Types of Installation

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A awesome video from Motive DVD "What the Fast" they take a look at manual & sequential transmissions and explain the different parts of them. 

 

A helical and straight cut the same size, a helical is generally stronger due to the amount of teeth engaged at one time, it’s just that a straight cut can often be made to fit into a small space so in a small gearbox you can make a stronger gear than factory. It also has less axial load, so less stress on shafts and casing, so a small gearbox doesn't need as much strengthening with straight cut. Overall, there is no general rule to which is stronger, it comes down to application and design, obviously the team at PPG are biased :-) 

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Gear Lever Operation

 

This is the standard option for sequential gearboxes and allows the driver to operate with a pull for upshift and push for downshift. The lever allows very good installation and very smooth gear changes can be calibrated. The normal operation of the system will be via a solid rod; linkage or Series 4 push pull cable. Each of these options comes with its benefits and enables the design to be optimised within the boundaries of the OEM installation.

 

The gear lever option has several variations available and calibrators decided based on the ECU systems ability as to what is best suited. As A company we always encourage end users to use a closed loop installation taking full advantage of any DBW (drive by wire) capability the ECU system may have.

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Gear Lever – No ECU Control

 

This is the most basic installation and can yield great performance if the driver has the ability to modulate the throttle on up and down shifts simulating an engine cut. The method has its inherent risks and can allow power on shifts that can destroy the dog rings and put excessive strain on the drivetrain. Ideal for Hot Rod and historic carburetor type application where electronics are not wanted.

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Gear Lever – Load Cell - Strain Gauge

 

In its very basic form the load cell method enables the calibrator visibility of when the driver is applying pressure or force to the gear lever. This information allows the calibrator to use this information to decide when and how long to cut the ignition or fuel in the ECU system to allow the torque on the transmission to reduce and allow the change to occur.

 

This system is widely used in lower tier racing as it offers a degree of simplicity but stops teams from automation of the gearshift phase. At PPG we don’t recommend this type of installation, basic cut time can cause power on engagement if the driver misses a shift which will result in damage very quickly.

 

However not all Load Cell based systems require an aftermarket ECU system to provide the cut phase. On many muscle cars in the USA we recommend to clients with OEM - factory ECU’s the “Lingenfelter cut box”.

 

This box will accept the load cell voltage and provide a cut based on force and time, therefore it is possible to determine the force at which to cut and the amount of time the cut should be maintained. We recommend customers cut based on barrel position and the initial movements they make to determine the cut start.

 

The system is very basic in its functionality but does provide some great installation and results with again the caveat of no protection should the driver miss shift during the shift phase.

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Pseudo Closed Loop – Load Cell & Rotary Position S

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This is a system that allows the usage of both the load cell and the rotary position to create a closed loop system using only basic ignition cut signals, such as with the common AEM ECU system. Currently they only support the most basic gear cut strategies and as above this can cause many problems should the driver have a failed shift using a time based cut strategy.

 

The EASY SHIFT from GEARTRONICS takes both input signals and uses the force to enable the cut and the rotary position voltage to signal the next gear state allowing the power to be handed back to the engine when the correct voltage is seen. They are a pretty smart box of electronics and for less than $600 you can have a system that offers a further degree of performance over basic timed cut; however they offer zero functionality to alter the 100% cut signal and zero ignition retard that a more advanced ECU can provide.

 

 

Gear Lever – Closed Loop Gearshift Operation with Integrated Rotary Position Sensor

 

This system is the optimal configuration for any sequential gearbox installed using lever operation. There are many variants, but to cover the main topic we will consider a gear lever with a load cell and sequential gearbox with a position sensor to read the rotary position of the sequential selector barrel.

 

Once you have a basic understanding of gear shift strategies you will understand why PPG’s exclusive technologies in the sequential gearbox market set them apart from any of their nearest competitor offerings.

 

The pioneering usage of the Gill Blade 360º sensor for rotary barrel position back in 2010 marked a turning point in data retrieval in transmission technology and turned a page to enable ECU calibrators to have previously undreamed of data acquisition. This system allows closed loop Motorsports ECU systems to see shift times down to as low as 38ms next gear stable.