Prius Pistons?????

[hatchbackkid82]

Anyone try putting Prius pistons in the 1NZ-FE yet??? Aren't these supposed to be really high compression when put into our motors?

[Nexus1155]

Yes, no one has done it yet, they're suppose to be compression due to the pistons only so it would be set there. The set you can usually find for around $50. No one knows the power gain without a tune but some say atleast 15hp with higher octane because you will be more prone to detonation from a higher comp ratio. Please be the one to try then dyno lol

[hatchbackkid82]

I'm tempted to. Trust me, just don't know how i feel about tearing my motor apart. So they will work for sure?

[WolfWings]

Only difference between the two engines is the crankshaft and rods, the pistons AFAIK are basically the same actually. Longer stroke = shorter rods. But yes, they'd fit. Just nobody's bothered yet.

[Nexus1155]

Search up the threads on scion life and echoboards someone did the researxh and they were sure to fit they said. If you ever swapped springs yourself you can get this done in a weekends time on such a small engine if you have some time to work. Make sure you have a new set of head bolts and some gasket sealer, because I think the bolts might be stretch bolts and not reuseable, stock ones are cheap. If you have the tools I can see it costing around 85-100 for the whole job seeing you need oil and coolant afterwards. No need for a hoist if you have an extra buddy, or a jack to lift the car over the engine and subframe

[hatchbackkid82]

I'm actually shopping around for a set right now.

[Nexus1155]

Heres some links for you to read through, they are a good read, some have debate issues, but you will find your answers here...

http://www.scionlife.com/forums/view...t=prius+piston
http://www.scionlife.com/forums/view...t=prius+piston
http://www.scionlife.com/forums/view...t=prius+piston

[cali yaris]

Head bolts should be fresh for sure.

[SEVEN]

So ... prius pistons for the win?

[Nexus1155]

^^^exactly

[Treyz]

How high of a compression are we talking about. Isn't too high not necessarily good in terms of cash?

I mean for an all motor setup I believe it's ok but for any forced induction, it's a not so (depending on how high)?

*EDIT*
OK so I went on the first link and I was right. What I meant in terms of cash thing was basically paying for the higher octane fuel; even finding a gas station that would have it. I've ran into this debate in the past when it was KA24E pistons into a KA24DE because of the higher compression.

With a 13.1, say goodbye to forced induction.

[Nexus1155]

oh yeah of course, you would never be able to run forced induction that high without being extremely precise in what you do, but high octane meaning 93 which we have on the east coast, thy only have 91 in cali. We can also get 104 i think pretty easy here as well.

I had a 240 before, i didn't even know the ka24e had higher comp ratio i would have liked to known back then lol, and that they fit too.

But with the prius pistons it would definately have to be all motor, but getting higher octane gas is all relevant on how it burns off compared to how you drive to how your tune is.

There are many deciding factors on wether it is worth it or not. But bang for the buck if it raises a good amount of hp, and does not compromise engine detonation, than i am all for it.

I would say to whoever does this. Test it out with a small tank of 89, 91, 93. And see how the gas works in terms of pinging

If you have ever read the Siphon magazin i have, they swapped in higher comp pistons/new cams/ valves and intake/exhaust port/mods and made around 200 hp all motor from an echo. Now thats impressive!

[Treyz]

Yeah, the bottom end of the KAE and the KADE are the same. I actually kept both of my 240's all motor and just with bolt ons and tuning I was making as much power as a stock SR20 motor into an S13. Left and sold the project unfinished because everyone and their mother has a 240. As a result, I now have started messing with the daily driver (1yr into it), the lovable Yaris!

With a 13.1 compression, I don't know if 93 would be enough unless that's what you need to put in the Prius.

When it comes to internals, I'm a n00b lol.

What octane did Siphon use?

[Nexus1155]

From my US 2001 Prius' Owner's Manual, page 144-145:
"OCTANE RATING
Select unleaded gasoline with an Octane Rating of 87 (Research Octane Number 91) or higher."

But you have to realise that the prius runs on a different cycle that our engines do, and is essentially the same engine, but different at the same time. This is why i said to test with different octanes.

Siphon didn't say what octane they used so i dunno, but yeah the SR20 stock is a bitch motor until you either raise stock psi of turbo or beef it up. I would rather have a KA-T

[Nexus1155]

http://www.scikotics.com/forums/showthread.php?t=46597

http://car-part.com/cgi-bin/search.cgi <--- look up a prius short block and call up a place for just the pistons and rings

Shake a leg? lol

Here, i snapped some pics form the magazine, apparently you would need rods too with those pistons, and i think i recently just read the prius ones are forged. I am trying to get everyone forged rods when prius already have them. Can anyone confirm this? Or are they crap as well.

[Yaris Hilton]

The Prius' intake cam holds the valve open longer while the piston goes up on the compression stroke, pushing air back into the intake manifold. Its effective displacement and compression ratio are both reduced this way, but on the power stroke the exhaust valve stays closed while the expanding gas pushes the piston down nearly to the bottom of the stroke. The gas expands through a higher ratio than it's compressed, extracting more energy. Original Atkinson cycle engines did this through a complicated mechanical linkage that actually varied the stroke. The Prius has a mechanical compression ratio of 13:1, while the Yaris has 10.5:1. The "Atkinson Cycle" intake valve hold-open drops the effective compression ratio of the Prius to about the same as the Yaris.

13:1 is a HIGH compression ratio for a spark ignition engine! Some large Diesels run in that compression range. Might work with E85. Might require a different ECU program to make it work on that fuel.

[Nexus1155]

Heres a link im reading through now

http://www.echodrivers.com/forum/vie...st=0&sk=t&sd=a

Some production cars, and often aftermarket pistons have a 13.5 compression ratio. There has been talk about the octant rating of gas for engines running this high of a compression, but this is on a larger displacement engine. With the amount of displacement this engine has, i think it would be ok, and there is always a way to add a thicker headgasket to drop it down a half point. So you would have 12.5 comp ratio, but if its true like you said not from the pistons then that might be a problematic swap.

Some quote from that post

In Prius' case, the engine physically has a 13.5:1 compression ratio, but by delaying the intake valve's dosing until the piston is part way up on its compression stroke, the effective ratio is 9.5:1.

[PHXDEMON]

With how picky our motors are this seems like it would rape the stock tune