Quickstart Guide
We offer complete plug-and-play solutions — you decide what you need!
Why choose the 8HP Transmission?
Nobody likes driving an automatic transmission—but what if I told you:
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You can still have a clutch pedal and use it like a manual car (but you don’t have to—use it as you wish!)
- You can launch it violently with a transbrake or launch mode (click here)
- It shifts gear in less than 100 miliseconds (click here)
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Street driving mode is incredibly smooth, like an OEM car—your girlfriend will be able to drive it effortlessly
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Highway cruising speed stays under 3000 RPM
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It can handle serious power and even more with upgrade kits (over 1400+ TQ with the Pure Stage 3 upgrade)
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You can retain the OEM interior look (ignore the missing carpet—we were building a cage!)
The Dodge 8HP transmission
2015-2021 Dodge Charger, Challenger, Chrysler 300C with the HEMI 5.7 and 6.4 engines
Note that the 2015-2017 are the second generation of 8HP70, 2018+ 3rd generation and 2022+ 4th generation.
These transmissions are incredibly robust and can handle significantly more power than their rated capacity.
Important: The transmission must be "shaved" like this before installation:
Transmission gear ratios are as follows:
Gear | Ratio | Gear | Ratio | |
First | 4.71 | Fifth | 1.28 | |
Second | 3.14 | Sixth | 1.00 | |
Third | 2.11 | Seventh | 0.84 | |
Fourth | 1.67 | Eighth | 0.67 |
Availability
We keep several used transmissions in stock. Contact us if you're looking for one!
Note: It’s also possible to use the Dodge 8HP45 transmission from V6-equipped models. However, this option is not recommended for applications over 500 WHP.
The Transmission Tunnel
Slight modifications are required to fit the Dodge 8HP70 into the Supra transmission tunnel, and same thing on the Lexus SC300/SC400 and Soarer:
The primary changes are near the firewall, where additional clearance is needed for the transmission bell housing.
No other modifications are necessary.
Our transmission mount kit is designed with a polyurethane mount that we've been using on our CD009 Adapter kits for a while.
The Differential
The 8HP70 transmission is compatible with a wide range of differential gear ratios:
The Supra 220mm big differential has a factory ratio of 3.26, which works well with this transmission.
Ratios up to 4.10 can be used without issue.
Note: When using a 4.10 differential, first gear is short. We typically program the transmission to start in second gear for street driving and use first gear for drag racing.
Highway Cruising RPM with 26" tires
With a 3.26 differential at 75 mph (120 kph) = ~ 2650 7th gear, and ~2100 rpm in 8th gear.
With a 4.1 differential at 75 mph (120 kph) = ~ 3300 7th gear, and ~2650 rpm in 8th gear.
The Driveshaft
We offer a variety of driveshafts compatible with differentials
We offer driveshafts for the factory Toyota differential 200mm and 220mm 3-bolt flanges
(available on our website).
Contact us for a custom driveshaft we can customize it for any application.
All our driveshafts are 3.5" aluminum with 1350 U-joints, capable of handling over 1000 HP.
The "Virtual Clutch"
(optional)
With the 8HP transmission, you can opt for a "virtual clutch." Don't worry—there’s no actual pressure plate or clutch involved.
The 8HP transmission uses a torque converter, but we offer a kit that includes:
- A clutch position sensor installed on the clutch pedal.
- A clutch simulator (replacing the clutch master cylinder) to provide authentic clutch pedal feedback.
This setup mimics the feel of a traditional clutch and integrates with the transmission controller to function like a real clutch.
With the virtual clutch, you can:
- Launch smoothly or aggressively like a manual car.
- Clutch in for shifting just as you would in a traditional manual transmission.
- Clutch kick for drifting and other performance driving needs.
The shifter
When it comes to the shifter, there are many options to choose from.
We prioritized keeping the OEM look, so we designed a solution that uses a sequential shifter positioned exactly at the factory shifter location. This setup includes a custom shifter hole block-off plate paired with the Perfect Tuning sequential shifter.
Functionality with Turbolamik Controller
Depending on the transmission controller used, the options vary. With the Turbolamik controller:
- The transmission starts in Park.
- Pull the shifter, and the transmission shifts to Drive.
- Push the shifter, and it shifts back to Neutral.
- Double push the shifter in Neutral to engage Reverse.
Additionally, the drive mode is selected via a rotary switch. There are seven driving modes:
- Modes 1–3: Automatic modes, ranging from smooth to race settings.
- Modes 4–6: Manual modes (with optional auto upshifting at redline and auto downshifting when coming to a stop).
- Mode 7: Drift mode, where the transmission never shifts automatically.
Additional Shifter Options
- Shift Paddles: While it’s possible to use paddle shifters, we currently do not offer a kit.
- BMW or Dodge OEM Shifters: These can be used over CANbus for seamless integration.
The Transmission controller
There are many options for controlling the 8HP transmission, including Turbolamik, MaxxECU, CANTCU, HTG, and more.
We believe the Turbolamik and MaxxECU are the best options currently available. At the time of writing, the Turbolamik offers the most comprehensive features, including launch mode and virtual clutch control. However, MaxxECU has recently announced support for the virtual clutch, and we will test this feature soon and share our findings!
Turbolamik:
What you should know about the Turbolamik:
- Direct Control: The Turbolamik controller requires the transmission valve body to be opened for the installation of a control board, allowing direct communication with the transmission. This is a complex procedure that we offer as a service but is not recommended for end users.
- Advanced Tuning: With direct control, Turbolamik provides precise transmission management and extensive tuning options.
- Documentation Challenges: Turbolamik’s documentation is minimal and difficult to understand. We’ve invested countless hours on the dyno, at the drag strip, and on the road to master its tuning.
We offer remote tuning sessions and tunes (click here)
While the Turbolamik can operate independently with the required sensors, it is typically integrated with an engine ECU over CANbus. Supported ECUs include:
- ECUMaster Black or Pro
- All Megasquirt 3 or MS3Pro
- AEM V2 and Infinity
- MoTeC M1
- Haltech
- Link
- Holley
- VEMS
- Delta ECU
- Syvecs
- MaxxECU
MaxxECU:
The MaxxECU is a state-of-the-art, fully programmable engine control unit (ECU). While it can manage the transmission via CANbus, it also excels at controlling a wide range of engines.
We recommend the MaxxECU Race or Pro, and we offer plug-and-play solutions for these setups. With the MaxxECU, you can control the 8HP transmission along with advanced engine features such as:
- Sequential mode for the 2JZ engine
- Wideband oxygen sensors
- EGT sensors
- Variable Valve Timing (VVT)
- Electronic throttle control (drive-by-wire)
- And much more!
Advantages of MaxxECU
- Controls both engine and transmission simultaneously.
- No need to open the valve body—just program the transmission with a flash tool.
- Supports multiple-gear downshifts (e.g., 8th to 4th) without sequentially stepping through gears.
- Offers four driving modes: Street, Sport, Race, and Drag.
- Supports transbrake control.
- Virtual clutch control and launch mode support are expected soon.
- Easy configuration of throttle blip when using an electronic throttle.
- Shift cut functionality for faster gear changes is straightforward to set up.
Questions ???
If you still have unanswered questions, don’t hesitate to reach out! Contact us at help@perfecttuning.net, and we’ll do our best to assist you.