GReddy Speed Cut Controller for Toyota

You are going to have worse gas mileage, but making more HP always involves more gas.

 

And I can't. That is why it is just theory to me! I regret every gallon.

 

Wasn't meant to be productive. Was meant to be funny.
:RollingEyes@NoSenseOfHumor

 

old jokes are seldom funny...
i used to want to somehow get more acceleration out of it. then i drove a 300TD for 2 years. Prii are quite peppy compared to that hideous slug. i kinda liked it though... the wife didn't. so now...

 

Maybe even just replace the head/valve train with a Corolla version. The bore/stroke are the same. The intake/exhaust headers may also be a bit different. Fuel mixture & ignition timing are probably quite different - but then that's what all the computer remapping is about.

So you could add 1/3 more power with rather simple changes. Of course you'd also end up with a 30 mpg vehicle instead of 50 mpg...

 

What did you expect, a parade in honor of your masterful wit?

Didn't you notice you're in a forum full of modders? You think we're here to pull each other's cranks?

 

Yeah, it's all relative. There are plenty of modern mini-vans that will toast a 1980's Ferrari off the line. Kinda sad.

The Prius can beat just about anyone in a race from 0-25... but after that, you can only get so much out of that 1NZ engine.

I never looked at the specs; just noticed the physical compression ratio is 13.0:1, but this compression isn't realized due to the extended open timing of the intake valve.

What about changing the intake cam to utilize all of that compression? If the 1NZ-FE didn't have the VVT, you could just drop its intake cam into the the Prius's 1NZ-FXE.

So... two options... get the 1NZ-FXE's intake cam ground to reduce the intake duration... or mod a 1NZ-FE intake cam to be fixed at a particular timing.

I don't know if there's space in the cam cover to fit anything... but if you had some room to play with, you could make the FE's VVT cam adjustable with an indexing wheel and some lock screws, as Forza Engineering did for the Ferrari 308/328:

 

A better shot of the adjustable cams... the tuner says 1-2 deg. of difference can change power output by 2-3%.

 

This is the Gen 2 Prius, you can see how much the intake timing can be altered. It would take a lot more range to make it to the Otto cycle. (Exhaust timing appears fixed)

 

And this is exactly the behavior we want to eliminate... the duration of the intake cam past BDC. Let's see that 13.0:1 compression! (and hope the pistons & con rods can handle it...)

 

I guess I expected people not to take themselves so seriously. That said, I appear to have touched a nerve, and for that I apologize. It was probably a lot funnier in my head.

 

It's not a nerve. The majority of us are smart enough to know it's a joke... and old and tired joke. And we're not here to swap jokes. Didn't you read any of the threads here? ...or do you just bust into a room and start firing before seeing who's in there?

 

so who's the brave one that will have their intake cam ground down? looks like about 25 deg should be taken off the back side of the lobes.

 

by grinding 25 deg off the closing side of the lobe, you'll have 50 deg less duration of the intake valve hanging open during the compression stroke. that would make a tremendous increase in dynamic compression. static compression is 13-1, but since the atkinson cycle ice lets the intake valve stay open well into the compression stroke, it ends up being closer to 8-1, and acts like a smaller displacement engine. so if we can close that intake valve early in the compression stroke, we're gonna get alot more power, but probably need higher octane fuel to avoid pinging.

 

I'd start with a milder grind than 25 deg... the 1NZ is a small engine and detonation problems might come on quicker than expected.

A good article on engine compression and related issues:
Engine Compression Ratio - Tech - Popular Hot Rodding Magazine


Looks like there's a lot to be done to cool the engine compartment in the Prius... coat the headers, use a colder thermostat, cold air induction, cooler plugs / hotter coils, etc. This all seems like prerequisites to grinding the cams.

 

He seems to be bound by tradition to use compression ratio, but admits expansion ratio is the interesting number.