Why RAM Air is a myth!!! Long Read (Wall of text)

[BumbleDs]

I agree, what do you mean by Ram Air is a huge question. Somepeople its just a differnt hood, let cooler in, or hotter out, or ramming air in. Guess it just how you take your tea whether its true or not....I dont like tea.

[Wacker]

Originally Posted by Halltech

The quote you posted in the first post has this statement:




The assumption that he is making is that the engine must have this a/f ratio to combust; this is not true except during closed loop. During WOT (over 19% throttle position) the LS3 is in Open Loop Power Enrichment not closed loop as he assumes. Combustion on the modern LS series motors during closed loop continuously and dynamically seek 14.7:1 air fuel, but that ratio is only reconciled by the O2 sensors under 19% throttle position. Ask yourself if ram air applies to his parameters.

Beyond 19% TP you go into fuel enrichment code which is around 11.3:1 air fuel ratio on the LS3. During fuel enrichment, there is plenty of excess fuel that could be burned by more oxygen in the intake IF you had a true ram air induction system. A perfectly built ram air box with converging air scoops, sealed, and preferably without a filter.

In addition, the Mass Airflow Sensor would register the increase in the mass of air and automatically increase the pulse width of the injectors to compensate fuel to the commanded fuel enrichment code.

Here is my point of argument with his statement: Ram air could never be effective under stochiometric circumstances or closed loop since you would necessarily have to have speeds of around 120 mph for ram air to work, and remember, closed loop only operates under 19% throttle. What car can do 120 mph at 18% throttle position? His statement of stoichiometry has no bearing on ram air dynamics, except to say you will end up with surging and bucking and likely lean codes. So why does he refer to circumstances that are not plausible in the real world?

Just asking.

30% on the LS3

[axis]

My problem with all the motorcycle tests is that they run a duct directly to the intake and tape it off to get a good seal. This brings back the leafblower turbo concept which has been proven to provide a small amount benefit. This DOES NOT show what will happen when you're driving down the road at X speed. I said it before in another thread that posted the same cycle links that these test aren't fair and aren't a indicative what might happen when driving down the road. It seems funny that NO ONE has done the easy thing in using a pressure gauge to measure pressure differences inside the manifold. Maybe they have and didn't like the data they got. The point is, until someone shows a + increase in pressure vs any other intake, it's not ramming air into the cyclinder. It's too easy to eleviate RESTRICTIONS in the intake tract and attribute that to + pressure inside the manifold. Are there benefits to a straight tube designed CAI? Absolutely if done right. To say that we got a HP increase on the dyno by using a massive fan blowing air, via sealed ducting, directly into the airbox, is manipulating the test in your favor.

[chappy48]

I love watching people argue against fluid dynamics and the laws of physics It's like watching someone walk into a wall over and over again

[Halltech]

Originally Posted by Wacker

30% on the LS3

The LS3 Corvette is 19% TP.

The LS3 Camaro actually goes into Open Loop at 25% TP (throttle position)

[Speedfreak]

calling on this one

[JANNETTYRACING]

All this discussion the the bottom line is RAM AIR will STILL Never be a reality on a Car under 150 MPH.

So in all Advertisements regarding intake systems, I say Replace RAM AIR with COLD AIR and stop BSing unbeknownst customers.

Ted.

[Halltech]

Originally Posted by JANNETTYRACING

All this discussion the the bottom line is RAM AIR will STILL Never be a reality on a Car under 150 MPH.

So in all Advertisements regarding intake systems, I say Replace RAM AIR with COLD AIR and stop BSing unbeknownst customers.

Ted.

There is no motivation to BS anyone. BS is when you make claims like "Ram Air is a Myth", or from the opposite camp "Ram Air gives you +40 HP". I merely posted some links to testing that has been done on motorcycles that make that same claim. Since when is posting an opposite point of view BS?

A properly constructed ram air system, could achieve +ambient pressures in the intake manifold at speeds less than 150, but I doubt seriously that anyone has achieved that. It is hype when claims are made that cannot be proven.

You are a very well respected forum member here, and I am not here to dispute anything your believe, in fact I agree 100% with you statement on another post that no system on the market is truly a ram air system. That does not mean that the concept is false, just the current and past claim by certain manufactures.

We have no plans on making a ram air system for the Camaro, and the one that is being made is another attempt to market snake oil in my opinion. My motivation in posting simple information on testing in this area, was not to promote the VR product, but was to show that ram air is real, it can be achieved, but only through proper methods. Those methods have not been employed yet on any intake I have ever seen.

Your company did a great job in the comprehensive testing of the intakes which shows a no BS attitude toward modifications. Keep up the good work. That is an asset to the forum.

Jim Hall

[axis]

Originally Posted by Halltech

A properly constructed ram air system, could achieve +ambient pressures in the intake manifold at speeds less than 150, but I doubt seriously that anyone has achieved that. It is hype when claims are made that cannot be proven.

I find it hard to believe that if it was possible, someone hasn't already done it and SHOWN the + pressure difference. The "RAM AIR" concept has been around since at least the 60's, yet NO ONE has SHOWN a + pressure difference while driving down the road. Dyno results mean absolutely nothing except the fact that you can skew results with unorthodox testing methods. Like I said above, it wouldn't be anything to tap the intake manifold, or even use a vacuum line to read pressure differences in the manifold, yet no one, to my knowlege, had done that. If I developed a "RAM AIR" that actually made + pressure in the manny, you can bet your a$$ that i'd have the pressure differences to back it up. I'd sell MILLIONS of them in the process.

[Halltech]

Originally Posted by axis

I find it hard to believe that if it was possible, someone hasn't already done it and SHOWN the + pressure difference. The "RAM AIR" concept has been around since at least the 60's, yet NO ONE has SHOWN a + pressure difference while driving down the road. Dyno results mean absolutely nothing except the fact that you can skew results with unorthodox testing methods. Like I said above, it wouldn't be anything to tap the intake manifold, or even use a vacuum line to read pressure differences in the manifold, yet no one, to my knowlege, had done that. If I developed a "RAM AIR" that actually made + pressure in the manny, you can bet your a$$ that i'd have the pressure differences to back it up. I'd sell MILLIONS of them in the process.

They did just that in Part 1: http://www.sportrider.com/tech/146_9910_ram/index.html

That is where the actual pressure was measured in the airbox of each bike.

For instance, here is one of the bikes tested:
YAMAHA YZF-R6: First up was Yamaha's 15,500 rpm YZF-R6. Note that the pressure drops below zero-that is, below ambient pressure-accelerating through second gear, and it finally builds once the bike gets past 85 mph. The spikes (present in all of the graphs) represent pressure buildup during shifts, since the throttle plates are closed momentarily. Pressure peaked at 17mb.

I think if you read the test of the article, you will see it answers your question.



Part 2 is where they duplicated the pressure they logged in each bike on the dyno to see what that exact pressure provided in horsepower.

There was another test done initially back in 1995 which showed the same type of testing by this magazine.

[Wacker]

Originally Posted by Halltech

The LS3 Corvette is 19% TP.

The LS3 Camaro actually goes into Open Loop at 25% TP (throttle position)

My bad...the L99 is 30%

[Halltech]

Originally Posted by Wacker

My bad...the L99 is 30%

Every platform is different. The C6 Z06 starts out at 48%, then migrates half way up the scale to 25%.

We actually use the ZR1 code on our E85 660HP Z06, and it makes a world of difference in bottom end performance. This is one of our old tuning tricks, which comes at a cost of fuel economy, since folks like to get their foot into it more often. Fuel enrichment=Oil company enrichment, except in case of E85, which is domestically produced 105 Octane Race Fuel.

[Wacker]

Originally Posted by Halltech

Every platform is different. The C6 Z06 starts out at 48%, then migrates half way up the scale to 25%.

We actually use the ZR1 code on our E85 660HP Z06, and it makes a world of difference in bottom end performance. This is one of our old tuning tricks, which comes at a cost of fuel economy, since folks like to get their foot into it more often. Fuel enrichment=Oil company enrichment, except in case of E85, which is domestically produced 105 Octane Race Fuel.

Interesting. What your doing simply gives them power sooner correct?

[Halltech]

Originally Posted by Wacker

Interesting. What your doing simply gives them power sooner correct?

Transition from closed loop (14.7:1) to Open Loop (approx 11.3:1 to 11.9:1 stock) provides more torque and grunt down below the curve, which creates a very nice feeling of power.

The primary reason for any fuel enrichment at all is to stave off knock from load and heat generated by horsepower. So, reduce horsepower with more fuel than the cylinder can burn, and you prevent knock by lowering BTUs and HP.

14.7:1 seeking fuel cell trims are a dynamic method of keeping it green, clean, and lean during normal running. Any a/f ratio below that is rich, since there is not enough O2 to burn the extra fuel.

Pro Stock bikes and I suspect cars try to run as close to 14.7:1 as possible for best power, but with 18:1 compression ratio, it is very difficult, even with very high octane racing fuel. We run 13:1 CR on our E85 Z06 and have zero knock and run 27 degrees timing at 7300 rpm. Fun to say the least.