I have a 1990 Nissan Pathfinder with a VG30E and an automatic that I am working on. The truck currently has a number of mods which have added hundreds of pounds of weight to the truck. Power is severely lacking.



The truck is primarily used for rock crawling, which is usually slower than a walking pace when the power counts, but it does see a bit of DD action with some highway miles. If this, along with the picture, doesn't already tell you something, I will add it here: I don't drive this truck like you would drive your boosted car. The truck is top heavy, it does not have sway bars, and it has parachute-like wind resistance. I use just as much gas pedal as is necessary to get me from point A to point B on the road.

I am most in need of very low end torque. I am expecting to put together a setup that most would consider undersized for the VG30E in order to get boost at very low RPM. The fact that it will be wheezy or worse at high rpms is perfectly fine, since the truck hardly ever sees rpm higher than 3200.

Has anyone here ever gone after low end torque at the expense of high end power? I've done some searching, especially on the VG30, and I've found very little.

After talking with a couple folks, I've come up with an initial plan. If I have understood correctly I can use the stock pathfinder (VG30E) ECU and injectors for my fuel control needs under boost, even though the pathfinder VG30E did not come boosted. I don't plan to run more than 8 psi, and I want to use a turbo (or turbos) that will spool up very early and will produce usable boost hopefully well under 1800 rpm. I will use the stock bottom end and basically stock everything but the modified exhaust and charge piping. I've read that there are people producing over 400 HP on stock VG30E bottom ends, so I think I should be ok running under 10 psi.

I might run an intercooler, might not. I migh build some log style turbo manifolds or I might use the stock manifolds and adapt the turbo about 6 inches past the driver side exhaust manifold flange.

I have a few questions.
First, do I understand correctly that the stock VG30E ECU will control my fuel/air under up to 8 psi of boost using the stock injectors?
What would be a good turbo choice for what I want to do? I'm assuming that even the stock VG30 T turbo used in the Z cars of the late 80's would be too large.
Would twin turbos produce better boost at lower rpms and still breathe enough to not kill high rpm power?

My main concerns are fuel/air control and turbo size. Once I have that figured out putting together all the components will not be too tough.

Thanks in advance for the help.

 

I dont think you are going to get the result you want with a turbo setup

No matter how small of a turbo you go with, even small twins. You will never see a nice gain for the money spent in the 1500rpm range, thats practically idle

I would look into a blower possibly, which still not make much if any power

 

That reminds me, one of the reasons I want to do a turbo setup versus a supercharger is the $$$. This will be a junkyard build for sure. If it just is not going to do what I want it to do then I will reconsider the supercharger. I really hope I can make the turbo setup work though.

I am also not looking to make 300 HP, I just need a little extra to beat the wind resistance and extra weight I've gained. I would be happy with 20-30.

 

you have jack ---- for room (my dad has a 94 p'up w/ vg30e and there is NO room, so you'd either run a pair of t25's or one t3, but might have to stick it up by the battery, the only place theres room. and good luck with reaching your plugs under the firewall.

just change your exhaust piping from the x-pipe back, with full 2.5" and gut the cat if you don't have emissions to worry about. i no longer need to grab 4th gear in my toyota to take the last hill before i get to work, i can accelerate in 5th up it actually. youll gain a few hp, and those motors love to breathe, think of 2" exhaust on a 300hp civic.

and bosch wr8(or 9)(px dx i forget, the x is the gap and the p is platinum) plugs are golden in that motor

 

I was planning to locate the turbo behind the motor, basically beside the transmission bellhousing. There is plenty of room there. I know a guy ran a T3 right off the stock manifold on the passenger side, he was able to make it work.

 

Dman son. What's your RTI score.

I kinda doubt that you will find a turbo that will spooland give you the extra power you are looking for at 1500 rpm without choking out in the higher rpms. I suppose one could build a sequential setup, but they are very complex and hard to tune from what I understand.

Maybe if you could find a small split scroll tubine unit you could block off one side at low rpm and have the other side open up for higher rpm. Just a thought.

Cool truck BTW.

 

you need some juice

 

ill say he rti's around 840, but it's not all about rti..

 

lol. I know but it is still pretty impressive. Loving the exo skeleton.

 

what are you running for a front diff? 4 linked? I dont think a turbo would work good for rock crawling at all, a small turbo would spool quick but maybe when you dont want it, a supercharger is more linear(sp) and more suited to your needs. will a supercharger and intake from a new pick up or xterra fit?