Dyno Time
Before spending the cash on a dyno run, I wanted to be sure Project SportRunner was performing properly. I kept an eye on my tune over a six month period and when I was happy with what I saw in the logs, I scheduled some dyno time at my favorite local shop. The shop I used was the same shop that dyno'd my 1999 Tacoma 4x4 TRD 5 speed years ago so I had something to compare my 4Runner to. It's well accepted that a stock 3.4L Tacoma or 4Runner has around 140 RWHP and 170 RWTQ, and this is what my Tacoma showed when I dyno'd it back in 2000, so I'm going to say the 4Runner is comparable stock.
The dyno shop I used is Performance Garage in Smyrna, TN. The guy that runs the place, Chris, is very nice to work with, intelligent, and has a calm demeanor which doesn't make you feel rushed. He actually stayed late to help meet my scheduling requirements with work, and has reasonable pricing so if you're looking for a dyno shop in the area, this is who I'd use. Chris has a lot of experience with all kinds of cars from Corvettes to Porches to Hondas and is a good resource when you need tuning help as well.
Chris strapped Project SportRunner to the dyno while we discussed how best to perform the runs. The 4Runner has an automatic transmission which makes dynos a little more tricky as you have to find that sweet spot in the speed range to keep the vehicle from downshifting during the run. It's not a huge deal, but having the run in a single gear closest to 1:1 makes for a much cleaner and more accurate dyno graph for viewing. Third gear is closest to 1:1 so we turned OD off, ECT on, and used my custom TRAC Disable switch to defeat vsc/traction control to insure a good clean pass. We found the sweet spot for WOT to be about 67 MPH.
Once the target speed was attained, I would give it WOT and let it run until the speed limiter kicked in at 108 MPH. With the supercharger installed this occurs right at 5100 RPM so I never could take the truck all the way to redline. Underdog Racing makes a speed limiter unlimiter to get rid of this restriction, but 100 MPH in a 4Runner is plenty fast for me, so I'm gonna leave mine alone. I'm left wondering if I might have shown more HP if the full RPM range had been captured on the dyno, but 240 RWHP and 259 RWTQ exceeded my expectations, so needless to say I was thrilled. That's a 100 HP gain over stock!
Be sure to check out my TRD Supercharger Analysis/Tuning page to see the LC-1 logged AFRs on the dyno, and then on the road test. The results may surprise you.