How To: Swap a Daihatsu YRV Turbo K3-VET into Myvi
First question is always, whether you should buy a Daihatsu YRV Turbo K3-VET half cut or an engine “kosong” or engine “lantai”. With a half cut, you can start the engine and test the gearbox, so you will know if it is in running condition complete with the wiring; whereas engine “kosong” or engine “lantai” has been removed from the car and may not be complete with wiring or may not be mechanically sound.
While the K3-VET and K3-VE are the same family of engines, the Daihatsu YRV Turbo uses subframe mount while the Myvi uses a 3 point body mount so this needs to be addressed. To transplant the K3-VET engine in, you will need a few things:
- Engine Mounting #1: Timing Chain Cover
- Engine Mounting #2: Gearbox
- Turbo Exhaust System
- Air Filter
- Basic Service
- ATF Cooler
- Cooling System
The timing chain cover on the driver side of the K3-VET does not have an engine mounting point. What you can do is transfer the timing chain cover from your original K3-VE engine to the K3-VET engine, or buy a new one for around RM8xx.
Left:K3-VET without mounting tab, Right:K3-VE with mounting tab & engine mount
On the original K3-VE gearbox’s passenger side, there are 3 holes for the mounting to fit the engine onto the Myvi. You can either custom make a bracket or find a Daihatsu YRV K3-VET gearbox case that comes with the mounting holes. Daihatsu YRV Turbo R has the mounting holes, and some Daihatsu YRV Turbo have the mounting holes as well. It is always better to have the stock mounting holes than to make a bracket.
Left:Gearbox without mounting points, Right:Gearbox with mounting points
The wiring is essentially reversed between the YRV and Myvi, and to make everything work electronically, the wiring must be modified to utilize roughly 1/3 of YRV’s wiring and 2/3 of Myvi’s wiring. This is time consuming, and its best to go with a workshop that has done it before as they would have memorized the wiring diagram at the back of their heads. Don’t be a guinea pig!
A glimpse of the wiring work required
Myvi’s stock exhaust system is ~1.6″ which is not enough for a turbocharged engine. Get an exhaust system of at least 2″ in diameter. For reference, the Daihatsu YRV Turbo has a 1.8″ stock exhaust system.
D-Sport 2″ Titanium Tip Muffler
The stock YRV Turbo air filter box will not fit into the Myvi, so you’ll need to get a small pod filter to fit. The best place is on the driver side as the radiator on the passenger side gets very hot. The smallest Apexi Power Intake Filter model number 500-A024 will fit with the Apexi YRV adapter, or a custom adapter. Several smaller diameter K&N pod filters will also fit.
Apexi Power Intake for Daihatsu YRV in Myvi
Get new spark plugs, v-belt, coolant, engine oil, atf etc. Don’t be cheap on essential items. I’ll post a service guide for the K3-VET engine soon.
The weather in Malaysia is hot all year long, coupled with the heat generated from the engine and the stress of handling the torque produced, the gearbox is under a lot of pressure. Even the latest Proton Saga FLX and Proton Inspira comes pre-installed with an ATF cooler from the factory. It is definitely a must to ensure trouble free service for Malaysia conditions. You can use an oil cooler from kedai potong or buy a brand new one. Remember its better to get a good used one, rather than a cheap new one.
Denso 13 row oil cooler salvaged from some Japanese car
The stock Myvi cooling system was designed to handle the heat of a 91 hp K3-VE engine. The K3-VET generates 138 hp, a 51% increase. You can add an additional fan for the radiator or even better, upgrade the radiator. The original YRV radiator can also be made to fit with extensive modification to the Myvi’s mounting.
Additional 9″ radiator fan in front of the radiator
This is the basic necessity to transplant the K3-VET into the Myvi. It should take around 2 weeks to complete the job. If someone tells you they can do it in 3 days, walk away. To know if a workshop knows their stuff, you just need to ask about the mounting and wiring and see what they tell you.