Posted: 2/4/2026 10:24:08 PM EDT
[Last Edit: Deerhurst][Edited]
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Going to make this a mini secondary project log and hopefully pick some forced induction brains. So, here goes. The host truck is a 1986.5 Nissan Hardbody 4wd. It has a JDM VG33 swapped in with the original TBI unit and Pacesetter Long Tubes. Has a 6 puck ceramic clutch. The drive line is well overbuilt, 233mm (9.17") rear end and 200mm (7.78") front end. The TBI unit cannot flow enough fuel for the VG33. Under heavy load it hits an artificial rev limiter around 4500RPM. Things like pulling a hill with a trailer or load in the bed, etc. The original goal was MPFI from TBI. I have a NA intake upper and lower plenum, injectors, TPS, throttle body and fuel rail that came with the VG33. After talking to a Nissan tuner (JWT) I got some more info on how to beat do this and hack up the wiring harness the lest. The TBI truck has 2 injectors in the throttle body which are separately controlled by the ECM. This gives me 2 channels to work with without any modifications. The ECM that will give the most features with the least mods is a 1988 or 1989 Z31 300ZX ECM. Per JWT it will plug right in. How to add 4 injector then? The 88/89 ECM combines firing order 1-3 and 4-6 in the ECM so those get the same pulse signal. I just get to connect the proper injectors at the injector harness when I strip and modify the VG33 harness. The NA Z31 ECM brings another issue. The hardbody uses a M12 Titania O2 sensor and the NA Z31 uses a M18 Zirconia O2 sensor. I will have to add the M18 bung as my exhaust has been modified. Normally it should be an M18 bung with a M12 bushing. A Z32 MAF was recommended. The Delphi MAF was recommended with the notes they have had so few issues with it in all applications they have used it in. Started looking at superchargers again because I've been wanting to do forced induction without turbos. And blowers sound better anyways. Found a take off blower, upper and lower plenum and intake piping, throttle body and picked up a rebuild kit for the blower. Hopefully I'll see that in about a week then start cleaning it up and replace all the bearings, oil, couplings, etc. Thinking I should paint it somehow but not sure of colors and such yet. I'll have to add a port for my boost/vac gauge in the lower plenum below the blower. My first question. Supercharger Bypass Valve. I know it's vacuum controlled. I won't/don't have a solenoid to control it unless I can re-purpose the EGR solenoid. Can the SBV be controlled completely off manifold vacuum? I assume just after the throttle body. I'll have to add photos as parts arrive. |
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Well, the MAF and O2 sensor are in. For O2 I need to add an M18 bung to the exhaust. For the MAF I need to design and fab an airbox. Not sure what filter to go with. Im OK with a cone filter but it has to be disposable. Not messing with those shitty oil type filters like K&N. I like my engine and want better filtration than a screen door. No pics since those are real exciting parts. |
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Originally Posted By thezentree: Here for it. Post pics of the truck This is the truck.  Already VG33 swapped with long tubes. Been extra busy but still working on sourcing a lower plenum. I think I have everything else but injectors. Just gotta make sure things fit and if they don't figure out how to mod it. Best part is it's all OEM parts. |
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Originally Posted By maslin02: I had a 5 speed supercharged Xterra for a long time, over a decade. Solid axle swapped it at the house, absolutely loved that thing. Scooted down the road pretty good with the VG33ER. https://i.imgur.com/sW8h26D_d.webp?maxwidth=1520&fidelity=grand Manual behind a VG3er is quite rare. What was your fuel economy like? I'm hoping to stay closer to where I currently am on the highway. I get 16-17mpg rubbing 31s and 4.11 gears. I'm hoping to make another 20+ftlb over stock. Maybe more. Definitely want to dyno it when done. |
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Originally Posted By maslin02: 14-15, but I was on 33's. Manual, Supercharged and SE (power everything), took me months to find that thing. They were rare in 2006, probably nonexistent now. That's not bad at all with SAS and 33s. I'd be happy with that! I believe it took a while to find. Very rare. Still waiting to hear back from the outfit I got the blower from. They said in their listing it had a lower plenum in the parts set. It did not. They offered a return or partial refund. I asked if they were willing to find a lower plenum for me. That was last Thursday. |
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Originally Posted By maslin02: That thing looks like a blast. I had a buddy in school who had a mini truck hardbody, just terrible enough to be cool. It's been a great little truck. Extremely reliable. I've had it for almost 20 years at this point. It's done DD duty, it's been out on trails in Moab, it's been used to pull hay for hay season. You name it. The ride is a little rough which is expected for suspension from 40 years ago. My only complaint is the interior is red. Very, very red. |
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Blew everything apart for cleaning. It was NASTY! Used supercharger oil smells terrible. I was told I made the room smell like, and I quote "marinating dirty hippy butthole". It was bad. Made half the building smell like that. I need to figure out how these things are supposed to be rebuilt. Appears everything is pressed together so I'll have to make sure it goes back on at the same spot. Good thing I have built AKs and know how to use a harbor freight 20 ton press! Lower plenum is hopefully in the mail, I'll have to take the truck out of commission, drain some coolant and test fit the mess. See if it all fits. 
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| Are you gonna take the blower totally apart and recoat the rotors? I was looking at rebuilding the supercharger on the Tacoma I sold last year and decided that if I went that route I was just going to have a shop do that for me since it's so involved and from what I gather special tools and equipment are needed to do it right. I think it was like $900 for a full rebuild for a TRD 3RZ blower. |
The hardest part about a zombie apocalypse will be pretending I'm not excited.
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Originally Posted By thezentree: Are you gonna take the blower totally apart and recoat the rotors? I was looking at rebuilding the supercharger on the Tacoma I sold last year and decided that if I went that route I was just going to have a shop do that for me since it's so involved and from what I gather special tools and equipment are needed to do it right. I think it was like $900 for a full rebuild for a TRD 3RZ blower. I'm doing bearings but I don't think I want to or need to recoat the rotors. |
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Tried pulling the rear rotor pack bearings. Nope. Didn't even so much as budge. Heated the entire thing in a 100c oven and still no dice. I will probably end up paying someone with the right tools to do it for me. I'll supply the bearings and coupler and seals. Normally a rebuild is ~$850. If it needs a rotor pack it's now a total of $1700. Yikes! That's half of what I paid for the truck .... In 2007! |
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Haven't been able last with this project for a bit. I started setting things on to see how the belt routing and clearances are. Still lots to go but gonna be pretty cool.  Didn't expect it but a JDM Pathfinder AC compressor will bolt right on even though the compressor is in normally on the opposite side of the engine bay. Did not expect that but makes sense. I'll be using it as an idler and maybe an air compressor later. Eventually I might just make a tensioner that will take up less space. |