The 2SZ-FE is a four-cylinder, in-line, water-cooled internal combustion gasoline engine. Gas distribution mechanism 16-valve, four valves per cylinder, assembled according to the DOHC scheme.
The rotational movement from the crankshaft is transmitted to the timing camshafts by means of a chain drive. The “smart” VVT-I valve timing system has significantly increased power and torque compared to the first engine in the family. The optimal angle between the intake and exhaust valves (the letter F in the name), and the electronic fuel injection system (letter E), made the 2SZ-FE more economical than its predecessor.
Characteristics 2SZ-FE Engine
|Length Width Height||3614/1660/1499 mm|
|Engine volume||1.3 l. (1296 cm/cu.m.)|
|Torque||122 Nm at 4200 rpm|
|Engine resource before overhaul||350,000 km|
2SZ-FE Specifications and Performance Summary
Here, we will investigate the characteristics and characteristics of this engine by referring to the data of the 2SZ-FE type naturally aspirated engine installed in Toyota’s SCP90 type Vitz F 2009/08 model.
2SZ-FE type naturally aspirated engine specifications
Toyota’s SCP90 type Vitz
|Vehicle model||DBA-SCP90 type|
|Car name & grade||Vitz |
|Inner diameter × stroke||72.0mm×79.6mm|
|Bore stroke ratio||1.11|
|Single cylinder volume||324.1cc|
|Intake method||Naturally aspirated|
|use fuel||Regular gasoline|
First of all, as a basic structure, the 2SZ type engine is a long stroke type engine with a bore (inner diameter) of 72.0 mm, a stroke (stroke) of 79.6 mm, and a bore stroke ratio of 1.11 (the stroke amount is larger than the piston diameter).
When the displacement and the number of cylinders are the same, the engine has better torque characteristics in the low rpm range than the short stroke type and is easy to handle, but in the high rpm range, the filling efficiency deteriorates and the sliding resistance increases. There is a concern that the output will drop.
Moreover, when the number of revolutions is the same, the average piston speed tends to be higher than that of the short stroke type, so the load on the engine tends to be heavier.
Among the models registered on this site, the oldest model equipped with the 2SZ-FE type naturally-inspired engine is the first Vitz [SCP13 type | 2004/04] released from 1999/01, and the newest model is.
It is the second generation Vitz [SCP90 type | 2009/08] released from 2005/02, and all 4 models of NA cars are registered, and turbo / SC cars are 0 models.
Evaluation from the viewpoint of transient characteristics and liter equivalent horsepower
|Image of engine performance curve|
|Changes in horsepower||65.9PS → 87PS|
|Transition of torque||11.8kgm → 10.4kgm|
Vitz’s in-line 4-cylinder 1296cc engine with a compression ratio of 11.0 and regular gasoline specifications, which is the reference vehicle for this time, produces a maximum output of 87 horsepower at 6000 rpm and a maximum torque of 11.8 kgm at 6000 rpm.
If you know the horsepower and the number of revolutions, you can know the torque, and if you know the torque and the number of revolutions, you can know the horsepower. The torque at 6000 rpm is 10.4kgm.
The horsepower per liter of displacement is 67.13PS / L and the torque is 9.1kgm / L, and the horsepower per cylinder (single cylinder volume 324.1cc) is 21.8PS and the torque is 3.0kgm.
When the 2SZ naturally aspirated engine is applied to a 10-step evaluation based on the deviation value aggregated from all NA vehicles registered on this site, the evaluation is ” standard ” with a converted horsepower of [ 5 ] and a converted torque of [ 5 ]. It is categorized as an engine with a typical output (bottom of the middle).
Displacement increase, compression ratio increase, bore stroke ratio change
|Normal displacement and compression ratio|
|Bore||Stroke||Displacement||Compression ratio||B/S ratio|
|Displacement expansion by bore up|
|Displacement expansion by increasing stroke|
There are three factors that determine the engine displacement: the number of cylinders, the bore diameter, and the stroke amount. By increasing or decreasing these, engines with various displacements are created.
Here, regardless of whether it is actually possible, the displacement when the piston diameter is expanded from the genuine 72.0 mm to 75.0 mm in 0.5 mm increments and when the stroke is extended from the genuine 79.6 mm to 84.6 mm in 1 mm increments. And, the change of the compression ratio when it is assumed that the combustion chamber volume does not change is listed.
* It is easy to say stroke up, but if you want to make a long stroke, you need a crankshaft and a compatible connecting rod, and if you can not divert it, you have to make it in one-off, so it is expensive anyway. It is a menu that requires considerable preparedness to put out.
Regarding the compression ratio, in most cases, the uneven capacity of the top surface of the piston changes as the diameter of the piston increases, so the compression ratio values in the list do not match, but the displacement. Please enjoy the atmosphere that the compression ratio will naturally increase as you increase the size.
B / S ratio is an abbreviation for bore stroke ratio, and as the bore diameter is widened, the characteristics of the long stroke type, square type, or short stroke type are approached. In the case of 2SZ type engine, the ratio changes from 1.11 to 1.06 when the bore is increased by +3.0mm from the genuine piston.
Increased displacement with engines with similar piston diameters
There are 45 engines with pistons that are close in size to the 2SZ type engine with a piston diameter of 72.0 mm, so let’s calculate the displacement when the piston is diverted and the bore is increased as a sideshow.
|Eg type||Piston diameter||Displacement|
For engines with similar piston diameters, Honda: L15B type 1496cc 73.0mm mounted on RW1 type CR-V, Mitsubishi: K12C type 1242cc 73.0mm mounted on ZC83S type Delica D: 2, Honda: RU3 type Vezel LEB type 1496cc 73.0mm mounted on Honda: L15A type 1496cc 73.0mm mounted on GE8 type Fit, Mitsubishi: K12B type 1242cc 73.0mm mounted on ZC72S type Delica D: 2, Honda: ZF2 type The LEA type 1496cc 73.0mm mounted on the CR-Z is applicable.
(Although the number of people who find pleasure in such a quest has decreased) No matter how close the diameter is, there are factors such as the diameter of the piston pin, the height of the piston, and the convenience of valve recess, so if possible, the same manufacturer, If possible, if you choose the same fuel and the same intake method, and if possible, the one with a similar displacement, the possibility of genuine diversion may increase.
Average piston speed
Next, let’s look at the average piston speed. The average piston speed at 6000 rpm, where an engine with a stroke of 79.6 mm produces maximum output, is 15.9 m / s , which is a piston speed that travels a distance of 15.9 meters per second (57.2 km / h at speed). It means that is moving up and down.
The average speed is 17.2 m / s at 4000 rpm, which produces the maximum torque, and 17.2 m / s when 6500 rpm, which is 500 rpm higher than the 6000 rpm where the maximum output is generated, is assumed to be the rev limit.
For reference, I calculated the change in piston speed when a 2SZ engine with a stroke of 79.6 mm is rotated up to 10000 rpm. Looking at this, it seems that the speed increases by approximately 5.30 m / s as the number of revolutions increases by 2000 revolutions.
Considering only 20.0 m / s, which is a guideline for general engines assuming mass production, it is mechanical to set the upper limit of high rpm to about 7540 rpm (whether it rotates or not). It seems to be preferred both mentally.
2SZ-FE Problems and Reliability
- The toyota 2SZ-FE engine retained atypical design features more suited to Daishitsu designs than Toyota. In the early 2000s, most series acquired lined aluminum cylinder blocks, with additional air cooling fins. The undoubted advantages of such a solution – simplicity, and therefore low cost of manufacture, as well as low weight compared to competitors’ engine, made us forget about one thing. About maintainability.
- The 2SZ-FE cast iron cylinder block is designed with enough strength and material to carry out a full overhaul. Excess heat resulting from the long stroke of the pistons is successfully dissipated by the massive engine housing. The longitudinal axes of the cylinders do not intersect with the axis of the crankshaft, which significantly extends the service life of the piston-cylinder pair.
- The common faults are mainly associated with the unsuccessful design of the gas distribution mechanism. It would seem that a chain drive should provide a high level of reliability and a long service life, but everything turned out differently. The length of the drive required the introduction of two chain guides into the design, and the hydraulic tensioner turned out to be surprisingly sensitive to oil quality. The leaf chain of Morse design, at the slightest loosening, jumps over the pulleys, which leads to the impact of the valve plates on the pistons.
- Mounting the drive of mounted engine is not brackets standard for Toyota, but tides made on the cylinder block housing. As a result, all equipment is not unified with other engine models, which significantly complicates repairs.
Unlike most production Toyota engines, the 2SZ-FE is designed for use in just two vehicle families – the Toyota Yaris and the Toyota Belta. Such a narrow “target audience” significantly increases the price of both the engine itself and spare parts for it. The contract engines available to the owners are a lottery, the winning in which depends more on luck than on other, more predictable, qualities.
In 2006, the next model of the series, the 3SZ engine, was released. Almost completely identical to its predecessor, it has an increased volume of up to 1.5 liters and a power of 141 horsepower.