Now that our Drive-By-Wire pedal and Motec ECU are installed, we turned our attention to simplifying and adapting an 80mm Ford Mustang DBW throttle body to the original intake manifold.
I admit that I was a reluctant “purist” whose opinion was that nothing will replace the feel and control of a cable connecting my foot to the throttle body of a car. However, after years of racing professionally, and being part of the development of OEM cars for Ford (such as the Ford GT, GT350, GT500, etc..), and for working on the calibrations of the throttle maps of these cars, I have greatly changed my stance and am a die-hard Drive-By-Wire (“DBW”) fan.
There is so much that you can do with modern ECUs, especially on forced-induction cars to reduce turbo lag, improve response and feel, improve idle control, add safeties that can save you tens of thousands of dollars, and most importantly: to digitally ‘craft’ and program the engine’s character and ‘soul’ through tuning of the engine and throttle maps. Needless to say, we were excited to get the DBW setup running on our NSX!
In Part-18, we removed the throttle body and installed the Drive-By-Wire (DBW) throttle pedal and pedal position sensor. With the throttle cable already removed, we looked into options to install the Ford Mustang throttle body.
The factory NSX has a 64mm diameter throttle body. Over the years, people have tried various methods to increase the airflow into the engine and ultimately, increase power. For forced induction, there have been claims of ~10whp gains by increasing the throttle body 10mm.
RF Yamato offers a 2mm larger throttle body (66mm) in a core-exchange program to stuff the largest blade into the factory housing. There are other options for 68, 70mm, 75mm, and 82mm throttle bodies. The problem with these larger throttle bodies is that they are still restricted by the factory ~64mm diameter of the intake manifold.
We decided to use the 80mm throttle body from the 2011-2023 Mustang 5.0L Coyote engine since they are plentiful, we had a few laying around, and it was larger than the more common 74-75mm throttle bodies used on NSXs. This throttle body has a few different part numbers based on the generation, but they are all 80mm:
Gen 1 (2011-2014 Mustang GT): BR3Z-9E926-C
Gen 2 (2015-2017 Mustang GT): FR3Z-9E926-A
Gen 3 (2018-2023 Mustang GT): JL3Z-9E926-A –
With our newfound 3D printing skills, we originally 3D printed a spacer to adapt the 80mm Mustang throttle body to the stock intake manifold. Since our NSX is going to be turbocharged, the position of our air to water intercooler (right) meant that the throttle body location with an adapter was not going to work.
8 comments
Very clean installation.
I like it when modifications are thoroughly thought out.
Any plans to replace the fuel rail crossover hose? Those get nice and crispy after 30 years of use.
Yes, the entire fuel system is going to be replaced and upgraded in a future article. Stay tuned!
This project is heating up! Excellent work and execution. I can’t wait for the next update.
So sick, bro.
I’d love to see an article about DBW and throttle mapping!
We could do that; there is a lot of information on HPAcademy.com though.
Not that it is necessary with forced induction here, but wouldn’t independent throttle bodies eliminate the space issue entirely? Gorgeous work either way.
While ITBs would eliminate space issues, it will cost (depending on which brand ITBs) $10K – $15K – $20K or more to have a DBW ITB setup with a custom plenum for forced induction. Our solution of cutting the stock intake manifold, making a billet adapter plate and used Mustang throttle body was around $500.