CMax03

iTrader: (3)

I would think that the shorter OEM Maxima UIM would have a higher RPM power output with the shortest runners allowing the engine to breathe better at peak power close to it's redline....the longer runner intakes should fall short of the redline, but produce a flatter torque curve....I would stick with the Maxima/300zx Upper IM and port match them as perfect as possible, and clean up any internal casting marks that could disturb the airflow...maybe you could make some phenolic spacers to reduce heat and spray paint the UIM and LIM with a heat barrier paint.

aw11power

Flow bench testing was done and posted on the RedZ31 website years ago. Heres the full link.
http://www.redz31.net/pages/plenums.html

There's quite a lot to read there. But the first thing I want to mention and show is that at all lifts(all RPMs) the stock 300zx plenum is lowest flowing plenum of any plenum for the VG30 or VG33. So Im definitaly not going to use that.

aw11power

This graph shows the data in a really easy to read format. Youll see that the stock maxima plenum clearly outflows the 300zx plenum across the board. It would be a major downgrade.
The pathfinder plenum is about 2 cfm behind the maxima unit at lower lift levels, which is made up for in better production of torque. You may observe that at higher lifts the pathfinder unit actually outflows the maxima. Which means it would prove to be less restriction at higher RPMs. Lastly theres the math. The formula for HP capability on an NA motor is CFMx0.255x#of cylinders. This gives you the max HP support of a given CFM.

aw11power

So.....The HP ceiling of a naturally aspirated VG using a pathfinder plenum would be 237.7 .
The ceiling on the maxima plenum would be 235.4 and finally the 300zx plenum peaks at 226.2 . So the smaller runners provide zero bottle neck for high RPM operation. That means I would need some serious head and compression work on an atmoshperic motor to surpass what the long runner plenum can breath. As I stated previously, the long runner plenum would provide better torque without a high RPM consequence. It has to do with the fact that the biggest bottleneck on the W series VG30 is the valves...So in conclusion, I am going to use a long runner intake.

aw11power

Ive been diggind through Z31 dyno results for VG30ETs and found that most people peak a little under 400RWHP with the pathfinder plenum and then upgrade to "engloid" style or gutted. 275RWHP seems be the most that people could hit with the stock short runner plenums before upgrading to pathfinder units. Side note, my co-worker has a fox body mustang that he swapped an L series chevy motor into. Its a drag car that runs a 100mm turbo at 27psi produced 1137RWHP. I saw the dyno. Hes using a thermoplastic plenum....you wont break it unless you have a lean backfire, at which point you just broke a lot of other stuff LOL! Im trying to build a streetable 250-300HP max that still has some torque off boost.

aw11power

So back to updates again. Still deciding on upper plenums, but had several other things to address in the meantime. Had a crack in the front exhaust manifold, it was welded up some time ago. Like most welds on cast it broke again....Almost in half!


I had a turbo manifold in good shape and Im going down that road anyway, so I started converting the equipment.

aw11power

I used a blank T3 flange and made a 2.5 in coupler for it so I could make a temporary downpipe until I can get the rest of the turbo hardware.

Thats all the N/A hardware removed.

Turbo manifold intalled with new gasket and studs.
And here is the temporary downpipe I made. Its not pretty, but it's funtional. Not too worried about it since it will only be on there a few months. It looks all haphazard because I built it completely out of scrap pipe from the shop. I didnt want to waste good materials on a piece that will eventually be thrown away. Once I actually have the turbo installed, I'll have to make a completely different down pipe anyway...

aw11power

Shortly after I fired it up, I heard a pretty noticable exhaust leak. Amusingly, It wasnt from the work I just did. The gasket on the rear manifold blew out! LOL! So Ill be replacing that gasket tomorrow, just in time for nismo fiesta!

CMax03

iTrader: (3)

Sounds like you've done your homework....

aw11power

Well, it looked like the gasket blew out but as it happens, 2 studs broke actually.
Heres all the old busted hardware.


Took forever to freakin get this out of the rear head.


I replaced ALL the studs


Got it all back together with heat shields on. I painted the heat shields with high heat, gotta look nice right?


I trimmed down the original NA front heat shield so it would fit over the T3 manifold.


I had already done a gasket match and casting smoothing on the T3 manifold a couple months ago so it was ready to go when I put it on. SInce I had the rear manifold off I gave it the same treatment, all about flow! At some point I plan to remake the center section of the crossover pipe so that it can flow a little smoother as well. This is all my updates from saturday.

aw11power

I had an excellent time at Nismo Fiesta in Austin TX today. fantasticly fun event. Entered in the show and was proud to display the Max. Not a show winner of course but I felt honored to have the chance to show it.



I also took advantage of the mobile dyno there...

134whp/161trq. Im pretty happy with these numbers since most stock VGs usually dyno around 120whp/150trq. So it looks like my mods were worth the time spent. Nowhere near done with this, I look at this run as mostly a baseline to compare my turbo build to.

aw11power

I put together a little video of the dyno time





Recorded and uploaded @ 720p

CMax03

iTrader: (3)

That OEM cross over exhaust is a waste of time....

aw11power

unless youre piping them to a turbo....The OE crossover pipe has been used in >400hp cars on the Z31. Never shown to be a bottle neck. Also, any other exhaust solution on this chassis would make it impossible to run a turbo and necessitate relocating the oil filter and re-engineering the shift linkage...

CMax03

iTrader: (3)

I'll get these 3rd gen manifolds fitted to my buddy's 2nd Gen I'm sure they will fit and flow better due to less angles for gases to change during exiting...

aw11power

So anyway, I will be using the OEM setup for now....I will build a different crossover if/when I opt for a larger turbo.
I'm still working out which way to go with the upper intake plenum, I've been putting some thought into using a pathfinder plenum as a template building a custom on off its flange and tubing...We'll see. In the meantime however, I put the car down for 2 weeks so my wife (an artist) could do a piece on my hood. I wanted something unique that reflected my own dorky tastes as a child of the 80s. So she did a geometric backround highlighting a tribute to 1986s "the legend of zelda". So here's the pics!!!!

Character close ups...

Ganon

Princess Zelda

Link

Cover art

aw11power

now for the finished product!




after she finished I used an HVLP gun and clearcoated over her work to preserve it.
It still needs a little more wet sanding and buffing to be perfect, but the finish is almost as glossy as I wanted now.







Well thats it for now. Hope yall like it! Ill be back with more performance upgrades soon!

aw11power

Oh yeah, I forgot to mention that this was all done with black and silver sharpies!!! freehanded characters and rulers for the lines of course.

maximase86

iTrader: (24)

Not bad on the Dyno numbers. My 2nd gen did 135whp, and 168wtq back in the day with a CAI, UDP, and a 2.5" catback. I have to say that I don't miss the top end the VG30E had....or the complete lack of it. The curve really shows that.

I agree with CMax, that crossover pipe doesn't help things. Converting to a 3rd gen probably would help a little, but probably would need to relocate the oil filter to make that possible. If there was a way to give it even up the exhaust runs too, that'd give it a considerably different note too. However it does make things convenient for force induction.

S

CMax03

iTrader: (3)

If you can't get the air out you definitely can't get it in.....

Nismo87SE

Good results my old 87se auto did 123whp/153wtq with cai, udp, exhaust. At the same time 2 bone stock 4th gen auto's did 147whp/161wtq. Your car makes me miss my old 87se.

Nismo87SE

IIRC the 3rd gen ex mani wouldn't clear the drive axle. The 3rd gen engine bay is much larger so the manifolds were routed better. For a turbo car the factory manifolds should be fine. Unless you are running more than 400whp you shouldn't need custom manifolds.

Crusher103

iTrader: (10)

What a fantastic thread.

One thing though you are very handy with creating your own parts and etc. With your lighting why not retrofit in some projectors. Seriously, it would end all your lighting problems and there and limitless choices especially with the maxima's large reflector housing. I suggest a bixenon projector like a TL or FX-R

aw11power

thanks guys, sorry for the lack of updates lately. made a big job change and its been quite a transition. so ill be working crazy weekday hours, but ill have most weekends off and make much better money. which means the max is gonna get some much nicer upgrades very soon. also, my friends 87 300zx has been in my garage getting head gaskets replaced in my spare time, so I havent been able to work on the max lately. its mostly seeing a lot of daily duty.

but I digress. it looks like my HP/TRQ numbers are pretty much on the mark. next up is gonna be catch can installation and hopefully finally changing out the upper plenum. also, waiting to hear back from another board member about a light weight crank pulley. Im hoping to get this motor up to 150hp/175trq in NA form before going turbo. its a slow process but making headway small steps at a time. Ive also got a line on an apexi neo, which when i get, ill make a write up on installation. many say the neo cannot be installed on this series motor because of a lack of throttle position sensor, i plan to get around that with some pathfinder parts.

and thanks for the compliment crusher, i find with a car like this you either have to be good at making your own parts or you cant mod it lol! and i do intend on a retrofit of some kind with the headlights eventually, its on the list haha!

aw11power

last week i changed the trans gear oil to motorcraft 80/90( i get it dirt cheap at work) and the trans is quieter and shifts way smoother. also got rid of the crappy valvoline 10w30 id been running and changed over to BG full synthetic 5w30. went thru a whole tank and the car is getting 2 more MPGs!

aw11power

New sneakers for the Max. Sumitomo HTR as p/02. I finally have the right size for this transmission's gear ratio. This tramshould is from a 91 with 3.650 final drive instead of the 88'same 3.428. So not only was my speedo off, but my highway rpms were too high. So I got rid of my 195/60/15 and mounted up 205/65/15. So my highway cruise rpms came down (hopefully helping my fuel consumption, we'll see...) and now my speedo is dead on (GPS verified). Also the car feels more stable at speed. The increased grip of the new tires however really make the car dive going into hard corners. Time to upgrade my springs!

aw11power

The bigger tires also fill the wheel wells better. I much prefer the look of the car this way. Now it needs to be lowered about an inch with some much stiffer springs. And I plan to paint the wheels. Thinking gun metal or some other dark gray, not sure yet. Thoughts?

aw11power

Today I got all the old useless bronze tint removed. went full limo. 5% on all rear windows and 35% on the front ones. thats as dark as you can legally go in texas.





its defanitely an aesthetic upgrade, but has the bonus of course of the car staying cooler. which matters in Texas lol!

aw11power

So....about a week ago a started noticing a smell of rich idle and decreased fuel efficiency. Checked my computer and got a code 23, idle switch malfuntion. Tested the switch with a voltmeter and found it wasn't sending and idle signal to the ECM. So it was idling at cruise mixture levels and wasn't cutting fuel on decel.that'll waste some gas lol! I went ahead and replaced the switch with a 240sx style that has the second throttle output with variable resistor(I'll need that for the next phase anyway). I also put a newer pigtail connector on since the pins were so darn corroded. It's still used, but better. Eventually I'll try to get ahold of a brand new one. Meantime, my idle is back to normal and smooth/not stinky again. Got a road trip down to the coast planned out this weekend, around 600 miles all together. It'll give me more than a chance to see if my fuel efficiency is majorly affected.

aw11power

Saw my friends at Austin Z clinic over the weekend and picked up some hard to find goodies for my turbo project.


1986 300zxT ECM. Set up from the factory for the turbo I'm gonna use. Plug and play man! Just gotta swap over 3 pins for idle controls.



Super, super rare Apex multi-checker made exclusively for Nissan.
It taps into a few ECM wires and allows you to live monitor RPM, vehicle speed, MAF percentage, ignition advance and injector duty cycle!


Old school Greddy EGT gauge. It'll be nice to know if I'm about to melt pistons lol!



And lastly, an Apex NEO air fuel controller for some fine tuning as needed.

I'll be working on getting all these installed over the next couple week nights after work. Hope to have em all in before my trip so I can start getting used to what kind of readingstuff are normal. I swear, sitting in the driver seat is gonna feel like a cockpit haha!
I also have a wideband, boost pressure gauge and fuel pressure gauge in the mail right now too. Those will all be mounted below the radio.

lowpost99

Did you have to use any solvents to get them opened? I tried to open mine and got as far asz three little screws and 6 metal clips. After that, I thought the glass would just come off but no they appear to be glued like with maybe a sealant?

aw11power

nah man, I just used a heat gun to loosen up the old adhesive/sealant and plastic pry bars from harbor freight to pry the glass off the back. It will be stubborn and youll need help from a friend. it took 4 hands to get em apart when i did it.

aw11power

sorry for the lack of updates guys. Im all over the place with the new job. and FINALLY bought a new car as a fun, comfortable daily driver (2013 Ford Focus ST turbo!) so the maxima has hit full time project so Im heading strong into the upgrades now!!!

I couldnt find compatable settings for my Apexi multchecker so unfortunately wont be able to use it. Im giving it to a buddy with a 240sx. So at least its getting used now lol!

On to progress. After gutting the carpet and main wiring harness to the ECU I got my Apexi NEO air/fuel controller installed end functional. I used an 87 300zx throttle switch since it has dual outputs, one to satisfy the factory ECU idle signal and one for the Apexi unit's need for a 0-5v throttle input. I stole 5v from the fuel temp ckt to power the sensor and used the ground control ckt wire from the EGR to be the signal line to the Apexi since my car has been sans EGR for a long time now.

Heres the map table adjustment screen on the Apexi


This is the 4 channel multi monitor mode




after all that I installed a 300zx 70mm mass air flow meter, upgrade from the stock 60mm unit.



And lastly I pulled my stock maxima ECU and installed an 84 300zx turbo ECM. ill be replacing the injectors next week some time. what people say about the rev limit is true also. Ill never drive it this high, but I found during some testing that the turbo ECM will let me rev to 7000 RPMs!

More coming this week.

aw11power

just a heads up guys, i will still be making updates to this thread but i have started a new thread in the advanced performance/turbo forum to document the turbo conversion. this thread will mostly be interior/cosmetic mods.

aw11power

Got my 4th gen short throw shifter installed today. it feels great!

TransAmBandit

Details on the short throw install? Interested to see some progress photos of that.

aw11power

I documented it all in my other thread. ill post some pics for you here too tho. Yesterday is the first time I drove it since i put it in, i had a bunch of other things apart at the time and just got time to put it back together. the shifts are much shorter and much more mechanical feeling. it takes deliberate effort to engage a gear. i can say its not for everybody, but i much prefer it over the old shifter. i also got rid of the rubber support bushing and mounted the shifter with a solid metal plate.

aw11power

old shifter vs new.



short shift base plate installed



stretched out the stabilizer spring because i prefer a tighter feel to the shifter.



this is where i put the solid support plate in place of the rubber bushing. i dont really have any pop out issues because i solidified all my motor mounts with EPDM rubber and silicone.



thats all put together with new shift **** and boot.



let me know if you have any specific questions about the install. it was pretty straight forward, i only had to do like 2 things slightly different during install because this is a 4th gen shifter, in a 3rd gen housing, in a 2nd gen car LOL

aw11power

catch can finally installed!!!! been so damn busy at work Ive barely been able to make time for the car.



Its a JLT catch can. lucky find from work. I do used vehicle inspection and repair on trade ins at a ford dealership. the newer model cars cant have aftermarket stuff on them. all aftermarket stuff has to be replaced with OE parts so we can sell the cars with a warranty. which means sometimes i get cool take off parts. this came off a 5.0 mustang.

my mess of an engine bay



also, i changed up the way my shift boot is mounted up. i think i like this way better. it never looks right because this car was factory auto trans and the correct trim piece is unobtainable these days.

aw11power

im looking into cars with similar floor board shape and size. i really wanna replace whats left of the old brown carpet and replace it with some new black carpet. any ideas guys?

also, my speedo cable broke. i cant find one anywhere. ive found several available listed as being for the 88 maxima with digital instrument cluster, but none for analog anywhere. does anyone know if these parts are interchangable???