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Discussion Starter · #1 ·
Im thinking of doing a transplant of the Prius powertrain into the Scion xA, using a salvaged Prius and a salvaged xA. There are a few problems though, im nto sure about the frame if its wide enough to take the prius engine. I would think after this transplant the curb weight for the scion xA would be about 2500 lbs or so. i posted on priuschat a procedure what do you guys t hink? close?

what it hink the procedure for doing this swap is :

1. Disconnect HV Service plug
2. Drain all fluids (brake, some engine oil, inverter coolant, maybe hv transaxle )
2. Disconnect the inverter, two ( or 3 on the 04 not sure ) HV plugs, and the 3 or 4 wires to the elec motor ( 3 bolts )
3. Disconnect inverter circuit breaker sensor, and the 3 wires on the right side of the inverter.
4. Remove inverter ( take out the neccessary bolts)
5. Remove air cleaner
6. Disconnect fuel injectors and spark plugs
7. Disconnect throttle body motor connector
8. Disconnect the sensors located on the front of the electric motor and air compressor and such.
9. Disconnect the fuse boxes ( not too sure if you can ? )
11. Remove the thingy that the exhaust is on, including o2 sensor connectors, and insert random other connectors
Then im not sure what to do from here, either go in the interior of the car strip it and disconnect all ECU's and pull the wiring harness through the firewall into the interior. then..
10. Support the engine and transmission with a jack and remove the mounting bolts including torque rod and remove the engine and trans.
12. Pull the rear of the interior apart, and disconnect the two HV wires behind the back seat, then route it through the floor and remove the high voltage wiring ( this is for the HV battery to inverter connection )
13. and random other Hv battery info stick here

also during this swap i believe the SRS will not work, or it will, it depends on the vehicle you are converting, i believe most new toyota and lexus's share similar airbags, but i believe the SRS is also connected through the HV ECU and the ECM, this is due to the circuit breaker that shuts off power in the event of a airbag deploying , seatbelt charge releasing etc.
and im tired so i wont continue maybe tommorow

oh yeah, after the swap you need to make sure that all the wiring harness's are properly stowed away in the safe places, especially the HV wiring that runs from the rear, also the ambient temperature sensor and random other stuff thats on the prius, its simple, just i hope toyota used connectors on the harness that are different for different ECU's, because im not sure how i would figure out which plug goes to which ECU unless i color code everything

im not sure if this applies to the 04-06 but i have worked on the HV system on the 01, including removing the inverter and charging the HV battery.
 

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Prius Transplant into Scion

I don't want to discourage you from doing this, but it is a really ambitious undertaking. Also, considering your age, do you have any basic electronics training?

As you probably know, the voltages in the Prius traction battery are not like the 12v DC system in most cars. The voltages are high enough to be as dangerous as the 220v AC system in home clothes dryers, air conditioners and heat pumps, which demand knowledge and respect. In addition, I think that the AC coming out of the inverter is 3-phase, which is like aircraft power, and carries much more current than single-phase AC.

An error won't result in some sparks and maybe a hot wire. We're talking voltages high enough to electrocute a person, and enough current to arc weld. Plus, little things that you don't worry about with 12v DC, like standing on a wet floor, can have serious consequences with high voltage. (You wouldn't work on a toaster while it was on, while standing in water, would you?)

Unless you have some formal training in electrical safety and are familiar with handling high-voltage circuits, I suggest that you find an experienced person to assist you, to avoid serious injury or possibly death.

I admire your spunk, and wish you luck in what may be a very challenging project. I am sure all of us will be interested in your progress, so keep us posted.
 

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Are you talking just the engine, or the entire drivetrain? You won't be able to use the engine by itself, since it is an Atkinson-miller cycle, and needs the electric counterparts to overcome the deficiencies (power I think) of the Atkinson cycle.

Also, consider you also need to transplant the brake system, since the hydraulic brake controls work in conjunction with the hybrid's regen braking. Thus you also have to consider the pedal controls as the car drives pretty much entirely by wire both with the accelerator and the brake pedal.

The wiring harness from the inverter to the HV ecu is extensive, since each phase of the motors, sensors, and a bunch of other stuff are individually controlled by its own wire.

If you don't have the Prius repair manual, or a subscription to Techinfo.Toyota.com, I suggest you get one and study how the car works and is built. Otherwise, there's no way you will succeed.
 

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Discussion Starter · #4 ·
ye

i have worked on high voltage systems on the 2001 Toyota Prius, i know the precautions with DC voltage and such, i have charged the HV battery on my 01 with a high voltage charger, i understand electrical safety. and yea i want to transplant the entire hybrid system into another car, from what i know the hybrid transaxle does not have much wiring harness connectors, mostly on the front of the motors, mainly sensors and the HV wiring from the inverter. Trust me i know the dangers working on high voltage DC systems, ive been working with electronics all my life, im A+ certified ( not worth much ) and MCP and CCNA just to show im very proficient in a lot of fields.
 

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I think it would be WAAAY easier to install your own custom, hybrid system to the vehicle.

This has been tried on several gas-only vehicles so far. An interesting approach is to try motorising the rear wheels. It's quite a simple approach - stick a battery and controller etc in the back, then power the rear wheels from grid-charged electricity. Hey-Presto - a DIY plug-in hybrid that would get better gasoline mileage than a Prius.

This guy has managed to get a long way with putting rear-wheel EV-drive on his Insight:

http://www.seattleeva.org/index.php?title=User:Rjf/Insight_Modifications#Rear_Wheel_Electric_Drive

With this approach there are thousands of EV conversion experts online that could help you with every step, and you wouldn't be constantly trying to cram something designed for one space into a smaller one.

Another approach is just to feed 5 kW or so to the engine directly. You just stick a small motor under the hood and connect it somehow to the crank or output driveshaft (by toothed belt or similar).

HTH! :)
 

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You still haven't addressed the brake system that is in synergy with the hybrid system, and there are quite a bunch of wires from the inverter to the HV ECU.

On 2002, there are 8 wires from MG1 to HV ECU, same for MG2, 25 from inverter to ECU.

MCP doesn't mean you know electronics. Even a CCNA doesn't mean you understand electronics, only networking. An A+ will get you started, but far from engineering a Prius transplant. A BSEE would be extremely helpful, nearly required unless you have related experience.

It sounds though, certifications aside, that you have enough experience to start. A transplant though is far different than rebuilding an existing Prius.
 

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Discussion Starter · #8 ·
dan sorry about mentioning about certifications, i mentioned it becasue it seemed like my age was a factor when it came to the amount i knew about electronics, and technology.

arent most of these wires that go from the inverter to MG's plug in, i know there are a few on the front of the MG, i mean, when i disconnected the inverter on my 01 prius that i rebuilt it had 3 wires in the back of the inverter ( left side box bolted down ) and 2 wires on the back of inverter ( right side ) and in front right there were from my memory 2 wires, and then the wires that connect to the side of the inverter which i think comes from the ECU's. And I unbolted the front brackets and rear brackets from the inverter and it came right out. ( maybe theres a few more tiny things i forgot )

Dan, im a kinda of a hack and fix type of mechanic, make it work and im happy. Im thinking that the Prius including the inverter/converter and MG's are connected via harness plugs, and since it is on a harness, i dont think i would mismatch the connector placement, the only problems are the ECU's. And about the braking system, during regeneration the MG's create a resistance that charges the battery correct? , putting the 04-06 prius aside, i would think that the braking system on a 01 -03 prius is simple, consisting of a hydraulic brake booster, a solenoid and brake ECU and the speed sensors correct? and a couple of sensors that go to the front and rear wheel cylinders. Does the 01 - 03 prius have a electronic power steering ECU and skid control?.


I dont think this is too big of a undertaking, minus the high voltage im going to be dealing with.

The major problem for me is the mounts for the engine and MG's
 

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Inverter might have 3 CONNECTORS, but hardly only 3 wires. Each transistor in the inverter controlling power to the MGs has a wire going to the HV ECU. 3 phases, 2 transistors each phase, 2 motors, 12 wires minimum. What goes to the MGs themselves is sensors so the HV knows the speed and position of the rotors, along with temp sensors and the like.

As for brakes, the 2001/2003 calls the ECU the ABS ECU. There are solonoids in the actuator to control the individual wheels though not to the degree of the 2004/2006. Still, it has to communicate with the HV so they can work in tandem and at appropriate forces.

For 2004/2006, the skid ECU completely controls the brakes. Under normal mode (no failures), the master cylinder has no hydraulic control of the wheels at all. The skid ecu receives the pedal stroke speed and distance, determines desired stopping force, asks the HV ECU to produce that force, HV responds with how much it can comply, then the skid ECU applys the difference hydraulically.

All Prius have electric power steering. After all, how would you have hydraulic pressure to turn the wheels if the engine is off?

If you don't have one, do yourself a favor and get the repair manual, New Car Features, and wiring diagram either in hard copy or from Tech Info and study how the car works. Re-engineering is vastly different from repairing, and to do what you plan to do, you'll need to understand the car intimately.
 

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HV ECU on the classic has 6 connectors, inverter has 6 connectors.
I10 appears to have 8 wires, I9 has 6, I12 appears to have 6, I11 has 6
Then the DC-DC converter has about 5 wires.
I may have missed a wire or two.

Now some of these wires are shielded, as they carry low voltage high frequency signals, so if you are going to make your own harness, keep that in mind.
 

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Discussion Starter · #11 ·
oh

wow thanks dan i didnt know the ABS ecu also was sending stuff HV ECU too, this car is crazy, and yes i do have electrical wiring diagram for 01-03 and 04-06 and repair manuals for both too.

Time to study some wiring diagrams
 

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I will admit I don't have as much knowledge on the classic as I do on the G2. For the 2003 I only have the wiring diagram. But I would imagine that the two ECUs would have to chat to determine who contributes what braking force.
 

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Discussion Starter · #13 ·
Dan does the SRS ECU also go through the HV ECU, i remember that on my crashed prius the vehicle would shut off the fuel pump and turn off ready mode, i have to study the electrical wiring diagram. I would imagine the 01-03 prius transferring into a other vehicle to be easier than using the 04-06, because the newer prius has a lot of more sensors than the 01, i just got my CAN upgrade on my Actron scanner, plus i bought a CAN to RS232 adapter so ill start seeing all the stuff i miss with my actron scanner. Im suprised they actually have a sensor on the 04-06 prius that measures the barometric pressure.

Yea well, i have to get to read these electrical wiring diagrams,

the problem i think with a transplant is the SRS ( other safety components ) and ABS, and related ride control components.
 

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Yes, the SRS ECU does communicate with the HV ECU. I thought I had read and saw a scoped output of the signal, but I can't find it now. If I remember right, there are 3 digital signal types sent to the HV: SRS OK, SRS malfunction, SRS deployed. When the HV ECU receives an SRS deployed signal during a trip, it disengages READY. You can afterwards continue on your next trip by restarting the car. Assuming of course that the car is otherwise drivable.

The body ECU is also sent the SRS condition which is also sent to the A/B pin 11 of the DLC
 
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