Toyota Echo/Yaris Coil pack conversion for RB25DET
This is a full conversion guide from RB25det to Yaris/echo coil packs.
In this guide, i'm going to try and include as much information as I can but please forgive me as i'm an electrician and not the best at writing.
This is an insight how I did it. Please treat this as a guide, and don’t crucify me if you don’t agree on something I’ve done cheers.
- Please read full guide before attempting coil pack conversion, cheers.
First, bit of background:
I decided to attempt to convert my RB25det to yaris coil packs, I found there's not a huge amount of information out there about this conversion other then people just selling "conversion kits". I found a few really good informative websites about coilpacks & wiring information (which i'll link), and a few photos of some rb's that have been converted, other then that I didn't really find any guide for it.
I personally was on a bit of a budget & thought what you got in the conversion kits for the money plainly wasn't worth it.
Why Yaris/echo coil packs?
-Cheap (i'll include prices of what i paid for everything.)
-Don't suffer from heatsoak as bad as Splitfires or OEM coilpacks
-Good for 100hp per cylinder
-Tried and proved method, common conversion for the 1j and 2jz boys.
-Heaps of information around for them, including dwell times etc
First thing to do is get some coil packs and plugs, I decided to go for Toyota Echo/Yaris coil packs part number:
I went to 2 local wreckers and found 8 coil packs for a total of $100, depending where you go this might vary. I could have got 6, but for the money & the chance of me blowing them up, I thought it would be a good idea to get spares.
A trip down to DIY Wreckers with a pair of side cutters looking for Corollas, Camrys, Echos and yaris’s for the 4PIN denso coil pack plugs, these cost me next to nothing, make sure when you cut them off you leave yourself plenty of wire to rejoin them.
Part 2: Mounting plate
After looking at a few of the conversion kits, & photos of finished cars this is what I came up with.
I used aluminium 4mm plate.
The 3 bolts I used to mount the plate to the cylinder head were 70mm long, same thread as the standard coil pack bolts that go into the head.
I also got a 12mm long bolt the same thread to earth the head using an eyelet using the last bolt. Think they’re 10mm metric.
Mounting coil packs to plate:
While I was at the bolt shop I also got 6 x 10mm bolts 35mm long, with 12x nuts.
I used the bolts from the bottom, up through the top of the plate & secured them with a nut, then with a washer & an extra nut secured the coil pack to the plate.
I don’t have measurements of these holes, as I marked them on the car with a sharpie.
Picture tells a thousand words:
Here we go, the wiring:
When using the Denso coil packs, I found the wiring diagram and information about the coil packs on:
[Pin 1] Earth / common ground: This grounds each coil to the body / earth, an electric connection to to the cam cover alone is not at all suggested.
[Pin 2] IGT / trigger: The signal wire to activate the firing of the coil, triggered directly from the ECU's ignition output. These can paired with another coil for a waste spark connection, for example using two ECU ignition outputs to run four coilpacks. See the next section for more on this subject.
[Pin 3] IGF / ignition feedback: Used by OEM ECU's to confirm the firing of the ignition coil. If a coil malfunctions the ECU will sense the lack of this fire confirmation and put itself into a fault / limp mode. This is not normally used at all with an aftermarket /stand-alone ECU and hence only three wires are used for each coil.
[Pin 4] Power (+) / ignition power: This is the main power supply for all of the coils, this power feed is activated when the key is turned to the "Ignition" position. The most common and suggested method of connection during a conversion on a four cylinder is to remove the power feed from the original single ignition coil and use it to power all four of the new coilpacks.
Pulled straight from SQ engineering, whoever you are thanks!!!! I’ll buy you a 6pack get in touch with me.
Now that we know the pin outs of the Coil pack, it’s simply easy to just work out the skyline coil pack trigger wire pin out, & use the factory 12v plug to give them power.
Coil Pack Trigger wire colours for S1 RB25det
Cylinder numbering goes from Front of block towards the back.
Cylinder 1: Blue and Orange
Cylinder 2: Blue and Black
Cylinder 3: Blue and Red
Cylinder 4: Blue and Yellow
Cylinder 5: Grey and Black
Cylinder 6: Purple and White
To join the factory trigger wires to the new coil packs, I cut the factory plug off the trigger wires, bought a 6pin water proof automotive connector from jaycar & terminated my new coil pack loom and the factory harness to the corresponding wires.
For 12v i cut the factory plug off the original 2pin connector off your old coil pack harness & solder that to your ground and 12v, think the white was + and black/red was -.
Use your multimeter to confirm this.
The ground wire (-) needs to be doubled up with the ground from the 2 pin plug & also your cylinder head.
Once loomed all taped up, plate and coil packs mounted.
Drives awesome, no hesitation at around 17psi.
This guide got way out of hand. F***.
If anything seems unclear please let me know so i can edit, cheers.