Ram Air Nets 5.1MPG gain...

[highwaylizard]

Originally Posted by Phantom

Not to offend but I highly doubt that there is a real ram air effect, more likely what you are experiencing is a less restrictive intake since there is now more area to pipe in the air and cooler temps allowing for more power.

No offense taken but I have to say that I do not think we are talking about the same principle here. The scoop, at highway speeds, gathers and forces more air into the air box than the engine is consuming which, by definition, is ram air. I guess in order to put this to rest I will hook up my manometer to the air box and record the pressure increase. And again, I am talking about air volume and not velocity. Pressure increase indicates more air entering the air intake than is being drawn into the engine.

Originally Posted by Phantom

To start the calculation using my car a 3.8l V6 @ 2000rpm consumes about 67CFM assuming 50% VE. For a straight Flexable 3inch pipe to flow 67CFM the velocity of the air in the pipe would need to be 1364.91fpm (Air Duct Calculator - EfficientComfort.net) or the speed of the air needs to be 930.62mph. Even if the speed of air is 11 times faster than the speed of the car I would need to be moving 84.5MPH.

Again, I disagree. I never said anything about air speed but rather air volume

Additionally, you state above that your car is a 3.8 liter engine and consumes 67CFM at 2000 RPM and then state below that my 4.7 liter engine consumes 39 CFM at 2000 RPM. Nope. Sorry.

Originally Posted by Phantom

Your truck at 2000rpm 50% VE uses 39CFM with the velocity needing to be 794.5 fpm or moving at 541.7MPH going by the 11 again (highly doubt the air would be moving that much faster than the car) the speed needed is 49.25MPH.

I believe your numbers are off a bit here:

• At 2000 RPM (I quoted 2200 RPM at 70 MPH but I digress) the engine would consume (285 X 2000 X .5) 285,000 cubic inches. There are 1728 cubic inches in a cubic foot so (285,000 / 1728) = 164.9 cubic feet.

• 794.5 fpm is a little over six and a half miles per hour.

Maybe I am not explaining this clearly enough. The ram air intake scoop has a frontal opening of 48 inches and converges at the rear where it connects to a flexible aluminum tube that is plumbed directly into the air box. Because of the direct connect the air box, at highway speeds, becomes pressurized because more air is gathered and directed to the air box and intake than the engine can consume. This is not theoretical formulas but empirical data.

I attempted to post pictures but apparently they are too big. Pictures and articles can be viewed here.

[Frank Lee]

Just what is the principle?

You've been concerned about fuel use your whole life... and you drive around in a pickup. It gets what mpg exactly?

Here ya go:

[highwaylizard]

Originally Posted by Frank Lee

Just what is the principle?

The principle is the amount of air per minute the scoop gathers at a given rate of travel versus the amount of air the engine consumes at a given RPM. Phantom offered that the improvement was based on cooler air and reduced restriction. I contend that, while it does draw cooler air with less restriction, the defining (ram) aspect is the extra air rammed into the air box which lends the most improvement. Even if someone wants to put it in terms of velocity the numbers given by phantom are incorrect. It does not make him a bad person nor do I feel a need to respond to him with sarcasm

"You've been concerned about fuel use your whole life... and you drive around in a pickup. "

or unicorn pictures. I am fairly certain he can speak for himself and I look forward to his response as I may learn something about how he approaches or views this modification.

Originally Posted by Frank Lee

You've been concerned about fuel use your whole life... and you drive around in a pickup.

I owned and operated a landscaping company and tree service for years. The truck was necessary for my business pulling trailers and carrying materials. It also carried my family for local trips and vacations.

Originally Posted by Frank Lee

It gets what mpg exactly?

Initially my truck was among the worst in fuel economy and therefore a prime candidate for improvement. 14 MPG AVG on the highway when I first got it. Currently running the highway at 65 MPH I average (for the highway portion) 20 MPG. Overall mileage from last year was 17.5 MPG which includes all types of driving.

It bears worth noting that I have done several modifications to my truck and the improvement is not a result of the ram air intake scoop alone.

Originally Posted by Frank Lee

Here ya go:

That's it! The unicorn is proof that my air intake scoop does not work. Thanks for clearing the air on that one.

[UFO]

I'm curious as to the principle of operation here. Assuming you really are pressurizing your intake, how would that translate to improved mpg?

[dcb]

Originally Posted by highwaylizard

...
14 MPG AVG on the highway... I average (for the highway portion) 20 MPG...last year
..
It bears worth noting that I have done several modifications to my truck and the improvement is not a result of the ram air intake scoop alone.

Your title of this thread is completely inaccurate, you don't have any credibility as a result. "Ram Air Nets 5.1MPG gain"

[Frank Lee]

I looked at lizard's blog... when I saw the glowing report on how the Fitch catalyst really works well, and the link to Pure Energy Systems (which should be named Pure BS Systems) I almost closed that window right then. But, I looked around a little more... there is no cohesive fuel log but most posts showed 14-15 mpg. You are losing to a V8 4x4 that only gets used for towing or hauling, pal.

Your testing is bunk and most of those theories and conclusions are too. What are you getting outta this?

[Phantom]

When I originally said your truck I was thinking of the car in the first post was you sorry about that and you are correct on my calculations I believe what I did was read FPM as FPS when doing the calculations.

As you do more testing you should move the manometer into the intake tube two inches or so that way you will see the pressure that in making it into the tube and not the pressure that is trying to make it in to a smaller tube.

[highwaylizard]

Originally Posted by dcb

Your title of this thread is completely inaccurate, you don't have any credibility as a result. "Ram Air Nets 5.1MPG gain"

I am not the thread originator. Learn to read.

[duffremle]

It seems to me that there is work involved in an engine sucking in air and if the forward motion of the vehicle can instead feed the engine air then there should be an efficiency gain. It should make the intake stroke just a little bit easier if nothing else.

[Blacktree]

Originally Posted by duffremle

It seems to me that there is work involved in an engine sucking in air and if the forward motion of the vehicle can instead feed the engine air then there should be an efficiency gain. It should make the intake stroke just a little bit easier if nothing else.

Yes, the theory is sound. The question is whether or not this particular execution of that theory is actually effective.

Cowl induction is another way of increasing the pressure of the intake air. But instead of sticking a pipe into the wind, you tap into the positive pressure bubble at the base of the windshield.

Highwaylizard: you seem to have the time and cash to try out lots of different gadgets. Maybe you could purchase a vacuum / boost gauge, and install in into your intake pipe, and record the results. If it goes hyperbaric, then you have your proof. If not, then you know you're wasting your time.