Will newer Engines be a direct fit on a 2006 model?

I believe you may need to stay within the same generation. 2009 or earlier would likely work.

 

I thought I seen a post where a newer Yaris 1.5 Liter was swapped in for the 06 Prius 1.5 Liter engine.....

 

I would do a bit more research on that swap. Unless the Yaris is also a Hybrid?? That 1.5 is not the same as the 1.5 engine in the Prius. The Con Rod's and the crank maybe different?? It was done in order to increase "Dwell, time at the top of the stroke," in order to make the auto stop/start more efficient, Ackerman Cycle.

The Internal Combustion Engine

 

There was “talk” of a Prius C 1.5 into a 2009 and down but many harness issues are present
along with ports, coolant, exhaust being off and not aligning

Low mileage 2009 and down Prius motors aren’t exactly rare, some have gotten them for $75 out of a wrecker

some have wished they could swap the Gen II into the gen III


And there is this guy @Grahams2

Can a 1.5 prius C engine be installed into a 2006 prius | PriusChat

he never did answer how or show any pics YMMV

 

Technically anything's possible with the right amount of money. But I highly doubt it can be done with only "minimal changes".

The hard part about Prii is the hybrid aspect. If you want to swap engine types, whether you want to keep it a hybrid it not, then you basically have two options.

One, swap the whole engine and transmission* out for a set from another vehicle with it's ECU. This will require a lot of fabrication.

Two, fabricate whatever mating plates you need to connect the new engine to the Gen 2 transmission* and then after you have the new engine installed rig up a stand alone ECU that can also control the hybrid drive train.

The reason why this is so prohibitive is that whatever you do you're likely going to be one of the few, or perhaps the first or only one to have ever done this. Also engine type swaps are normally done on non-hybrid vehicles where a universal or engine specific stand alone ECU can be used and the transmission can work by itself without the need to be integrated into the ECU. But the ECU on the Prius needs to control it's own specific engine and it's own specific hybrid drive train at the same time.

You're best off with another Gen 2 Prius engine. And if you want to increase efficiency then you're best off looking swapping the whole car to like a newer Gen Prius or some sort of EV or Plug-in Hybrid.

If you really want to increase efficiency on a Gen 2 Prius then aero mods, weight reduction, hypermiling, plug-in conversations CAN Bus spoofing and/or CNG conversion are your next best bets before engine type swapping. Even modifying the Gen 2 Engine to something like a miller cycle engine would probably be more cost effective and produce better results than engine type swapping.

*Or transaxle, gear box, power split device, CVT, or whatever else you want to call the transmission.

 

Hmm, a Prius C engine?? Well that looks a PIA for a straight forward R&R?? But the OP say's he has a line on a more "normal" 1NZFXE, from a Yaris?? And while it is not the same as the OEM engine in the Prius, it does appear that it can work??

So if that is the case?? You have to ask why did Toyota feel the need to change it to a Ackerman cycle engine?? I don't know?? But they must have had a reason??

Generally speaking, you can build a motor for torque, hp or durability pick two. As a general rule you can't have all three?? Least way's I have not been able to do so, thus far?? Chrysler is the one trying right now 707 hp or more I don't know with a factory warranty! But generally speaking ... they know those car's are gonna hit a tree or some immoveable object long before the warranty is done ... just saying.

It would be more expensive and time consuming but I'd go with rebuilding the OEM engine that is in the car now?? Short of a rod going thru the block or breaking the crank?? The OEM motor should be rebuildable?? Not cheap but back to OEM reliability if done right. With a used motor you don't really know what you are getting???

 

Fuel economy

or maybe they were attack on Titan fans

 

If it's from a non-hybrid, it'll be a 1NZ-FE, not -FXE. The X version is the Atkinson one used in hybrids.

A 1NZ-FXE from a c will probably bolt up ok to the transaxle and the mounts. But it will have an electric water pump that the existing ECM won't know how to turn on, and an EGR system that the old ECM won't know about (and a different exhaust manifold for the EGR to tap from, which might not line up with the old exhaust pipe), etc.

 

Just three years ago it was thought that a Gen 4 engine couldn’t be used in a Gen 3, but we all know how that turned out.

 

Your Volunteering to swap a Gen IV in a Gen 1?

I would love to see a Prime into “other Prius” swap

lots of folks say this is impossible though he had it mostly finished in a few months

1946 Chevy pickup truck is world's oldest Prius hybrid. Really.

 

The Atkinson cycle engine gets 150% better gas mileage. That is about it, if you can live with 66% of the MPG, converting to the Otto cycle COULD be done.

Atkinson cycle - Wikipedia
Otto cycle - Wikipedia

 

I think the biggest issue is would the Gen 2 water pump and belt tensioner bolt up to the newer timing cover. I think the EGR, or lack thereof would be an easy manifold swap.

 

time for question marks anonymous????

 

I'm sure even just changing from the Atkinson cycle engine to the Otto cycle version of the same engine won't play nice with the ECU, even if the only change was the camshaft from Atkinson cycle to Otto cycle. A/F ratio tables and spark timing tables will be completely different, not to mention throttle positions, EGR levels and cam timing's. The engine might not even run at all.

 

Thanks, I did not know why the change was made?? But that makes sense!

But is building a lower mpg Prius with an unknown motor, worth the hassle to the OP?? I don't know?? Rebuild as opposed to replace with an unknown motor x?? Is always a question that has to be asked?? I'm just throwing plan B out there, no more than that.