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.
On the back of this testing this unit, we’d have no trouble recommending the 5530R as a solid 400kw turbo - ideal for street and track 2.0 - 3.0 litre engines looking for big area under the curve. We've proven this wheel geometry to 40psi, so you're likely to make its rated power on a range of engines with the right supporting mods and enough boost.
The New All-Rounder
72lb/min 58mm compressor & 55mm turbine (R-5830)
Just a short while later James had the 5830-R bolted down and gave us the green light to push on.
Moving up to the 58mm compressor whilst retaining the same 55mm turbine on the 3 litre proved to follow a very similar static response curve - the 5830 was still able to deliver any commanded boost from 3000rpm after a few seconds. Part of this is simply the efficiency island being close enough for the compressor to grab onto if the turbine and housing combo can deliver enough wheel speed. Once the wheel rolls in to its sweet spot, boost climbs rapidly if it's unhindered by surge or other losses. For the 3 litre, the 58mm wheel was still happy to come in strong and quickly at low speeds - making over 30psi from 3000rpm without a peep or whistle.
First run on gate pressure net 395kw at 15.5psi showing that the 5530s’ 55mm wheel measured similar efficiency at these low pressure ratios and that both the 5530 and 5830 can move some serious air mass at low boost. With the ECU in open loop control it was easy to quickly throw large numbers at the wastegate solenoid and increase boost between runs. Dialling in %30 duty with some top end correction showed 440kw easily. Another run in with a serving of duty we were at 460kw. The next 15kw came a little harder, with some fuel touchup and the the gate pegged shut by 6500rpm the car produced 475rwkw @ 25psi in the top end, with a ripper torque curve and great power for a street driver 3 litre Supra.
The advantages of the 5830s’ compressor and the latest enhancements became evident at low engine speed where the small turbine was able to drive the compressor to high pressure ratios. What we saw in practice was that this compressor will go where ever the turbine can take it - sitting happily at 25psi+ @ 3000rpm in steady state testing.
With sloppy machine work or a mismatched compressor - the first casualty is always low RPM, high pressure surge resistance. As boost builds, the pressurised gas is looking for any reason to push back out through the shroud edge of the compressor wheel. The higher the boost goes at a given mass flow - the closer a compressor gets to surging. As a wheel approaches its surge zone to the left of the compressor map, efficiency suffers and the wheels blades seem to loose grip on the charge air. Even if it's not surging, it's sapping exponentially more energy from the turbine wheel - a tax the engine is paying via volumetric efficiency loss. Once there’s some flow instability the wheel shifts into Star Wars mode - a characteristic noise we're all familiar with.
Compared with the 55mm variant, the 5830R showed around a 300rpm spool penalty but gained around 45rwkw. We all agreed that a print over 470rwkw makes this a potent turbo which suits a range of engines from 2 litres displacement up. Even though the cold side is 72lb/min capable, it showed a wide surge margin and an exceptional operating range - qualities that make this reverse staggered cold hot turbo an exception to the rule.
With mid RPM gate duty floating at around %65 and the top end pegged at %90, we definitely felt the compressor had a few more mass pounds to push. After a quick back of the envelope, it was clear we would could go much further with the 7mm larger 5835R hotside.
Contender for Best All-Rounder
72lb/min 58mm compressor & 62mm turbine (R-5835)
We strapped the bigger 5835 on, took a break to check over the car and arranged a bite to eat. Dicing over some good local food we came to a consensus that 500kw was the minimum acceptable power from the 5835R. Rick and James both caught send-it fever and the pressure mounted..
A base line pull with no duty showed the big turbine doing its thing, up a full 25kw at gate pressure and putting down 425rwkw @ 17.5psi. With the 58mm compressor and 62mm turbine wheel in an 1.06 open T3 turbine housing, both the cold side and now the hot side felt perfectly matched for the engine. Off boost the transients into boost felt crisp and linear, complements of the compressor tipping into its efficiency island quickly. With a roll of the throttle pedal from 3500rpm, the 5835 quickly ramped up to full torque within a second under any kind of steady state testing - the bump up to a larger 62mm turbine not really felt with the transients.
Cranking the wastegate duty in the mid-range and comparing it to the 5830R we saw the same torque at 3psi less boost over the smaller 55mm turbine wheel - a clear testament to the difference improved turbine side total efficiency can make to engine breathing.
After a quick re-strap and re-fuel, we gunned to made the 500kw print and more. With top end gate duty pegged at %90, the smaller than mid-ship 5835 pushed an clean and snatch 515rwkw - over 690 whp - at 27psi through the Supras' rear tires. Mixtures on the rich side left us with no doubt there's a 700whp+ print hiding there for anyone willing to look for it.
Having reached our goal and in the interests of time, the boys unstrapped our new favourite Street Car turbo. The time was here to make our way into what felt like more common Supra turbo size territory.
The 62mm Challenger
83lb/min 62mm compressor & 62mm turbine (R-6235)
Rick initially floated the idea of a mid-ship '35' frame 62mm compressor turbo about a year ago. Spotting a gap in the market for a quality watercooled 62mm turbo it was a no-brainer. We knew we could stretch a 62mm compressor over 83lb/min mass flow and well into the 500rwkw region on Ethanol. Looking back with hindsight - that was a good call given the 5835's performance. With some geometry tweaks we settled on a high speed compressor design that would ultimately end up paired with the 62mm turbine wheel. This well engineered piece becomes our first and only production 62 comp 62 turbine turbo.
Having started our day at a 3am to make early flights, we decided not to light the other end of the candle and knocked off early. This left something in our tanks for another long day of testing. By early evening we had made it through half of our turbos comfortably - and apart from a couple of galled stainless steel manifold adaptor studs - the day went without incident. James' rain dance had worked and the humble stock block 2J took anything we threw at it like a champ.
Loading up the 6235 for the first time, the lag penalty over a 5835 wasn't drastic. It still felt linear and sharp strapped to the 3 litre motor. Static tests showed a slower 'time to boost' but the same final boost numbers at low rpm. The 62mm compressor still managed run-away boost with the gate shut from 3000rpm and needed more than a few stabs added to the VE table above 15psi throughout the RPM range. The results of added cold side efficiency showed immediately - with the 6235 pushing out the highest base pressure power run so far at over 445rwkw, 17.5psi.
Primed with good feels, successive runs saw the power output rise as fast as we could throw wastegate duty at it. Easily surpassing the 515 mark set by its smaller 5835 counterpart - our newest favourite street turbo still had plenty of gate duty in the tank. Between 20 and 25 psi of boost the 6235 traversed what could be aptly described as a Goldie Locks Zone of turbocharging. Gobs of power per pound of boost.
With the top end wastegate duty all in and a thorough watering in the mid-range - the 6235 punched out more power than we expected. Our new underdog was able to surpass the 550rwkw mark and bring home 556 solid kilowatts at 29psi of boost.
Having taken the 6235 so far, the questions mounted - would the 6535's 3mm larger compressor take the 62mm turbine any further on a 3 litre stock head engine? Or did the 62 comp have more in it?
Big, Small Frame Performance
88lb/min 65mm compressor & 62mm turbine (R-6535)