Month: December 2025

3S: Drive by wire installation

Watching / learning a lot about how to tune the car on an aftermarket ECU (LinkECU G4X) has been a process and one of the things often mentioned is how DBW is the best way to control idle (compared to stepper motors, etc) and it also reduces potential air leaks. I also realized if I converted to DBW, that would free up several new AUX channels on the ECU for my Coil on Plug install that is coming later this winter…. so I went down the path…

Throttle Body Installation

The Bosch 68mm throttle body is said to be a “direct” fit and just needs to be drilled out… and generally this is the case. The throttle body is already set up for M6 bolts, while the 3S Plenum is M8. So you need to drill this out to about 9mm. I had two drill bits that were close in size, I tried the smaller one 11/32″ (8.73mm) and couldn’t install it still, and ended up using 3/8″ (about 9.5mm) and it worked fine. Once you do that, the next problem I ran into was the stock bolt fitment… they technically fit but I couldn’t fit a socket over them. So I swapped them out for M8x1.25 55mm socket head caps and used some purple thread locker (retainer). The next problem I ran into was the bracket that holds the plenum up ran into the throttle body motor so I had to remove that (which was a pain if you don’t want to remove anything else).

I covered up the connector and the whole housing to prevent any metal shavings from getting into it while drilling it out…
Very tight fitment with the stock bolts and the socket on the bench. When trying to install it on the car, it wouldn’t fit…
Custom 3D Printed TPU Gasket installed (linked below).
Brackets which I removed. The one on the back of the valve cover had three bolts, 2 12mm sockets and 1 10mm socket iirc. The steel braided oil lines to the turbos are pretty rigid which made the removal more annoying. If you pulled the plenum off it would have been easier….
Finally installed with the brackets removed.
All buttoned up. The previous silicon coupler fit, but it was tight. I had to increase the size of the t-bolt clamp. The previous one was 67-75mm (iirc) and this is just a tad too big. I have a 73-81mm ordered. I do not plan on replacing the silicon coupler though.

350Z Pedal Installation

I bought the pedal adapter from Outsider Garage over the EvoSpec one as the pedals were much more commonly available and significantly cheaper I think I paid $55 shipped for mine (used) versus most evo ones were close to $200. The pedal adapter was only $45 which was cheaper than I could make / design this myself (as I was going down this path originally).

There is a piece of folded medal on the back of the 350z pedal that needs to be removed, otherwise you only have about 1/2″ – 3/4″ travel on the pedal (probably about 30% it’s total capacity). I removed a good amount, and now the pedal hits the floor. I would argue I have about 80-90% the total throw now, and once you get it into the ECU you calibrate it and so it’s not a big deal. I do wish the angle on the adapter was a little steeper so that pedal stuck out further, but it is what it is. I know outsider garage sells a replacement pedal for this, and maybe that fixes some of my complaints.

The adapter shifts the pedal to the left a bit as it’s more inline with where the stock one was.
You can see it sits a bit lower than the brake pedal, but it’s in a good position (horizontally)
Back of the pedal trimmed down.

Wiring

Wiring was my least favorite task of this whole effort. I really didn’t know where I wanted everything pinned to in the ECU, but I eventually came out with a solution that cleaned it up a little, but didn’t require me to re-wire everything. I had a lot of wires on my expansion “ports” for the ECU previously but I moved them to the main harness and used the expansion port for the DBW as it was designed for that. The throttle body and the pedal both need 2 sensors each ( redundancy ), and the TB needs two (three) AUX ports.

Throttle Body Connector is a Tyco Electronics Micro Quadlok System (TE MQS 6 Way). I originally purchased this from Haltech as it was convenient, but they are expensive and don’t give you any extra pins and I messed up the first one which was annoying. You’d think for $16 they could include an extra pin that only costs them pennies. Anyways it used a lot smaller pitch crimp, I don’t recall which exactly it was, but it was around 1.6 in size based on the “Engineer” crimper I have.

The pedal I bought came with a pigtail that was long enough for me to swap it over to a TE Deutsch DT connector which I use for all the connectors I can. While it’s a bit larger in size, it’s a good strong water proof connector. I am 99% positive the Nissan 350z is a Sumitomo MT branded connector. I have linked it below in the event you need it.

I’m not going into the tuning process at all. That’d be a whole discussion by itself. I will admit I messed up one setting when I first turned it on. I changed everything to the throttle position…. except my “startup offset” which was set to 10, which meant it added 10% throttle to the idle base position… so the car idled at 3k RPM on a cold engine… thankfully that was an easy fix, but I rather not idle at 3k on a cold engine…

This is my overall pinout. At the point of this post, I have completed everything in Part 1. The left column is where it was prior to the install, the yellow highlight is things that are pins that have moved from their stock location. The orange ones are the proposed changes for each “part” of the upgrades this winter. Hopefully Part 2 will be all that I ever have to do for this car [we know it won’t be].
This is my expansion ports on the Link G4X Plug-in ecu. I never really thought I was going down the DBW path and didn’t realize that connector 2 was really made exactly for the DBW setup… so that’s why i had to move most of my sensors to the main harness.

It Runs!

Testing out the pedal and throttle.
Actually running!

Parts List:

Bosch 68mm Electronic Throttle Body – 0 280 750 156
Throttle Body Gasket (Makerworld)
Outsider Garage 350z Pedal Adapter
Nissan 350z Pedal (with pigtail or Sumitomo MT-6S-3)
TE 6 way MQC (OEM P/N: 1-967616-1)
M8x1.25 55mm Socket Head Cap Bolts (4x)
Mishimoto 73-81mm Constant Tension T-Bolt Clamp

Disclaimer: This is just where I bought stuff from based on prices and shipping times. You can probably find cheaper / better parts if you look around more for some of these items.