That's what makes building cars so fun. Where someone's idea of the "prefect" 4runner is keeping it as factory as possible (no lift, maybe roof rack, 265's AT tires) and others think the min. "prefect" 4runner doesn't start till 2.5" 285's. There's no right or wrong way to build YOUR rig, and having all the longevity isn't going to protect your car from the distracted driver that hits you and totals your 15yo + 4runner.
As far as factory specs, isn't a S/C Corvette ZO6, just as much in "factory specs" as a non-S/C Corvette C6? That's why the "factory" TRD supercharger appeals more than just getting a URD kit. My factory specs are long gone from this vehicle (from the 2.5" lift, 285's vs 265's, Non-factory BMC, Non-factory intake, Ungraded radio/speakers, lights, exhaust... the list goes on). My dream car comes factory with 240hp+, I plan to build it/daily drive while building it up to 1000hp. So I might be a little too far on the performance side then longevity. :shrug:
I wouldn't go as far as saying staying within factory spec, however there is a difference between building it and building it right. A lift can be accomplished simply by throwing in a body lift... I see that as the incorrect way of going about it, however if its only to get the "look" and it will never get off the pavement then that is fine.
The distracted driver theory can happen to anyone, at any time, in any vehicle, so I think that is an irrelevant point.
Getting back to "factory spec" though... Short answer is
NO... a S/C Corvette ZO6,
ISN'T just as much in "factory specs" as a non-S/C Corvette C6. The "supercharged" ZR1 is based on an LS3, which has thicker cylinder walls than that of the "non-supercharged" C6 (LS2) or Z06 (LS7), which was not used block was not used due to the higher cylinder pressures created by the supercharger requiring the thicker cylinder walls of the LS3.
These are things that need to be thought out, as its not a simple as just slapping on force induction and going. How does this relate to the 2UZ? The 2UZ is based off the 1UZ, but instead used in SUVs and trucks. The largest difference between the two engines was the displacement being increased from 4.0L to 4.7L, AND unlike the 1UZ the 2UZ received an iron cylinder block, as opposed to the cylinder block of the 1UZFE is aluminum. This change was done in order to increase reliability with the increased load of an SUV or truck.
Toyota Racing Development offered a bolt-on supercharger kit specific for the 2000–2002 Tundra/Sequoia and the 1998-2002 LX 470. Why wasn't the 2003–2004 Toyota Land Cruiser, 2003-2004 LX 470, 2003-2004 Tundra/Sequoia, 2003–2004 Toyota 4Runner or 2002–2004 Lexus GX 470? Some of which are smaller platforms than those listed as what the TRD kit is specified for.
Going back to engines being designed for higher compression, these revisions were made throughout the life cycle of the 2UZ both before and after VVTi was implemented.
Initial design
230 horsepower @ 4,800 rpm
302 lb-ft @ 3,600 rpm
Minor revisions were added
232 horsepower @ 4,800 rpm
311 lb-ft @ 3,600 rpm
Toyota’s VVT-i system was added
271 horsepower @ 4,800 rpm
315 lb-ft @ 3,400 rpm
Once again, minor revisions were added
282 horsepower @ 4,800 rpm
324 lb-ft @ 3,400 rpm
As you can tell from these numbers, the 2UZFE ended up with 52 more horsepower, and 22 lb-ft more than it started with. The largest jump occurred when Toyota added VVT-i, which added an impressive 49 horsepower. These numbers don't just come out of tuning... components are replaced internally, change of materials, compression, etc.
I will be upfront and say I don't have exact information stating the revisions completed to achieve these numbers, however I think we can all agree Toyota as a company is extremely conservative, especially back in these years and one can only conclude that the only approved or recommended the TRD kit be put on the vehicles that had the necessary internal specifications to deal with the higher compression over long term use.
Otherwise why didn't they make it applicable to all 2UZ platforms?
