NmexMAX

iTrader: (22)

Most of us know how a MEVI and 00 VI work. A MEVI and 00VI both work from resonance, here's a small excerpt from the internet for a little more insight... "The principle rests on the pressure waves of the gas columns inside the intake ducts, waves induced by the cyclic openings and closing of the valves. If the period of these waves enters in phase with the rhythm of opening of the valve, phenomenon which occurs in a rev range determined by the length of the duct, some supercharging effect is obtained without the assistance of a compressor."

IMO. The 00 VI has longer runners initially from the TB than the MEVI, thus the added midrange grunt. Neither one is a true 2 runner design also. Someone that knows differently me now so I won't be misinformed about that.

Now since we have a basic understanding of these manifolds, let's compare to the FWD (Murano/Max/Alti) 3.5 IM and RWD VQ(350Z/G35/FX35/M35). We all know the HP differences between all these vehicles differ slightly, but so do the power curves. Most noteably, the Maxi will top out at 5.6k, then start to drop off, unless you're SR20DEN, whereas the G/350Z version has a nice smooth flat torque curve that peaks out later in the rev range.

350Z

5.5g Maxima
http://www.bhamani.org/dynorun.002.jpg

What's the difference between the 2? Does the Z/G have a "VI" like the 5.5g does? If so, when does it activate, and when activated what does it do? I know what the 5.5g does, and so do a few other people. Here's a quick and dirty explanation. 02+ IM has a top and bottom 1/2, each in charge of 3cyls. Before 4k, there's a throttle body sized hole that has a butterfly flap that is open, 4k comes around, flap closes therefore dividing and separating the top and bottom 3 cylinder ports from each other. The power surge is noticeable, and it's also seen on a dynograph. Ok, now how does the 350Z IM work? From my readings, which haven't been very extensive, it's just a single runner. Some facts can back this up, because the FWD 3.5's usually pout down more torque than HP, in typical cases, when compared to RWD versions.

I also have overlaid comparisons that relate the above 5.5g dyno with SR20DEN's that I will post later, b/c they're at home and not here right now. Pretty amazing, they're both nearly identical, then at approx 3800rpm, SR's explodes with power and never looks back, and also does not exhibit the small dip in power that typical 5.5g's do at about 4k either, this could be his IM design and/or A/F tuning.

What resonance or any other effect are at play with these IM's? How could it be made better for high rpm HP/flatter tq curves? What about modifying (make taller/shorter) the lower IM such as the G/Z guys do? Is there anything that can be done to the upper portion? Why does it have a square like design before the runners head into the cylinder heads?

JClaw

iTrader: (17)

Yeah pretty interesting how SR's dyno goes up the pole only around the 4k switchover. That's a pretty good hint, but I doubt we can give it anything more than "educted" guesses.

I think Tilley's dyno went from 233whp to 238whp by keeping the butterfly always open or something like that (not sure), giving him slightly more top end but nothing even approaching the kind of power that SR makes at 5-6k.

I don't think what SR20DEN has done to his IM is very extensive, because of the nearly identical curves before 4k, and because he once mentionned (when he was still planning on selling some modded manifolds), that he did not have a price yet, but that it would be "inexpensive compared to the amount of HP" it would produce. So it does make me wonder...

NmexMAX

iTrader: (22)

Not sure about the science behind it, but from an analysis POV, keeping the butterflies open on the MEVI, it yeilds about a 5hp increase and about the same torque decrease, as compared to with it completely closaed or even working properly in open/closed mode. A lot of people notcied this when dyno testing the MEVI as to where the ideal switchover should be at, meaning running one run 100% open, and 100% closed, and using the medium as the switchover rpm. And also, I hear that the 02+ VI mod is less obvious than the 00 "power valve" removal procedure. Funny because from opening the 02+ VI, there's not much that can be done .. or so it seems, but things aren't always what they seem. Peoplve over on the Alti forums were saying that all he had was a port and polish ... highly unlikey due to cost, IMO, but I'm hardly ever right ...

steven88

iTrader: (28)

Nmex when do u plan to hit the dyno? I am curious to find out what those mods gain...

Oh yeah my friend's dad is a welder for an aircraft company....I might ask him to cut me a piece of steel to cover up the place where the gold actuator attaches to. This method will completely remove the valve altogether....it's better than keeping the valve stuck open becuz now....there is no more valve....matter of fact, nothing there at all...just a piece of steel covering the intake manifold....

anyway I don't know when I should hit up this project....I've been waiting for you to hit the dyno to see if this is really worth it....

NmexMAX

iTrader: (22)

Well, if you welded a flat piece of metal there, it would be like it always is after 4k rpm, and you would only lose low end tq/hp.

I'm dynoing a dead actuator, which would allow both upper and lower IM's to always be in "communication" and never secluded. I didn't get there last week because they were having some promotional thing, and this weekened is tied up too .. maybe ...

IceY2K1

iTrader: (3)

Just for helping show the HUGE difference the 350Z/G35/FX35 manifold has....

350Z top half:


2003-2004 350Z bottom half('05 Track&35th Anniversary are different):

IceY2K1

iTrader: (3)

Also, the DEK manifold might use slight resonance tuning, however what it really does is just shorten the intake path length(suction port length) by allowing all the runners to feed from the 2ndary chamber when above 5000rpm. Therefore, the suction port length isn't from the back of the intake valve to the throttle-body like below 5000rpm, but only from the intake valve to where the powervalve sits.

NmexMAX

iTrader: (22)

^^ That's how the MEVI works as well.

6spd_Hayes

iTrader: (3)

I have also looked at SR20's dyno numbers and graphed them over mine:


I know it is small but you can see that before the VI kicks open at roughly 3900 rpm, the graphs track right along nicely in HP and TQ. So, that makes me want to think nothing was done with the 'long runners' on the lower collector. See below, middle red box.


But once the VI kicks open, that is where he makes the big numbers. Now, he has quite a few more mods than me. I am only running a PR CAI and Cattman Y-Pipe. He is running UDP, Full header back exhaust, some intake, and ,ah, his secret sauce IM. (Plus a possible few I left out, SAFC-II, and maybe the TechnoSquare ECU). I am curious though that he shows an increase in HP all the way till 250 rpm before rev limiter, where my peak is 750-1000 rpm before rev limiter. Maybe this is from the part the Technosquare ECU cuts out about the throttle starting to close as you get closer to the rev limiter, so you don't hit is essentially full throttle.

Oh, for a good demo on how the Varible Intake runs, check out below link:

http://www.nissanusa.com/vehicles/Me...,43701,00.html

Just more food for thought....

6spd_Hayes

iTrader: (3)

I just check out at the dealership, the cost from Nissan for the Upper collector, Lower collector and intake manifold.

Upper Collector - 14010-8J105 - $220.14
Lower Collector - 14010-8J160 - $426.00
Intake Manifold - 14003-8J105 - $360.46

All infor is for a 2002 Maxima. I don't know if this applies to the 2003 also.

The parts guy said if I got them all, he'd knock 20% off of the total. Think I will look to the local junkyards first.

6spd_Hayes

iTrader: (3)

Anyone got any pictures of the inlet, outlet of the Lower Collector, and of the port where the Power Valve for the VI fits? I have looked around but not been succesful.

Nismo3112

iTrader: (12)

What! I paid less than that for an entire VQ35 engine... Thats even if he took of the 20%

JClaw

iTrader: (17)

You can get both upper and lower intake manifolds for 300$ off www.car-part.com.

So you think the front of the IM hasn't been touched?

It REALLY breathes at high RPMs, and doesn't seem to lose much down low (identical 'till 3800-3900).

NmexMAX

iTrader: (22)

Well whatever SR has done it must be good because it stills etains the low rpm grunt we've all grown to olove, only in older threads he states that there will be a loss from 1-2k, but for the top end gain I wouldn't mind it at all. And it;'s also a Non-vi too, so who knows but I'd nearly kill to have one.

6spd_Hayes

iTrader: (3)

Please IGNORE the above statement. I just picked up Intake Manifold, Lower Collector, VI Valve, Upper Collector, Throttle Body, and some other goodies on top of the engine at a junkyard for $100!!!

JClaw

iTrader: (17)

What's your plan?

6spd_Hayes

iTrader: (3)

Apparently I have been smoking crack and did not have a good understanding of the secret sauce mainfold, but based on old post, I think I have a handle on it now.

JClaw

iTrader: (17)

Now the only thing you have left to do is to duplicate it and dyno the beast. Piece of cake

6spd_Hayes

iTrader: (3)

Once I clean up the necessary parts, I am not sure. I am thinking about modeling the elbow, upper plenum, and lower IM in 3D, then doing some flow characteristic on it with some other software I have at work.

6spd_Hayes

iTrader: (3)

I am not going to tread on another mans territory. He has done a GREAT job, hopefully I can be a customer eventually.

JClaw

iTrader: (17)

Yeah I know. Notice the

JClaw

iTrader: (17)

http://www.nissanusa.com/vehicles/Me...,43701,00.html

Looking at that sheme you posted earlier, it looks like SR's manifold has identical airflow till the VI switchover, and it seems the same switchover occurs, only it's more dramatic. I don't understand how that can be done, since the butterfly valve has to be the same size on his anyway. Even if he bored/increased the size of the second runner that opens at 4k, the valve would still be the same size, and let the same amount of air anyway.

UNLESS he bored the other runner, which would result in a loss of tq but help at high RPMs, and the 4k switchover would still occur, and combined with the first, bigger runner, would increase the impact of the 4k switchover???

Maybe he just regrouped the low end loss by perfectly tuning his A/F...

Since I am going to be stuck with the 2k2 manifold for a while, do you think it's worth simply taking out the butterfly, since I already have all that lowend torque in a 2900 lbs car?

NmexMAX

iTrader: (22)

Do what you want, you'll never be as cool as the Wizard ... and neither will I ...

NmexMAX

iTrader: (22)

Well, you cannot dispute the wizard ... we just wish we could all be so lucky ...