INFINITI Reinvents The Gasoline Engine — VC-Turbo

[teoman]

Are we talking about this:





Or this :




The first one is very foable, the second one is also doable (for me) but the mnf will take a long time and if it doesnt work it i do not think that i can invest the time to do it again.

[Daschicken]

Originally Posted by teoman

Do you know the input parameters? I.e lengths and rpm ranges etc?

I am pretty handy sometimes

Could you snap a photo of your intake?

Is it just the intake length after the air filter?

My variable intake doesn't use another set of runners, rather it has a chamber connecting either sides of the runners with a flap in the middle that opens at 4000, or 4900 RPM(don't know for sure which one. On the J25 it opens AFTER VTEC. I think on my J30 it opens before VTEC.). I don't know if it has any variable rpm/throttle position logic. Either way, the first transition is quieter than the second, if that helps you figure it out.

Here is a drawing. You can see the firing order listed, so when cylinder 1 is charged, it sucks all the air coming in down into cylinder 1. Cylinder 1 fires and the next cylinder is cylinder 4. With the flap closed, the air has to reverse and go all the way back around the loop and into cylinder 4. With the flap open, the air has to reverse and can go through the center of the intake manifold, shortening the path.


The older V6 accords did not have the variable intake manifold(the J30 didn't at least, don't know about C27), and here is what their intake manifolds look like.


My generation looks like this.


This is what my manifold looks like on the inside.

Originally Posted by ksa8907

I don't know for sure, but I am going to go out on a limb and say that with variable valve lift and cam phasing, variable intake length may not make a big difference anymore and not be cost effective.

Probably true, most likely won't make a big difference, but it should still make a difference. It would be nice if they would develop these parts and make it an option to have them, or you can get the el-cheapo engine. I know which one i'm picking.

[serialk11r]

Variable intake is primarily useful on NA engines, whereas the trend is to go turbo. But yea they can be very effective. The 911 GT3 and Lexus LFA engines are NA, non-switchable cam profile 9000+rpm, but they have pretty good low end torque thanks to 3 switchable intake runner lengths.

[Daschicken]

Originally Posted by serialk11r

Variable intake is primarily useful on NA engines, whereas the trend is to go turbo. But yea they can be very effective. The 911 GT3 and Lexus LFA engines are NA, non-switchable cam profile 9000+rpm, but they have pretty good low end torque thanks to 3 switchable intake runner lengths.

I sure wish my CBR 250R had a variable intake... 17,000 RPM+, BIG headers, very oversquare, carburetors... It is not a recipe for good low or midrange torque. I still operate it at 3,000 RPM or below frequently though. It doesn't help that 45 mph in 6th gear puts it at 5,600 RPM(AFTER dropping 3 teeth on the rear sprocket), but I try.

[teoman]

Pre air filter length doesn’t count right.

I was thinking of doing the same with a hot air intake.

[Daschicken]

Originally Posted by teoman

Pre air filter length doesn’t count right.

I was thinking of doing the same with a hot air intake.

I’m pretty sure it’s pre throttle body that you are thinking about, but even then I have heard about pre throttle body intake piping that can be important.

[Daox]

Here is a Toyota version from a performance 4 cylinder (5E-FHE).

[gone-ot]

Lengthwise...it's from atmosphere to intake valve (actually to mid-point inside cylinder between cylinder head and piston top).

[Stubby79]

Originally Posted by serialk11r

Variable intake is primarily useful on NA engines, whereas the trend is to go turbo. But yea they can be very effective. The 911 GT3 and Lexus LFA engines are NA, non-switchable cam profile 9000+rpm, but they have pretty good low end torque thanks to 3 switchable intake runner lengths.

Ditto with the Mazda KL engine in one of my cars...very flat(read: maximum), very wide power band. Zoom-zoom!

[ASV]

that's a crazy complicated over weight system
I can think of three different ways to do that
with less part and weight