Depends how wild you're going to get with the boost... others can give you more specifics but I think as long as you keep the boost in the single digits you should be fine...
IIRC the 2.4 Turbo was only about 5-6 lbs max boost...

if you're going to go for double digit boost numbers then you might have to do a bunch of upgrades to the eng. and fuel sys.

 

I'm going to agree with aviator on this one... the relative safety of forced induction is a function of the total HP you're adding to stock specs. As you're probably aware, stock output for the 5VZ-FE is 183 hp (142 kW) at 4800 rpm. Your engine internals were designed to withstand the full torque of 260 HP (the maximum optional HP available on that engine), as is your automatic transmission. The difference in performance will be delightfully obvious between as little as 220 HP, and as much as 280 HP, about the upper limit for the type of upgrade you're considering. If I correctly recall my last conversation on the subject with Gadget at Underdog Racing Development, pushing up towards the 300HP mark will start to stress your internals to the point where it might be wise to consider beefing things up.

The guys @ URD, fyi, are THE guru's with respect to forced induction and Toyota VZ's, and I strongly recommend picking their brains before beginning the kind of project you're contemplating.

So, internals aside for a moment, the bigger problem for you is going to be fuel-supply at even modest HP increases, such as those afforded by off-the-shelf TRD superchargers. The dealership is the first to admit that adding fuel is mandatory, to which end they will be happy to sell you TRD's 7th injector kit, the complete package ultimately affording the 260 HP mentioned above. My beef at the time was the cost... outrageous IMHO on a per-HP basis to attain a less-than-80HP increase. Here's a link to a discussion on it nonetheless.

At the bottom line, if you add boost to your 5VZ-FE, you're going to need fuel. Rather than steering you towards your dealer however, I'm going to recommend URD's more comprehensive fuel-system upgrade, specifically designed to handle their proprietary S/C system, but easily adaptable for turbo'ed induction projects... AND it comes in @ under $1K retail! Here's the link.

As you add even modest HP increases, I highly recommend a racing-type clutch, and a disc brake conversion in the rear so you can stop the beast!


From the archives of my personal experience...

The 5VZ-FE engine is a nearly perfect design for twin-turbos. The firing sequence and valve durations are such that only one exhaust valve is open at a time on either side. As for engineering, the belt-driven fan needs to be replaced by a high-cfm dual electric, to make room forward, where I would recommend sweeping the primaries, with the collectors located as far forward as possible. There is room on either side up front for intakes, one for each turbo unit. A dual-intake intercooler has plenty of room behind the grille, with a single outlet off the top, feeding your existing fat-pipe intake leading to the throttle body, which will also need to be upgraded in diameter.

Using baby Garrett's, I can't remember the sizes right off, I was calculating a potential 500HP at the wheels, using the turbo-port fueler system here, and running dual 3" exhausts off stock Thorley headers and fat cat-converters and racing mufflers. The project required a lot of additional components, waste-gate controllers and a complete engine management system to co-ordinate it all. I remember joking to a mechanic friend of mine that he'd come and tow me back to the shop when I blew the rear end out of it jumping some dune or other!


As a final aside, if your friend is interested in picking up a little work on the side, you might encourage him to post pictures of the turbo-manifolds he comes up with for your 5VZ-FE, along with his contact information. No one is making them right now, and I think he might find modest demand... as the support components to complete such a project are available. Why, I might even buy a set myself...

Good luck!
Doug DeWitt

 

Thanks to all for the valuable input! I am aware of the fact that I would have to upgrade my fuel injectors (my friend told me my stock fuel pump would be sufficient). He has on hand a small collection of various diffirent fuel injectors (mainly for Nissan V6 motors, but he has 3 sets that are for the late 90's model Turbo Supras). According to him he should have something that will work or can find something that will work, and still keep my costs down. I was originally planning on boosting it 7psi and I think I will stick with that train of thought. It is after all a truck, not my Nova... I just wanna be able to scoot down the road a bit faster.

When it comes down to actually doing this I have only one issue (though it seems to be a desperate struggle for me to obtain another toy)... there's a 15' Boston Whaler with a 50hp Johnson in great shape down here for $2,500 w/ trailor. I have a tow package and am tired of borrowing my dad's smallest boat (a 14' sail boat w/ 6hp motor). I want the boat way more than the turbo to be quite honest, but my wife (here it comes... yeah, married men every where can feel this) says that we don't have the money for the boat... she cares much less about spending 1 grand vs. 2.5, though I think she's just being like a squirel in winter (trying to save all our $ for the cold season). I would have the money for both, but then we'd be pretty dried up in the savings department. I'm trying to convince her to approve one or the other, but the boat it seems, may be a far stretch (at least this month haha... I will keep pressing the issue of course!!).

 

Oh yeah.... if you guys would like to talk to my friend I can ask him if he'd mind me giving his email out/ facebook. He has picks of his Maxima on facebook. He did a swap from a twin turbo 3000GT and then built the motor, removed the stock turbo set up and is now running through a single custom turbo set up that he fabricated (turbo is about as big around as a soccer ball.. no joke). He took me down a clear straight double lane road (about a mile long) and went 0-194 in 12-14 seconds!! He was running 20 psi that day, but has boosted up to 38psi before running over 700 whp.