Revved Modification Map: Power Thresholds For Tuning Toyota’s 2JZ

As a relic of an era when the world’s economy was booming and Japan had intentions to design tech-heavy, rapid, plush, and accommodating sports cars, the Supra Turbo and its sturdy engine exemplified the ’90s performance car. The Supra’s 2JZ-GTE is a motor that is lauded in all circles as a force to be reckoned with, powering drag racers into the 6-second range while proving formidable on the road circuit, and the streets. Even the detractors have the odd compliment for the powerplant, since the numbers are hard to argue with, and it is this grand level of technology that has allowed the 2JZ to stay relevant to this day, powering modern drifters, drag racers, and general speed fiends the world over.

The import scene was in its spool-up stage when the Supra dropped in 1993, so it’s high-for-the-time $45,000 price tag hindered its popularity as a tuning platform early on. As the cars hit the used market, or came off of a lease, prices went down and tuning went up. By 1997 or 1998, the Toyota had hit its stride as a tuning star with examples from Craig Paisley, Vinny Ten, Ken Henderson, and others making news with big power and big reliability. HKS and GReddy drove popularity from Japan, while tuners like SP Engineering, PowerHouse Racing, Sound Performance, Boost Logic, Wide Open Throttle Motorsports, Jotech, and many more carried the torch in America.

What made the Supra’s 2JZ-GTE inline-six engine so appealing was its ease of modification, sturdiness, smooth-revving, inline configuration, and distinctive note; full of pops and whistles from the turbochargers. But the most critical factor by far was computing power. The Toyota’s ECU was advanced for the time, but the Supra rose to prominence as the aftermarket’s ability to produce programmed engine control computers made a leap forward in evolution. The stock ECU had the capacity to compensate for power parts as there were piggyback computers that bridged the gap to full stand-alone, programmable-engine-control units. These piggybackers are brutally vague by today’s standards, and they were hit-or-miss back in the day, as some were much more capable than others. Some were horrendous.

Basic Performance Upgrades — Up To 450 Horsepower

The potential was so intoxicating that many modified their 2JZs to make increased power. In many cases the first step forward is often referred to as BPU, or basic performance upgrades. These modifications are quite easy to attain and install, and can net another 60 to 100 whp with some tuning. Moreover, they offer a louder, raspier exhaust note, better throttle response, and a clearer indication of how much potential the engine has. As much as 450 whp horsepower has been seen with BPU modifications, and only for the modest price of roughly $2,000.

The BPU 2JZ is inconspicuous and still powerful enough to outrun most cars.

Also referred to as “boost up” among some of the Japanese tuners, the BPU tuning program revolves around freeing up backpressure and turning up the boost pressure on the stock turbos as well as the factory cams, injectors, and ECU. The exhaust system and a downpipe are the first pieces added, and the reduction of backpressure these offer helps spool the snails a bit faster. With a variety of exhaust systems available, there are plenty of routes to amplifying that wonderful straight-six growl.

At left: 1990's boost control. The HKS EVC has a volume knob (what's up with that?). It also has a low- and high-boost push button. The leading edge tech in the Turbosmart e-Boost2 allows the user to control, monitor, map, and compensate boost. But it can also control water spray, methanol or nitrous injection, manage shift/warning lights, and read/monitor RPM.

Adding a boost controller is the next step. Back in the day, the unit could have been a pedestrian manual controller or a basic electronic controller, but the BPU class includes the more sophisticated controllers with ‘fuzzy logic,’ like the early HKS EVCs. With the boost controller installed, the computer needs to be fooled, to prevent the defensive fuel cut measure, when boosting more than 14 pounds. Adding a fuel cut defender, also known as a boost cut controller, allows the computer to bypass these restrictions and boost to be raised to around 18 to 20 psi possibly. But, this puts the stock CT20s at their efficiency limit. Today, boost control is much more sophisticated with units like the Turbosmart e-Boost2 serving as a boost gauge and a controller that take total command of boost generation.

With a couple of thousand dollars spent, high 10s can be had down the quarter-mile, assuming the tires and chassis are up to snuff. For a few, this is enough, but it’s not often one sees a BPU Supra lurking around, since the next step isn’t exceedingly expensive and the potential is mouthwatering. Moving up to the next stage is increasingly complex, but it’s where the 2JZ’s modern day-credibility is found.

Moving out of the BPU realm begins to take a toll on some of the ancillaries, though most of the engine is robust enough to survive the demands. The injectors and fuel pump both max out at the same fuel flow, and the latter piece is good to about 450 whp. After that, you’re gambling. In addition, dirty injectors can lead to a lean-out situation at this point. Over-engineered for the requirements, the fuel lines are reasonably large and can support up to 500 whp. Fueling isn’t a massive issue at the upper reaches of the BPU stage, but moving into single-turbo territory requires some significant changes to the fuel system.

Big twins have fallen out of fashion, so these days, the most powerful 2JZs tend to use a massive single turbo.

Advanced Performance Upgrades — 600 – 750 Horsepower

Bumping output into the 600 to 700-horsepower range requires some considerable alterations, but the process remains surprisingly inexpensive. In fact, a few reputable tuners will admit that tuning to 500, or to 700 horsepower, costs about the same. How that power is delivered, and its usability, is where the extra money is spent.

With this next stage, the sexiest modification is the single turbocharger. This big, shiny snail not only spruces up the engine bay, but the whooshing sound it produces is so exciting. With modern, twin-scroll turbochargers, quick-spool valves, and the prevalence of E85 fuel, upgrading to a bigger turbo does not necessarily mean eons of lag. In fact, a medium-sized turbo can be as responsive as one would like, assuming the complimentary parts are well-chosen. The Street Torque kit from PowerHouse Racing offers great low-end response, and one of its kits fitted with a 6266 turbocharger “will easily make 30 pounds of boost under 4,000 rpm,” according to Clint Baird, Dinosaur Performance‘s director.

A large single turbo, matching valve cover, and a GReddy intake manifold complement a stylish, but tasteful engine bay.

Full Race out of Arizona fabricates some of the most awesome turbo manifolds on the market. These things are art and it's a shame the turbo gets in the way.

In the case of the computer, “the stock ECU doesn’t work consistently over 450 horsepower, and the overall control and safety a standalone offers makes it a no-brainer,” according to Reid Dawson of Sound Performance, one of Chicago’s foremost Supra tuners. Dawson says there are plenty of advantages to running a standalone ECU, such as Haltech or ProEFI, aside from being able to handle more in the way of boost. The AEM Infinity does just about everything, including rolling anti-lag, flex-fuel accommodation, and launch control. Though the stock ECU (albeit one fitted with a piggyback) can handle some increased boost pressure, it is deemed inconsistent and unreliable. For the single turbo, a piggyback won’t cut it.

Endorsed by TItan Motorsports, Haltech’s Platinum Sport 2000 can tune the 2JZ within a multitude of parameters.

Getting the most out of this new addition requires bigger injectors and a fuel system. For mid-range application, a set of 1,000cc injectors should do the trick, and if a front-mounted intercooler hasn’t been added yet, now is the time to do so.

In the case of the 2JZ, the most important modifications at this stage, pertain to the turbocharging and fueling aspects of the motor. Internally, it is sturdy, though the bottom end is near its limits at the 700 horsepower mark. It turns out that smaller turbos tend to put more strain on the connecting rods, because of their sharp, punchy power delivery. However, a bit of tuning can soften the delivery and remedy this situation. Again, proper tuning is all-important when modifying the 2JZ. So the threshold for upgrading rods and pistons has been reached, and it may make sense to get a beefier crankshaft if you have loftier expectations.

Getting the most out of a 2JZ requires many hours on the dyno.

Typically at this point, bigger cams are added to prevent valve float and increase the width of the powerband. To further widen the powerband at higher revs, an intake manifold is a suggested add-on at this stage as well. Though not totally necessary, most will find that these two upgrades will avoid a drop off at higher revs. Plus, what better way to spruce up an engine bay than with a glossy, hand-crafted manifold? Dawson noted, “an aftermarket intake manifold is one of the best bangs for your buck, as long as you’re content with sacrificing some mid-range.”

GReddy (pictured) and Veilside, a Japanese fabricator, had the most popular large-plenum intake manifolds back in the day. Today there are a variety of companies/fabricators making beautiful sheetmetal manis for the 2JZ.

It seems that, for a street-driven car, there is something of a sweet spot when it comes to power. Kenny Tran of Jotech Motorsports insists that, “750-800 is the best range to aim for, for multiple reasons. One of these pertains to turbo lag. Whereas the biggest GT47 turbos won’t light until 6,000 rpm, a more modestly-sized turbo can be accessed more easily. The tires need to be given some consideration at this point. Drag slicks become mandatory above this power level, and they can be hard to come by in the event of a puncture. Sticking to a more conservative setup allows for the use of off-the-shelf tires and pump gas, and offers the driver some peace of mind.”

Four-Digit Fury — 1,000, 1,250, 1,500 Horsepower And Beyond

Transcending the four-digit mark invites a little more anxiety. Parts that need to be replaced, including the head studs and billet main caps, and a mechanical fuel system needs to be installed. With the internal weak points revised, more boost, fuel, and cooling are required. Making the power is one challenge, but having a sufficiently-wide powerband is another. The most effective 2JZ is one that can provide lots of power, more of the time.

To reach 1,000-plus horsepower, a seriously big turbo is needed. Here, the GT47 turbocharger dwarfs the engine itself.

This is because those big numbers are not so useful if they can only be accessed across 1,000 to 1,500 revs. To improve low-end response, headwork can help the motor produce a little more power off-boost. Similarly, increasing the displacement to 3.4 liters will spool the turbo 500 to 1,000 revs earlier — but it limits how high the motor can rev.

Refining the head to improve flow is one way to make the 2JZ more responsive.

Alternative fuels, like E85, can generate more exhaust energy to spin those impellers and improve low-end grunt, but tuners generally rely on increasing the revs to extending the rev range. If one intends to rev the car to 9,000 rpm, the internals need to be lightened to move that quickly. One thing to consider is that the factory oil pump fails over 9,000 rpm, and it’s around this mark a dry sump system is required. Though some dedicated drag machines are capable of revving higher than that, most 2JZ engines never spin that high.

Making The 2JZ Modern

The 2JZ was designed more than 20 years ago, and it isn’t employing much modern technology. True, Japan received an updated version of the engine with variable valve timing in late 1997, but even still, the motor benefits from some retrofitting. Kenny Tran suggests “lighten up the valvetrain, rotating assembly, flywheel, and clutch. Lightweight wheels, and even titanium wheel studs make a noticeable difference.” With old school tech and a relatively heavy makeup, the 2JZ lacks a little in the response department, and as a result, can feel like an archetypal turbocharged engine if built poorly.

Some of the laggier turbos border on ludicrous.

It seems in order to keep up with modern engines that develop torque across a wide rev range, the 2JZ needs a healthy dose of perkiness. With modern standalone systems, increasing the compression can help the motor make a little extra off-boost and significantly aids response. Quick-spool valves, like those available from Sound Performance, help bring that turbocharger on-line quicker and modern, V-mounted intercoolers help shorten the length of the piping — further improving response.

At the end of the day, the 2JZ needs some work to get running, and, despite the fanfare it receives, it isn’t indestructible. When it comes to improving upon the stout engine, there are parts which support massive power, and other parts which make that power accessible. For instance, the cast pistons are not tolerant of detonation, and should to be replaced with forged units to deal with the increased cylinder pressure. This is one example of a piece which serves to support growing power levels.

On the other hand, the valvetrain is one aspect that isn’t necessary to modify, unless massive power is the goal, but it is an example of one-piece that can improve overall performance. After all, a huge quantity of power that isn’t easily employable is no fun. With the 2JZ, finding those power levels isn’t the tough part, but making them useful is. Whether it be through modern ECU tuning or a clever retrofit of the head, there are plenty of ways to make 600 horsepower feel, and perform, more like 800. To illustrate the importance of a usable powerband and one of the 2JZ’s biggest shortcomings, many people cite an age-old joke, which goes:

“What do a 600 horsepower Supra and a 1,000 horsepower Supra have in common?”

“They both run 12-second quarter-miles.”

About the author

Tommy Parry

Tommy Parry has been racing and writing about racing cars for the past seven years. As an automotive enthusiast from a young age, he worked jobs revolving around cars throughout high school, and tried his hand on the race track on his 20th birthday. After winning his first outdoor kart race, Tommy began working as an apprentice mechanic to amateur racers in the Bay Area to sharpen his mechanical understanding. He has worked as a track day instructor and automotive writer since 2012, and continues to race karts, formula cars, sedans, and rally cars in the San Francisco region.
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