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Romans 2005 Toyota Echo


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It's the same block, same rods, same head as the non hybrid version. Likely even softer valve springs but I'd need to change those in any case as the current 7200ish valve bounce limit is ruining my day.

But it has different pistons (high comp) and different cams (270 deg duration intake) to make it atkinson cycle.

Here's a pic of the factory pencil rods vs some considerably beefier looking aftermarket ones 

Speedhunters_Project_bB_7I2A7687-1200x800.jpg.3c4b84fdf728768b9c3de4525d6bf82b.jpg

The upside though is that it's got a fairly decent rod/stroke ratio.
Which is probably why it can get away with such shit looking rods in the first place.

I've found a few more examples of people using prius pistons in normal 1NZ engines though. This dude had 140hp at the wheels and 8k rpm on standard rods.

1670240786_POWAAGarageToyotaVios1NZ-FENABuildPartIV024.thumb.png.f62f2653665b01a31ff9ceeecb2170a9.png

In a toyota Vios though which is a big chunka compared to an Echo. 

Looks like it goes alright though
 

 

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Probably better than the graph implies, as that's likely rolling onto the throttle there rather than it's full power. 

I'm more wondering why he's not revving it even higher, would lift his average power on gear changes (answer: factory rods. haha)

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Ahhh not sure yet. Definitely bang the headers in but not sure if I'll be able to do the full rest of it before drag day.
It'll probably not acheive much without the rest to go with it though. 

I finally got consent for my shed so hoping it'll be up by christmas or not too long after. So some busy weekends ahead! 
And otherwise a bit tight on cash till end of the year at least.

Once I've got shed up there's no reason not to hoard more stuff for a C56 & big block swap instead of doing other stupid stuff like getting Carina going. 

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So I hooked up a MAP sensor to a single runner, and as expected it's useless because the voltage fluctuates like crazy. 

But then its interesting to view with an oscilliscope instead. 

This is the MAP signal when the car is idling normally. Peak to peak is 720 degrees of engine rotation

41819829_0degadvance.png.a9071f85ac8207294ea6b0ca7659acea.png

So when the intake valves are open and the piston goes down you can see pressure starts dropping as you'd expect.

Look what happens when you add 40 deg intake cam advance though. 
 

1107749042_40degadvance.png.f7f35012c7be60777bb8f39384af0fe2.png

Now there's a period of time where the inlet cam and the exhaust cam are both holding their sets of valves open. 
So the intake side intake low pressure and the exhaust side high pressure means exhaust gas scoots right back over the piston and rushes to fill in the intake. So pressure goes up.
Then the exhaust valves shut, piston goes down and then the pressure starts to drop like normal. 
Which is why you get that fully sick 3/4 race cam idle on your 4k that goes hard for what it is.
I wonder if it's actually better economy having this happen so you're heating the air fuel mix. Hah.
I'll hook up some more sensors to it to give some context and see if there's anything interesting happening at full throttle.

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Did you play around with injector timing at all? 

You could try set end of injection to say 240 BTDC and might mitigate fuel blowback issues 

EDIT: Oh yeah it's gonna be a lot worse if you have a plenum and also batch fire injectors.

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On 07/11/2020 at 04:56, Roman said:

It's the same block, same rods, same head as the non hybrid version. Likely even softer valve springs but I'd need to change those in any case as the current 7200ish valve bounce limit is ruining my day.

But it has different pistons (high comp) and different cams (270 deg duration intake) to make it atkinson cycle.

Here's a pic of the factory pencil rods vs some considerably beefier looking aftermarket ones 

Speedhunters_Project_bB_7I2A7687-1200x800.jpg.3c4b84fdf728768b9c3de4525d6bf82b.jpg

The upside though is that it's got a fairly decent rod/stroke ratio.
Which is probably why it can get away with such shit looking rods in the first place.

I've found a few more examples of people using prius pistons in normal 1NZ engines though. This dude had 140hp at the wheels and 8k rpm on standard rods.

1670240786_POWAAGarageToyotaVios1NZ-FENABuildPartIV024.thumb.png.f62f2653665b01a31ff9ceeecb2170a9.png

In a toyota Vios though which is a big chunka compared to an Echo. 

Looks like it goes alright though
 

 

So when are you selling up and getting a Proton Saga? Would be interesting to see what has been done to that lead car, that original 4G15 would probably move like that!

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17 hours ago, Roman said:

Did you play around with injector timing at all? 

You could try set end of injection to say 240 BTDC and might mitigate fuel blowback issues 

EDIT: Oh yeah it's gonna be a lot worse if you have a plenum and also batch fire injectors.

I can somewhat time the injectors, but they still have to fire twice per cycle as only two drivers with microsquirt

I was going to adjust the injection timing but couldn't cope with the low oil pressure so ended up swapping the cam at same time as crank grind.

Interesting thing is that the new cam uses less fuel at idle than the factory one, about 8 cc/min when warmed up

Could just be that the engine is less worn out now though

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https://www.msextra.com/forums/viewtopic.php?f=101&t=68504

Supposedly possible to modify one, just strongly advised against doing so. Requires cutting traces on the board and doing some other bodges.

It would be interesting to see if there would be much difference in how the car performs, but it's just a 4K so the improvements wouldn't be much

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