Manual transmission elitists need to get with the times. Driving an H-pattern gearbox is fun and makes you feel connected to the car, but it doesn’t hurt to leave some of the work to automated systems. This rings especially true if your main goal is improved performance, such as a sequential gearbox and its ability to change gears in only a few milliseconds. Manual transmissions require more input from the driver, which also results in more room for error with grinding gears, lengthy shift times and poor rev matching. Not everyone can afford a dual clutch transmission, and not everyone can heel-and-toe shift, so Tractive Technology put together the AUTO-BLiP to take care of rev matching for you. In a hunt for improved drivability and consistency, we installed the AUTO-BLiP on an AP2 S2000 CR to test its ability to automate rev matching and let the driver focus on driving.
Text by Cameron Parsons // Photos by Cameron Parsons and Joe Singleton
DSPORT Issue #180
Changing Gears
The AUTO-BLiP is designed to blip the throttle during downshifts so that you don’t have to, but why is rev matching so important to begin with? If you ever attend a racing school, at some point the instructors will ask you why you should downshift as you approach a corner. Most students incorrectly answer that it is to help slow the car down. While some people downshift to use engine compression to slow a car on the street, the task of deceleration should only be left to the brake pedal when on track. Changing to lower gears before a corner serves the purpose of keeping the engine RPMs inside the power band for when the car leaves the corner. Although H-pattern gearboxes are the most popularly produced and driven form of a manual transmission, they come with the drawback of requiring extra care when shifting.
When you depress the clutch and change gears with the shifter, the timing of your actions affects the entire powertrain from the engine, to the clutch, to the transmission, to the differential, to the wheels and tires. Each of these components spin at high rates when the car is in motion and are tied to each other to spin in synchrony. When the chain is interrupted, you risk damaging components and losing control of the car. For example, if you push in the clutch pedal and shift to a lower gear without any input on the throttle, the engine RPMs fall back toward idle speeds. When you release the clutch pedal, the engine has to spin up to match the rotation of the transmission input shaft, now rotating at a different speed due to the changed gearing ratio. If the clutch is released too quickly, a sudden jolt interrupts the drivetrain, the driveline components wear quicker, and the driving wheels and tires break loose from the road. If a short but significant press on the throttle (“blip”) in between gear changes were added, the engine speed would match the input shaft speed. This smooths out the act of downshifting and thus results in reduced drivetrain wear, less clutch slip and consistent grip on the driving wheels and tires.
Getting in Sync
While a car drives in a given gear, a whole chain of important components spin in harmony with each other. When the clutch disengages (clutch pedal depressed), the engine and transmission can then spin at different speeds. If the transmission and engine internals spin at different speeds due to excessive throttle blip or not enough, a quick clutch engagement (clutch pedal released) forces the engine and transmission to suddenly match speeds again. This sudden shock can damage parts or cause traction loss.
Human Error
A problem arises with the process of slowing a car, blipping the throttle and downshifting a manual transmission for a corner: two feet to control three pedals. This is where good timing and coordinated footwork come into play. Heel-and-toe requires the right foot to apply brake pressure while the left foot depresses the clutch pedal to prepare for a gear change. With the brake applied and the clutch disengaged, the driver moves the shifter into neutral, then pivots their right foot for a quick blip of the throttle without backing off of the brake pedal. Depending on the car, the driver can simply roll their foot past the right edge of the brake pedal to reach the throttle, or they can keep the ball of their foot on the brake while swinging their heel over to reach the throttle. With the engine RPMs up and falling toward the matched input shaft speed, the driver can then engage the next lower gear and release the clutch pedal.
This process requires lots of patience and practice before it becomes second nature. Even when the timing is right and the technique is smooth, drivers commonly produce inconsistent brake pressure. The motion of using one foot to control two pedals causes a tendency to lift off the brake pedal in order to reach the throttle. This results in earlier braking points to compensate for the poorer braking performance, or wheel lockup if the brake pressure fluctuates too much.
Heel-and-Toe
1. Brake The right foot applies the brakes as the car enters a corner or deceleration zone. The le foot is ready to press on the clutch pedal and the driver’s hand is ready to change gears.
2. Clutch and Blip While continuing to apply the brakes with the right foot, the le foot presses the clutch pedal to the floor. During the moment that the clutch is disengaged, the driver changes to a lower gear and the right foot either rolls its right half onto the throttle or pivots the heel over. In most cases, a quick blip of 50-percent or more throttle su ices for a proper rev match.
3. Clutch Release The brakes are still applied as consistently as possible. As the RPMs fall back down a er the throttle blip, release the clutch the moment that the engine and transmission speeds match. The proper timing of this di ers between cars, and only comes naturally with a lot of practice.
4. Brake During the entire Heel-and-Toe process, the brakes were applied consistently. A er the downshi (s) are complete, the le foot returns to its resting position.
Automated Solution
If you’ve tried and couldn’t get the heel-and-toe technique right, alternative fixes used to be limited to switching to a sequential gearbox or automatic transmission. Now, Tractive Technology introduces the AUTO-BLiP as an affordable solution to retain an H-pattern gearbox while removing the need to heel-and-toe. The device monitors the car’s accelerator, brake and clutch pedals, in order to trigger a throttle blip at only the appropriate time. The blip delay and duration are adjustable with two knobs on the face of the device, allowing for fine tuning toward smoother downshifts to match anyone’s driving style and shift timing.
Although installation of the AUTO-BLiP is simple, it requires some digging underneath the dash to locate the proper wires.
Installation
While the AUTO-BLiP would potentially serve for more fun when driving on the street, its given purpose is best suited for the track. To this end, we chose to install it on a 2008 Honda S2000 CR, built for autocrossing and time attack. The unit is universal to cars with throttle-by-wire systems, requiring access to only four sensor wires, along with power and ground connections. The AUTO-BLiP splices into these wires with the included wiretap connectors, which required a couple do-overs in order for us to get consistent connections. If you plan to keep the AUTO-BLiP installed permanently, we strongly recommend soldering a connection instead. In this test with the wiretap connectors, installation from start to finish took less than an hour. With the wiring in place and a quick sensor calibration process, we set out for a test drive.
Perfect Timing
The adjustment dials on the AUTO-BLiP provide a wide range of throttle blip levels as well as a delay range of 0 to 0.5 seconds. After just a couple test runs with different settings, we found the sweet spot near the middle for both parameters. From there, the AUTO-BLiP worked flawlessly, displaying the brake and clutch lights when both pedals were engaged and then adding the necessary throttle blip for perfect rev matches. It was a weird feeling at first for the car to handle rev matching without driver input, but it also enabled much simpler and more consistent braking by removing the need to heel-and-toe downshift. For $395.00 and less than an hour install time, the AUTO-BLiP serves as an excellent driver aid on the race track.
Do What You Want
Tractive Technology’s AUTO-BLiP device removes the need to heel-and-toe which, according to some purists, takes away from the driving experience or even devalues your driving ability. But for those who don’t know how or don’t care to employ heel-and-toe, this device handles the task with no downside. As long as your timing with downshifts is consistent in the braking zones, the AUTO-BLiP’s throttle input ensures smooth gear changes every time. Some drivers may still prefer to maintain full control of every aspect of their car when on track. For others, why do extra work when there’s a device that improves performance and makes driving on track a little easier?
For most applications, the AUTO-BLiP rarely requires adjustment once you’ve found the right settings. Therefore, it can mount in more hidden areas to maintain the looks of the interior.
The Bottom Line
The AUTO-BLiP is affordable, easy to install and can be switched on or off at any time. So why shouldn’t everybody go buy one right now? Some drivers prefer the feeling of complete control over their cars, even if it results in some amount of human error. The feeling of the car adding throttle input for a blip without your doing certainly takes some getting used to. However, if you find difficulty in learning to heel-and-toe or simply don’t want to, the AUTO-BLiP handles the task for you without error. Better yet, it allows you to use your right foot to control the brake pedal without interruption. Many racing drivers and track day enthusiasts struggle to maintain a constant brake pressure when applying heel-and-toe, which slows lap times and opens the door for other drivers to pass. Since the AUTO-BLiP takes care of that for you, you’ll find yourself braking later and with greater precision.