Spoiler alert: The new R-Series Supercore range displayed strong real world performance to match its paper specs - in most cases pushing well ahead of rated power. The new compressor and compressor housing designs brought together excellent low engine speed performance with big millimetre for millimetre airflow potential.
Details of the compressor, turbines and some of the features of the turbocharger range.
Compressor and Turbine
R-5530 - 65lb, 55.0mm 65 TRIM compressor / 55mm 84 TRIM turbine - 675hp
R-5830 - 72lb, 58.0mm 65 TRIM compressor / 55mm 84 TRIM turbine - 725hp
R-5835 - 72lb, 58.0mm 65 TRIM compressor / 62mm 84 TRIM turbine - 775hp
R-6235 - 83lb, 62.0mm 65 TRIM compressor / 62mm 84 TRIM turbine - 850hp
R-6535 - 88lb, 65.0mm 65 TRIM compressor / 62mm 84 TRIM turbine - 875hp
R-6566 - 88lb, 65.0mm 65 TRIM compressor / 66mm 84 TRIM turbine - 925hp Compressor : 55, 58 and 62mm compressors feature 9 blades, 65mm features 10 blades
Turbine : 55, 62 and 66mm turbines feature 10 blades
R-Series Turbocharger Features
* High flow 3D geometry compressor wheels point milled by 5-axis CNC from 2618-alloy
* High strength CNC machined alloy compressor cover backing plate
* High temperature Inconel Superalloy turbine wheels with up-rated shaft assembly
* Dual 9mm, cageless, full complement, angular contact ceramic ball bearings
* Optimised compressor cover with Map Width Enhancement
* Drop in to any 10 blade wheel '30' or '35' size T3, T4, V-band turbine housings inc divided
* 4 inch inlet, 2.5 inch outlet easy weld compressor cover outlet
* Ni-resist housing options available from Intense Turbo soon!
A quick look at the current state of the aftermarket world and there's pretty clear trend with cylinder head flow and peak cylinder pressures - both are increasing over time. The kind of power we saw with a 67mm turbo on race fuel just 10 years ago, we're now seeing with 58mm turbos running ethanol blend.
The demand for compactness and small frame performance isn't showing signs of slowing down. To keep up with these trends and by virtue of the dynamics at play - turbo rotor speeds have increased. Higher rotating speeds equal more demand on the turbo's bearing system and subsequently the turbos cooling system.
With this in mind, we designed the R-series with unique, high speed, high mass flow 65 trim compressors. The range features 9 blades on the 55, 58 and 62mm models and 10 blades on the 65mm. Using forged 2618 alloy base stock, each wheel is point milled into existence using a 5-axis CNC machine.
We designed in a hard working compressor blade that didn't load up at high speed and settled on a 6 radii shroud with complementary hub profile. Gunning for every last point of efficiency, a new compressor cover design featuring enhanced surge resistance and an improved diffuser was engineered.
An Intense Turbo staple, we opted for our tried and tested full complement angular contact style of ceramic ball bearing. These cage less bearings feature a higher ball count and withstand more load than their caged bearing counterparts - making them most suitable for heavy duty aftermarket applications.
We needed a reliable and consistent car with a proven track record for testing. Knowing that the GameOn Motorsport garage wasn't short of these - we hit up James and after a few calls he unwrapped Alex's White MKIV and sent us a thumbs up.
Over the years, Alex's MKIV has proven itself as a staunch test bench for everything Supra related. Still running an original Toyota Japan assembled 2JZ long motor, the head bolts were replaced one at a time with ARP studs to increase clamping force on the factory issue MLS gasket. Standard cams were swapped out for a set of staggered Kelford 264/272 items and Kelford Beehive valve springs. A short, simple but effective list of long motor changes that have proven reliable for a couple of hundred dyno runs above 500rwkw, years of street duty and more recently a good slew of roll racing events above 30psi of boost.
We knew that it'd be difficult to get consistent and reliable runs to the rollers without careful strapping and loading of the tires. Max power runs were pre-loaded by setting start speed at the point where the engine developed around 7psi/0.5bar of boost pressure before feeding in road speed. This allowed the dyno to capture high torque consistently without burning through tires. We also tested and recorded the boost threshold for each turbo at low engine speed - feeling that these numbers may be a good indicator of the street ability of each unit.
Before diving too deep, James stopped everyone, asked for quiet and executed what looked like a rain dance to protect the stock block - then we got to work.
THE NEW INBETWEENER
65lb/min 55mm compressor & 55mm turbine (R-5530)
We initially intended to build this turbo for 600hp with smaller compressor housings, but on the back of testing with our RS-series standard location turbos we opted for a slightly larger comp wheel capable of 65lb/min+ mass flow at usable boost. We knew a 55mm wheel would function well in the big R-series compressor cover and suit a wide range of engines up to its new power designation. A solid 675hp turbo also gave any future '28' size R-series turbos some room to grow into - without leaving too large a gap in our product range.
Bolted to the relatively big 3 litre 2JZ power plant with a 1.06 open housing - and running on mostly corn juice - the baby 5530 rolled off a solid 388rwkw first run in with boost floating around 15psi - enough to put a smile on our faces.
In steady state testing, the 55mm compressor quickly made any target boost up to and over 25psi before 3000rpm - a pretty magic number in the long runner aftermarket manifold world and a serious reason for anyone to explore smaller, lower inertia turbos with larger turbine housings for their engine.
Having had a much larger turbo on it previously, the transient region of the VE table moving through 2000-4000rpm needed dollops of fuel added to stay on target - the mid range leaning right out through 20+psi complements of the smaller compressors early efficiency island.
After adding some duty to fatten up the midrange and reduce boost taper, the 5530 pushed out 426rwkw at 21psi without any additional infill timing or fuel trim. After a few runs in it was evident that the pairing of a mild 3 litre with the 55mm compressor and 55mm turbine would make for a potent street car. Spinning out 25psi from 3000rpm through 5000rpm and tapering it to 21psi at peak power - the engine delivered over 400rwkw for most of its power band.
After only a couple of runs on the board and already punching well over it's rated power - we left it there - no doubt with some horsepower on the table. Despite the already stellar result - we believe a another 10 to 20kw was possible - all in - fuel and timing optimised.