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

[cRiPpLe_rOoStEr]

Originally Posted by SpeedyCorky

i've been thinking about swapping a fuel efficient motor (hybrid likely) into a MK1 MK2 for years now....

With a supercharger to overcome the discompression from the intake valve timing it would be great.

[mr220v]

Originally Posted by cRiPpLe_rOoStEr

With a supercharger to overcome the discompression from the intake valve timing it would be great.

This is called a millercycle engine. This was actually implemented in the late 90's Mazda Millenias.

[Daox]

I'd love to try a 2nzfe or 1nzfxe in my 93 Tercel... alas that is a bit far off for me at the moment (funds & time, not enough of either). Great idea though. At one point I was considering a 1nd-tv too...

[cRiPpLe_rOoStEr]

Originally Posted by mr220v

This is called a millercycle engine. This was actually implemented in the late 90's Mazda Millenias.

That was good, since it didn't have a performance decreasement like the so-called "Atkinson" ones. It also had some popularity in stationary/industrial and marine engines in the 40s and 50s. May be nice to work around it into a Diesel, with a twincharger setup (then, the supercharger would also help to overcome the turbo-lag). Lots of possibilities, afterall...

[serialk11r]

Originally Posted by mr220v

Atkins cycle refers to a motor with a power stroke longer than it's intake stroke. Originally this was accomplished with weird crankshaft/engine designs, but can also be accomplished with offset cams and cam timing, which is what this motor does.

Offset cams are often used in race engines (or by cheap 4age modders who only want to buy an intake cam). But again, the object there is to increase intake and exhaust cam overlap (better efficiency at higher rpms), not to delay closing of the intake valve to actually waste a significant portion of the compression stroke. That would be counterproductive in a race engine.

Again you're sorely mistaken. Overlap is for exhaust scavenging, late valve closure is for maximizing volumetric efficiency due to acoustic intake effects. The inertia of the column of air traveling down the intake provides very significant pressure at the peak of the "wave".

Some engines have nominal 300 degree cams. Do you really think these cams close right after BDC? Hint, they close LATER than a 1NZ-FXE.

This is why I'm getting my 1ZZ-FE intake cam reground for higher duration: Improved efficiency AND improved peak power.

[mr220v]

Originally Posted by Daox

I'd love to try a 2nzfe or 1nzfxe in my 93 Tercel... alas that is a bit far off for me at the moment (funds & time, not enough of either). Great idea though. At one point I was considering a 1nd-tv too...

If you're really interested, if you jump on it before March, I'd do your wiring for free on a 1nzfe or 2nzfe on a stock ecu.

Looks like there are a few 2nz's on ebay for cheap.

[mr220v]

Originally Posted by serialk11r

Again you're sorely mistaken. Overlap is for exhaust scavenging, late valve closure is for maximizing volumetric efficiency due to acoustic intake effects. The inertia of the column of air traveling down the intake provides very significant pressure at the peak of the "wave".

Some engines have nominal 300 degree cams. Do you really think these cams close right after BDC? Hint, they close LATER than a 1NZ-FXE.

This is why I'm getting my 1ZZ-FE intake cam reground for higher duration: Improved efficiency AND improved peak power.

What I suspect with the 1nzfxe is that the way this intake cam is degreed, you get less scavenging than you otherwise could.

I wonder if the 1zrfxe intake cam would fit the 1zz?

[serialk11r]

Originally Posted by mr220v

What I suspect with the 1nzfxe is that the way this intake cam is degreed, you get less scavenging than you otherwise could.

I wonder if the 1zrfxe intake cam would fit the 1zz?

That should be the case, the reason why VVTi works so well and most manufacturers don't have multiple cam profiles like Honda is because by adjusting the cam's position alone you can cut out the overlap for stable low rpm operation, you can increase overlap in ranges where the acoustics will help scavenging, and at high rpm the valve closing point is more important than scavenging so you don't give up too much power, especially with a higher compression ratio.

The bore spacing is different between a 1zz and a 1nz, so it wouldn't fit, but I'm going to get a regrind on a spare 1ZZ cam to ~270 from 240 stock and then degree it so the peak is like maybe 7-10 degrees later. That would make the valve close 22-25 degrees later and open 5-8 degrees earlier, for a tiny bit of increased overlap (which hopefully doesn't cause any problems) and at low load it should be running at ~60% VE instead of the 77% or whatever it is at stock. The 1ZZ is only 10:1 compression so hopefully the tiny bit of extra overlap doesn't do too much damage.

[ksa8907]

What about using one of these engines for a house generator?

[mr220v]

Originally Posted by serialk11r

The bore spacing is different between a 1zz and a 1nz, so it wouldn't fit, but I'm going to get a regrind on a spare 1ZZ cam to ~270 from 240 stock and then degree it so the peak is like maybe 7-10 degrees later.

Not NZ, ZR. That would be the current year 1.8L Prius. 2010 on I think. Might be the same spacing and worth looking at. Would make a good intake cam blank if it fit.