drive by wire conversion

alanjuggler

alanjuggler

Member
hello chaps,

I'm currently still working on the 180SX RB25DET thing, I've just invested in a Haltech Nexus plugin for the ECU - from Jez @ Horsham Developments. Essentially just to get away from MAF.

as part of that, I'd wanted to go drive by wire, for all the assorted benefits. I have an E51 Elgrand as well, so was playing around, and realised it uses the same throttle potentiometer as the 350z, then realised the bolt pattern was the same.

The E51 pedal assembly bolts in to the S13 chassis, is about half the price of the 350z unit people use (I paid £40 with the wiring connector and a couple of inches of pigtail) - and with some blow torch work to bring the main bend closer to a 90 degree bend, with the one closer to the pedal bent the other way to correct that angle, lines up rather well. It doesn't have the kink to the right I think the 350z pedal has, so I think is more suitable.

I'm just documenting this fact here in case anyone else ends up doing it - I can't say whether it's the same on the S14 but I can't see why not.

The throttle body itself is £150 or so, the adapter for the RB25 Greddy manifold Q45 pattern is £100, and the 'sleeve' type arrangement for the front of the throttle was £60 or so.

With the costs of the wiring, connectors etc - I think it'll be all in for £400 or so.

I suspect no one will see this for a while - but at least it's in the internet now :D
 
didn't realise my subs had lapsed. paid up. A forum write up? I feel like I've gone back in time :D

Before I even start this - you need an ECU that's capable of running a drive-by-wire, Haltech, Link etc. and second, I'm using a Haltech Nexus plugin for the Skyline blue 76pin ECU plug, the Elite range has some changes (mostly the wiring assignments, see here: https://support.haltech.com/portal/en/kb/articles/drive-by-wire-throttle-wiring-7-4-2020).

Third and finally, if you want it easier and don't want to crimp connectors on wires and mess around with wiring diagrams, you can buy a complete kit from OutsidersGarage.

https://outsidergarage.com/products/nissan-s-chassis-s13-s14-s15-complete-dbw-conversion-kits - they do an R chassis variant too.

A tight bugger on the other hand (like me :wack: ) - carry on reading.

Shopping list:

Pedal (£40 - ebay)
ThrottleBody (£140 - ebay - PartsinMotion)
Connectors and wiring for both of the above (you can get the bosch connectors on ebay for £5-8) (about £50 total, assuming you have the tools)
Sleeve for the throttle to go to either silicone hose or the wiggins style clamps, whichever you fancy (£50)
Adapter for the throttle to go to your chosen intake manifold (£120 incl shipping from the US)

Pedal:

The vehicles you can get the two bolt pedals off that I've found, the sensor is the same part number 18919-AM810 - the Elgrand is the cheapest, though most often gets the wiring cut right by the plug by the eBay breakers. Elgrand didn't need much to correct the pedal position with a MAPP gas blowtorch.

T30 X-Trail (seems to use a different potentiometer, check before buying)
E51 Elgrand
Z33 350z

There may be others, they're just the ones I've found.

Modification needed for pedal angle - click through for the full size versions.



S13 Throttle pedal original position



E51 Throttle pedal final position:




Throttle Body

I chose the 68mm, I think most people go for the 74mm but I'm after maximum driveability without having to try and tune around it. I think 74mm is more popular, so stuff is easier to source.

68mm throttle part no: 0 280 750 156
74mm throttle part no: 0 280 750 474
84mm throttle part no: 0 280 750 473 (plus possibly 0 280 750 101 which is the 'motorsport one').

Wiring:

Wiring for throttle body:

I'd heard that running unshielded wire to the TPS on the throttle body can cause issues with various bits, here's the best wiring source I found for shielded, twisted pair 'tefzel' wire, that didn't need me to buy 1000m reels.

https://www.gps.co.uk/product/2-core-20-awg-screened-airframe-wire

I used unshielded 18AWG (0.8mm2) for the motor power and earth, the screened/shielded wire above for the TPS 1/2 pins in 20awg (0.5mm2) (make sure you only ground one end to the ECU, not both ends), and then unshielded 20awg for the 5v in and earth.

Pin 1 & 4 are the motor power & earth - these go to your 'half bridge' outputs on the Haltech (AUX7&20 for me) Pin 2 goes to signal ground on the Haltech (AUX10), Pin 3, TPS +5v gets it's power from the Haltech +5v rail (AUX23), Pin 5 & 6 are the two outputs for the TPS, these are the shielded ones, they again go to your Analogue Voltage Inputs on your Haltech (AUX8&21)

Wiring for pedal:

I used unshielded 20awg for it all, if I have problems with the signals, I'll feel a shielded/screened cable through.

Pin 1 & 3 get joined together and sent to Haltech Sensor Ground (AUX10 for me) Pin 4 & 6 get joined together and get sent to Haltech +5v (AUX23). Pin 2 & Pin 5 go to your selected Analogue Voltage Inputs on your Haltech (AUX 9 / 22).

Haltech is configurable, so you can pick whatever you want, this is what the Nexus plugin defaulted to.

OutsidersGarage post the pinouts you'll need:

https://outsidergarage.com/pages/installation-help

Double check the pinouts I've posted, I take no responsibility for people doing it wrong and breaking things.

For wiring into the Haltech after you've changed your throttle choice to whatever Bosch unit you may have bought, the wiring need to be assigned / checked. I'm using the Aux connector, just because the Haltech came with spare pins, though you can re-assign stuff in the OEM Nissan connector if you fancy.

Haltech-pinouts.jpg

Haltech-HBO.jpg

Haltech-Pins-5v-ground.jpg

Haltech-Sensor-Pins.jpg


Sleeve:

I bought mine here:

https://motorsportsupplies.co.uk/ - they do ones for all 3 major variants of the Bosch throttle.

Adapter:

I bought mine here:

https://outsidergarage.com/collecti...tronic-throttle-bodies?variant=44810616111265

Superforma/JDMGarage sell some that go to the RB25 manifold in the UK but they only reference the 74mm & 82mm, so I caused myself problems here.

Idle control gubbins

This is one of the main reasons I'm doing this, the old Nissan stuff is getting difficult to find and I've always found it limited once you've moved too far away from OEM, understandably. You'll need to fab or buy a plate to cover the original manifold hole and blank off the idle bypass from the intercooler pipe.

Software setup

Change the settings from cable throttle to your chosen throttle body, it'll open up the wiring assignments, change the colours to whatever wiring colour you used, run the calibration, it figures it all out.
 
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nearly, for cruise control in Haltech you need a clutch switch and brake switch wired in.

Brake pedal switch is easy enough to tap from the original, the clutch switch would need adding, probably easy enough to weld a plate on with another cheap brake light push switch bolted in but more fab and a little bit of wiring.

You'd need some nice way of triggering it and showing it's activated. Haltech make their keypads - and you can 3d print one for the ashtray hole in the S13.

https://cults3d.com/en/3d-model/various/haltech-keypad-mount-for-s13-240sx-200sx-silvia

I can't bring myself to get rid of my JDM 'NON SMOKERS BOX', too much of a nerd, so I'll have to figure something else out.

The other thing is traction control, I'm tempted to add hall effect triggers to read wheel speeds and then it can do that too.

I've got the alloy bell Apex 310mm kit, so I think it'll pick up off the back of the nuts with the right bracket etc.
 
this is excellent, i used a 350z pedal in my s14 but it never crossed my mind that an e51 pedal would also work, having the same engine and driveline, this is a great idea!
 
forgot to update this - on the clutch switch side of things, if you buy the proper metal bodied brake light switch for an S13, you can just use it as a pedal stop anyhow, so it takes 30 seconds to remove and re-fit.

I realised when I saw a 240sx as they have a clutch switch 'on' required for starting the engine because America.

I've just been driving it but recently took some damage parked on the road in a cul-dec-sac. no note. turns out I had filler on the back corner from a repair in Japan that just fell to bits so have been pulling that straight and remembering why I hate painting cars :D
 
I’ve got the 350Z pedal in my S14 all wired and working but in wrong position as it’s just bolted straight in currently. Did you use a bracket or bend the leg?
 
there's a rubbish thumbnail up there of what I did - I closed down the upper bend and then opened up the lower bend to get it back. blow torch, a vice and some water pump pliers.

there's 3d print files I've seen online for it too - little shim type things.


I've probably got mine set about a centimeter higher than I really want - but that's to be sorted in winter. From memory, 350z pedals have a kink that's awkward to sort out with the blowtorch route - the Elgrand E51 is straight like the S13.
 
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