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PostPosted: Fri May 16, 2008 4:09 pm 
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I was wondering if anyone has tried routing the air filter housing intake ducting to an opening in the solid sheet metal plate in the front of the car ahead of the engine?? I wonder if it would be too much 'boost' at 65mph? The engine will only run on the amount of air that you allow through the carb butterfly, so I can't imagine that it would cause any problems. I am thinking about making an aluminum baffle box in the front plate. I got 47mpg on my last tank, and I think I can get a little more without doing anything else to the car, other than the intake air.


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PostPosted: Sat May 17, 2008 12:23 am 
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Ram air is typically used for improving power by forcing more air into the engine. That only works because with more air you could get more fuel. More air& fuel doesn't improve mileage. Normally, improvements in efficiency are good, but this really isn't...

Theoretically, I suppose there might be aerodynamic gains by "worming" air thru the car, but it would be minimal...


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PostPosted: Mon May 19, 2008 8:11 am 
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i have a cold air intake set up on my 01 swift. ive seen huge mpg gains. i was getting around 40-42 and thats with me running 60-70mph and running kinda hard around town at this point i had a short ram intake (open element filter)which sat in stock location. then i rerouted the piping down in front of the front bumper so all fresh air!!!! and ive been getting 46-48mpg so i guess just try some different setups see what kinda results ur getting.

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PostPosted: Tue Jun 10, 2008 7:11 pm 
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I think one of the big magazine company's (road&track, Car&Driver etc..) did a test on the whole "ram air" set up with the SS and the WS6 and concluded that it only made 5HP over stock. Btw they only showed a 5 HP bump over 80mph.....

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PostPosted: Tue Jun 10, 2008 8:03 pm 
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yeah at something like 100mph it was tested to not even produce a 1psi difference of pressure

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PostPosted: Tue Jun 10, 2008 8:46 pm 
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svtthis wrote:
I think one of the big magazine company's (road&track, Car&Driver etc..) did a test on the whole "ram air" set up with the SS and the WS6 and concluded that it only made 5HP over stock. Btw they only showed a 5 HP bump over 80mph.....


Remember, that's a 5 hp increase on a 300 hp engine. Divide by six to see how much increase you can expect on a 50 hp engine.

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PostPosted: Tue Jun 10, 2008 8:58 pm 
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COOKIEMNSTR wrote:
i have a cold air intake set up on my 01 swift. ive seen huge mpg gains. i was getting around 40-42 and thats with me running 60-70mph and running kinda hard around town at this point i had a short ram intake (open element filter)which sat in stock location. then i rerouted the piping down in front of the front bumper so all fresh air!!!! and ive been getting 46-48mpg so i guess just try some different setups see what kinda results ur getting.

How about a pic or 2?

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PostPosted: Fri Jun 13, 2008 7:24 am 
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i put a pic in my album you can see what i mean.

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PostPosted: Tue Jun 17, 2008 7:59 pm 
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Woodie wrote:
svtthis wrote:
I think one of the big magazine company's (road&track, Car&Driver etc..) did a test on the whole "ram air" set up with the SS and the WS6 and concluded that it only made 5HP over stock. Btw they only showed a 5 HP bump over 80mph.....


Remember, that's a 5 hp increase on a 300 hp engine. Divide by six to see how much increase you can expect on a 50 hp engine.


good point......

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PostPosted: Tue Jun 17, 2008 9:56 pm 
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svtthis wrote:
Woodie wrote:
svtthis wrote:
I think one of the big magazine company's (road&track, Car&Driver etc..) did a test on the whole "ram air" set up with the SS and the WS6 and concluded that it only made 5HP over stock. Btw they only showed a 5 HP bump over 80mph.....


Remember, that's a 5 hp increase on a 300 hp engine. Divide by six to see how much increase you can expect on a 50 hp engine.


good point......

but you would feel 1-1 1/2 HP when you are starting that low


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PostPosted: Wed Jun 18, 2008 12:01 pm 
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COOKIEMNSTR wrote:
i have a cold air intake set up on my 01 swift. ive seen huge mpg gains.


Cold air isn't the same as ram air.

Ram air is going to take some speed to achieve. All it will do is shove more air into the intake, which you won't need at cruising speeds. I don't think ram air would do anything for economy, but that's just my opinion.


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PostPosted: Mon Jul 21, 2008 3:59 pm 
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I have ram air in my '91 Geo. Nobody believes it is worth any significant horsepower, I won't go there.

It changed the sound of the engine. It improved throttle response. The engine runs smoother, easier. It isn't working to pull air in to the throttle body. I go 85 mph with the wife and luggage on vacation and got 52 mpg averaging 65 mph. Of course I've done other things to the car since.

Reasoning - If your resonator box is restrictive then Cold Air might be "neutral" and ram air would ad something. How much, who cares. Or you can pay for turbo or supercharging.

It was simple. Measure your air cleaner cover circular diameter. Mine was about 2" OD so I went to Ace Hardware and got 2" ID black PVC in plumbing. 3-90 deg. elbows, 2 feet of straight pipe and a 3" to 2" adapter. My choice was thru the bumper or under the bumper. I went thru the bumper. Pull the sheet metal plate (header bug shield) and drill a hole big enough for the PVC tube in the lower left corner (Dramel tool), aligned with the bumper opening, and reinstall it. Cut some of the bumper flash to fit the tube thru. Install a 90 at the snorkel, the frame and down at the hole. Straight 2' out the hole and the 3" adapter sticks out just beyond the bumper. Makes it look clean. Zip tie it to the frame cross member at the headlight. Wrap with insulated heat tape. Your assembly might be different.

Doesn't work for you, you didn't waste much money and all you did was cut a hole in the bumper and pan. Any ideas on how to improve it, let me know. I almost went with a Shop Vac 2" floor attachment for collecting air.


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PostPosted: Mon Jul 21, 2008 4:07 pm 
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it almost seems pointsless of "ramming" air through 3 90* elbows

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PostPosted: Mon Jul 21, 2008 4:58 pm 
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swift13b wrote:
it almost seems pointsless of "ramming" air through 3 90* elbows

Adding an elbow is equal to adding 40 diameters of pipe. That means each 2" elbow equals 80 inches of pipe.
And if you really want to know:
the loss coefficient of the 90 elbow for the same flow velocity is from 2 to 5 times higher than the loss coefficient at the 45 elbow.
For water, steam or air the loss of pressure is equal to THETA times the velocity squared divided by a system constant. The faster we drive the more loss.
For 1.5" to 2" pipe THETA is
0.98 for 90 degree bend
0.18 for 45
0.04 for 22.5
Notice that a corner made from 4 bends of 22.5 degrees = 4x0.04 = 0.16 and the 90 bend is 6 times that!
For smaller pipe THETA increases. eg. a 90 degree in 3/8" pipe has THETA of 1.53 .
This is why some toilets take 5 minutes to fill. :(

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PostPosted: Mon Jul 21, 2008 8:18 pm 
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well, it would look cool at least 8)

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PostPosted: Mon Jul 21, 2008 10:19 pm 
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So kassaq, check out my album. I just down loaded how I got from the Air Cleaner Upper Case to the front of the bumper. I didn't want to go throught the headlight, or make a grill for my hood (1-90, maybe 2-45s) or just do cold air. Already paid for one K&N air filter. Can't do what Colorado did right now but it's unique, eh.

I work in a carport on a dirt floor, and can only get a part-time job in this little town. Also The Wife has a "matching" '95 red Geo Metro. She just got Bosch +4s and a new Magnaflow catalytic converter. So if it looks cheap, it is. But damn it sounds great and runs smooth.

Gas mileage. Longest drive last month was 120 miles RT, 4-60 mile RTs and local stuff. That's 358 miles, 6.923 gallons of gas for 51.7 mpg. All at around 5,000 feet.

As for air pressure, I think the MAP, IAT and BARO sensors would account for elevation, temp and pressure changes. The 90 deg. elbows insure you won't get to high of pressure.

Edit: I only made a 2-1/2" hole in the "header bug shield" and cut some plastic out of the bumper opening. So if you don't notice any improvement when you run the car up to 65 mph next time you can easily remove the plumbing and take 'flex heater hose,' run it thru the hole and vertically up the bug shield, tie with zip-tie. This will get more cooler air into your engine compartment. Picture in Album.

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'91 Metro, rescued from trip to junk yard. SuzukiRD Underpulley & Header. 3Tech 9mm plug wires & 218/350 cam +10 gear, Bosch Plat. +4s, FlameThrowerII, synthetic fluids. K&N, Optima, Catco, Jones glasspack, & KYB struts. Vortekx Generators, Air dam, 7mm ground system, Ram Air. No TBI bridge. No A/C - roof scoop works.
'96 Metro - The Wife's car: SuzukiRD Underpulley, 3Tech econo cam +10 gear, K&N, KYB, Bosch, Syn. & grounded. No TBI bridge.


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PostPosted: Mon Aug 18, 2008 11:21 am 
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Location: Chatham Co., NC / USA
swift13b wrote:
it almost seems pointless of "ramming" air through 3 90* elbows


Air is a fluid. "Ram air" is a misnomer at legal (+?) speeds. In the 19th century, an engineer named Henri Pitot was contracted to design a bridge across a French river. He needed a means of measuring water velocity at various levels under the surface of the water...and at various widths of the river. So, long story short, he "invented" what has become the pitot tube.
The equation P(ressure) = 1/2 rho v(elocity) squared was formed. Basically, this says the pressure of any moving fluid is a function of the fluid's viscosity (rho) and its speed (velocity).
Since for any given fluid, rho is a constant, we can say P is directly proportional to the square of the velocity.
OK .... The car is a pitot tube. The faster the car goes, the more pressure...right? Not exactly. At speeds equal to (or less than) 46 MPH, P= zero! No pressure! This is how air behaves ... it is an elastic medium. Compressible, stretchy, however you want to visualize it. So the stuff easily flows around an obstacle ... until 47 MPH occurs. Then, it tends to resist opening up...and pressure begins to show up. A very tiny pressure. This P builds rapidly ( the exponential part of the velocity parameter) as the speed exceeds the 47 MPH mark. Pressure pushing the car (or the fluid in the intake pipe) backwards. This is exactly the rational behind more gas to go faster ( slow down to increase MPG).
Regarding the effect at the entrance to the induction system ... at legal speeds in this country ( no autobahns ) there is not enough pressure formed at the mouth of a perfect pitot tube ( square cut, smooth, no restrictions, etc.) to do much; this is BEFORE you mount an air cleaner. Stick an air cleaner restriction in the picture...and your pressure changes to a negative value ( suction). Sorry, folks! The IC engine is a humongous air pump.
"Ram air" began with the tuning of engine intake manifolds ... and involves reversal of inductive pulses (reversions) created by the intake valves opening and closing at high RPM. These occur very fast; the flow velocities are enormous! The pulses themselves involve the speed of sound. The aim was not to "supercharge", but to reduce the suction
necessary ( reduce pumping losses).
Inlet air temperature is another parameter. I won't take any more time....


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PostPosted: Mon Aug 18, 2008 12:05 pm 
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yeah, so to sum up. dont waste your time

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PostPosted: Tue Aug 19, 2008 12:43 am 
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1. http://www.vararam.com/ramairinaroadcar.html
2. http://www.installuniversity.com/instal ... 262000.htm
and http://fasttoys.net/shop/product_info.p ... cts_id=325

SPORT RIDER tested small engines: bikes. They dyno'd the bikes "A pair of huge 185 cfm portable air compressors normally used with jackhammers were employed."
To clarify: The pressure build-up can be defined using the Pitot-static tube theory: P = .5 x r x v2 Pressure (P) is force divided by an area. In the English system of measurement the units of pressure are (lb - force)/in2 which translates to psi. Density (r) is mass divided by volume. The units of density in the English system are (lb - mass)/in3. Velocity (v) is air speed, with units ft/sec. Plotting pressure vs. speed gives a graph that has theoretical pressure rising with the square of speed, and this is why ram air has much more effect at greater speeds. For a speed of 150 mph, the resulting maximum theoretical pressure would be about 27mb (approximately .4 psi). Millibar (mb) is a metric unit for pressure. We used millibar instead of psi to give more workable numbers. RESULTS YAMAHA YZF-R6: Here is obvious proof that ram air works on smaller-displacement engines. Ram air helps the R6 hold its peak power higher and longer (12,000-14,000 rpm), and the torque curve is higher and flatter as well. This isn't just an incremental increase on top, either. We're talking about an average difference of five horsepower through the midrange and a far more usable power spread. HONDA CBR1100XX: Well what would you rather have-115 horsepower or 122 horsepower? The CBR-XX obviously reacts well to ram-air induction. The horsepower and torque curves literally mimic the non-ram-air graphs, only with a five to seven horsepower increase and three to five additional foot-pounds of torque.
http://www.sportrider.com/tech/146_9910_ram/index.html

Home made installation on a Cobra. http://www.corral.net/tech/powerplant/ram-cold-air.html
Edit: Can we use a little more horsepower doing 85+ mph on the freeway? That's retorical, I scared a Beemer by staying with him in traffic.

I improved the air flow by adding a 4 inch diameter collector and three 45 deg. angles replaced two 90s. The collector goes from (pi x D) 12.56 sq. in. to 6.28 sq. in. increasing the venturi effect. http://www.efunda.com/formulae/fluids/v ... r.cfm#calc

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'91 Metro, rescued from trip to junk yard. SuzukiRD Underpulley & Header. 3Tech 9mm plug wires & 218/350 cam +10 gear, Bosch Plat. +4s, FlameThrowerII, synthetic fluids. K&N, Optima, Catco, Jones glasspack, & KYB struts. Vortekx Generators, Air dam, 7mm ground system, Ram Air. No TBI bridge. No A/C - roof scoop works.
'96 Metro - The Wife's car: SuzukiRD Underpulley, 3Tech econo cam +10 gear, K&N, KYB, Bosch, Syn. & grounded. No TBI bridge.


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PostPosted: Fri Aug 22, 2008 11:58 pm 
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Location: East Texas
Just came across this thread looking for something else. FWIW and I have zero personal experience with it and not sure its remotely relevant to our cars on this board. But, in researching multiple carb setups on Chyrsler Hemi's (or in my case DeSoto Hemi's) I learned this. We've all seen the chrome 'scoops' mounted directly on top of a carburetor, usually on hot rods or old dragsters with multiple carb setups. Everyone always faced them forward to get the 'ram air' effect. Actual dyno testing on several different manifolds (3x2, 4x2 and even 6x2s) showed no HP gain at all when faced forward however, a slight (too slight to warrent giving an actual number I guess) gain when faced BACKWARDS. Appearently due to the decrease in turbulence.

Like I said, no idea if it means anything, but thought I'd throw it out there.

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PostPosted: Sat Aug 23, 2008 12:42 am 
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how do you test ram air on a dyno??

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PostPosted: Sat Aug 23, 2008 9:34 am 
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Not sure why I said 'dyno'. Call it late and fuzzy headed from beating my head against the Geo. Though I guess you could use really big fans! The actual mention (which was just a picture caption and not part of the subject of the book, though I've read a few discussions confirming it) said 'testing has shown'. So I'm guessing timed runs but for all I know they had my 7 and 4 year old daughters stand in front of it and talk. That oughta simulate a 47mph wind quite well.

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PostPosted: Sun Aug 24, 2008 4:54 am 
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So, dhdickey, you are discussing 3x2 or 4x2 intakes, in line? Please post your referance. In line like:===. Certainly the intake drafting off (hiding behind) the first and second would get less air. That would reduce horsepower. That makes sense. Reverse the inline intakes and it's like Cowl Induction ala NASCAR. That works.

Bottom line. kassaq wants to know if drawing air from infront of the engine will help gas mileage. COOKIEMNSTR has done it and gets 6 more mpg.

I have ram air from a collector flush with the bumper and my engine sounds really sweet. Better throttle response, less effort to reach 6K rpm and more power in 4th gear. It's cheaper than turbo and if it gets a little more horsepower at 85 mph on the 405 in L.A., I'll take it. (It did :D ). Keep my foot out of it for 52+ mpg at 60-65.

Opinions are that ram air is a waste of time at best. That's OK, COOKIEMNSTR gets 6 more mpg for his modification. So, if it is a waste then the IHRA nation is wrong and drag racers are doing it backwards, even with superchargers. That's bad news.

Oh, yes the dyno...
SPORT RIDER - Ram Air Test: Part Deux... 'The Eddy Current dyno was chosen because of its ability to hold a steady rpm; this made it a lot easier to set the correct airbox pressure, compared with the common Dynojet dynos that can only make a complete run through the rpm range. With the Pi System 3, measuring the airbox pressure at speed for the first segment of our ram air test was a simple task..... Our biggest obstacle to completing this experiment was figuring out a way to force enough air into each of the airboxes to simulate the pressure encountered at speed while running on a dynamometer. There is an incredible amount of wind energy at 150 mph... We required more than a fan setup that ran up huge cfm (cubic feet per minute) numbers. It would need to supply that volume at pressures above ambient, requiring a large, high-horsepower fan and the necessary ducting-not something readily obtained without spending huge amounts of money, nor easily built and mounted in the limited space and time we had available. Several fan options were tried... The setup we finally used may seem a bit unorthodox but it definitely gave us the necessary amount of wind energy and pressure. A pair of huge 185 cfm portable air compressors normally used with jackhammers were employed, and the requisite three-quarter-inch hoses directed the airflow.'

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'91 Metro, rescued from trip to junk yard. SuzukiRD Underpulley & Header. 3Tech 9mm plug wires & 218/350 cam +10 gear, Bosch Plat. +4s, FlameThrowerII, synthetic fluids. K&N, Optima, Catco, Jones glasspack, & KYB struts. Vortekx Generators, Air dam, 7mm ground system, Ram Air. No TBI bridge. No A/C - roof scoop works.
'96 Metro - The Wife's car: SuzukiRD Underpulley, 3Tech econo cam +10 gear, K&N, KYB, Bosch, Syn. & grounded. No TBI bridge.


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PostPosted: Sun Aug 24, 2008 3:27 pm 
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First let me say that if a person gets better mileage or more power (whatever they're after) by doing something, be it ram air or tires or just washing the car, then I don't think it matters what the 'science' says. Even if its not necc. directly traceable to the modification itself, in the end what does it matter?
As for my quote, which I'm not sure has any bearing on this topic or reality in general, the entire quote, which is simple the caption to a picture of vintage 4x2 intake for a 1st gen. Hemi is as follows:
"Vintage Aluminum carb stacks do look cool. Lots of rodders thought they provided some ram effect. Truth is, according to Jere Jobe, testeing ahs shown they work better pointing to the rear so they are exposed to still air."
Over the years, I've read a fair amount of talk (chat boards, old articles, etc.) that agree. Unfortunately none of it is stuff I can quote as its just stuff I came across when researching mult. carb. setups for my DeSoto (I have what has to be the oddest after-market intake ever made for it). The chapter the quote appears in is a general overview of different carb setups (the book, btw is Tex Smith's 'The Complete Chrysler Hemi Manual'. Basically a primer on the original Hemis) and seems to be more an example of 'looks cool, but running w/o air cleaners is DUMB than anything else. The talk on 'Ram Air' just reminded me of it and so I threw it out there.
FWIW Chrysler thought the same as Cookiemnstr. My '53 DeSoto, and all of that era's Mopars had hood scoops positioned so that fresh, cooler, air was forced directly into the top of the air cleaner, which Chyrsler advertised as increasing performance and economy. And THIS was with full oil-bath air cleaners that weigh almost as much as the entire G10.

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PostPosted: Mon Aug 25, 2008 3:16 pm 
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The old Mopar factory drag racing studies found a turbulent boundary layer of air over the hood approx 2 inches deep. That's then when they lifted the scoop up 2 inches into the "clean" air flow and got more air. Notice how the Subaru WRX STi hood scoops have gotten taller over the lifespan of that model. That red colorado Geo that Badbent shot in his album actually has it all right. Assuming you get a little pressure in the air box, one would hope fuel injection tables referencing Manifold albsolute pressure and Intake air temp (and certainly Mass Air Flow, assuming you had one) for pulsewidth would have enough adaptibility to keep AFR correct. If not, flash the ecu after logging VE error and applying corrections. Carbs are screwed, very difficult to change the AFR curve to accomodate anything over ambient atmospheric pressure, with the exception of dedicated blow through blower carbs from the specialty carb shops. Any way you tackle cold air plus ram air, you need a wideband O2 to know for sure what tuning changes are required.

Most of the big 3 mfrs also found the air stacking up at the base of the windshield, creating a high pressure area approx 6 inches thick. Smokey Yunick used it in '66 on his banned Chevelle, the 1st gen Camaro had an expensive optional cowl induction air box connected to the firewall, and of course the famous SS Chevelle got the pop up cowl induction for the same reason.
All the older cars with cowl intake for interior foot vents could be converted to feed the intake pretty simply. I don't see an easy way to do this to a Metro.

Badbent's trumpet intake in the bumper looks like the cleanest solution to getting air in. I'll be kludging up something similar after baselining the next engine. Can anyone comment on throttle body injection mods or replacement throttle bodies that aren't so ugly in the airflow department?

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