2005 Prius engine into 1986 MR2: mk1 1nzfxe Prius swap (gas only)

[mr220v]

This is a 1nzfxe from a 2005 Prius. Here's a picture of me getting ready to put it in:




Yes, most people will be able to pick this motor up and carry it around. It weighs about as much as an e153, the transmission out of a mr2 mk1SC and mk2 turbo.

Aside from the weight and fuel economy, this is an atkins cycle engine. Well, it has an atkins cycle mode depending on what position the vvti cam is in. I currently have it set for on/off. This gives me two settings. 13:1 compression using the full 1.5L and 6:1 at 750cc's.

Here it is installed:



Just driving it around, it actually feels stronger than the original 4age. This is in the 13:1 1.5L mode of course. The low comp/displacement setting will leisurely pull away from a light flooring it.

Toggling modes manually, I was able to get 37mpg where the various 4age's I've had would get 30, and the beams 3sge would get sub 30. This is running an echo ecu and no o2. Really a tune just good enough to run and drive.

[Daox]

Very cool, cant wait to hear more!

[mr220v]

where it sits right now. I'm currently tuning it with a microsquirt. Running it on the 1nzfe ecu, it was pretty clear that high setting wanted to be richer, and the low setting wanted to be leaner. A stock ecu to run this would be nice....but simply doesn't exist.

In addition to having fuel economy benefits, I'm looking at cheap performance ideas for this motor. Say something that would get it to 4age 20v levels. Basically finding uses for $200 Prius engines.

[jeff88]

A few questions:

Just to clarify, is this the 1nz-fe or 1nz-fxe?

Originally Posted by mr220v

Well, it has an atkins cycle mode depending on what position the vvti cam is in. I currently have it set for on/off. This gives me two settings. 13:1 compression using the full 1.5L and 6:1 at 750cc's.

Toggling modes manually, I was able to get 37mpg where the various 4age's I've had would get 30, and the beams 3sge would get sub 30. This is running an echo ecu and no o2. Really a tune just good enough to run and drive.

So the vvt-i isn't automatic? On my Corolla, I don't do anything with it, it just does it's thing. Is this because your ECU doesn't have the software to control it?
What do you mean by full and half for the compression? Are you talking about half throttle? Also, why would the compression be half at 750CCs?
How do you get away with no O2 sensor, in terms of the engine running properly? I don't think I could do that here in CA, regardless.
Does this engine have belt driven accessories or electric? It looks like from your pic there are pulleys, but I just wanted to confirm.

Originally Posted by mr220v

I'm currently tuning it with a microsquirt. Running it on the 1nzfe ecu, it was pretty clear that high setting wanted to be richer, and the low setting wanted to be leaner. A stock ecu to run this would be nice....but simply doesn't exist.

In addition to having fuel economy benefits, I'm looking at cheap performance ideas for this motor. Say something that would get it to 4age 20v levels. Basically finding uses for $200 Prius engines.

What was wrong with the rich and lean settings? Did FE decrease with the stock ECU?

Was the 1nz engine really only $200?!

Also, TURBO!!!!! Just kidding, but seriously if you want performance, then that would be an option.

[mr220v]

A bit on Atkins Cycle. Atkins cycle is where you delay the closing of the intake valve part of the way up the intake stroke. With vvti, I have the choice to use the entire stroke, or delay the closing of the intake cam until halfway up the intake stroke. This gives me two displacements and two compression ratios. Closing at the bottom, it's 1.5L and 13:1. Closing midway up it's 750cc's and 6:1. With a better ecu I could use some of the intermediate settings, say 1.3L and 8:1 or so, but for now I'm using a cheaper ecu.

Normal vvti is more to optimize cam overlap/duration. Less overlap at lower rpms and more at higher rpms. This is something that works with engine speed whereas what I need with the 1nzfxe is more based on throttle position. The idea with the 1nzfxe is to bring on the 1.5L 13:1 setting at above say 70% throttle and cruise with the 750cc setting.

With the lower comp settings, I could do FI. That's called a miller cycle engine, which is found in late 90's mazda millenias.

Yes, $200. Good condition. The reason is because Prius's don't end up in the junkyard because of their gas engines usually, and once there, the engines aren't used in anything else.

1nzfe's and 2nzfe's are a good choice for somebody not wanting to experiment like me. I'd say SZ engines would be good too, but those don't get imported into the US.

[RobbMeeX]

Badass! I envy you!

[jeff88]

I see what you're saying now, it just took me a second explanation to understand. You are choosing when you want the intake to be closed, which determines the compression and the effective size of the engine (or at least effective displacement). Do you have a button inside the car to tell the system what you want or is it still automated?

So, since it is from a Prius, that means you have the FXE? How do you get around the hybrid battery stuff? Is that why you need a different ECU?

I've gotta find me a place that sells these! For $200, experimentation is very possible!

[E.Roy]

Cool and resourceful

[mr220v]

While running it on the echo ecu it's on a button. My aftermarket ecu can control engaging based on throttle position.

Car-part.com has lots of listings for these. Total throwaway engines.

One thing to keep in mind though is that you do need some 1nzfe parts to make this work, which raises the cost of doing this, but overall it's still cheap.

[MetroMPG]

Creative modding! Adding this to the home page.

What year is the MR2?