Industry standards are an ever-changing beast that always hungers for innovation. In the intricate world of automotive engineering, the transmission serves as the silent conductor orchestrating the harmonious dance between an engine's power and a vehicle's wheels.
The traditional manual transmission has always been known for its place in performance vehicles as the superior choice for going fast, along with the immersion of the driver, allowing the feeling of ultimate control. Automotive technology is a very competitive market that has been relentlessly seeking that new level of driver experience. When the word "performance" is spoken in the car market, most would not think or consider the vehicle has an automatic transmission in years past. The automatic transmission has been around for its fair share of years, allowing anyone to be able to drive a vehicle. Automotive manufacturers have clearly seen the benefits of catering to a larger market, which has driven the ongoing advancement of the automatic drivetrain.
In the performance car industry, it has been known from day one that shifting is a direct correlation to going faster. The development of sequentially shifted transmissions started in the 90s, almost 100 years since the first manual transmission. The sequential manual shifted transmission has and is still relatively expensive compared to the standard H pattern transmission. This has put sequential types of transmission to mainly be used by professional motorsports teams, unobtainable for the majority of automotive enthusiasts.
Where does this leave the average automotive enthusiast who also wants to go fast but can't afford the cost of a sequential transmission along with the high maintenance cost? We started the blog off speaking about OEM manufacturers' pursuit to deliver that performance feel in a solution that anyone can use. This has brought us transmissions like the BMW DCT, 8HP, Ford 6r80, 10r80, Chevrolet 6L80, 8L90-E, Lexus AA80e. All of these transmissions push the limits of how fast they can shift between the gears, offering that peak performance the OEM manufacturers have been seeking.
Now, the average automotive enthusiasts could go and purchase one of the vehicles that has one of these transmissions, but many of us would like to customize our own vehicle with our own choice of engine. This urge has driven aftermarket engine management/GCU companies to create control strategies for these gearboxes.
This is where Tuned By Shawn has been introduced into the world of the ultimate feeling of a crisp, virtually imperceptible lag of a modern aftermarket-controlled OEM transmission for half the cost of a less expensive sequential manual transmission. Personally, growing up in the era of video games, I have many fond memories of playing racing games utilizing paddle-shifted vehicles. When we got the opportunity to drive our good friend/customer Andre's DCT 13B-REW FD Rx7, it was as if we lived that feeling in real life. We facilitated Andre's build, doing the wiring, integration between the aftermarket ECU and GCU. At the time, it was no easy feat due to our lack of experience paired with the lack of community knowledge. Between our friends Gus (BMW DCT E36) and Andre's ambition to make this particular transmission work, we inevitably were successful in giving them the ultimate custom driving machines.
Now, we accomplished the goal at hand; we started to think about how complex the actual implementation of the control strategy of the DCT really is. We had seen many individuals give up entirely on the process due to a lack of knowledge, poor installations of the DCT transmission. Through our conversations with others, as we were one of a handful of individuals who first accomplished this in the United States, at the time an individual Nik C had told us about the Lexus IS-F transmission. This transmission did not have the TCU (Transmission Control Unit) located inside of the box. This just clicked for us that if we can accomplish the control of this transmission, it would be an easily replaced transmission controlled under one software suite (Haltech NSP) and no soldering, significantly reducing the complexity of utilizing a modern transmission.
The AA80E (Lexus IS-F) is a robust automatic transmission created by Aisin AW, a Japanese automotive parts manufacturer. Originally for luxury and performance-oriented vehicles, this transmission has found its way into various models, offering a blend of efficiency, smooth operation, and responsive handling. The Lexus IS-F AA80E transmission boasts one of the world's fastest shift times for a street-legal production car at 0.1 second upshifts... yeah, DCT FAST! It has a direct feel unmatched by conventional automatics, made possible via clutch lockup (yes, like a manual) employed in second through eighth gears. The uniquely designed gearbox is relatively light (212 lbs) and uses a special planetary gear set that allows a more compact design. The results speak for themselves but are rooted in two key areas: Shift/lockup clutch operation and shift control. It's also nice to have eight speeds in the gearbox.
The lockup clutch is not new to auto transmissions, but how it's controlled in the AA80e is. Normally automatics have used the lockup clutch to make them more efficient by creating a direct power path between the engine and the transmission. This is done in the upper gears and in low load operations to preserve smoothness while gaining fuel economy. The AA80e turns this idea on its head by employing lockup in all gears except first when in manual mode. This eliminates any power loss from the torque converter from 2nd to 8th gear while preserving desirable torque multiplication in first gear for amazing launch acceleration.
In order to create the DCT-Fast instant upshifts, Lexus engineers developed new methods to control the hydraulic pressure that actuates the transmission clutches. A high flow-rate linear solenoid is one of the key factors that work together with special computer programming to provide quick and precise control in concert with engine torque. Ultra-quick shifts—when you demand them—are the outcome. The ability of the transmission to respond only to your commands nets a manual mode that is true to its name. It shifts only when you ask it to, and not when it thinks it should.
Now that I have your attention, the hype train is going, and you want to install the AA80E transmission into your project car, right? We have been diligently working to make this available to the public, which has been no easy task. The first steps we took a look at multiple documents on the transmission to make sure that the Haltech Software (NSP) could be programmed to control the transmission. On initial overview, the transmission has 5 shift solenoids, a line pressure solenoid, torque converter lockup solenoid, and 2 additional solenoids used for a total of 9 solenoids. Additionally, it has 3 speed sensors - Input speed, Intermediate shaft, output shaft, temp sensor, and pressure switch.
We used the Haltech NSP software to create a control strategy for the transmission that, with every bit of testing, has led us to further the progress of delivering a smooth ultra-fast shifting transmission. We have also needed to utilize Haltech's generic functions in order to match the OEM shift solenoid control. The progression of tuning the transmission started with it simply going from forward/backwards motion to 4 forwards gears to all 8 gears. We are now able to offer a "race" shift quality in the transmission. The goal and what this 3rd round of testing is to give the end-user that smooth cruising shifts for that ultimate street machine. The 3rd round, we are going to be moving our IO around from the Haltech PD16 to the Nexus R3 - Previous versions we utilized the Elite 1500 ECU + PD16, and we would like to rule out all variables.
We chose the K24 engine as it has been our primary interest due to its popularity in the swap harnesses we create for the Mazda Rx8. This particular engine was a decent option for testing the transmission due to a popular question we see: how many RPMs can it be shifted at, paired with the most asked question: how much power can it handle? We can say 9,000rpm shifts seem to be zero issues so far, zero cavitation detected from pressure sensor data.
The transmission fits surprisingly well into the Mazda Rx8 Chassis trans tunnel with a fair bit of room around the entire transmission, which made it easy to fit a 4" exhaust. Yeah, we intend to push this build to over 1000rwhp to answer both of the popular questions. We have to thank our good friend Sean Nagle for taking on this engineering task, utilizing his talented skill sets from scanning both the engine block and transmission. Created the Adapter plate, engine-to-flex plate adapter, ring gear to flexplate/torque converter adapter in CAD, along with machining the parts in his home garage! Notably, Sean did all the initial fabrication for v1 proof of concept, but we also did utilize Nicholas Perttula with Arcbright Welding and fabrication to upgrade the turbo to a G40-1150, Radiator, Transmission coolers.
