Ram Air VS. Upper grill block

[LeanBurn]

My post was merely to point out that Hondas new Insight is designed to do both a cold air intake coupled with a duct from in front of the radiator taking advantage of a high pressure zone. They could have done the intake just like the previous generation Insight at a much much cheaper cost, but they didn't. They have obviously gone through the trouble and money of testing and reached this design. Being a mild hybrid, it relies a great deal on the naturally aspirated ICE and these intake properties are of value at speed, while obtaining decent fuel economy, so full throttle was not primary. I don't even think they use lean burn mode on these engines (do they?)...so the tuning aspect would be for fuel economy, within our grasp with the stock ECU.

There must be some positive results from having the intake like this. I plan on doing a version of this and see what kinds of results I can get. As far as better results from grill blocking, I am sure a 4inch hole in the block will not have that much of a penalty if not entirely offset but what this modification can do and then some.

[euromodder]

Originally Posted by pete c

Is it possible that a properly sized slot used as an air intake has an actual aerodynamic advantage over a block? A block means pushing the air aside, which is drag. An intake that is sucking air in at something close to the car's speed, should be pretty clean, aerodynamically s[peaking, I would think.

For any given speed, you can know the rpm and calculate how much air is going through the engine.
You can also measure the area of the intended intake, and see how much air will pass by at that same speed.

[Tesla]

LeanBurn
Is it possible to block entire upper grille & still draw on the pressure air coming up from the lower grille, giving you both advantages?
If all holes around radiator are blocked, there is still a large pressure build up in front of the radiator from just the lower grille anyway.
I have seen this with both my vehicles after upper grille blocking.

[LeanBurn]

BMW OEM does something like what you are describing on some models Tesla, so that must also work.

Not sure why Honda choose this method for the Insight, but they did.

[jtbo]

I got inspired by this topic and was thinking about doing this mod, however I could not find any proper way to get air tubing past radiator, which means I made it by insane method, I put tube under the radiator, which leaves it around 50mm from ground, which is insanely low.

It is quite bit back from front edge of bumper, so that must hurt performance a bit, I try to put that tomorrow so that it is nearly at front bumper level, which should place it to high pressure area.

Just temporarily for the experiment.

I did just test drive with badly positioned tube and when coasting down a hill at idle, I can't see any measurable difference in boost gauge (it does measure vacuum too).

When driving my typical speed, it might have been bit higher, it might have pulled bit better, but it can be as well plasebo effect, surprisingly sound seems not any louder than before, even I had to remove intake silencer out to be able to fit this tubing.

I must drive tomorrow bit further so I make adjustments, try to estimate effects and try to remember report back, which all is quite a lot for my poor head.

One thing that worries me is that it is potentially increasing frontal area and also drag in current position, so it might be better to punch a hole to hood or something like that.

[oil pan 4]

Any boost you will pick up from ramair will only be measurable in inchs of water.
Its not going to be measureable inside the intake mainifold, only the intake.

[jtbo]

Originally Posted by oil pan 4

Any boost you will pick up from ramair will only be measurable in inchs of water.
Its not going to be measureable inside the intake mainifold, only the intake.

That is of course correct as there are not enough exhaust to propel the turbo any faster at the idle and engine shut off turbo will be restricting air flow so that there can't be pressure increase so that is why I would need to measure pressure change before and after the filter and before the turbo.

I did found some reading, which should be taken with grain of salt, but still, guy has put effort into testing and documented some of the test methods and results, with modification to airbox and ram air, or cold air intake which ever one classifies it, he got 20% better than EPA consumption on his vehicle.

Here is link where one can read more, I found out angle of pipe effecting air flow to be most interesting part, surprisingly small change in angle seem to cause drop in airflow:
Ram Air Project

That is perhaps only one diy build where I have seen some measurements being made and as he put pipe same place that I have put, some results should be comparable in my setup, even pipe is same size and material.

[ECONORAM]

Interesting thread. I saw this article at Autospeed for testing consideration: We have a record! . I modified the intake on my wife's 08 Avenger a bit to feed more air to the engine, and I did see an MPG increase (sorry, I didn't know about ABA testing back then, but I can see an increase in the fuel logbook).
For the life of me, I cannot recall where I saw this, but someone has a Honda or Suzuki they modified the intake so that it was pulling air from the rain tray, with a piece of window screen and a sock or rag as the filter. Certainly extreme shade tree style, but it would let him take advantage of the pressure at the base of the windshield (like cowl induction). The pictures are: 1 grill w/hood popped--see small bump on bottom of hood; 2 factory intake scoop--red is where I cut open the side that was blocked; 3 factory intake still--red is where I cut into it and added a 2" PVC elbow to complete the blocked side as a viable intake (I tried to foam insulate but later figured that wasn't such a good idea); 4 raised hood with intake bulge clearly visible.

I previously owned a 91 Jetta. It had a plastic shroud around the right headlight to feed air to the intake, about one or two inches in front of the air filter box. Upon inspection, the air filter box had a snorkel inlet shrunk from 4" down to a 1" opening. I removed that and sealed the gap between the filter box and the shroud. Worth about 2 mpg and a bit of loud pedal.

Might provide you an idea...

[slowmover]

"Cowl induction hood". A ram air Chevrolet used on some SS Chevelle & Camaro muscle cars ca. 1969.



A popular mod for Dodge Diesel pickups in the late '90's. Several reports of, once done, sounded like having a 747 engine behind the glovebox. Turbo re-alignment in later models precluded this.



.

[oil pan 4]

We should note that diesels normally see an increase in MPG with cold air intake.
Gas engines usually do not get the desired MPG boost.