Something MKC went the extra mile with was with the vacuum lines. They used all stainless steel lines and fittings in place of rubber.
Here’s a close-up of the lines around the PT6766 dual-ball bearing turbocharger and dual Precision 46-mm wastegates. Using stainless lines is not only a nice touch, matching our oil feed line going into the turbocharger, but we'll also never have to worry about a vacuum line blowing off.
Here’s a shot of the lines going into our AEM boost solenoid. This is another area you definitely don't want a line to blow off from.
With our Project Supra parts now covered, it’s time to get into the dyno numbers. But first, let’s check out where we left off before Part 1 even started—before the #1 Piston meltdown. In the previous setup the car sported an “open”, journal-bearing Precision Turbo 71-GTS with .81 AR, which is a little larger than our current PT6766. Our new turbo, featurd in Part 4, has a twin-scroll housing with a 1.15 AR, and has a dual ball-bearing center section.
This graph shows where we were on pump 93 octane and methanol injection with the PT71-GTS on a stock block—before this project even started in MotoIQ. The 760-plus whp run represents the highest the Supra has ever pulled on that tune, which was at 29 PSI on 275/35-18 tires. The lesser one shows my final tune on MKC’s dyno at around 25 PSI, which was the power level I was enjoying on 305/35-18 tires.
The reason the higher PSI graph shows what appears to be a much better spool has to do with the different tire sizes between the two runs (the one in the 657whp run was significantly taller), since this run is plot over “MPH” in the X-axis. We’d show you over RPM, but unfortunately the tach pick-up wasn’t working during one of these runs. But the spool-up over RPM was actually very similar. With the taller tire (blue line, bottom), you’re doing much more MPH at lower rpm, so it appears to be a laggier setup because you’re at a higher MPH. It's laggier by MPH, sure, but it's actually a tiny bit improved in the RPM–like when you test in a higher gear.