![]() Furthermore, you have no safety - if you downshift too early, there is nothing to stop you selecting a gear too low, thus causing engine damage, or even going from past 1 st to neutral. You will manually need to 'blip' the throttle on downshifts also. This is because you need to reduce engine torque to unload the dogs to allow the shift. Starting with a simple implementation, there is nothing stopping you buying a sequential gearbox and fitting it to your car with no other external control at all we would, however, say this defeats the object of the transmission in the first place - you'd lose the super quick shifting speeds that are associated with sequentials as you'd need to lift the throttle when changing gear. You have a range of options, from no electronic control and a manual shifter mechanism for a very basic implementation, all the way up to a closed-loop ECU controlled shifting strategy with paddles. We will now move back to how we implement a control system for this.įirstly, when deciding to move to a sequential gearbox, you need to decide how you are going to implement it into the chassis and how you want to control it. Ok, so that's the brief overview done - if you'd like to learn more about the inner workings of a sequential gearbox, there is a host of great information online for your reading pleasure. In the image below, courtesy of Xtrac, you will see the straight cut gears and the barrel that drives the selectors: The only major downside for some is the noise (we quite like it!), the cost and that the gearbox will require considerably more maintenance than a traditional helical cut gearbox. Whilst this sounds brutal, it is what in fact enables the gearbox to shift so quickly and without the use of a clutch in a correctly set up system. ![]() As mentioned above, sequential gearboxes use dog rings, which in effect force the gears together rather than smoothly engaging as they would if using a helical cut gear. Sequential gearboxes utilise straight cut gears, which have the added benefit of less power loss to the driven axle. This barrel (or drum depending on which term you'd like to use) has tracks machined around its circumference to help guide the selector forks, which in turn initiates the gear change when the barrel rotates. On a sequential transmission, the shift lever or electric/air powered actuator (if using paddles) operates a ratchet mechanism that converts the forward and back motion of the shifter into the rotation of a selector barrel. This minimises the chance of engine damage occurring from a missed or wrongly selected gear. We are, however, seeing sequential transmissions being used on the road more and more, but the original sole purpose of them was always intended to be for motorsport use.Ī sequential transmission can produce faster shift times than a traditional synchromesh manual transmission by using 'dog rings' whilst also restricting the driver to selecting only the next or previous gear. I suppose we should start this article with a brief overview of what a sequential gearbox is and why we'd want to use one.Ī sequential transmission is a type of manual transmission used mostly in competition motorsport vehicles. This article will be predominantly based on how we do this with a Syvecs ECU, however the theory can be utilised on a variety of engine controllers – we'd recommend checking they have the necessary feature set you need to control the gearbox and its subsidiary systems. Our second Tech Insight is going to revolve around sequential gearbox control and the appropriate systems you need in place to do this correctly and safely. Welcome back to Volume 2 of our Tech Insight series! We hope you enjoyed our first article which gave an overview of how basic maths channels are used in the motorsport world if you missed it feel free to check out the article and let us know what you think here:
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