What he said

 

>Is that a true ram air that vents into an air box? My guess no.

Bad guess..





The one in the photo does have covers over the ram air holes, but that hood is fully funtional if you add the airbox in top photo.

>A sports car has the chance of using the ram air at high speeds that this >truck will not get to easily.

Actually it is the opposite. A "blunt" faced truck creates more high pressure in front (the hood/grille area) than a Sleek streamlined Sports car.

Your first statement should read more like this ... "A truck can make better use of a Ram Air Hood than a Sports Car and do it at MUCH lower Speeds".

In reality the ONLY High pressure area on a modern sports car is typically in the radiator grille area or just above the front spoiler. The hoods on those cars have the LEAST amount of air pressure area.

>Wheels have their function unless you choose 20' or up then you are just >adding extra usless weight in a very bad place.

Wrong again! If you take the exact width and height 17" and 20" wheel/tire combo the 20 will always be lighter (I ship wheel/tire combos daily and know the weights). You forget that aluminum is lighter than rubber and a 20" has less rubber and more wheel!!

 

Your statement about the Sports Cars is absolutedly true, but that statement doesn't aply to a "flying cinderblock"... i.e, truck.

See my last post above.

On the other hand with the sports cars I deal with the ram air is brought in from above the spoiler and on hundreds of actual dyno testing (Dynojet 248 series) using only a 20" "home" box fan we pick up 10-15 hp with the fan on vs. with it off. It is all about where you try to get the ram air from, and most people get it wrong.

I agree completely about the "otherwise stock" part of that statement.

 

On this same subject, the funniest thing I have seen lately is a "Ram Air Hood" on a truck AND he also had a "Bug Deflector" on the hood which was shooting the air right over the top of the hood...DUMB!!

 

How much HP do you think the hood adds to the intake at 65MPH? What would you figure the increase in pressure inside the intake is with the hood vs without it?

 

Oh, just for entertainment and education purposes, here is an actual Air Flow Pressure Chart on a typical Sport Car (older 83 or so Porsche 928).. BTW, the lower number "1" at the bottom front is pressure and the higher numbers across the top are vacuum (inches of Mercury) with the exception of the windshield base area which is a slight pressure zone.

 

Ok so you can get a functional ram air. At 75 you can start to see gains because of the extra air instead of 100+ in a sports car.

Since you know the weights and work with wheels everyday how about weighing a stock wheel and showing us the difference. I would really like to see the weight of a 18X9 Helo Maxx 6 wheel vs the stock 18' fx4 wheel.

I'm not going to debate/argue anything on the internet lets just see facts.

 

I don't know exactly and do not speculate on such things. I have a pressure testing rig I am currently using on my prototype 928 Twin Screw Supercharger kits and the next time I get a chance I will measure the pressure inside the air box at various road speeds and report back exact info. I also plan on doing a before and after dyno on my truck before install of an Intercooled SC kit and will do some with and without fan runs (stock and boosted) to get exact data.

On the other hand I do know my gas mileage went from 14-15 to 16-17 on the exact same long intersate highway trips(bed fully loaded and 4 people plus a 100+ lb German Shepard) before and after I added the airbox mod. That was good enough for me and warranted no further testing in my mind.

 

>Ok so you can get a functional ram air. >At 75 you can start to see gains because of the extra air instead of 100+ in a sports car.

... and I cruise on the Interstate at 75-80mph, don't you?

>Since you know the weights and work with wheels everyday how about weighing a >stock wheel and showing us the difference. I would really like to see the weight of a >18X9 Helo Maxx 6 wheel vs the stock 18' fx4 wheel.

I don't have any of those to weigh (The wheels I weigh don't fit F-150s), you can contact Helo for specs on their wheel and then weigh your stock one for comparison.

The comparison I was talking about was a 17" (or 18") vs a 20" wheel, yes the wheel will be heavier (given same width and depending on if it is forged or cast) but the tire in the same width and overal diameter will weigh less. Given the same physical overall measurments (Tire height and width). less rubber and more aluminum adds up to lighter everytime.

However in reality when any of us go bigger for example to 20" wheels, we always go wider too. There is no doubt that my 305/55-20 tires and Forged Weld Racing Wheels weight more than the Stock Ford 18" wheels with 275/65 tires , but that is not "apples to apples" .


>I'm not going to debate/argue anything on the internet lets just see facts.

I agree 100%, that was the whole point of my previous posts. Let's not speculate too much unless you have "Been There Done That" in some shape or form... On the points I usually discuss I have a closet full of T-shirts.

 

What intake did you have before you added your airbox?

 

Stock.

I have tried those "Airbox Tube thingys" in the past on other vehicles and all they gave me was a lot of intake noise... sure made the vehicle sound faster, but it wasn't.

 

So it would be fair to say that your gains with the airbox were pretty simular to what others and myself have experienced with an Airaid, Air Force 1 and other free-er flowing after market CAIs compared to stock. Which is basicaly what I said that the ram air hood and airbox is not much (if any) better than a standard CAI. There is no doubt its better than stock. The 5hp max gains I was talking about was comparing two cars with identicle intakes, one with "Ram Air" and one without.

 

>Which is basicaly what I said that the ram air hood and airbox is not much (if any) better than a standard CAI.

Common sense would dictate that having air forced in from a high pressure area (front of hood) would yield better results than having air "sucked" in from under the hood (hot air) or from inside the fender (stock, low pressure area). BUT only back to back dyno tests in a 60mph wind tunnel would absolutedly prove it either way.

I will give you a recent example, this was on a sports car, but should demonstrate the power of pressurized air vs. "static suction". I was doing some dyno tests (24 runs that afternoon) on my car with an Autorotor Twin Screw SC. The tests done with the ram air tubes in place, the hood closed and a 20" box fan in front of the car showed 15 Rear Wheel HP and Torque more than runs made identically but with just the hood opened. Now a 20" box fan doesn't come near to simulating even 40mph of air pressure on the front of the car, much less 60 or even 100mph. Ironically when we removed the Ram air tubes, Filters and ran just exposed Throttle Bodies (it is a twin Throttle body setup) the power was also the same 15 down from the "ram air" supplied system. BTW, I have the same results hundreds of times, but slightly less (usually 8-10 loss) on the same type of car without an SC, so that is not the issue.

If you have done as much dyno testing with Ram Air Systems as I have (you may have done more) then there would be no doubt that a properly designed ram air system will be more powerful than a negative pressurized air tube system any day on any vehicle... All you have to do is look at ANY race car and they are using a ram air system (think about those big holes over the F1 drivers heads).

I plan for more dyno runs next week and will probably trailer my car with the truck. If I have the time I will strap the truck down and do some totally stock (the removal/install of the Ram Air Airbox I have is same as changing the stock filter) runs, then runs with the Ram Air Airbox with and without a fan in front. I will post the dyno sheets here (good or bad). I also challenge (in a friendly informative way) anyone else to do the same (stock and then with one of those fancy cold air tubes on the same truck) on their truck. FYI, posting of "Airbox Mod manufacturer's" dyno sheets is irrelevant (and never "real" IMHO) and also considered "cheating" :-)

 

Keep stock wheels for winter use.


I would go with the wheels and tires first.


Wish I had a truck to put the hood on.

 

I agree...thats why I said it may be good for 5HP. The big question is how much air is being forced into the intake and how much of a pressure increase there is inside the sealed airbox vs the relative atmospheric pressure. Factor out the benifit of the cooler air, just how much of a gain is caused by the air being forced into the intake by a hood scoops? A Powerdyne supercharger at 6lbs adds roughly 60HP from the dyno numbers I have seen. Thats 10HP per pound of boost (and I know thats not a true comparison because you have to take into account the parasitic driveline loss of the SC and the increased heat of th compressed air) roughly. Thats why I asked how much "boost" does the ram air effect of the hood give you? I wouldn't think the pressure inside the airbox be much more than a half pound at most more than than the outside pressure at full throttle. Basicaly your engine will be sucking in as much air as can possibly be forced in by the twin hood scoops...thus little to no pressure inside the airbox, and little no pressure means little to no increase in HP.

I think the telling factor would be if you can measure the pressure inside the airbox at WOT at around 65-75mph.