SLOPE TEST

The Surbo development car, a Peugeot 405 1.6 with Twin Surbos, was tested on a slope 400 feet long (service road for Beauty World Centre and Plaza, located off Upper Bukit Timah Road, Singapore). At the bottom of the incline, first gear was engaged, and clutch released and accelerator never pressed. The car went up the slope steadily at 1000 rpm and never stalled. Neither the clutch or the accelerator was ever pressed during this time. At the top of the slope, it was 2 storeys above where it started.

Normally a manual car under this situation would stall and need restarting. How did this self-pushing of the engine occur? This was due to the Surbo system's action. As the Surbo is a back-pressure system (see How It Works), it works well (compresses the air leading to high compression and more power in the engine) when the throttle is fairly closed. With the right foot off the accelerator, the throttle was as closed as it could be. Thus, the throttle back pressure towards the Surbo was at a maximum, resulting in a vortex and air pressure to drive the engine. At the same time, the engine was drawing air of the highest density through the smallest throttle opening and maintaining its 1000 rpm engine speed.

This result simply means that the low rpm power of any Surbo powered vehicle is maximised, in a way that has never been heard of. Being a manual, this shows that 100% clutching as possible at even a low speed, needing no slip (by depressing the clutch). In an automatic car, there is also a torque converter that allows slip, preventing stalling at low speeds near or at idle, by lessening the direct contact between the engine and the gearbox with gear selected. As the driver accelerates, the slip is gradually lessened till the engine is at a higher rpm and has more torque to run or accelerate steadily. With a Surbo, since the torque is increased from low down and the engine steadier, this slip can be lessened and the automatic car can have faster breakaway acceleration. It eliminates the "waiting" time that usually occurs after the accelerator is pressed, which is the time required for the engine to accelerate with slip till it is torquey enough to be more clutched to the gearbox. Fitting a Surbo in an automatic car removes this pick-up retardation. It would become "punch and go".