me and ethan have been scheming again and we both have thought in the back of our heads what about a 2k intake manifold. they might not look pretty but they don't get hot AND they scream right to redline and i bet they will fit easier then a 350 Z one. so i'm thinking, they switch over based on RPM cus we disconnected Jeff's(RU4REAL) vacuum linme to the butterflies and they still opened and he didn't get a CEL. so if it will fit i'm thinking that we might lose a few FT LBS of TQ which i'm more then happy to give up but gain maybe 10hp maybe a few more. the engine between the 4th gne and the 2k is pretty much the same other then minor exhaust tweaks and hen the intake. any insights from anyone before we proceed.

 

We discussed this one several times guys. If you really want to try it out then go ahead but here are things to consider.

You will certainly have to use both the upper and lower parts of the manifold. The injector fitting is different and you will have to find O rings that will seal up the smaller fit Peak & Hold injectors we have. Gaining hp is mere speculation at this point and you could easily lose a few instead of gain. Instead of just going through with the project it may be wiser to have all three manifold assemblies flowed (VQ35, VQ30-K and VQ30 MEVI). That way you can have the facts on paper before you wasted too much time and effort.
At this point I doubt the older manifolds are capable of flowing more than the new one but it would be nice to see someone try this out and put this speculation to bed.

 

Does't the 2000 and 2001 have "Plastic type intake manifold"? I keep hearing about it not switching over at 4800-5000 because of the poor materials used. Correct me if I'm wrong. Just a thought.

 

I would think the drive-by-wire throttle body would pose the biggest problem.


Dave

 

I disagree with this. I beleive the 00-01 manifold will flow better up top then our 2002 manifold. Reason is because on the 00-10's they breath very well all the way up to redline. Now if the VQ30DE-K breaths well up to redline I belevie the same would hold true for the VQ35. Of course this is just a logical guess here, the incresed air volume going into the VQ35 may over welm this designe but judging by modidied 00's the manifold breathes well up to 205 WHP.

As for the injectors not fitting properly.. This will only be a problem if the lower manifold does not match up. I will have to get a good look at a 00-01's lower manifold. I think our lower manifold may be the came minus the holes for the injectors. Well see..

 

But wouldn't the car make more power without that brass butterfly thingy blocking the air?

 

Wrong. Prior to 2002 Nissan used saturated injectors that were seated intot he lower intake manifold with large rubber seals. The 2002 injectors are peak & hold and have a much smaller footprint. They use much smaller rubber seals to mate to the lower manifold. Look for yourself and see.

 

No i'm not wrong, lol.. I said This will only be a problem if the lower manifold does not match up. Now if the lower manifold mathes up I will not even need to touch the fuel injectors. See what I'm saying here?

 

Actually, it works off both a RPM signal sent from the ECU at 5K and TWO vacuum sources. IF you guys disconnected one vacuum source the other must be sufficient to open the valves.

I have the system description next to my desk at home and I can double check TONIGHT. However, I don't think providing a vacuum source is going to be too difficult, but coming up with a vacuum control valve that opens at a certain RPM, may be.

BTW, why did you give up on the 350Z manifold withOUT trying the bottom half?

 

Does the power curve of the 350Z manifold go up to redline nicely like the 00-01 maxima? I am just curious since it just seems weird they would skip it over for the 2k2. Unless they were trying to "detune" the 2k2 so that the power level would not be even closer to the 350z.

SuDZ

 

I did some cfm calculations, im not an expert or anything, but just thought i could help. The 3L VQ at redline needs 297cfm of air, while the 3.5 @ redline needs 347cfm. The long runners on the VQ30DE-K intake manifold, is roughly the same flow of the VQ30DE manifold on 4th gens, and 4th gens run out of breath around 5500rpms, I assumed running out of breath meant the intake manifold couldnt flow that much more without it being forced in, and it showed that the long runners would flow up to 247cfm while still being efficient. The VQ30DEK manifold, makes power up to 6400rpm, which is about a flow rate of 288cfm. doing some reverse calculations with the 3.5L, the long runners would start to run out of breath around 4700rpms, and IF the short runners ran out of breath at 6400rpm on a VQ30DE-K, then it would also begin to run short on the VQ35 around 5500rpms.

None of this is completely accurate or precise, i just thought id figure out how much air each engine needs, and if the intake manifolds were the factor in how much air the engine could take in, u might not see any gains at all. It just shows that the VQ35 swallows significantly more air than the VQ30.

 

I didnt factor in that it could be the cams slowing the flow of air, so again, all my calculations could mean nothing, other than that a bigger engine needs more air.

One more note, the VQ35DE @ 5700rpm, needs as much air as the VQ30DE needs at redline.

 

Be serious Ethan. There is no way that thing will line up and fit. If the 350Z top was so much different than ours what makes you think the other one will be any more close?