Here is a comparison of Project Supra’s runs with the PTE 6766 CEA Ball Bearing turbo at different boost levels, starting with 17 PSI (wastegate), 22 PSI, 25 PSI, 29 PSI. Going much higher won’t give us the same marginal rate of return up top because we’re getting closer to the limits of the PTE 6766 CEA Ball Bearing turbo, which seems to be somewhere around 900 WHP, although it's rated to 935 BHP.
The fuels used were as follows:
Blue: 17 PSI (wastegate spring), pump 93
Red: 22 PSI, 54% ethanol
Green: 25 PSI, 64% ethanol
Purple: 29 PSI, 80% ethanol
My experience with dyno testing has always shown that if you leave a car tuned the way it was on the dyno, you're probably going to see 2-3 more PSI boost on the tarmac, which in our case we were seeing around 32 PSI. It's way too much torque for these not-so-tall BF Goodrich 295/35-18 G Force tires, and fourth gear was rarely hooking up unless it was 75F-plus outside. So, I dialed out about 40 kPa from the tune (or about 6 PSI) from where it was. Another reason I dialed out some boost is to give me some room for error, because I really want to make this motor last a very long time. Still, 26 PSI is good for over 750 WHP and 575 LB-FT of torque. That's plenty for me to manage now, and we're off to get the AEM Infinity's Traction Control next, but I've first got to get new wheel speed sensors. Notice how you can also tune for boost by gear, which we'll play with soon as well.
Here's one of the main stars of the power show, the Precision Turbo and Engine 6766 CEA Ball Bearing turbocharger, featured in Part 5. It's got a 67-mm billet compressor wheel with a 66-mm turbine wheel, and a divided 1.15 exhaust housing. It's also rated at 935 BHP.
For those looking to run a turbo class limited to a 67-mm compressor, but are looking for an extra 150-plus horsepower over what the PTE 6766 CEA Ball Bearing turbo can give, PTE also has its 6785 CEA Ball Bearing turbo, which uses a significantly larger turbine and is rated at a whopping 1100 BHP. Even more surprising, I've already seen a dyno graph proving this 67-mm turbo is good for over 1000 wheel horsepower!
In the same 1100 horsepower family, PTE also recently released the PTE 6870 CEA GEN2 Ball Bearing turbo, which uses a 1-mm larger compressor wheel and 4-mm larger turbine than our PTE 6766 CEA Ball Bearing turbo. PTE claims the same 1100 BHP, but I've already seen graphs from two different 3.0-liter Supras on two different dynos, and the both of them also registered well over 1000 WHP with the PTE 6870 CEA GEN2. This is crazy!
To show you how far along our engine has come even aesthically, this is what Project Supra’s looks like now. It's full of polished parts by Power House Racing, and custom fuel and vacuum lines by Modified by KC using Aeromotive fittings. Oh, and we can't forget that pretty intake manifold and throttle body by the well known Australian outfit, Hypertune.
See? It's got a nice curve. The fact that it runs a similar turbo setup and makes very similar numbers to our own Project Supra makes me want to compare the two graphs. Oh why not. Let's see how they compare on the next page…