mtcookson

iTrader: (2)

I think this is the intake plenum the 510 guys said was the best flowing ones. the look good too http://cgi.ebay.com/ebaymotors/ws/eB...tem=1871829576

male

Nice. You should consider it dude. Wait, you've got the VGT with the Maxima-like intake right? Maybe for simplicit you should stick with that. Know that the Maxima lower intake has much bigger ports that the US vgt version, so maybe the claims of better flow come from this too. IE someone put this upper on a vgt lower and got some gains, but has anyone flowtested this one. That upper does look like a good design. Have your upper extrude honed. Do the lower too. and the O2 housing, and the exhaust manifolds/crossover passage, and port and polish the heads..DO IT UP MAN!

Chris91SE

iTrader: (1)

i still don't see how the TB etc will bolt on to that...looks like you'd still need more pathfinder parts to get that to work...

male

Yeah, probably th epathfinder TB and IAC valve. BUt hell, if you arre going to do this, you have ot expect a little cuson work. Does that lower look polished on the inside..pretty smooth for cast aluminum.

mtcookson

iTrader: (2)

that 520 site said the pathfinder intake flows 30% better than any other vg30 intake so i'm sure it would be good, it would just be a pain to get in probably. Also, talk to Egnloid about extrude hone, he has a really good point about it not being the best way to make air flow better.

Nismo87SE

I say stick with the 3rd gen IM. Looking at the pathfinder VG30 it makes 153hp/182tq, while the max does 160hp/182tq. However the pathfinder peaks around 4000rpm but the max peaks at 2800rpm. The max IM should have more torque from 2500-6000rpm over the pathfinder setup. Since the cams are the same specs the only difference in power is from the IM.

male

Pretty sure the cams are different. and I was sure the vg33 makes 170 hp, but regardless,

mtcookson,
I know Engloids theory on extrudehone, but it is alot easier than sectioning your manifold, hand porting it, and TIG welding it back together. Also, I'm not sure that Extrudehone actually behaves the way Engloid describes, I mean, it is under pressure not just flowing freely through the passage. Also,the way to get better airflow through a passage is to straighten the passage as much as possible, right, because air doesn't like to make turns. So the putty is being pressed throught the passage, it reaches a bend and what does it do? It wants to go straight, pushing against the outside of the bend, removing more material forom the outside of the bend, thereby straightening the path. Sound logical? I know, Engloid's idea sounds logical too, but the only way to really find out is to try hand porting Vs. Extrude Hone and flowtesting it.

Nismo87SE

Yes the VG33 makes 170hp, but the VG30 from 88-96 make 153hp/180tq. Therefore the 3rd gen IM is the better one.

male

The 3 liter version was put into the pathfinder with a lower hp rating? That seems pretty stupid..Anyway, I think the Max IM would be fine, especially boosted..

surfermax92

I think that the max IM would be fine if it was ported and polished- I'm sure that you could open it up enough that it is not restricting airflow. Anyway, isn't the max's VI better than the non-VI equipped manifolds?

surfermax92

BTW, does anyone know whether the vg33e heads flow better than our max heads?

male

I've heard they are more efficient, but that's about it. The thing is, our engines have very high volumetric efficiency, that is of all the air that comes in on the intake stroke, nearly all of it is expelled on exhaust. THis is accomplished by carefully engineering the shape, length and diameter of the ports and runners. THat is why ported exhaust manifolds have very little positive effect on performance, nor does porting and polishing the heads or intake manifolds and plenum..whatever vg you've got. The big improvements only come when you turbocharge it. But you can have a bone stock engine, no porting or anything, put a well designed turbosystem on it and get 350 hp out of it. Porting and stuff will get you the extra 30-40 hp on top of that, but only when you run high boost. NA engines see little improvement form porting mods..alot of $$ and work for little gain. BTW, max lower manifold has ports much larger than a vgt's, so rest assured that the lower is fine in unported form. Talk to Engloid abou this..he ports alot of manifolds for z31 enthusiasts..he told me that his ported manifold (vgt) end up with ports about the same diameeter as a max's lower manifold in stock form. SO it's good. But back to your original question. If nissan used the same "maximum displacement theory" to design the vg33, then I'd say to maintain efficincy in proportion with the increased displacement, the heads and the iintake passages would have to flow a bit better. SO grab the vg33 heads and intake, and put them on a vg30, you might lose some torque and bottom end do to a loss of velocity, but power in the upper rpm range might significantly improve. Anyone agree?

Engloid

Yeah...but make the ports straight, and they will not only go through the intake walls, making holes, but it will not get air to your cylinders. It's erosion...just look how straight the ohio river is..haha

Granted, I will admit that I think ExtrudeHone would so better on this pathfinder intake than it would on the maxima and Z intake just because it has 2 primary runners that branch off (sharp curves) that would not do as well with this process.

male

I meant straighter, not straight. WOuldn't work too well with holes in the intake walls!

Engloid

right...and imagine this...

if you have a port traveling to the right..and curving downward... then you erode it internally like the extrude hone process does..

it will take more material from the point near tangent to the straight part, and on the outer radius. As this point erodes more and more, it will begin to make a dished area there, creating turbulence and worse flow.

mtcookson

iTrader: (2)

what do you guys think about sand blasting the inside? has lots of air going through like an intake would do but you also have sand to kind of clean it up and stuff.

male

Aluminum will pitt way to easily for that, unless you se plastic beads or something made for aluminum, but you have little control over the pattern, so you might end up putting a divit in an inside wall. You could never get it even. all you could do is hand port/polish as deep as you could reach, or cut it horizontally (laterally) so you end up with 2 pieces, a top and a bottom. Then you could port it really well, and TIG it back together. The key would be cutting it nice and level through the middle. I am tempted to get a used one and try it. Wha the hell, it would be a leeson in a skill most people never bother to try. You could even pay someone to TIG it for you, wouldn't cost that much I'd imagine. I'd feel alot more comfortable porting a mainfold than a set of heads. Heads can easily be ruined, but the manifold wouldn't be too tough, more margin for error.