1JZGTE Non-VVTI CAMSHAFTS
The 2.5L Toyota 1JZ engine platform was produced from 1990 to 2007 (still in current production in the Mark II BLIT Wagon as the 1JZGE). Cylinder bore is 86mm x 71.5mm stroke. The 1JZGTE employs twin CT12A turbochargers from the factory, blowing through a side-mounted air-to-air intercooler. Features 8.5:1 compression, OEM power output is pegged at 280HP at 6200 rpm. The early 1JZGTE’s are most commonly available with an auto tranny, but a 5 speed manual version was available in the Supra 2.5L GT. Yamaha is believed to have had a hand in the development and/or production of the engines, specifically cylinder head design. In the following year (1991), the 1JZ-GTE was slotted into the all-new Soarer GT. Output remained at 206kW/363Nm and, again, most examples come tied to an auto trans. These 1JZ-GTE powered Soarers are quite common on the Australian market (as ‘grey’ imports).
1JZGTE VVT-I CAMSHAFTS
The third generation of the 1JZ-GTE was introduced around 1996, still as a 2.5-litre turbo, but with Toyota’s BEAMS architecture. This included a reworked head, newly developed continuously variable valve timing mechanism (VVT-i), modified water jackets for improved cylinder cooling and newly developed shims with a titanium nitride coating for reduced cam friction. The turbo setup changed from parallel twin turbo (CT12A x2) to a single turbo (CT15B). The single turbo is in part made more efficient by the use of smaller exhaust ports in the head, this allows the escaping exhaust gasses to have more velocity as they exit the head, which in turn, spools the turbo faster and at lower RPM. The adoption of VVT-i and the improved cylinder cooling allowed the compression ratio to be increased from 8.5:1 to 9.0:1. Even though the official power figures remained at 280 metric horsepower (210 kW) at 6200 rpm, torque was increased by 20Nm to 379 newton meters (280 lbs·ft) at 2400 rpm. These improvements resulted in increased engine efficiency that reduced fuel consumption by 10%. The adoption of a much higher efficiency single turbocharger than the twins as well as different manifold and exhaust ports were responsible for most of the 50% torque increase at low engine speeds . This engine was used primarily in Toyota’s X chassis cars (Chaser, Mark II, Cresta, Verossa), the Crown Athlete V (JZS170) and in the later JZZ30 Soarer, as the JZA70 Supra was long discontinued by this time.