Project MKIV Supra: Part 15 – Preliminary testing of the Precision CEA 6870 Gen2 turbo.

Project Supra is rockin’ a built 3.0-liter using JE Pistons, K1 rods, and ARP studs, and was built by FRP Performance and MKC Performance in Kansas City. The head features Ferrea valvetrain, Titan 272 cams, AEM cam gears, and ARP head studs. The PTE CEA 6870 Gen2 turbo pumps air through an ETS 4-in intercooler and Hypertune intake manifold, and out a PHR S45 exhaust manifold and MKC-built 3.5-in exhaust system. The car is flex-fuel tuned by MKC using AEM’s Infinity EMS. Today we get a glimpse as to how well all of this stuff puts power to the ground, including with a speedo video!

Project MKIV Supra: Part 15 – Preliminary testing of the Precision CEA 6870 Gen2 Turbo

(and some little things that count)

by Pablo Mazlumian

In Part 14, you probably noticed my excitement as I moved past the fantastic Precision CEA 6766 turbo—a turbo I probably could have stayed with forever—to PTE’s latest mid-power turbocharger, the CEA 6870 Gen 2, which features a 1mm larger compressor wheel, but also a turbine wheel which is a significant 4mm larger. I’ve had plenty of time to enjoy the car, and it’s been running flawlessly.


Here’s a look at the compressor side of the Precision CEA 6870 Gen 2, featuring a 68-mm Gen 2 compressor wheel. The back end is 70-mm turbine wheel.

Since our PHR S45 exhaust manifold features a divided flange, we got a 1.00 AR divided housing. We chose a 1.00 over a 1.15 this time to counter any increase in lag over the outgoing CEA 6766 turbo. The white coating is Swain Tech's White Lightning coating. We've also got the PTP turbo blanket on top of that.

The only issue of today is that we will not be able to communicate with the AEM Infinity EMS because the serial port may be slightly damaged. Having not reinstalled the EMS with the factory Supra metal backing plate behind my passenger’s footwell, I fear repeated pressing of the floorboard—a natural reaction of the passenger due to the acceleration rush—may have bent the port a little bit since we keep the wire plugged in.

While it’s my bad, it still hasn’t eliminated the possibility of driving the car. The only problem is, I can’t get it tuned to better suit the turbo. But, with the AEM Infinity tuned by Chad Charlton at Modified by KC, that’s okay for now because the ECU is tuned for the same E85 fuel I have been and will be using, and using volumetric efficiency, which adapts to the increased air flow just fine.  In fact, the car hasn’t had a hiccup yet, and it’s been pushed pretty hard!

The downside to all of this is the fact that I can’t raise the boost while on the dyno to see what it really does.  On the street, when the weather is cooler than 65F, the CEA 6870 Gen 2 is set to a wicked 30 PSI boost.  When the weather reaches around 95F, it drops to around 25 PSI. With everything in between, the boost drop is fairly linear and predictable.

On the dyno, however, without the load of the car’s weight and the fact it pushes against air, the boost is dramatically different. To duplicate the boost on the road, you have to turn it up on the dyno (and vice versa when you leave the dyno unless you plan to drive with significantly more power than tested with on the rollers!).  Still, this didn’t stop me so I called up MKC Performance so I could at least give us all an update with the gist of how the car is running.

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