Sorry about the misleading title, this is not ram air, as it is not really pressurized, it is cold air venting directly to the air filter. I made use of some 4.5" silicon tubing I had laying around. I had previously butchered the area where the windscreen reservoir was by adding a 5" hole to make an air path for my abandoned SCRAMJET project.

The coolest available outside air travels through the passenger's side fog light hole, then makes a smooth 90 degree sweep through a 4.5" silicon elbow and shoots directly up into the air filter from below the air filter.

This is now providing lots of the coolest available air into the air box area. I like this system because it is pretty much a straight shot into the intake tube through the filter, the air does not have to change direction very much.

The last pic is of my current engine bay, the cold air shoots up from below the open filter.

 

I have a suspicion that any horsepower gains will come from colder air being delivered to the engine by a more efficient intake system and slightly better throttle response you would get from that efficiency.

What I remember, and I have no source for this info, is that a "ram air" system needs for the car to be going in excess of 160 MPH to really gain any positive pressure.
Vector

 

agreed.

This is Not actually ram air, just colder air.

I stand corrected.

 

What is the size of the hole in the bumper?

Make sure you measure the vacuum in the intake elbow 1st, then do a measurement with the new ram air one, and you will know if it works.

 

The hole in the bumper is 3". The air is funneled down as it goes to the smallest 3" opening. I'm using 4.5 because that is what I had around.

 

Its small of course, but the funnel will help again. Are you fabricating your own airbox over the m92 maf unit? You do realize that you take away the M92 advantages with the small opening.

Yes the map sensor is good to use. You could do a test in 2nd gear (put leaver in 2nd so it hits the rev limiter), and one in 3rd, then you will see if the ram air is making a difference.

 

The "box" I will make is only walling off the rear and engine sides. The air is still free to come in from behind the headlights and I will try to get some sort of cooler air to vent through the stock opening in the fender. I would not have had only the fog air vent with a 3" opening as that would be a small bottleneck and completely defeat the purpose. Even my TB is now 3.25"

My air box will be something like the fine example in this photo

 

Then I don't think it will work, or at least barely measurable.

The stock airbox setup does have a larger opening, with the bellhouse shape, and in the fender (at least for the XK models) you already enjoy cold air and even some ram air effect. This as the air is coming thru the front opening of the bumper and as not all air will go thru the radiators, it creates a slight over pressure in the fender as it can flow there, and I guess the setup is similar to the xj.

The least you could do that might possibly give you an effect at high speeds is to have both the left and right hole in the bumper used, pipe them together to an airbox (so closed system so you can actually enjoy ram air). But even that remains to be seen to be honest, so only good measurements will give some proof.

 

I understand you are saying that if I do not have a box I can pressurize, then I do not have any pressure. Logical says Spock.

I'll keep thinking about how to make a box with a small chin scoop to significantly increase my frontal area and then feed the collected pressure through the 4.5" tubing to a real sealed box, thereby getting a decent size ram air effect. There is sufficient room to make a box that would have lots of surface area (like a 12 x 2" scoop) in a high pressure area. I am avoiding cutting the fog light hole larger because, so far, all my mods are more or less reversible.


I have "other" uses for the driver's side fog light hole that are far more entertaining than a ram air system. Things that should not be posted on the internet "Cue evil laugh"....

 

Always nice work and always nice to see you push the Eaton envelope.