prius c 1nz swap

[Zedicus]

this thread is a conglomerate from my postings on other forums, one of those is basically dead, and the other is non-public. also i have taken a fair amount of info from yarisworld. so you guys may find this stuff useful. long story short, i aquired an XB with a bad engine.

https://www.yarisworld.com/forums/picture.php?albumid=1297&pictureid=6382

put in a junkyard yaris engine that did not live long. but i got to drive it about 2 weeks.

https://www.yarisworld.com/forums/picture.php?albumid=1297&pictureid=6383

rebuilt the original engine with prius c pistons and stuff but the original Cams must have been fractured from before i got it. they broke when i went to start that engine and before i figured out what happened it pushed metal through the second rebuild ruining it. instead of having the thing crushed, i stumbled upon a 200$ 3822 mile prius c engine. (now that you are caught up, continue)

https://www.yarisworld.com/forums/picture.php?albumid=1297&pictureid=6388

the installed cam in the prius c 1nzfxe is atkins cycle, the lobe is much more rounded and longer duration. the yaris cams will be going in. the springs are a different part number, but visually quite similar so i am going to leave the prius springs in place. i suspect the prius springs may have a slightly lower spring weight to them but i am not building a race car and theres only about 1000 RPM difference in the redline of the 2 engines so i am going to run it and see. (typically i would change the springs out, but i am getting tired of tossing money into this pit so this is getting a try it or take it to the crusher last ditch effort)

other minor differences like no waterpump, no alternator bracket (it would have been on the waterpump mount) and watercooled EGR, as well as slight differences in the belhousing mount. nothing that i think cant be remedied. (the prius C engine was dumb cheap, if i can sell the prius c waterpump the engine will have been free.)

benefits: this prius c engine had 3822 miles, comparatively the yaris and other 1nz junk yard engines are 100k plus. My last rebuild was hampered by used cams and i do not want to do a real full rebuild for a 2500$ vehicle. the electric waterpump should free up some horse power, i can not use the toyota one as it is connected to the prius ECU. debating how to handle power steering and alternator. at a casual glance it looks like the power steering pump will bolt up, alternator will need a little work. rebuilt and went to start the engine:

https://www.yarisworld.com/forums/picture.php?albumid=1297&pictureid=6386


power steering pump does not bolt up with out custom bracket. (not an issue for yaris people) i gutted it and made the xb rack manual. could have used an echo rack, or a MR2 electric pump, or converted to a yaris rack and electric motor assist, however i am a cheap bastid.


https://www.yarisworld.com/forums/picture.php?albumid=1297&pictureid=6385
https://www.yarisworld.com/forums/picture.php?albumid=1297&pictureid=6389

alternator needs custom bracket.

https://www.yarisworld.com/forums/picture.php?albumid=1297&pictureid=6390

had to swap the lower case to accommodate starter location, A/C, and help make it easier to bolt the transmission up.

https://www.yarisworld.com/forums/picture.php?albumid=1297&pictureid=6391
https://www.yarisworld.com/forums/picture.php?albumid=1297&pictureid=6387


waterpump = davies craig aftermarket EWP.

TODO


Engine Mounts

Energy urethane. the scion mounts are the same as the 04 body style yaris so if you need mounts use those. the next body style yaris (07) you can mount 2 of the scion mounts in the roll stops if you have a press.

besides some cosmetics, the yaris 1.5, 1st gen XB, and echo, are virtually all the same cars.

fixing post, check back soon

[thebarber]

Following

[Neinris]

^^^ Ditto...

[Zedicus]

Prius C motor mounted in the 1st gen XB with the scion xb transmission.
2012 Prius C engine. 2006 Scion XB.

https://www.yarisworld.com/forums/picture.php?albumid=1297&pictureid=6401

i do have the alternator mounted (NOT where it is sitting in the pic) , for some reason it may need slight shimming. just eyballing the belt path and it seems to stick forward about 3 MM. unsure shy, as the bracket i made follows the line from the front engine case. nothing a washer can't fix.

i also have the Davies Craig EWP mocked up. it will basically go where the Prius C EWP was and i really only had to cut up the OEM hose to make things line up. i did have to add a section of 1/2" return coolant line to go from the heater core back into the pump. i am hoping to be doing final install on the Davies Craig EWP this weekend so i will finally have some more pictures. once that part is done it will be on to test fire.

(crappy update i know, more to come though, sorry)

[Zedicus]

davies craig EWP test fit.
https://www.yarisworld.com/forums/picture.php?albumid=1297&pictureid=6404

intake test fit with alternator and ewp.
https://www.yarisworld.com/forums/picture.php?albumid=1297&pictureid=6403

a look down in
https://www.yarisworld.com/forums/picture.php?albumid=1297&pictureid=6402

and the top
https://www.yarisworld.com/forums/picture.php?albumid=1297&pictureid=6405

just have to hook up all the sensors, the wiring for the EWP is partially complete, getn close!

[Zedicus]

i am a stones throw from test fire. it was midnight when i stopped and i still had to shower and be at work first thing in the morning.

TODO:
airbox install
add upper coolant temp sensor for EWP
finish wiring EWP controller

after test fire:
install axles
test drive

after test drive:
detail this pig, its gross.

engine install:
https://www.yarisworld.com/forums/picture.php?albumid=1297&pictureid=6407

Dash pod for EWP:
https://www.yarisworld.com/forums/picture.php?albumid=1297&pictureid=6406

[Zedicus]

i drove it around last night at midnight. Prius C engine with Yaris cam, there is a NOTICEABLE seat of the pants power increase. i think i could easily keep up with the local civic kids. Also, as i had hoped, loosing the power steering is unnoticeable at all but a dead stop.

https://www.yarisworld.com/forums/picture.php?albumid=1297&pictureid=6410

just another engine bay image. the plastic cover that is included with the scion XB would fit perfectly in its OEM location. i do not like the plastic cover and i think the engine with the aluminum valve cover and COP ignition looks better with out the cover.

https://www.yarisworld.com/forums/picture.php?albumid=1297&pictureid=6409

interior still needs work. i have a alpine head unit out of a late model Scion to mount. yes, the EWP controller wires are just stuck into the stereo harness at the moment. like i said, it was midnight and i wanted to drive it for proof of concept last night.

https://www.yarisworld.com/forums/picture.php?albumid=1297&pictureid=6408


While this seems like it is all but done, i did run into an issue. my home made flange has a pinhole leak in the weld when the engine heats up. so i need to yank the intake and my flange and get that fixed. still, this is a success.

quick list of mods that i can remember:

fidanza flywheel
exedy clutch disk
energy engine mounts
davies craig electric water pump (the only required part for the swap)
2012 prius c engine with 3822 miles
yaris OEM cams to remove the atkins cycle
yaris fuel injectors (has updated spray pattern, do not use the prius injectors)
nylon shifter cable bushings
various gaskets and suspension bushings while it was apart.

there is again a good performance increase while doing NO horsepower mods to this. it is on the OEM intake and air box, OEM exhaust. if i was doing this build for a customer i would use a MR2 electric power steering pump just to keep the OEM steering feel.

[thebarber]

super rad.

[xnamerxx]

Throw some 100 in it, you'll see a big difference. I also found it kind of interesting that with no cat the exhaust had no smell as well. Keep an eye on oil consumption though, getting the rings to seal at higher rpm's is a issue.

[CrankyOldMan]

Crazy!

Did you consider an electric power steering assist from a current gen Yaris? You'd have to add the wiring to power it and possibly fabricobble the mounts, as well as spoof the speedo sensor to deal with the speed-based assist level. On second thought, that seems like more hassle than it's worth. =)

[Zedicus]

super rad.

thanks

Throw some 100 in it, you'll see a big difference. I also found it kind of interesting that with no cat the exhaust had no smell as well. Keep an eye on oil consumption though, getting the rings to seal at higher rpm's is a issue.

i am hoping that as this was a fairly low miles prius engine that i can flog it enough to get a good ring seal. overall i won't be cruising at 7000rpm so i am not too concerned. and we only have 91oct here unless i want to register and buy AV gas.

Crazy!

Did you consider an electric power steering assist from a current gen Yaris? You'd have to add the wiring to power it and possibly fabricobble the mounts, as well as spoof the speedo sensor to deal with the speed-based assist level. On second thought, that seems like more hassle than it's worth. =)

i did, and went through that same thought process. really, an MR2 electric pump could be added too the Scion XB system and be nearly bolt on. however even that is more work than needed.

[xnamerxx]

thanks

i am hoping that as this was a fairly low miles prius engine that i can flog it enough to get a good ring seal. overall i won't be cruising at 7000rpm so i am not too concerned. and we only have 91oct here unless i want to register and buy AV gas..

Its more to do with how low tension the prius C engine rings are, its just something to keep an eye on didn't seem to hurt power all that much. On 91 it would still hit the knock sensor so 100 made that not happen, a whole lot more torque midrange between the two. Don't run avgas its got lead in it and it'll cause problems with your O2 sensors. If you're in Kansas try running 93 if you can find it.

[thebarber]

the 1nzfxe from the prius C is 13:1 compression?

[Zedicus]

13.4:1 actually.

for clarity, the prius c engine has pistons that are 13.4:1. the atkins cam makes the engine around 8:1 dynamic comp depending on vvti.

moving to the Yaris cams moves that up a lot. i figured dynamic comp of prius c pistons with yaris cams to be 11.8:1 - 12.6:1 through the vvti range, give or take. so even premium 91 oct is a little low for max performance, but the knock sensor and ECU can keep premium within acceptable.

running low grade gas in this setup would be detrimental to engine life.

previously i had actually swapped prius c pistons and rods into a bone stock yaris engine and ran the Scion cams. that combo had a little better torque curve. i believe that since the toaster is more box like, it uses a torquier cam. if you follow along up top, the scion cam is the one that broke so i moved this build over to the yaris cams i still had.

[Zedicus]

i spent a day buffing and detailing, and i dropped the newer head unit in. i wish this site supported bigger pics, but still if you look at the reflections and headlights it is pretty obvious. i still need to get the USB port and bluetooth installed, and sub and amp. but still progress.

shiny on the outside.

https://www.yarisworld.com/forums/picture.php?albumid=1297&pictureid=6411

not gross on the inside. EWP controller looks like it belongs there.

https://www.yarisworld.com/forums/picture.php?albumid=1297&pictureid=6412

[Zedicus]

i have put about 200 miles on it and so far all is well. considering i had the entire rack out and the front end all laying on the floor, the alignment is only a little off. i will be getting an alignment this week.

the accessory belt now only drives the alternator and air conditioning compressor. the belt path meant some small adjustments had to be made and also, there is about 1/4th the contact area on the a/c compressor as before so belt tension is critical. so far my modified alternator bracket and adjuster seems to be doing its job.

sadly, my 30$ alpine head unit has a bad USB port (the single feature i wanted it for.) i pulled it apart and tested the port and managed to get it to connect to USB briefly, but it seems to be more deeply broken then i care to diagnose so i will be doing something different here.

i ordered replacement keyfobs, and i am still tidying up loose ends. and now that it is shiny, there is clearly a name keyed into one of the doors. also, the top of the body is sunburned beyond being able to buff it out. debating painting or plastidip up there.

this thing clearly had zero maintenance from its previous owner. and the C50 manual transmission seems to have butter soft synchros. the ones in this transmission are all but vaporized. luckily i learned to drive manual in old pickups and dump trucks so rev match and heal-toe is fine for me. (the gas pedal is a long ways from the brake in this thing). but at some point i may have to address the tranny.

[Zedicus]

Status update:
the American alternator tensioner bracket just does not work in this configuration. i tried 3 times to turn it into a vertical and linear adjuster. while mechanically, it is possible. the strength of the item makes it not work long term. i broke it 3 times and even after welding in added strength, it would just break somewhere else.

so i replaced it with the world spec part, it is listed on this forum as a alternator bracket https://www.yarisworld.com/forums/showthread.php?t=25758 and i modded it slightly to add vertical tension. so far it is working fine. time will tell.

the other issue, even with 91 octane gas, this car makes too much power. (such a terrible problem) it has pretty much eaten a brand new stage 1 clutch. i am probably going to have to install a ceramic fiber disc and heavy duty pressure plate. (stage 2.5 or 3, for the tuner crowd)

and last note, i was correct in assuming that losing power steering would be a non issue. while it is noticeable when in a parking lot, it is not much of a difference even then. The mechanic i had do the alignment even said he only noticed when he was at a dead stop trying to turn the wheels.

final thoughts:
while i would say this is a success. i would not recommend just randomly swapping to the prius C block unless you need at least a bore job on your current block. that is about the cuttoff for it being worth the effort to swap in. OTHERWISE i would recommend swapping to the prius C rotating assembly, and Scion XB cams. that combo gives a noticeable power bump with the biggest hit in midrange. the combo i am currently on is prius C complete engine with yarris cams, the biggest increase in power with this combo seems to be in the upper RPM range. it is still pulling substantially up at the 6200 RPM redline. i have not attempted a ring out run to see how far it would run out, i suspect that since it is manual, there is no actually limiter. as such it would just run till valve float and knowing my luck the higher comp pistons would smack a valve.

with the electric water pump, no power steering, cams, and high compression pistons i fear i am putting 130HP to the wheels. this is on stock exhaust and intake. i make trips to denver a couple times a year and i am going to try and get it to a dyno shop one of these days for verification.

[06YarisRS]

Amazing thread! Impressive work!

[RomanDave]

Thanks for the posts, Zedicus!

I'm planning on doing this soon but with aftermarket ECU and some ITB.

Prior to reading this I would have been caught off gaurd about the sump swap, but managed to get one in advance.

I've seen big power gain just from ECU and intake swap on a standard 2NZ, so looking forward to what a high comp 1500cc setup is capable of with a good tune.

It's amazing how much the standard plenum and throttle body is a huge bottleneck on these engines.

[remcafee]

how does it run with stock ecu? any drivability issues? no check engine light on? i am very interested in doing this

[ccyaris]

Great effort and success and nice writeup, I was looking at replacing my mechanical water pump with ePump and noticed that the C blocks were different, which leads me to your post, thanks

[Zedicus]

1 year on update:

car runs really good, no check engine lights or any issues...EXCEPT!

The stage 1 EXEDY clutch is absolutely TOAST. on 3/14/2021 i pulled the trans and replaced the exedy with a McLeod Street Elite. i wish i would have taken pictures but i was in a borrowed garage and just did not have time. The exedy disk surface was not too bad but had been very hot, the hub and springs were trashed. the springs had been stomped mercilessly and were crushed and nearly falling out of the housing. even the splines in the hub showed significant wear. the pressure plate had gotten hot enough to deform and cause the through out bearing to ride and groove it. THANK HEAVENS i had put a fidanza flywheel in last time, it had gotten warm but was still fine.

if you do a similar engine build rather it is complete prius, or prius rotating assembly you MUST get a GOOD clutch. the EXEDY stage 1 is rated for +30% HP over stock and it slipped almost instantly. i nursed it and got almost 1 year out of it. the new McLeod clutch makes the car feel amazing, 2nd gear chirps the tires just messing around, first gear makes me wish i would have put an LSD in it while it was apart. the McLeod is rated for +50% to 70% more HP, has a massive hub and spline area, and much higher clamp load. there is a little more clutch feel at the peddle, if that bothers you, well too bad.

after the last couple months of nursing the clutch, the little toaster is exciting to drive again. watch out CIVICs, the streets are MINE.

NOTE: due to location, mostly it is guys in diesel pickups that always want to race me.


Thanks for the posts, Zedicus!

I'm planning on doing this soon but with aftermarket ECU and some ITB.

Prior to reading this I would have been caught off gaurd about the sump swap, but managed to get one in advance.

I've seen big power gain just from ECU and intake swap on a standard 2NZ, so looking forward to what a high comp 1500cc setup is capable of with a good tune.

It's amazing how much the standard plenum and throttle body is a huge bottleneck on these engines.

with the slipping clutch i have avoided doing ANYTHING that might increase HP more. Now that the clutch is fixed i will be doing an intake and exhaust sometime this summer. and hopefully i can make it to a dyno in Denver. i am going to play dumb and when it shows 130hp to the wheels or something crazy for a 1NZ i will just nod and say cool, and drive off.

[Zedicus]

i should probably mention that the EWP cools SIGNIFICANTLY more than the stock mechanical water pump. i have the majority of the frond air grill blocked off with plexi glass and when we had our subzero winter days it was still all the little engine could do to keep 160 degrees in it.

we did have a 100 degree day last summer but i did not get out on the highway, i did drive around town with the air-conditioner running and did not experience any overheating. i still have the 1 OEM fan in place and it is still connected to the ECU, so it kicks on at 205. but even getting to 205 BARELY ever happens.


also, with premium gas, my MPG is around 36 in town...when i can behave. so about the same MPG as my motorcycle.

[speedworxs]

the concerns about the fxe low tension rings, no extra oil usage?
factory ecu runs it fine? must run premium (not a big deal)

i found a low mileage fxe at an auction, and figured shortblock , cam swap would be all i need

[TheTruckster]

Very interesting write up. If you pick up a piggyback timing calibrator you can run the FXE intake cam. In fact, you could possibly use 2 FXE intake cams!

Now hear me out. On the intake side, advance the cam by one tooth on the sprocket.

On the exhaust side, a second intake cam should fit in the journals and the exhaust sprocket. Obviously the timing mark will be wildly off, so you’ll have to experiment. But IIRC, it’s +/- 11 teeth.
I don’t recall if the FXE intake cam has more lift. But the duration is something like 270 degrees. That’s better than the Scion/Echo or Yaris cams. Go price a new FXE intake cam from your local dealer.

Now, back to the piggyback timing calibrator…..probably the most expensive part, if you don’t have one already.
Anyway, just retard static ignition timing by 20 degrees. That’s all it takes to eliminate the Atkinson cycle.
If you’re worried about the piston rings? Then maybe look into a Total Seal ring package.

BTW, Toyota achieves the Atkinson cycle on all their hybrids the exact same way.
Therefore, 2zr swappers can use their hybrid variant cams too.

[Compeer]

Cool build and great that you are fixing it up and returning her to the road!

[J_Shabang]

1 year on update:

car runs really good, no check engine lights or any issues...EXCEPT!

The stage 1 EXEDY clutch is absolutely TOAST. on 3/14/2021 i pulled the trans and replaced the exedy with a McLeod Street Elite. i wish i would have taken pictures but i was in a borrowed garage and just did not have time. The exedy disk surface was not too bad but had been very hot, the hub and springs were trashed. the springs had been stomped mercilessly and were crushed and nearly falling out of the housing. even the splines in the hub showed significant wear. the pressure plate had gotten hot enough to deform and cause the through out bearing to ride and groove it. THANK HEAVENS i had put a fidanza flywheel in last time, it had gotten warm but was still fine.

if you do a similar engine build rather it is complete prius, or prius rotating assembly you MUST get a GOOD clutch. the EXEDY stage 1 is rated for +30% HP over stock and it slipped almost instantly. i nursed it and got almost 1 year out of it. the new McLeod clutch makes the car feel amazing, 2nd gear chirps the tires just messing around, first gear makes me wish i would have put an LSD in it while it was apart. the McLeod is rated for +50% to 70% more HP, has a massive hub and spline area, and much higher clamp load. there is a little more clutch feel at the peddle, if that bothers you, well too bad.

after the last couple months of nursing the clutch, the little toaster is exciting to drive again. watch out CIVICs, the streets are MINE.

NOTE: due to location, mostly it is guys in diesel pickups that always want to race me.




with the slipping clutch i have avoided doing ANYTHING that might increase HP more. Now that the clutch is fixed i will be doing an intake and exhaust sometime this summer. and hopefully i can make it to a dyno in Denver. i am going to play dumb and when it shows 130hp to the wheels or something crazy for a 1NZ i will just nod and say cool, and drive off.

Do you still have this xB? I have one and would really like to follow in your footsteps. Could I use the 1NZ-FE block with the FXE cylinder head and pistons?

[Zedicus]

Do you still have this xB? I have one and would really like to follow in your footsteps. Could I use the 1NZ-FE block with the FXE cylinder head and pistons?

it is still my daily. i did get some bad gas on a trip to denver and it caused some overheating and detonation and hurt the middle 2 pistons a little bit. but even with the internal damage i have still been driving it.


sorry all, i am not on here much but i will post some info about things i have been asked momentarily.


NOTE: the FXE valve springs are SOFTER, you will get VALVE FLOAT at 6100RPM or there abouts. use aftermarket or at least the Yaris ones. VALVE FLOAT IS BAD WITH VVT OPEN!!!

NOTE2: i had some questions about the ARP studs. hopefully you all figured it out, if not here is what i can say. if you are using ANY OEM cam, they will hit somewhere. and there are some different VVTI solenoids, some hit, some do not. basically you have to install the studs and see what hits and trim what needs trimmed. it is a long process.

[Zedicus]

the concerns about the fxe low tension rings, no extra oil usage?
factory ecu runs it fine? must run premium (not a big deal)

i found a low mileage fxe at an auction, and figured shortblock , cam swap would be all i need

no extra oil usage.

yes, factory ECU works fine, though if you get garbage gas it can not pull enough time to keep detonation from happening.

remember the lower engine case is different and will also need swapped to the Scion/Yaris motor type. and you will still only be able to mount 7 of the 9 transmission bolts. mine has ran like this fine for a long time now.

[Zedicus]

how does it run with stock ecu? any drivability issues? no check engine light on? i am very interested in doing this

my only code was for removing the power steering. i finally made a fake pressure sensor to account for the power steering line removal and now i am code free.

[Zedicus]

melted the throw out bearing, the shift fork looks to be trash, and the fulcrum ball is worn down.

doubling the HP on what was a disposable vehicle to begin with seems to hinder long term reliability. *sigh*

unfortunately for my wallet, my daughter has grown rather attached to this thing. i foresee a transmission rebuild happening this summer. and an engine refresh as some bad gas caused detonation and burned 2 pistons quite badly.

i wish this thing would not have been as fun to drive, and the looks on peoples faces when they realize that no, they will not be able to pass this particular Scion xB.

all it takes is money and time.

[Zedicus]

engine ate another clutch disk to to chatter. didnt even get an oil change out of this disk, need to address chatter, or maybe the driver.

center 2 pistons eaten from detonation caused by bad gas and the high compression pistons. hopefully i can find serviceable used pistons, ceramic coat them, clean up the head and reassemble. i should have the head off tonight.

Kaaz LSD off ebay on order.

also my home made alternator mount has some adjustments that need done.

[remcafee]

try a puck style clutch and get a new flywheel or have a GOOD machine shop that knows what they are doing resurface the original flywheel, working at a shop resurfacing flywheels has put a bad taste in my mouth lately as they dont machine the teo step surfaces even and cause vibration and all sorts of weird noises afterwards

[remcafee]

clutch masters also makes a chromoly flywheel those are basically bulletproof and its also slightly lighter too, stay away from aluminum flywheels