Your example shows the decreased air volume in the stock box provided. Open filter was able to flow a higher velocity across the MAF.

Like Doug said on heat ...once you get moving or have a fan at a dyno it will not be a factor.


Doug, that 5 seconds might hurt you from the stageing lanes / to leaving the line on your 12 second run

so enclose it .....

 

Tim

The original statement was that no one has addressed as what power levels the stock arrangement or ANY closed filter becomes a restriction. Your "Not True " aside that question has not been answered that I have seen.

The second point was that You were assuming that the volume of air was the same in both scenarios .. Again - Your "Not True " aside - You backed up my statement So we are arguing on the internet about a solution that doesnt exist - The JLP box is open - The stock box is too small and the media is too small - NO other vendors solution is Big enough and draws air from outside the Engine compartment.

Since there is no closed solution that is big enough. My point in restating my experience with MY IAT's in Dallas Heat was that IN My opinion the small temporary loss of HP using an open filter is likely on MY truck, outweighed by the abilty to pull as much air as needed at all throttle positions.

Since we agreed that the Windtunnel dyno is not an option - I was never trying to make a case that was provable to a scientific or legal certainty. I was simply trying to convey the reason I made the decisions I did and my beliefs about the commonly available solutions. AND the appearance of the filter and the sounds of the supercharger ARE important to me and to many other consumers... The level of importance varies person to person, BUT assuming you have to identically performing solutions - One is attractive and allows the sound of the supercharger to be heard its likely that one will be more popular.

Doug

 

Ok I do know this, With the vehicle completely stock, and checking the Boost with a Lunar gauge. (OK "not completely stock", add a gauge) The engine would make 8 PSI, on hot days… Now, then I cut Two 3.5” holes in the bottom of the stock air box, no other changes!! All of the sudden, I would get 9.5 PSI on hot days and a solid "10-PSI" on cold days. (What happened??????) (Some engineer must have not converted from Milliliters to Inches)!!!!

 

Well, let's give it a shot right now:

According to well-documented tests run by Richard Holdener, the stock airbox ran out of steam somewhere between 400-450 rwHP (the exact point is a little unclear).

According to Sal of PSP: "The stock or modified/stock airbox is fine if you run stock or up to +3 PSIG extra, but it's definitely not for trucks running over +4 PSIG. On the dyno, trucks set up like that will drop off in power early, from the lack of adequate airflow. Happens every time."

That was one reason why I put the JLP airbox on my stock engine. When the power levels go up from mods, I do not have to worry about the airbox being a restriction. I doubt that I will ever take the engine to the point that either the JLP filter or airbaox openings cannot supply the required airflow.

Although it appears that very little air is able to get into the gap between the top of the JLP airbox and the bottom of the hood, I am thinking of tossing the lid and installing a gasket to completely seal against the bottom of the hood. Maybe that difference is only important on paper. We may never know.

 

You are not alone. Almost everyone who has modified the airbox or replaced the filter has seen 1-2.5 lbs more indicated boost.

This is an unexplained measurement anomaly, not real boost. If it were really 2 lbs of real boost, we would see large increases in HP. Much larger per PSIG than overspinning the SC with a pulley, because the "freed up" boost would not be accompanied by the dramatic rise in outlet temps that overspinning causes. So while some have reported slight (less than 10 rwHP) gains from replacing the filter on a stock engine (many others have seen a loss), no one has reported gains consistent with the increase in indicated boost.

My Auto Meter electronic boost gauge reads 10-10.5 lbs peak with just the JLP filter. But I did not gain any appreciable HP from the filter swap -- as measured either by the butt dyno or the G-Tech.

Perhaps some Ford engineer can explain this anomaly.

 

Guys, guys, guys! Just order part no. 1Z-324-986-YEH-RITE in the Ford Racing Performance catalog for the "big mouth" intake enclosure. It's right next to the 130 mm MAF on page 46!

 

I'll know...and air density knows., seal that baby up and stick that IAT sensor in a cup of dry ice


The MAF on a stock box truck and the MAF on a open filter JLP or AFOne truck flow the same "mass of air" ..... the open filter will draw more air through the MAF by increasing velocity than a stock box will. The MAF senses the extra velocity, temperature, pressure and cross sectional area at the point of mesurement for the ECU......

The question is density. Yes, most believe the stock box will allow intake air to be denser than the open filter will below approx. 35 mph..... ok then....enclose the larger aftermarket filter for the same temp. results as stock and enjoy more air over stock and let that monster motor emplode you filter with that increased air velocity.aka more air.

Like you said, this is why many see good gains with the addition of holes in the stock box to a certain HP level.....400-450 ish...

 

This is explained as residual boost(boost residing in the intake manifold). Since the intake is where the boost gauge reads from, you can see more boost here with an open element. As Tim has said this may not be usable boost making greater extra power. You could easily modify your heads to flow more efficiently and see a drop in boost pressure, but you are actually gaining power as this means more boost is being transfered inside the motor and not just sitting in the intake.

 

Thats great - Since Im only making 410 or so HP on a good day then I should go back to the stock airbox and filter -

Wait - Im running a 4# pulley so I need to run an open filter...

Im sooo confused - How can a truck that is running 2 or 3 lbs of extra boost make 400-450 HP ?

These 2 examples that sem to contradict each other show that there is NO consistent data. They both suggest however that the stock airbox is a restriction at relatively mild HP levels. That means that EVEN though an open filter may breath in hot air its likley a better solution than the closed stock box for even mildly modded trucks

If we agree on that then Kenne Bells statement about closed filters seems a bit confused because why would someone want to spend 4k for a Kenne bell and tuning just to make 400-450 hp ??

Bell doesnt make or sell a closed airbox for either the Lightning or the Mustang and we agree that no aftermarket filter is truley a closed system, ( except the one called Volant I think ) yet his statements suggest that no customer of his will be warrantied if the use an open filter and accompanied with the data from above that means they are limited to 400-450 hp and 2-3 extra pounds of boost ...

Its all so confusing....


Doug

 

I don't disagree with your conclusion, Doug. But the signal-to-noise ratio of this once clear thread has gone down the toilet.

To summarize:

======= open versus closed topic begins =========

The central issue raised by this thread is not whether an open, non-restrictive filter is better than a restrictive closed filter, the issue is whether a given filter -- sufficient to meet the airflow needs of your engine -- is better open or enclosed. I just don't know how to say it more clearly than that. And there is no debate on this issue. Enclosed is better. Period. It's better on the engineer's drawing board and, as the data cited and referenced in this thread proves, it's better in real life. And it's not confusing at all.

========= open versus closed topic ends =========


Alert -- topic change:


======= limits of the stock filter topic begins =========

The data cited does in fact conflict. But it does agree that there is no mechanical (as opposed to cosmetic or aurual) reason to replace the stock filter on a stock truck.

========= limits of the stock filter topic ends =========


Alert -- topic change:


===== application to the available choices topic begins ====

The practical aspect of getting an enclosed filter of sufficient flow to support a given horsepower is another issue altogether. As you correctly observe, the Volant appears to be the only completely enclosed option.

But that overlooks all of the semi-enclosed designs. Some use "ram air" ducting, some just use "air dams" to separate the fenderwell air from the engine compartment air. Some have used Rubbermaid trash cans. Some have used a gasket on top of the open airbox top to seal it to the underside of the hood. Partially blocking the hot engine compartment air is the next best option.

The bottom line: The enclosed or semi-enclosed boxes like the Volant, PSP, and JLP are the best currently on the market.

Can they supply enough air for any modded 5.4? Dunno. But they surely can supply enough air for the vast majority of the Lightnings on the road. And there is just no reason to buy an open filter of the same airflow capabilities.

 

Tim, Dr. Phil 8pm Channel 4: “How’s that working for you?”

 

So Tim a JLP AIR RAM AND RAM AIR HOOD SHOULD DO THE TRICK RIGHT? THANKS Bob

 

Could it be that the increased boost is already in a hot/overspun range for the blower, so that while there is increased boost, it's not making much power?