Rothman

iTrader: (4)

Manolis you are the man. That is shear genius right there!

kenkaru

Wow... I was like why the F is this thread still going?
Then I watched that animation.
That is awesome. Lookes simple and reliable. Let's see a prototype!

The_Quiet_001

Go to his website, he's got that on a civic and some other kind of engine. Lots of pictures and explanations. Check out his site, it's worth your time.

edit: Oh yeah, he's got videos too.

kenkaru

Damn! I can't believe he actually has an awesome idea AND a working prototype!?
Soooo.... who's gonna try to fab this up for an LS1?

manolis

Good question.
I do not know why.
Maybe they know.
And as they refuse to talk to us, if you or anybody else can contact their heads, PLEASE ask them ‘why’.

Manolis Pattakos

Quick1998Z28

iTrader: (1)

imagine being slow and realizing you pass emissions because anywhere under 7000 rpms you are making almost no torque or HP. VVT is a crutch to squeeze an extra 10 HP out of what is typically a ball-less turd of an engine. It's unnecessary and the fastest hondas ditched VTEC long ago; its easier to tune without it.

manolis

I propose to start surfing in pattakon site with the animation
http://www.pattakon.com/vvar/VTECtoV...peration2D.exe
which is very explanatory. It shows, in three modes, the mechanism working in the Honda Civic prototype. Use again the mouse and the SpaceBar.
This mechanism is very similar to the one for the pushrod engines.
The rev limiter is set to 9000 rpm not to protect the valve train system but the parts beneath (connecting rods, pistons, crankshaft).

Before leaving pattakon site I propose to the technically oriented to read the
www.pattakon.com/vva/VVA_Idle/VVA_Idle.htm

Manolis Pattakos

manolis

Is there someone really ‘interested and capable’ to built the parts and apply the modification on LS1 engines? To apply exclusively the LS1, LS2 etc modification in USA being technically supported by pattakon?

Are there in your forum more than twenty owners of LS1 interested in applying the modification on their cars?

What are the differences between LS1, LS2 etc? If a ‘modification set’ is made for an LS1, does it fit to the other models too?

Applying the VVA (variable valve actuation) exclusively on the intake valves and leaving the conventional exhaust is more cost efficient. The absolute solution is to apply the VVA on exhaust valves too.

In Europe/Greece you cannot find such engines, so the exact drawings of the LS1 head are needed to start (or even better a damaged cylinder head for measurements etc).

By the way, does LS1, LS2 etc owners like independent throttle bodies?
Think that being able to use continuously variable intake valve lift from zero to a maximum allows you to get rid of plenum and throttle valves. This way the independent throttle bodies (they do not need throttle valves inside so they are just trumpets fixed on the intake ports) is the cheaper thing to have.

Manolis Pattakos

Quick1998Z28

iTrader: (1)

Individual tuned runners are nice, but I do not like the idea of having the car completely 100% dependent on algorithms to run properly. I don't see how you can have open stacks on intake ports and expect it to run properly; maybe I'm reading it wrong, but it sounds like you intend to remove the throttle completely. this simply won't work. Cams are already continuously variable lift, the variable valve timing effects the duration more than the lift. It provides longer duration at higher RPMs to add more HP and the computer is tuned to recognize this change and adjust when the system, like VTEC is engaged. The throttle is the only thing that prevents the engine from taking in all the air in the atmosphere and mixing it with fuel.

cantdrv65

iTrader: (3)

Not in his method. He mentions the throttle actually controlling the valve lift, which would act just like a throttle blade, hence no need for it.

manolis

You wrote: 'this simply won't work'.
Beleive me, it does work this way every day, for a long time now.
In the Honda prototype the plenum is eliminated as well as the throttle valve. If you remove the air filter and look inside the intake 'tubes', you can see the intake valves working but you cannot see any throttle valve.
Think: having continuously variable intake valve lift (i.e. the MAXIMUM per cycle intake valve lift is able to change continuously, i.e. what is changed continuously is the length of the stroke the valve performs) from zero to a maximum, the intake valves can act as excellent throttle valves. This way a set of simple trumpets act aerodynamically as the most efficient ITB set, being at the same time of negligible cost.
With 0.2 mm intake valve lift and 500 rpm the vva engine can take-in (suction) only about 1/5 to 1/6 of its full capacity. This way it idles.

On the other hand, the ITB is only an option, not a necessity. If you like to have the pushrod 'VTEC' (Pushrod VVA is more correct) and still use plenum and throttle valve, you can.

As regards the 'algorithms' and the complication you wrote, just note that proramming the ECU of the VVA Honda prototype is easier than programming the original Honda VTEC engine: think that with the VVA modification the Honda no longer needs two fuel and two ignition tables to work, i.e. one for the high rpm lobe and one for the low rpm lobe. The VVA Honda prototype uses only one lobe per pair of intake valves, so a unique injection table and a unique ignition table (based both on revs and valve lift - i.e. a TPS on the intake control shaft).
In other words, modifying an LSx engine the ECU needs only a reprogramming of the injection and ignition maps, with main parameters the revs and the signal from a TPS sensor rotated by the control shaft. That simple.

The ITBs photos are really nice at the currently active thread 'Nice intake manifold... - The ITB thread'. Reading for their prices I was thinking how much more cost and fuel efficient the Pushrod VVA is: just a racing camshaft compined with the Pushrod VVA, with a cheap set of trumpet and a reprogramming of the ECU.
This way you can have all in one engine:Manolis Pattakos

LTSpeed

Very nice work. I can't believe some of the ridiculous comments I'm reading here. The throttle body does nothing but get in the way in this setup. I suspect you might have a little trouble in cold weather startup and with some emissions management, but that's nothing a little controls work can't iron out.

What are you using to actuate the VVA assembly in the Civic? Are you using the original V-TEC controls at all? And did you mod the oil system at all?

manolis

The VVA assembly in the Honda prototype is controlled directly from the right driver's foot:

Open the following set of slides

http://www.pattakon.com/vvar/OnBoard/Assembly.exe

and look at the slides 1, 8, 9 and 10.

You can see an F shape 'lever'.
When you press the gas pedal, this F shape lever rotates - for some angle -pressing both control shafts to rotate for some angle too. This way you change the valve lift used. When the F shape lever is released, the valve springs restore the control shafts and the F shape lever to their 'minimum' or 'idle' position.

So when the driver needs more valve lift he just presses the gas pedal deeper. The gas cable from the gas pedal pulls the F shape lever to rotate for a few more degrees, the control shafts rotate for some degrees and the valve lift is increased to another value. All those are pure mechanical and direct (no oil involved). The original VTEC control (oil cirquit, rocker arm pins etc) is not used.

As the intake control shaft changes angular position, a TPS sensor follows the control shaft's motion and informs the ECU for the current valve lift.
According instant revs, the ECU (taking under account water temperature, air temperature etc) decides -based on the modified ignition and injection tables- for the injection duration and the spark advance.

The original VTEC Honda uses as basic parameters for the engine control the revs and a MAP sensor in the intake manifold. The VVA engine has permanently full atmospheric pressure just before the intake valves. So a TPS sensor is rotated by the intake control shaft and its signal is fed at the MAP input of the ECU.
It seems tricky but it is not: the ECU waits in its MAP input an electrical signal between 0.5 to 5 Volts. If you feed this input of the ECU with the electrical signal from the mentioned TPS, the ECU cannot see any difference (you have just to keep this signal in the expected range of 0.5 to 5 volts). Then you have just to modify the injection and ignition tables.

For the emmision managment please read the
www.pattakon.com/vva/VVA_Idle/VVA_Idle.htm

As regards the cold weather starting, the system seems to improve things a lot. I say seems because here in Greece saying cold wheather it is meant zero degrees centigrade. The prototypes never saw -20 or -30 degrees centigrade. But comparing their behaviour to the original car behaviour things get much better with the VVA. For instance with the original car used for the first prototype, before the modifivation, you had to keep the chock ON for a few minites having the idle at 1200 to 1500 rpm otherwise the response was bad. After installing the VVA on the first prototype you can start with 500 rpm and immediatly drive without any lack of response. The same and more happen with the VVA Honda prototype.

It seems the fuel droplets are so finely atomized - passing through the tiny gap between the valve head and the valve seat - that the resulting mixture is homogenous and vaporous.

It seems that the extreme mixture velocity resulting from the narrow entrance area (which leads to a very fast and stable combustion) makes the big difference.

Manolis Pattakos