Tuning

Induction

 

Carbs
We supply carbs from all manufactures but we recommend De’llorto. It has an excellent array of needles and tubes, which allows us to meter the carb to meet the perfomance required.
We cut and polish carbs to our own design this gives us variable draw on the carb as the throttle is opened. Our tuning techniques improves the gas flow through the carb and throttle response.
We provide various stages of tuning, these are largely based on your racing budget. For club racing, stage I is sufficent to give you perfomance you need to win. For championship level, stage IV is needed to be at the front of the pack.
Call for a chat where we can discuss your needs.

 

Timing
Fixed Induction Timing – DISC VALVE
Valves have a fixed timing. This provides a good top end power but the engine’s pickup is poorer from low engine speeds than a reed.
We use steel and carbon valves. They are cut from complete circles so we can set our own open and close angles. Carbon Valves can not be used direct against aluminum cases as the carbon destroys the metal and ceramic coatings to the cases have to be applied.

 

 

Variable Induction Timing – REED
Reed valves vary their timing depending on the engine’s rpm. they give lower top end power than disc valve engines, but have a more consistent pick up. Timing can be varied by using different valve materials or different petal combinations. This effects the stiffness of the material and hence its harmonic response.
We modify our engines to take various makes of reeds and reed blocks, these include 4 and 6 petal blocks, carbon and fibre glass reed petals.

 

 

Combustion

 

Ignition
We produce passive advance/retard ignition boxes for all major ignitions. We make boxes for other tuners, so if you have a ’spark box’ it probably came from us!
We also use PVL digital ignitions and can have our curves burnt into PVL ignition coils.
All of our ignitions are tested on our rig. This allows us to accurately plot the timing curve and get the best out of the ignition. This is used in conjunction with the dyno to maximize performance.
If you are having problems with your ignition or engine, we can test your unit for problems. Ignitions can partially breakdown which produces intermittent faults or abnormal timings at certain rpms.

 

Porting
We cut and polish barrels, inlets and exhausts. We match our port timings to our ignition, indution and exhaust settings.
Why polish? Polishing is essential to control the gas speed in the engine, the more polished the less friction the gas experiences. By altering the surface roughness of ports, gas flow can be adusted to keep the flow from becoming turbulent. This improves the amount of ‘charge’ the engine inducts and ultimately burns. The more charge that is burnt, the more power the engine can produce.
Why cut ports? Cutting the height determines the length of time the ports are open, cutting the width determines the amount or charge during the time the port is open. Care has to be taken not to put the ring under to much stress.
Why cut inlets/ tracts? Gas flow is a function of gas speed and cross sectional area through which it travels. Varying the cross section of an inlet will effect the speed of the gas. The speed of the gas affects the pressure. Altering the geometry can create suction effects and control the speed of the gasses in the engine. It allows better control of the gas in the combustion cycle.

 

Heads – Volume
Pavesi heads are fitted with a bronze insert. We can provide a range of inserts or even produce one to your own design.
The following paramaters can be changed;
- volume
- Squish angle
- Squish band

 

 

Exhaust – Silencing

 

Pipes
We supply the standard exhausts for the Pavesi engines and the alternative versions also available from the factory.
We also have exhausts fabricated to our specifications. This may be due to mounting engines on unconventional chassis, or for Twin engined machines.

 

Silencing
We can provide many differing types of silencer. From lightweight carbon cans to aluminium mechanincal types. Each have their own properties on engine power and vary in weight.

 

 

Output

 

Dyno Testing
We use a dyno that takes the whole kart as raced at the track. We can measure the power perfomance at the wheel. This will take into account the power loss through the chassis and drive train.
The dyno can be hired by the hour, with or without a technician to help you make choices to get the best out of your time.
Your results are confidential and will be kept for your next visit for comparisions. You can view the curves through various mathematical corrections as this will give a large variance in the results. We will help you in deciphering the information so you are confidant the session was valuable.

 

Ignition Testing
We produce passive advance/retard ignition boxes for all major ignitions. We make boxes for other tuners, so if you have a ’spark box’ it probably came from us!
We also use PVL digital ignitions and can have our curves burnt into PVL ignition coils.
All of our ignitions are tested on our rig. This allows us to accurately plot the timing curve and get the best out of the ignition. This is used in conjunction with the dyno to maximize performance.
If you are having problems with your ignition or engine, we can test your unit for problems. Ignitions can partially breakdown which produces intermittent faults or abnormal timings at certain rpms.

 

 

Gear Ratios
Internal Gears
Pavesi supply many differing gear ratios for the gearbox and final drive sprocket ratios.
1st gear is fixed shaft so can not be altered, along with the primary drive (crank to clutch basket)
2nd – 6th can be changed to dial out problems on a circuit and provide good power delivery at the desired corner speed. 5th and 6th come as a joined gear and have to be changed together.

 

Final drives
Pavesi supply Simplex sprockets from 13 to 19 teeth. We can supply Duplex sprockets for the engine where finer control on the final drive is required.