One of the next products that I plan to release this year will be a drive by wire system for VG30DE/DETT. I’ve been watching a lot of you upgrade to latest engine management systems like Haltech Elite 2XXX series and felt like we are just barely touching the surface of that that engine management is capable of. I think one of the HUGE functions that the Elite series (as well as a ton of other engine management systems) offer is electronic throttle control. These cars are making some huge power numbers now and it is easy to get yourself in trouble with a car that is very tail happy. Modern standalones offer excellent traction control features which will keep you and your car much safer. Also, features like launch control, cruise control, integrated idle speed control, cold idle, and most importantly emergency throttle cut off are some of the must have features that come to mind. You will have a much safer car all around.
Just like with everything else Z32 related, this was a rather challenging project. I looked at external throttle motors that I could find, but they were way too expensive, required additional linkages and did not have the best reliability track record from what the forums said. Installing DBW throttle bodies in factory location is not possible because of clearance issues and I wanted my setup to be bolt-on.
After a few weeks of research it became evident that I would have to start from scratch. I removed factory throttle control assembly, measured off dimensional constraints and got to work. I sourced genuine Bosch electric motors, Bosch gears and an array of throttle position sensors. Dozens of CAD hours later I had an assembly that housed the motor, a main Bosch gear and a throttle return mechanism designed by yours truly. Dozens of hours of 3D printing hours later, I was able to select correct throttle return springs to match the factory Z32 springs that are installed on throttle bodies. Please keep in mind that the throttle remains cracked open in its resting state and there are two sets of springs that keep it in that position. Dozens of hours more of tinkering with return mechanism and main shaft mounting, I had a relatively well working prototype.
Currently I have been testing the assembly at about 50% of its potential power and speed. At full power, the operation is so fast that the motor kept breaking my 3D printed gears and throttle linkage. I am having all these parts machined from hard aluminum alloys and should be able to test operation at full blast next month.
Those of your who are familiar with DBW systems know that an assembly needs a dual TPS to accurately measure throttle plate position as well as the rate at which throttle plate is moving. At first I wanted to integrate the TPS into my assembly, but decided against it to avoid unnecessary complexity, reduce cost and make trouble shooting easier. This setup will come with an external hall effect dial TPS that will be mounted on the passenger side (USDM) throttle shaft. There are many reasons why it needs to be passenger side that I won’t get into here. I will be using an excellent hall effect OEM sensor in my assembly that has no contact points and has plenty of table available for Haltech interface for when we start dialing things in.
The whole system will come with new cover for top of the intake manifold. Of course writing and logos will be edited later on.
As of right now, this is about all I want to share. I just wanted to let people know about some of the stuff that is in the works and should be available shortly. In all likelihood, this setup will first be available to shops that are familiar with Haltech and DBW setups. I am also in contact with a number of guys who expressed interest in this project and are very savvy with electronics. You guys know who you are and I will be offering a few of these for testing in the next few weeks.
- Billet aluminum housing
- Custom, all-metal return mechanism construction with dual return springs
- PTFE bushings for main shaft mounting
- Genuine Bosch electric motor and main gear
- Dual hall effect throttle position sensor
- Direct bolt on to use with factory and factory replacement throttle bodies
I have already started playing around with Haltech and setting things up to have these controlled with an electronic pedal. I will be able to complete the testing phase as soon as stronger metal gears and mechanism arrives to let me turn up the power.
Above: DBW conversion box is activated by physically pressing a pedal (mounted on the floor). ECU is now in sync with APP sensor, TPS sensor and motor. At this point we are able to control the throttle plates by pressing accelerator pedal. It is hard to convey it in a video, but pedal to throttle plate link is very sensitive. You can move the throttle body a fraction of a degree. Once this system is installed on a car, ECU will also activate idle air control function.
This is what the setup looks like installed on a Z32 300ZX intake manifold (aftermarket in this case, but it bolts up to factory counterpart just as well).
This is the system in its resting state with ignition "off". As you can see, the throttle plate is not full closed. This is a mechanical failsafe of an electronic throttle control system. In case this system loses power for one reason or another, the throttle plate would remain partially open to allow engine start, idle, and if driver is careful, to get home. This was a very difficult feature to replicate from mechanical point of views since we are still using factory return springs.
Price… I hate that question before the product is ready for ordering. It will be priced fair and affordable to all those who at a point where they need DBW system.
Any feedback is welcome. I can only answer what I feel like sharing at the moment. This project required a stupid amount of work and I want to keep details private for now.