Technical data

ManualsBrandsSeaDoo ManualsMarineSP

Section 04 ENGINE

Sub-Section 02 (TOP END)

040-02-16

VALVE FULLY OPENED

VALVE FULLY CLOSED

The RAVE valve does not allow an engine to make

higher peak horsepower than an engine not so

equipped, it can make moving the peak higher

practical because of its effect on the rest of the

power curve. Item 2 in the following figure is the

power curve of an engine with the RAVE valve

held fully open through its entire RPM range. Item

6 notes the peak power produced. That peak will

not change if the exhaust port time of a similar

engine without a RAVE valve was the same (with

all other features equal).

Item 1 is the power curve of the engine with the

RAVE valve closed through its entire RPM range.

The shaded area (item 3) is the improvement in

power at lower engine speeds that is gained be-

cause of the lower exhaust port. If the port re-

mains at this height, however, the power would

peak as noted in item 5. Raising the exhaust port

at the proper RPM (item 7) will allow the engine

peak power to continue to rise (item 6).

Item P1 in figure is the pressure of the return

spring against the diaphragm. The exhaust pres-

sure must be high enough to overcome this pres-

sure before the valve begins opening. Item P2 is

the pressure required to completely open the

RAVE valve. Between P1 and P2, the usable pow-

er curve of the engine is moving from power

curve 1 to power curve 2. This transition takes

place very rapidly at full throttle and from a practi-

cal standpoint can be considered to be instanta-

neous at item 7. Gradual application of the

throttle, however, will result in the RAVE valve

opening much later.

If the RAVE valve opens too late, the engine will

bog or hesitate momentarily as the RPM increas-

es. Full peak performance (item 6) is still available.

From a functional point of view. It is better to have

the valve open a bit early than a bit late.

Maintenance

There are no wear parts anywhere in the system

and there are no adjustments to be periodically

checked. The only possible maintenance required

would be cleaning of carbon deposits from the

guillotine slide. Cleaning intervals would depend

upon the user’s riding style and the quality of the

oil used. Using FORMULA XP-S synthetic injec-

tion oil, we would suggest annual cleaning of the

valve. If a customer uses a lower quality oil, more

frequent cleaning may be required.

No special solvents or cleaners are required when

cleaning the valve.

F01D7GA

F01D7HA

POWER

RPM

A18C02A