If you followed the NR series, there were no turbocharged engines up until the birth of the 8NR-FTS, which opened for more possibilities for this series. However, with its emergence, the engine received different comments regarding its characteristics and antics.
As part of the Toyota inventions, the engine somehow proved itself to be a reliable engine. Let’s have a look at this 8NR-FTS engine.
The Toyota NR engines, which have four valves per cylinder, also employ multi-point or direct fuel injection. Dual VVT-i is standard on the 1NR, 2NR, 3NR, 4NR, 5NR, 6NR, and 7NR engines, while VVT-iW is standard on the 8NR engine, which allows it to function in both the Otto and modified-Atkinson cycles to increase thermal efficiency.
As the name indicates, the 7NR-FE engine is a member of the NR family of engines. Toyota’s NR engine family includes a range of tiny inline four-cylinder engines with capacities ranging from 1.2 to 1.5 liters.
What are Toyota 8NR-FTS Engines?
The Toyota 8NR-FTS engine is a notable member of the Toyota NR family. Perhaps not because of its tail-end production but because it is the only factory-fresh turbocharged engine in the family. Though the other NR engines can be bolted or installed with turbos, it does not come straight from the factory.
It is also capable of running in Atkinson/Miller cycle.
The thing with the 8NR-FTS engine is that it has lesser thermal efficiency in comparison to other NR engines, which is 36 or more. But that does mean that the 8NR-FTS is inferior in this category. To be fair, the 8NR-FTS consumes lesser fuel with a higher output.
As we can see in the numbers and records, the maximum power output of the turbocharged 8NR-FTS engine is far larger than the 1.5L variant of the same family. Putting more emphasis on the fact that the 8NR-FTS requires less consumption for a higher power.
It also reaches its peak power earlier, in RPM, over other NR engines.
The numbers displayed and shown by the 8NR-FTS engine are enough to satisfy and silence the doubters of this engine. Some roadside experts have complained, though, for maybe the lack of understanding of this engine. But, with its smaller displacement, it is a compact engine with monstrous output.
Other engines of the same capacity show less performance. So, it is a win situation.
Further, this engine has the same characteristics as other NR engines with some tweaks and developments to cater to the needs and to eliminate some issues prior to the latest release.
Engine Specifications and Design:
- Production Run: 2014 – Present
- Cylinder Head Material: Aluminum
- Cylinder Block Material: Aluminum
- Configuration: Inline 4
- Bore: 71.5 mm
- Stroke: 74.5 mm
- Valvetrain: DOHC four valves per cylinder
- Displacement: 1.2 L (1197 cc)
- Compression Ratio: 10.5
- Weight: 190 lbs.
- Maximum HP: 114 HP at 5,200 RPM
- Maximum Torque: 136 lb-ft at 1,500 RPM
The motor of this engine is completely different than any other in its series. It has a strengthened cylinder block, and Toyota also implemented a variable valve timing system VVT-iW. Not only that, the engine is capable of running in Miller and Atkinson cycles.
The engine has eight counterweights, a supply pump driven by the additional cam of the intake shaft. On top of that, the engine has a vacuum pump driven by the exhaust camshaft used for brake booster operation and turbocharger control.
The cylinder head is made from aluminum topping it off with the exhaust manifold integrated into it. Toyota also applied sodium-cooled valves for this.
Crankcase Ventilation System
The term “boost” refers to an increase in the volume of crankcase bypass gases and the inability to use them using the standard way of employing the intake vacuum. As a result, the ejector is located in the headcover so that in boost mode, hydrocarbon-rich gases do not escape into the atmosphere but instead return to the intake and burn in the cylinder.
Another separator chamber has been added to the crankcase.
Crankcase gases are expelled via the ejector to the intake in the boost mode. The ejector acts on the Venturi principle – crankcase gases are drawn into the stream of flowing compressed air. Without a sufficient boost, crankcase gases are sucked through a standard PCV valve.
Miller and Atkinson Cycle:
In the Miller cycle with decreased compression, the inlet valve closes much later than in the Otto cycle, causing some of the charge to be returned to the intake port and the real compression process to begin in the second half of the stroke.
As a result, the effective compression ratio is smaller than the geometric compression ratio, which, in turn, is equal to the expansion ratio of the gases at the work stroke. Reducing pumping losses and compression loss increases the thermal efficiency of the engine by around 5-7 percent, as well as the equivalent fuel economy.
By the mid-2010s, new engines with a broad range of variable valve timing (VVT-iW) that can run on both the Otto and Miller cycles were released. When the geometric compression ratio is 12.5-12.7, the range of intake valve closure is 30-110° ABDC in atmospheric versions, and 10-100° and 10.0 in turbo variants.
The VVT-i technology or Variable Valve Timing – Intelligent allows the valve timing to be changed smoothly in response to engine operating circumstances. This is accomplished by moving the exhaust camshaft relative to the driving sprocket by 50-55° or more commonly addressed as the crankshaft rotation angle.
Two thermostats are installed in the engine. The first is the traditional thermostat in the water intake, which has an opening temperature of 176-183°F regulating the coolant flow through the radiator. And another thermostat on the cylinder block has an opening temperature of 169-176°F, regulating the coolant flow through the block, allowing for rapid warming.
The built-in cylinder head exhaust manifold cools the exhaust gases before they enter the turbocharger.
The Toyota 8NR-FTS engines are equipped with a fuel injection system. A sort of direct management in the combustion chamber that is coordinated with piston position. The gasoline from the tank pump is delivered to a high-pressure pump, which then pushes it under pressure into the fuel rail and, lastly, into the cylinders through injectors. The injection can be repeated numerous times during the cycle.
At the intake, there is a single-plunger with a control valve, a relief valve, a check valve, and a pulsation damper. Mounted on the valve cover and driven by the camshaft’s four-lobed cam.
Depending on the driving circumstances, the fuel pressure is adjusted between 348 psi and 2900 psi. Further, the fuel rail is made from forged iron. It has a fuel pressure sensor for feedback.
The slotted nozzle injector injects fuel into the cylinder as a precisely shaped spray, drawing in a substantial quantity of air and increasing mass admission. Sealing Teflon rings minimize vibration even further.
Applications of Toyota 8NR-FTS engine:
- Toyota Auris E180
- Toyota Corolla E210
- Toyota C-HR
Problems Surrounding Toyota 8NR-FTS Engines
These are only a few examples of what might go wrong with a four-cylinder engine, especially when it is turbocharged and can operate on multiple cycles.
There aren’t necessarily greater challenges than usual, but they’re worth addressing because many people aren’t aware of these potential hazards yet or believe their automobile is in fine functioning order.
Because of its unconventional and erratic approach as an engine, the Toyota 8NR-FTS engine has become a different engine on its own. However, like any other equipment, it has weaknesses that must be addressed and identified in order to avoid problems later on. Let’s have a look at some of the more prevalent concerns of the Toyota 8NR-FTS engine.
Some of the issues here can be seen at other NR engines since they share most of the issues. Among them are the following:
1. Excessive Soot Deposits
There are instances, and it is also declared as a problem with some engines. It has been discovered that some Toyota 8NR-FTS and other NR engines take longer than the normal time required for ignition but also due to residue buildup within specific components such as pistons.
Excess soot deposits in the combustion chamber, valves, and valve seats can cause compression to be reduced, as this was the case across all NR engines, as we mentioned earlier. This causes the engine to take longer to start, resulting in the display of DTC P1604.
The problem is recognized by TSB EG-00037T-TME as an excessive deposit of this type, which may cause a reduction or loss of power.
2. Excessive Oil Consumption
The most well-known and common problem with NR engines, not only in the 1NR-FE, is high oil consumption, which generally presents itself at less than 60,000 miles. According to Toyota’s usual explanation, the piston rings are trapped.
Although cylinder block reboring is not required, the need to replace pistons and connecting rods at the same time prevents a low-cost engine renewal.
In TSB EG-0095T-1112, oil usage was noted as a source of concern. Early in 2017, production changes were implemented, such as revised rings and pistons with connecting rods, as well as valve cover replacement for those with greasy valves or nozzles.
3. Clattering noise from the Timing Chain area
Another issue that you might need to magnify is the foreign noise in the timing chain are. Well, you may have heard the grinding or clanking sound of your timing chain, which can be an indicator that it needs to be replaced. This is detailed in TSB EG-00039T – Toyota’s technical service bulletin for this issue.
There are two options available; either do nothing or just replace one part by installing a new tensioner arm on top of their already installed engine block without changing any other parts.
4. Rattling or Knocking Noise During Operation
During engine operation, large deposits in the combustion chamber cause a rattling or banging noise. This problem is acknowledged and explained in TSB EG-0094T-0714, which describes some production adjustments introduced at the beginning of 2014 to fix it for good.
The engine’s performance can be dramatically improved with this part’s new, more customized variant. You’ll also want to get your hands on ECU firmware that has been reprogrammed for increased gas mileage and power output.
5. Work mentioning TSBs
- 8NR-FTS Turbo Overboost DTC P023400 EG-00014T-TME
- “Rattle noise from exhaust (front) due to damaged heat insulator bracket,” EG-00105T-TME
- “8NR-FTS Noise from the vacuum regulating valve” EG-00113T-TME
- “8NR-FTS Engine Coolant Flow Noise” EG-00219T-TME
- “8NR-FTS Cylinder Misfire DTC P030100, P030200, P030300, P030400, P030027, P030085” EG-00094T-TME (ignition coils replacement is prescribed)
This applies to 2019-2021 JDM automobiles equipped with an 8NR-FTS engine – Corolla, C-HR. Due to low resistance against pressure, the welded section of the high-pressure gasoline pump may shatter, resulting in fuel leakage. The High-Pressure fuel pump should be replaced.
The Toyota 8NR-FTS engine would be a different kind of machine if you lined it up along with its brothers in the family. For sure, it is the true definition of small but powerful in the takeaways in the NR family. Even with its small displacement, the engine is still impressive on its own.
Having its own turbocharger and pushing the numbers a little bit south of the 150s. It’s safe to say, and also fair, to call this engine the best option on the NR family. However, it does have the issues of the NR engines, but those are easily fixed.