Yes .... premium fuel always. PERIOD I paid over $4.23 a gallon today.
IMO a proper set up for a TRD supercharger system should have at least some kind fuel management system and Air/Fuel Gauges so you can see whats going on.
If none of the above is available. I would do some additional test for the biggest and most damaging problems with TRD S/Chargers it is pinging.
Pinging is damaging and hard on the engine. I would test drive with a OBDII plugged in so you can see the air/fuel mixtures. I would begin by rolling to 2500 rpm then go wot then slow to 1500 rpm roll to 3000 then go wot. I would do this through 3500, 4000, 4500, 5000, 5500, 6000 roll to then wot for a couple of thousand rpm. All the while listening for pinging. If it's pinging you can assume that's been going on since new and the risk involved to the 135K mile engine. It may/may not throw codes Po171 or others which is another indicator that you have a leaning problem.
Once this is done and you know what you have, then you can decide if thats what you want to purchase.
Kowning what I know now......a MUST is have someway of monitoring the air/fuel at all times. You can do this with an Air/fuel gauge or ScanGauge.
Also a fuel management system. I have the URD 6injector kit with Fuel/Air calibrator which requires alot of tweeking which is good for fine tuning the engine. The cleanest and most effectively easy fuel management system is URD 7th injector. Lastly, a larger fuel pump is needed regardless.
As far as my experience with the TRD S/C . The preformance is there but remember its a 4000lb SUV and not a sport car. The NA 3.4L is very capable for most of what normal 4runner owners want to do with them. The S/C is cool but IMO not a must, I specificly looked for one because most of my toys are with either S/C and Turbo'd modded high performance vehicles.
The MPG are already a challenge with the 4Runner and the S/C will challenge that further. We get about 12 mpg and thats normal driving at 4500 feet mountion area. At other elevations of 1200 feet we may get 14 mpg city/highway combined.
Buying a S/C engine that has not been managed and maintained can be costly to repair or replace if needed. My son and I collectively have the tools, equipment and HIS knowledge to do most of the work needed to our vehicles which equates to substancial savings not afforded to most.
Having said that, these engines are very forgiving but not bulletproof. S/C put alot of pressure on the engine keep that in mind when having your truck evaluated and tested.
I commend you for researching this forum for information. Good luck with your purchase, assuming all works out with your purhcase. I can tell you these things S/C are fun and much faster than stock. WOT it hauls A$$...
Hope this helps........8sm
