GENERAL ADVANTAGES FOR Perodua Kelisa:
10% fuel saving on average due to less accelerator pressure required for the same speed.
Higher rpm capability, more torque and bhp over wider rpm range.
Acceleration time from zero to 100 kph cut by 1 second for faster models and up to 3 seconds for slower models.
Higher top speed by up to 30 kph (as reported by customers).
Less CO2 output due to less fuel input required for the same rpm.
SPECIFIC ADVANTAGES DEPENDING ON TYPE:
For automatic Perodua Kelisa: instant take off from standstill with no torque converter slip due to increased torque, higher revs in D mode between 4500 rpm to red line depending on gearbox, and easy gear kickdown. More..
For manual Perodua Kelisa: achieving rpm limit with just 1/2 throttle, and even higher revs if the rpm limit is removed. More..
For turbocharged Perodua Kelisa: reduced turbo lag, and ability to anticipate the turbo. More..
A shortage of air causes automatic gearboxes to shift up too soon, because in a higher gear, less air is required. This also makes downshifts more difficult, as more air is required for higher rpm in a lower gear. So, often the accelerator has to be pressed deeply to allow more air in to induce a gear shift down. The result is foot fatigue for the driver.
Regarding vacuum action: when the accelerator is pressed more, the vacuum in the engine manifold drops. However, the vacuum is the force that draws air into the engine. The moment the accelerator is pressed fully, the vacuum is minimized, and air induction force is depleted. Also, with the accelerator on the floor, fuel injected is maximized and over-fueling and even knocking can occur. Acceleration quickly becomes zero for the gear, and a gearchange up is necessary for further acceleration. Acceleration begins to slow significantly from third gear, and in the top gear, the rpm limit cannot be reached. Therefore, the top speed of a typical 1.6 litre sedan is only about 190kph.
Regarding emissions-since the accelerator has to be pressed all the way down sometimes, the emissions will be maximized at those instances. Fuel is wasted and fuel economy can be poor.
Compression method: by slightly easing off the accelerator for 1 second, a backwards air pressure is formed towards the outlet of the Surbo, causing it to *spin air internally and jet air at its outlet, compressing the air. Upon subsequent acceleration, the Surbo guides the air to continue jetting and back-pressurizing itself, so that the rpm limit is achieved with just 1/2 accelerator pressure.
*Regarding the Surbo design: When the accelerator is gradually closed, a back pressure wave towards the Surbo's outlet is formed, sending the straight flow through the Surbo to turn under the surf-like fins, to avoid the back pressure. Jets are then emitted from the sharp tips of the fins, at a high speed due to division by zero tip area. The curvature of the fins are set to around engine back pressure level to make this possible.
When the air is charging between the Surbo and the engine, the engine also puts out exhaust gases of increasing pressure, thus helping the exhaust system to blast out the burnt gases from a lower rpm (which aids low end torque). For turbocharged engines, since the turbocharger is driven by the exhaust, the response time of the turbo is reduced so it comes on sooner.
For autos, since the Surbo feeds the engine with more air, the engine is allowed to rev higher before changing to a higher gear, and this gives more speed and makes better use of the original engine torque which is maximized at the upper mid range. Similarly, due to more air on standby, downshifts are easier to induce with just a light press on the accelerator. Once the Surbo is on, a second downshift can also be induced for even more acceleration.
Regarding vacuum with Surbo: since the accelerator is never floored, a good portion of the vacuum is still present for drawing air into the engine forcefully, so acceleration is extended till the rpm limit is reached. Often, the Surbo-assisted vehicle is so strong that it will reach the rpm limit even in the top gear, and top speeds of 220 kph for 1.6 litre sedans are consistently reported by customers. The top speed can be further raised by adding another gear, or by removing the rpm limit if the accelerator has still not been floored, making a low cost race car a possibility.
If top speed is higher, it follows that the vehicle has more horsepower, so it will have better acceleration, easier cruising, and better fuel consumption because of a higher power-to-weight ratio.
Regarding emissions-since the accelerator never has to be floored, emissions are kept low. All the fuel is used properly either for more acceleration or more mileage.