Intake air flow modification

[Compaq888]

Originally Posted by SVOboy

You could make that intake switcheroo deal if you want, it'd be rather easy with just a hacked up vtec activator or you could make something special to read the rpm signal off the distributor and have it going that way.

I have a MSD digital window switch. I can make anything attached to it turn on or off at any rpm I desire. But I don't want to spend anymore money on my car. I'll just use what I got and attach a long hose from the bottom of the car to the airbox. That way when the car goes up really steep hills it will stay in 4th or when I accelarate a little bit harder. After extensive research my car gets the best gas mileage with the stock intake system. The stock intake system is just not good for going up steep hills because it doesn't supply enough air.

[kickflipjr]

Originally Posted by MetroMPG

in order for pumping losses to be reduced, you want to have as close to ambient pressure as possible in the manifold. i don't understand how adding a restrictor upstream of the throttle addresses that. sure the throttle is open further, but the upstream airflow is now restricted, so the pressure in the intake manifold can't be as close to ambient as if there were no additional restrictor.

How does this work. Buy adding more restriction you can open up the throttle more. It doesn't seem like would work. Restriction=Bad. Velocity=Good.

Maybee a second throttle that you could adjust on the fly would work. It would be a better way of restricion (even though i don't think this is a good idea in the first place).

[Compaq888]

Think of it like this. You need restriction for constant speed. You need a good flow for accelaration.

[krousdb]

Originally Posted by MetroMPG

but i still don't understand the theory behind adding an additional intake restrictor (i say additional, because the throttle is also a restrictor by definition.

Admittedly, I too am having difficulty understanding the benefit of a second restrictor. The only thing I can think of is that on vehicles that use a TPS, you could achieve higher vacuum at a certain throttle position, thereby causing the ECU to trim the fuel differently. meh. Or maybe the MAP sensor would give a different reading causing a different fuel trim, but I don't have a MAP sensor so, again, I say meh!

[SVOboy]

Or maybe the MAP sensor would give a different reading causing a different fuel trim, but I don't have a MAP sensor so, again, I say meh!

Where'd your map sensor go?

Mehbe someone else with a fuel meter could go and test this out, meaning you.

[krousdb]

OK, then maybe I dont have a TPS. I don't have both do I? Anyway, I would like to know why two restrictors works better than one before testing.

[SVOboy]

I don't have both do I?

Yeah you do. Your TPS is on the side of the TB facing the firewall and has three wires coming out of it, and you MAP is on the top of the TB with three wires and says MAP sensor on it or mounted on the firewall right behind the TB and says MAP on it. B7s I have been seeing at the junkyard in civics with firewall mounted sensors, which makes me think that my IM/TB is not from a b7, or something, mehbe just the rail and tb, I dunno.

Anyway, I would like to know why two restrictors works better than one before testing.

Anyway, I would like to think that this is just the opposite effect of sticking a big *** 4" CAI, except with a small *** 1.5" HAI. So it'd follow basically the same principles, and as kickflipjr was saying, it would increase velocity as there is less cross-sectional area.

[Matt Timion]

Originally Posted by SVOboy

Yeah you do. Your TPS is on the side of the TB facing the firewall and has three wires coming out of it, and you MAP is on the top of the TB with three wires and says MAP sensor on it or mounted on the firewall right behind the TB and says MAP on it. B7s I have been seeing at the junkyard in civics with firewall mounted sensors, which makes me think that my IM/TB is not from a b7, or something, mehbe just the rail and tb, I dunno.

Wait, you've been seeing B7s with with firewall mounted MAP sensors? Firewall mounted MAP sensors were obd0. OBD1 Map sensors should be on the intake manifold/TB. I can take a picture of my z1 if you guys want to see where it's mounted.

[MetroMPG]

Originally Posted by SVOboy

Anyway, I would like to think that this is just the opposite effect of sticking a big *** 4" CAI, except with a small *** 1.5" HAI. So it'd follow basically the same principles, and as kickflipjr was saying, it would increase velocity as there is less cross-sectional area.

but the HAI feeds the engine less dense air, that's why the throttle has to open further. it needs a higher volume to do the same amount of work.

if you don't change the density of the air, then forcing the throttle to open further because airflow is being starved by an upstream restriction offers you no advantage.

analogy:

1. you're drinking a thick milkshake through a straw with the "mouth" end 75% closed (squished).

2. you squish the "cup" end of the straw 75% closed, which permits you to open up the "mouth" end fully.

have you experienced a change in the amount of effort to drink through that straw? any effeciency gains from the perspective of pumping/throttling losses? i don't see any.

[SVOboy]

Wait, you've been seeing B7s with with firewall mounted MAP sensors?

Yeah, three of them today, wanna fight about it?