Removing the stock intake and air box virtually destroys the "tuning" with respect to the pulses. After all, that is where all the Hemholtz resonators are in the first place. The only other areas that have a huge impact on the effect of the pulses (on the intake side at least) are the intake manifold runners and the overall length of the intake tube, from heads to open air, which is also drastically altered by most aftermarket intake systems.
There are many other reasons engines are more efficient now than they were back in the day. Compared to direct injection, variable timing, overhead cams, lightweight pistons, and tighter tolerances, tuned intakes are relatively minor.

in the end I think your attacking something that is not a real bottleneck for you, you want more power there are better ways to go about it than building a Frankenstein manifold. now everything before the manifold & TB I'll agree that I think you yourself can make an improvement over even what the aftermarket has done, but the manifold itself, the only way I think you can improve it yourself would be to replace it, & even then it can be a bit questionable weather it really is an improvement or not because it not only has to be better in flow but also better in a match to the VE of the engine as it exists... I think there is so much room elsewere before you should even have to worry about the intake manifold itself.

I think my goals are pretty reasonable and are not strictly performance oriented. I agree (as does my wife ) that my time could be better spent elsewhere but I enjoy the challenge and I'd like to see if I can create something new. At this point, it had better work because I've dug myself a pretty sweet hole in this forum.

To recap; These are my goals and criteria for the upper plenum:
1. Must attach to existing lower plenum.
2. maintain existing internal volume +3/8" spacer.
3. Provide equal flow to all cylinders.
4. Reduce flow restrictions.
5. Avoid using a hood scoop.

 

[gto]

That's really taking advantage of muti-quote replies.

 

[turbocad6]

OK, I'll stop trying to talk you out of it now it's just that if I see someone that appears to be getting into something that they may not be fully aware of all the complications involved, then my first instinct would be to try & help them see all the complications they may not have realized, but at this point is is very obvious to me that your determined beyond just a casual thought, & once it is decided that you are going ahead no matter what then trying to talk you out of it at that point is not constructive or helpful even, so seeing as how you ARE going into it head first, I'll try to be more positive & helpful, but honestly even though I do know some of what's involved I honestly don't think that I know enough to actually even try to do something like this myself, so my only input can be from the little that I do know.

maybe your right, & maybe I am putting too much value in the pulse waves issue at hand, but I honestly think that there is a whole lot to the pulse wave theory's & mechanics that goes on in the manifold itself, between the intake valve & the throttle body itself... everything before the throttle body is also dictated by pulses, but I think the bulk of the work before the throttle body is more for noise control than anything else, & a z tube & cold air intake should address that part of it, but the pulses & waves that go on inside the manifold are still very significant & affect the power band of the engine & throttle response enough that they are def factors to at least be aware of & try to take into account as much as your resources will allow anyway.

the plenum is like an accumulator for these pulses & plenum volume has an effect on the overall pulse tuning of the lower manifold design.



OK, so:

To recap; These are my goals and criteria for the upper plenum:
1. Must attach to existing lower plenum.
2. maintain existing internal volume +3/8" spacer.
3. Provide equal flow to all cylinders.
4. Reduce flow restrictions.
5. Avoid using a hood scoop.


OK, I understand your recap above, but my question to you now is, what is the end goal? what problem are you having now that you are trying to correct/compensate for? you do realize that tuning any particular part of the power band is going to negatively affect other parts of the power band, so what exactly is the end goal here? are we trying to make more peak HP & are we willing to sacrifice some low end torque for this end goal? or are we trying to increase mid range torque & willing to accept sacrificing some of the top end HP? is it just to achieve the most "even" flow & if it is, how do we know how uneven it even is now, at the point of a 3/8" spacer installed?

even cylinder flow is important of course when your pushing the motor to the limits, the more even each cylinder is compared to the others the more close to the jagged edge you can get in your tune because you don't have to worry about variances, for example if you try to run the engine a bit leaner you don't have to worry as much about having one or 2 cylinders leaner than the average your reading through gas analyzing & winding up being too lean in just one or 2 cylinders, but this is more of a factor at the jagged edge of tuning... how much leaner are your leanest cylinders compared to your richest cylinders? to me, to be able to really try & tune what it is your talking about you will need to monitor each cylinder individually, otherwise you can't really see what it is your working on in the first place. are you considering using a temp monitor or a wide band sensor at each of the 6 exhaust ports? if not, how will you really know that you have made an improvement at all? are we working to solve a real problem or a perceived problem? I do agree that Nissan did have to work around tight constraints in it's design & had to make sacrifices for the overall packaging in the z, but do we really know just how much of a difference we are talking about? you talk about increasing flow, but how do we know that there is a flow deficiency that the engine will really take advantage of anyway?

in the end I think your nuts, but, I can totally respect that too because I have had people tell me the same on more than one occasion , I love it when people tell me I can't do something & then I'll just go & prove them wrong, so in the end if your so determined I'd say go for it & best of luck with it. I don't think for one second that it is totally impossible for you to make an improvement, but I do think that it will be harder than your realizing & I honestly still think you are attacking an area that is not as much of a limiting factor or as much of a problem area as you may perceive it to be in the first place. I also think there are more direct routes to solving whatever it is that you are ultimately trying to solve, but again, this is your area of focus for whatever reason you have for this, so more power to you bro, nothing wrong with being nuts

 

[gto]

And that's coming from one nut to another

 

[turbocad6]

you said it brother

 

[tchuck]

OK, I'll stop trying to talk you out of it now it's just that if I see someone that appears to be getting into something that they may not be fully aware of all the complications involved, then my first instinct would be to try & help them see all the complications they may not have realized, but at this point is is very obvious to me that your determined beyond just a casual thought, & once it is decided that you are going ahead no matter what then trying to talk you out of it at that point is not constructive or helpful even, so seeing as how you ARE going into it head first, I'll try to be more positive & helpful, but honestly even though I do know some of what's involved I honestly don't think that I know enough to actually even try to do something like this myself, so my only input can be from the little that I do know.

Wow man, I wasn't expecting that. Thanks!

maybe your right, & maybe I am putting too much value in the pulse waves issue at hand, but I honestly think that there is a whole lot to the pulse wave theory's & mechanics that goes on in the manifold itself, between the intake valve & the throttle body itself... everything before the throttle body is also dictated by pulses, but I think the bulk of the work before the throttle body is more for noise control than anything else, & a z tube & cold air intake should address that part of it, but the pulses & waves that go on inside the manifold are still very significant & affect the power band of the engine & throttle response enough that they are def factors to at least be aware of & try to take into account as much as your resources will allow anyway.

the plenum is like an accumulator for these pulses & plenum volume has an effect on the overall pulse tuning of the lower manifold design.

From what I've learned so far, (admittedly not a whole lot) the harnessing of pulses is only effective in a very narrow powerband unless you have ultra high tech things like variable intake manifold runners. I'm not saying the effects are insignificant but properly addressing them is far beyond the capabilities of my resources, both physically and mentally. I'm going to keep the changes as minimal as possible and hope for the best in terms of pulse tuning. That is absolutely the reason I am matching the new plenum volume with the existing.

OK, I understand your recap above, but my question to you now is, what is the end goal? what problem are you having now that you are trying to correct/compensate for? ...
... is it just to achieve the most "even" flow & if it is, how do we know how uneven it even is now, at the point of a 3/8" spacer installed?

The end goal is to improve the stock upper plenum, to put it as simply as possible. I want to see if my proposed changes have as great an effect as I think they will. I'm not expecting a whole lot, but if I can achieve an equal air flow to all the cylinders without changing too much else, I do think it will be a noticeable (positive) difference across the board.
Since I've only lived with the stock plenum, I can't say whether or not I am currently experiencing a problem.
If I had to choose between high rpm and mid range power, I'd choose high rpm power because of the "split personality" effect it would have. What I mean by that is that I would like the FX to be a little less powerful for my wife (under 4K rpms) and a little more powerful for me (above 4K rpms). Is this an unrealistic goal? I don't know. I have driven cars like this before though, so I know it's possible.
I think the fact that the stock upper plenum "starves" (for lack of a better term) the front pistons is a universally excepted notion from what I've read, but to answer your question: I have no concrete evidence of this phenomenon.

even cylinder flow is important of course when your pushing the motor to the limits, the more even each cylinder is compared to the others the more close to the jagged edge you can get in your tune because you don't have to worry about variances,...
...I do agree that Nissan did have to work around tight constraints in it's design & had to make sacrifices for the overall packaging in the z, but do we really know just how much of a difference we are talking about? you talk about increasing flow, but how do we know that there is a flow deficiency that the engine will really take advantage of anyway?

Theoretically speaking feeding a symmetrical chamber from the center of the sources of suction HAS to even out the air flow to said sources of suction. Whether or not this will actually translate to an increase in power in the real world, I don't know. That's one of the aspects of this project that I am really excited about. For an example of the flow deficiency, look what a difference adding a 3/8" spacer makes... Also, check out the video I posted earlier in this thread where the guys have a 350z on a dyno with a "Frankenstein" plenum. The dude pulls a plug out of the top at around 4K rpms (effectively eliminating any restrictions imposed by the upper plenum, intake tube, and filter while at the same time feeding the cylinders from the center of the plenum) and it makes a HUGE difference. I'm not saying I want something like that for a plenum, and I realize that the plug stayed in during the first half of the pull for a reason, but it certainly demonstrates that there are restrictions in the OEM upper plenum and intake tube that have a significant impact on high rpm power. Also eludes to the idea that feeding the pistons equally (from the center of the top of the plenum) could have an effect as well.

in the end I think your nuts, but, I can totally respect that too because I have had people tell me the same on more than one occasion , I love it when people tell me I can't do something & then I'll just go & prove them wrong, so in the end if your so determined I'd say go for it & best of luck with it. I don't think for one second that it is totally impossible for you to make an improvement, but I do think that it will be harder than your realizing & I honestly still think you are attacking an area that is not as much of a limiting factor or as much of a problem area as you may perceive it to be in the first place. I also think there are more direct routes to solving whatever it is that you are ultimately trying to solve, but again, this is your area of focus for whatever reason you have for this, so more power to you bro, nothing wrong with being nuts

Touche' my friend. If I'm wrong about this I'll mail you a beer.

Funny side note, I can now type your quote heading from memory... "...quote=turbocad6;135919..."

 

[gto]

we're already starving for low end grunt.
While this discussion & saga is sorta interesting altogether, anything that takes away from what little we have avail IMO is FAIL. The wifey's gonna complain big time & not worth the argument, nor even your disappointment when you get passed up by a Tercel while attacking that on-ramp.

 

[tchuck]

we're already starving for low end grunt.
While this discussion & saga is sorta interesting altogether, anything that takes away from what little we have avail IMO is FAIL. The wifey's gonna complain big time & not worth the argument, nor even your disappointment when you get passed up by a Tercel while attacking that on-ramp.

Nice. That's funny. I just looked up the last Tercel (1998): 98HP, 100ft/lbs and a 10.4 0-60 time. If I fuck up that bad, I'll send you the new plenum and you can destroy it.

Personally, I agree with you about the low end and I'm not specifically TRYING to reduce it. It's just a concession I'm willing to make if it means a big enough increase in top end. My wife however has complained in the past about how "brutal" the launch in the FX can be so maybe a small decrease in throttle response would be nice. Especially for people like her mother, who's head has been bounced off the headrest a time or two. The situation is completely reversed in our Audi, which has an extremely manageable low end curve that is surprising to nobody. Push the pedal down however, and it becomes a completely different car. That is the direction I'd like to go with the FX without going FI. As I said before: "more crotch rocket, less muscle car".

 

[gto]

Well fingers crossed then.
Anyone ever tell you you overthink things? lol

I'm curious, . . what other mods have you done to other stuff? cars, appliances, whatever. Fail or no fail

 

[tchuck]

Well fingers crossed then.
Anyone ever tell you you overthink things? lol

I'm curious, . . what other mods have you done to other stuff? cars, appliances, whatever. Fail or no fail

EDIT: Moved to new thread called "Other mods"

 

[gto]

Haha. Great read. Love the amp!
So one guesses you play. What do you play & what music are you in too?

 

[fxBeast]

That TV unit is priceless! (nice legs! ) ...and Celestions are the best!

BTW... We just upgraded to SolidWorks 2010 @ my work... Man, for the up-cost and extra seats, you could buy another FX w/twin turbos! Good luck with the flow simulation add-on, should be fun, regardless.

 

[ghettojiggalo]

nice trick running speaker wires behind crown moldings, gonna store that idea in my memory banks for future use.

 

[tchuck]

Haha. Great read. Love the amp!
So one guesses you play. What do you play & what music are you in too?

Thanks.
I don't want to stray too far from the point of this thread, but to answer your question I play guitar, bass guitar, sitar, drums, piano, and a little mandolin. I think I could find an artist in any genre that I like, from Hank Williams to Tupac to Tool.

---------- Post added at 09:16 AM ---------- Previous post was at 09:15 AM ----------

That TV unit is priceless! (nice legs! ) ...and Celestions are the best!

BTW... We just upgraded to SolidWorks 2010 @ my work... Man, for the up-cost and extra seats, you could buy another FX w/twin turbos! Good luck with the flow simulation add-on, should be fun, regardless.

Thanks!

---------- Post added at 09:22 AM ---------- Previous post was at 09:16 AM ----------

nice trick running speaker wires behind crown moldings, gonna store that idea in my memory banks for future use.

I can't take credit for that idea but I agree that it's pretty slick. The alternative was to either go down through the floor with the wires (I don't even know if that would have been possible) or tear out enough drywall to drill a 1"dia hole through every single ceiling/second floor joist. This way I was able to use a wire fish to run the wires between the ceiling joists to the speaker locations and do very minimal drywall repairs. Crown molding is kind of a pain to install but it was cake compared to my other options.

 

[turbocad6]

ha ha, glad no one asked me what mods I've done in the past


sorry bro, but a few of my most important (to me) questions remain unanswered, namely:

how much leaner are your leanest cylinders compared to your richest cylinders? to me, to be able to really try & tune what it is your talking about you will need to monitor each cylinder individually, otherwise you can't really see what it is your working on in the first place. are you considering using a temp monitor or a wide band sensor at each of the 6 exhaust ports? if not, how will you really know that you have made an improvement at all?


any thoughts of building a dual stage intake? this is where my mind goes from our recent discussions here

 

[tchuck]

ha ha, glad no one asked me what mods I've done in the past


sorry bro, but a few of my most important (to me) questions remain unanswered, namely:

how much leaner are your leanest cylinders compared to your richest cylinders? to me, to be able to really try & tune what it is your talking about you will need to monitor each cylinder individually, otherwise you can't really see what it is your working on in the first place. are you considering using a temp monitor or a wide band sensor at each of the 6 exhaust ports? if not, how will you really know that you have made an improvement at all?


any thoughts of building a dual stage intake? this is where my mind goes from our recent discussions here

Don't be sorry, this is exactly why I created this thread. I got sidetracked with the "other mods" issue.

I don't have any way of monitoring each cylinder individually but I know that the shape of the upper plenum is not conducive to providing equal air flow between the cylinders. I know this as a logical person from looking at it, from the things I have read about the subject, and from the universal similarities of the "good" aftermarket plenums. (ie, not slanted down above the front cylinders)

If my theory proves correct, the difference will be a noticeable improvement across the board, especially in high rpm situations. If all goes well, I plan on a fairly comprehensive dyno comparison.

I dont know about the terminology but I have considered a varied diameter intake. To be honest I haven't given much serious thought to that portion of the intake yet. What did you have in mind? My little brother just showed me this the other day: Is this what you mean?
http://www.passwordjdm.com/Uploads/HTML/PasswordJDM_Carbon_Fiber_PowerChamber_Intake_%28EG__EK_Civic%29_866_1.htm

If you mean a dual stage intake MANIFOLD, then no. That's way to complex for me.

EDIT:

Here's a great pic of the 350z clearance issue.

 

[tchuck]

Secret mod!!

I have a thread update coming tonight, but I'm going to dinner right now and don't have time to write it out. For now, check this out...

 

[fxlr8]

nice, do you plan on sealing off this area?