So Ram Air does not work....

[Fiesta48]

Check this guy out.
Ram Air Project
I've gotten better gas mileage on my V-10 too. Especially going into the wind. My gas mileage hardly drops even into 30 mph headwinds.
I removed the very restrictive downward rear facing intake, to a behind the grill/fascia intake using a plastic dryer vent facing forward. <$10 Lowes & HD.
I removed the flapper. Turned the opening upside down and attached it with sheet metal screws to the bottom of the air cleaner.
I've driven in heavy rains to no ill effects. You can use your stock air filter but I use gauze filters. Have for hundreds of thousands of miles in dirty environments with no dirt/dust upstream.
I get 9-9.5 mpg in all weather/winds.

[Full.Monte]

Interesting! I read the writeup on his project and didn't understand the part about the angle of the intake relative to the road surface. Intuitively, it would seem that pointing the intake directly forward would give you the best boost, but the drawing and test results don't seem to say that. Can you explain? Thanks!

[jlyon69]

I've often looked at that rear facing shield at the bottom of the air filter box on my V10. Seems that configuration would produce negitive air pressure.

I've often thought that just spinning it 180 degrees (facing forward) would produce a fairly good positive pressure. I'm heading out on a 3000+ mile trip in a few days, I think I'll just try this and see what happens.

[jlyon69]

Quote:

Originally Posted by Fiesta48 Check this guy out. Ram Air Project I've gotten better gas mileage on my V-10 too. Especially going into the wind. My gas mileage hardly drops even into 30 mph headwinds. I removed the very restrictive downward rear facing intake, to a behind the grill/fascia intake using a plastic dryer vent facing forward. <$10 Lowes & HD. I removed the flapper. Turned the opening upside down and attached it with sheet metal screws to the bottom of the air cleaner. I've driven in heavy rains to no ill effects. You can use your stock air filter but I use gauze filters. Have for hundreds of thousands of miles in dirty environments with no dirt/dust upstream. I get 9-9.5 mpg in all weather/winds.

I took the intake/air cleaner assembly off my '99 to take a look at what I had. I saw there was a velocity stack on the bottom of the air cleaner box (behind that shield), which pointed toward the front. After thinking about this a bit, I grabbed a 1 ft piece of old sewer hose (fit perfect) and attached it to the velocity stack. I attached the other end directly to the front grill pointing it right down the road. (I left that shield off.)

At that point it certainly looks like it will FORCE more air into the intake, especially on the move at freeway speeds. I of course was still skeptical of any real gains. Anyway, I decided to go top off with gas and propane for my trip to FL in a few days, which is about 15 miles away. I had to make 4 short stops.

I have a ScanGuage II and I was rather shocked it was reading 11-13 MPG at 55. After the 30 mile round trip, it reported 10.6 MPG average. This is quite different than the 7-8 MPG I'm use to getting. However, the 7-8 MPG is with pen and paper and pulling my 3500 lb trailer. My ScanGuage is new and I still don't have it dialed in yet, but this is looking promising. If there is a significant improvement on my way to FL, I'll report back here.

[Piledrive]

Quote:

Originally Posted by Fiesta48 Check this guy out. Ram Air Project I've gotten better gas mileage on my V-10 too. Especially going into the wind. My gas mileage hardly drops even into 30 mph headwinds. I removed the very restrictive downward rear facing intake, to a behind the grill/fascia intake using a plastic dryer vent facing forward. <$10 Lowes & HD. I removed the flapper. Turned the opening upside down and attached it with sheet metal screws to the bottom of the air cleaner. I've driven in heavy rains to no ill effects. You can use your stock air filter but I use gauze filters. Have for hundreds of thousands of miles in dirty environments with no dirt/dust upstream. I get 9-9.5 mpg in all weather/winds.

Interesting! I too have read about Ram Air in our F-53's, and their conclusion was, waste of time and effort.
However, my big concern would be water intake. My engine has the added plastic shield covering the front of the updraft port. Many have said they have had problems with so much water intake that it starved the engine. I would like to hear more of your progress and will be looking for additional posts.

[Full.Monte]

Well, since it doesn't rain all the time, would it be smart to have an intake with a front-facing ram-air intake that could be switched to a rear-facing intake on the fly? I could see something like two dump valves accomplishing this, with actuator handles in the cockpit.

[jlyon69]

After a 1500 mile trip, I had to conclude that this "may" give you .01 - .02 MPG better. There are just too many variables to prove any significant gains.

My logic tells me that there should be a slight increase in pressue at the intake. This "could" give some ease of resistance to the engine in sucking in the air. But when you really think of that, it has to be minute. Should be no increase in A/F ratio since the ECM would compensate for any changes.

I did drive in light rain and snow without any problems. I would have stopped and changed the position had either been heavy.

I cant give this myth a "busted", but I have to say inconclusive, but cant hurt.

Would I spend $ to control air flow direction from the dash, no.

[trainsktg]

Quote:

Originally Posted by Piledrive Interesting! I too have read about Ram Air in our F-53's, and their conclusion was, waste of time and effort. However, my big concern would be water intake. My engine has the added plastic shield covering the front of the updraft port. Many have said they have had problems with so much water intake that it starved the engine. I would like to hear more of your progress and will be looking for additional posts.

When I first bought my MH, short trips under 300 miles with the original rear-facing shroud installed resulted in no water being sucked into the air filter. When preparing for an 8,600 mile cross country trip last year, I decided to try the dryer hose trick...just to 'be safe' of course. The second day out the engine started missing in a Utah snowstorm and I had to change the air filter out. It was completely soaked, and the air filter housing also had about 1 cup of water in the bottom too. It got so bad during the trip that there was a point that we couldn't drive more than 150 miles before completely soaking 3 air filters. I tried every conceivable placement of the hose inlet in an effort to prevent the engine from sucking water...forward facing, rearward facing, pointed up within 1/2" of the top of the engine compartment, facing downwards...nothing helped. After returning home I reinstalled the factory shroud. I haven't driven in rain since so I can't report if the problem remains but it can't be worse than with the dryer hose. Of note...the Bounder's engine compartment in the area of the wheel wells is open, not closed off. I believe MHs with enclosed engine compartments have a much lower chance of sucking air, so the hose dryer trick might work.

Keith

[VanDiemen23]

Sorry folks - but if you think you are getting increased MPG as a result of ram effect you are barking up the wrong tree. Ram air is free "turbocharging" - meaning that the purpose is to increase the density of the charge through an increase in pressure. Since fuel systems deliver fuel based on mass air flow, any increase in air density means an increase in fuel flow and a DECREASE in MPG. You do get increased HP - that's the point. But you have to be going very, very fast.

If you look at my avatar you'll see a black scoop - that device doesn't see usable Ram effect until over 100 mph - and it was designed in a wind tunnel for that purpose.

Improving inlet efficiency may be a factor, but the chances of backyard engineering yielding significant gains over something that a designer spent months on with CAD and CFD is luck at best - and most likely will see a number of unintended consequences that the designer had to eliminate - like intake howl and the water ingestion problems eluded to here.

For increasing MPG on a motorhome the low hanging fruit is drag reduction.

[Fiesta48]

I have documented proof positive that cold ram works because....
1. I reduced the negative inlet air pressure the OEMs designed when the undersized (by 1") inlet tube was behind a rain deflector which was against the radiator. A truely poor design in 3 regards for economy and HP. They were trying to keep out water, get more hot air and reduce noise.
2. I've done this on several vehicles (20?), for several hundred thousand documented miles.
3. I've driven in terrible rain storms with no problems.
4. My intake in the pic above is back about a foot that helps keep out rain and there is a 135 degree turn at the top of the filter housing at least 20" up.
5. The positive intake pressure now in the inlet track allows the engine to suck less hard, therefore produces more HP. A little like turbos/blowers do.
6. I only use gauze filters. Again 20+ vehicles for hundreds of thousands of miles and no ill effects.
7. And in headwinds my MPG drops very little, <.5 due to even more air being rammed in. Before I did this I would lose 2-3 mpg.
8. Did everyone read the attached link? That guy added 30+ HP and 5+mpg on a car.
9. If you haven't tried this, please find out for yourself.

[Fiesta48]

I believe if you've done a cold air ram system and had water soaking paper air filter elements that is the problem. Gauze filters are soaked in oil. Water can't soak into them.

[Gary - K7GLD]

IN short, UNLESS you have an existing air intake system so poorly designed, and restrictive, the BEST attempt at "Ramcharging" is a pure WASTE of time, effort, and money. The SIZE of the intake, and SPEED you have to travel for measurable pressure increase is TOTALLY outside the capabilities of the average MH!

Any "gains" in HP or MPG, will ONLY occur IF the original intake setup was extremely poor to start with...

Not just personal vague theory - I've tried it myself, and used sensitive measuring equipment to see what changes were made to intake air temperature and PSI right at the intake manifold at normal vehicle speeds - and they we ALWAYS totally negligible as compared to the OEM setups!

[smiller]

Yes. Physics cannot be denied, normal road speeds are just not anywhere near sufficient to generate significant ram effect/pressure increase in the airbox. However on well-designed systems it can start to produce some extra power at triple-digit speeds so maybe if you just speed up a bit...

[mpaton]

I'm glad you're happy with the results of your experiments. However I am unsure that you understand what "Ram Air" would actually do for your engine if indeed you have successfully converted air speed into pressure.

Let's say you were successful. If so, then at 60 mph if your intake gave perfect pressure recovery, then you would have gained about 0.14 inches of Mercury, a pretty small amount.

However, what would you use this pressure for? You could indeed use it for more HP. As with any spark ignition engine, the amount of power you get is proportional to the engine rpm and to the manifold pressure. When you want full power out of your engine, you open the throttle, and remove the restriction that it imposes, and then your ram air would indeed boost your power. By a small amount.

So your point 5 below is valid.

However, most of the time we don't want full power, and so we don't have the throttle fully open. In this mode, any extra pressure that ram air gave us would be pressure we don't need, and so the we would close the throttle somewhat to remove the effect of the extra pressure we found. And this reduced throttle operation is where we operate when we want best mpg.

So whatever you are doing to get better mpg, it isn't the ram air.

If you're getting better gas mileage, then you probably are doing something.

Point 7 below is invalid because ram air can only affect your engine if you let it get past the throttle.

Quote:

Originally Posted by Fiesta48 I have documented proof positive that cold ram works because.... 5. The positive intake pressure now in the inlet track allows the engine to suck less hard, therefore produces more HP. A little like turbos/blowers do. 7. And in headwinds my MPG drops very little, <.5 due to even more air being rammed in. Before I did this I would lose 2-3 mpg. .