Which Kelford Camshaft is Best for me? | 600-850hp 2JZ Testing
Q: I have a 3.0L 2JZ with a Precision Turbo 6466. What cams and boost are best for me? How much power should I expect?
A: With a 6466, we’d select the T202-C i264°/e272° 9.90mm camshafts and target ‘pump-gasoline’ usage with boost in the 14-21psi range, expecting incredible response and:
14psi for 620hp / 480tq with <1.2:1 Engine Pressure Ratio
21psi for 750hp / 575tq with <1.3:1 Engine Pressure Ratio
28psi for 850hp / 700tq with <1.5:1 Engine Pressure Ratio
*Gasoline power production may be ~5% lower with slightly lower exhaust pressure.
2JZ Engine Dyno Testing
Purpose:
Real St.’s mission is to catalog various build stages and questions encountered by our customers’ most common engines and platforms.
The stock-stroke, un-ported cylinder head Toyota 2JZ-GTE and the Precision Turbo 6466 Next Gen are two very common choices in the racing community given that the 2JZ’s cylinder head can support in excess of 1,000hp without porting.
Precision Turbo’s 6466 Next Gen Turbocharger is its most powerful offering ever for the 66mm Turbine Wheel. The 66mm Turbine wheel was released in late 2012 along with the then-newly-released Gen2 64mm Compressor wheel. The turbine was an evolution of the P-Trim and F1-65 turbine wheels of 30 and 20 years ago respectively. When the motorsports community began embracing these size turbochargers, this size turbine wheel was previously called upon for 600-650hp sort of applications. The 6466 Gen 2 spent 12 years being one of the industry’s most called upon units until the Next Gen’s release last year.
Now, the 64mm Next Gen compressor wheel is rated at an astounding 1,000hp. Given this new capability, we want to help the market understand how to most efficiently and reliably utilize these products.
We aim to accurately conduct repeatable tests on our varied engine combinations while striving for operation under similar circumstances. Furthermore we aim to present the community with easy-to-understand and informative education in order to make informed decisions for their needs.
To do this, we need to first present the conditions at which the tests were conducted:
Intentional Starting Variables:
Test 1: Kelford T202-B Camshafts (260* Adv. Dur. / 9.60mm Lift)
Test 2: Kelford T202-C Camshafts (i264*/e272* Adv. Dur. / 9.90mm Lift)
Test 3: Kelford T202-D Camshafts (i272*/e278* Adv. Dur. / 10.20mm Lift)
Test 4: Kelford T202-F Camshafts (i282*/e286* Adv. Dur. / 11.25mm Lift)
Constants & Conditions:
Engine: 3.0L 2JZ-GTE w/ 9.0:1 C/R w/ Unported Cylinder Head
Turbocharger: Precision Turbo 6466HP Next Gen
Exhaust Housing: T4 Divided 1.15 A/R
Exhaust Manifold: Artec Cast T4 Divided
Intake Manifold: Plazmaman w/ 72mm Throttle Body
Intercooling: Plazmaman Air to Air
Fuel: One Ethanol 112S
Dyno: Superflow SF-Powermark
Engine Acceleration Rate: 600 rpm/sec
Conditions for Run 1: 4,000-8,000rpm & 100kpa (14.50psi) Target
Conditions for Run 2: 4,500-8,000rpm & 150kpa (21.75psi) Target
Conditions for Run 3: 5,000-8,000rpm & 200kpa (29.00psi) Target
Conditions for Run 4: 5,500-8,000rpm & 250kpa (36.25psi) Target
Avg. Starting Oil Temp.: 191.1°F (88.4°C)
Avg. Starting Water Temp.: 176.6°F (80.3°C)
Avg. Starting Ambient Air Temp.: 84.7°F (29.3°C)
Unintentional Starting Variables w/ >10.00% Deviation:
Avg. Density Altitude: 1,775’ [1,484-2,076’]
Test Notes:
We utilize a SuperFlow SF-Powermark Engine Dynamometer for our testing. This is a high-capacity water brake dyno that precisely controls load and speed of the engine using SuperFlow’s automated closed-loop systems to test high-output engines up to 15,000 RPM and over 2,500 HP.
For these tests, we looked to test the 6466 at various boost levels as we look at how the 66mm turbine wheel copes with the flow capacity of its 64mm compressor wheel. We also examine the affects of moving to larger camshafts by targeting the same boost levels for each test and showing you the differences in how the engine breathes.
The way an engine dyno operates and the data that we’re able to achieve is not always directly comparable to a chassis dyno. On a chassis dyno, the vehicle’s various components are still in play - torque converter, traction, etc. On an engine dyno, since we can load the engine at any RPM we want (even at idle), you cannot directly compare the early powerband of an engine dyno to a chassis dyno due to the elimination of those variables that affect spooling characteristics.
The entire turbo system remained the same between the four camshaft tests. All tests were performed through an Artec divided T4, twin-gate, exhaust manifold, through a Plazmaman air-to-air intercooler and a Plazmaman street intake manifold with 72mm throttle body on One Ethanol 112S fuel.
Results:
The 6466 with a Kelford C cam is a great combination. This camshaft picked up ~20hp everywhere at the same boost as the B cam, and with the still-mild specs of the cam, there should be negligible loss in low rpm driving characteristics. The T202-C is a 264* Intake / 272* Exhaust duration camshaft with 9.90mm of peak lift. The B camshaft produces nice predictable behavior, and we bet that a turbo or application more geared to ~600hp would prefer this camshaft.
Here you can see the Run 1 and 2 Results
6466HP NG T202-B Run 1: 587.5hp @ 7,300 & 13.5psi (20.98hp/psi) with 468.5tq
6466HP NG T202-C Run 1: 605.2hp @ 8,000 & 13.2psi (21.85hp/psi) with 469.3tq
6466HP NG T202-B Run 2: 728.1hp @ 7,900 & 20.2psi (20.98hp/psi) with 576.9tq
6466HP NG T202-C Run 2: 750.7hp @ 7,600 & 20.0psi (21.76hp/psi) with 583.4tq
Wow, over 21hp/psi! So at 36.25psi boost, that should be over 1,050hp. Can we just keep turning it up?
No, not really. While the flow from the 64mm compressor wheel is astounding, it is still moving through that same turbine that used to be called on for 750-850hp type of work, so the exhaust pressure will increase as the boost continues to be turned up, which is going to start to reduce our power production efficiency.
Here you can see the 6466’s Exhaust Pressure with the T202-C in Run 1, 2, and 3.
T202-C Run 1:
Power: 605.2hp @ 8,000rpm & 13.2psi
Peak HP Production: 21.85hp/psi @ 8,000rpm
Exhaust Back Pressure (& Pressure Ratio) @ Peak Power: 15.5psi (1.17:1 PR)
8,000rpm Exhaust Back Pressure: 15.5psi
8,000rpm Engine Pressure Ratio: 1.17:1
T202-C Run 2:
Power: 750.7hp @ 7,600rpm & 20.0psi
Peak HP Production: 21.76hp/psi @ 7,600rpm
EBP (& PR) @ Peak Power: 24.3psi (1.22:1 PR)
8,000rpm EBP: 26.1psi
8,000rpm Engine Pressure Ratio: 1.29:1
T202-C Run 3
Power: 879.3hp @ 7,100rpm & 28.7psi Boost
Peak HP Production: 20.35hp/psi @ 7,100rpm
EBP (& PR) @ Peak Power: 34.9psi (1.22:1 PR)
8,000rpm EBP: 39.7psi
8,000rpm Engine Pressure Ratio: 1.48:1
Here you can see the power graphs of the three runs above as well as the best attempt we had at the 250kpa target. This had a slightly elevated boost target over our other tests, but the elevated exhaust pressures made the system difficult to control.
You can see that as you request more air and fuel to travel through the same size space (turbine) its pressure increases. Also of note, the peak power production seems to keep moving back since we are crossing 1:1 pressure ratio earlier and earlier when we run the turbo harder.
The boost controller / manifold / wastegates all struggled to keep the boost target maintained, and you can see where the pressure was overwhelming the system. While there are methods to try and force the gates closed, and we were employing some of them here, we are demonstrating this to show you that this is probably not the best operation for this turbo.
T202-C Run 4:
Power: 922.3 @ 6,400rpm & 37.7psi
Peak HP Production: 17.67hp/psi @ 6,400rpm
EBP (& PR) @ Peak Power: 42.3psi (1.12:1 PR)
8,000rpm EBP: 65.5psi
8,000rpm Engine Pressure Ratio: 1.94:1
Okay so if my turbo is best suited for 700-900hp, could cams make it better?
So here we’re showing you the 6466 at 150kpa and 200kpa targets with the C and D cams. This is where the bulk of people will be using the 6466 on these engines, so this is where most people will focus.
You can see that even with the longer duration and higher lift of the D cams, there was not a substantial increase in power production at either of these boost levels. At the point that reducing vacuum and changing the breathing of the engine doesn’t pick up a noticeable amount, it doesn’t seem to be the right move for this combination.
Interpreting these results:
All in all, our recommendation and takeaways from the 6466 portion of this test are that it’s a fantastic turbocharger capable of taking the 66mm turbine family to previously unheard of power levels for people pushing the boundaries. Even at our 250kpa testing on the larger cams, we did not reach the speed limit of the turbocharger, so this compressor wheel on a smaller engine like a SR20, B18, or the like would be outstanding, even at higher power levels than suit this 3.0L application.
For the 2JZ, this continues to offer the 66mm turbine family and incredible amount of capability for the response it offers. This turbocharger may benefit from a larger turbine housing, but the turbine wheel itself is still the main pinch point of the system. The 2JZ shows that it welcomes the larger lift and duration from the C camshafts even at 13-15psi & 600hp levels. Further testing of applications in that range is needed to optimize the combination. But for now, those with 6466 Next Gen and Gen 2 units should feel good about operating their systems in this window, and can use these results to help figure out if they have an appropriate camshaft for their combination.
Special Thanks to:
Kelford Cams & Precision Turbo for their willingness to test and experiment to answer these questions with us, as well as Plazmaman and Artec who both contributed products used in this test.
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