Having an original ram air hood with an Edelbrock intake I am not able to fit the factory top on the air cleaner . I used a Chevelle air cleaner ring and foam seal to make contact with the hood . This gives a constant "Ram Air "to the carb. at speed . For two years I have been getting 7 to 8 MPG. Last week I took some 1" foam and stuck it in the hood openings ...... A BIG IMPROVEMENT !!!!!!!!!! 14.8 MPG with no other changes .Here is the magic foam trick

 

So you are saying no ram air.....blocking off the outside air intake gave you double MPG?
thanks
joepenoso

 

That was the Only change . 1500 miles driven with the hood open giving crappy mileage . However only 240 miles driven with the hood blocked . Goodguys this weekend will be another good test .

 

Interesting......

 

I thought maybe you were using a Vornado!

 

I would think this kinda makes sense. At least for it to increase some. Not as much air going into the motor, less fuel can be burned. I would say there should be a noticeable performance decrease though.

 

Using that logic if you disconnected seven cylinders mileage would improve to 45 MPG?
joepenoso

 

how much performance power did you lose choking off the air flow?

 

Meh

A scientific test with actual numbers might be in order.

Your air cleaner still has that snout, whose flow area is far greater than that of the carb bores that the air must pass thru.

So, what you did was partially block off the supply of cooler denser air from the hood scoops, which was used only during low vacuum conditions such as wide open throttle anyhow... and ensure that mainly hotter underhood air is supplied to the engine.

This seems to defeat the idea of OAI- which you may have noticed EVERY vehicle now uses.

I would say that, at best, if indeed your fuel consumption decreased it would go hand in hand with a sizable power decrease.

 

Sorry, but I don't believe it. As Chris pointed out, you have't restricted airflow at all. All you've done is drawn in hot underhood air instead of cooler outside air. If all you did was block the cool air, and you really DID get that kind of improvement, then the engine was SO rich previously that the plugs must have been solid black soot.

You didn't tell us anythign about different driving styles (city vs. highway), different gasoline use (ethanol vs. not), or even different ambient temps (winter when the choke was on vs. summer when it's not. WAAAAAY too many variables for any kind of meaningful comparison.

 

Most of the mileage comparisons are 90% highway use during summer the months. I tried several different carb./ jet set ups , 3 different camshafts and milled heads to increase compression with little change .Granted this was only one tank run thru it but I have never gotten more than 160 miles between tanks . The only thing I can come up with is ALMOST ALL RAM AIR STYLE OUTSIDE AIR air cleaners have some vacuum , electrical , or mechanical door that opens to the hood on full acceleration or low vacuum . After some more miles I hope the results are the same. I also agree it makes no sense but if it continues to work on the next 2 tanks I will run a tank with out the foam to confirm the results. Joe ,I know I did not restrict the air flow , just the "air pressure" into the air cleaner. I never did check to see if there was any positive pressure in the air cleaner but it only makes sense that it would have been there . I JUST HOPE IT CONTINUES TO WORK

 

I installed these on my hood just because I was afraid of something getting sucked in while driving.. I get great gas mileage something like 12-14 mpg on the highway, the only thing I wanna do next is install the foam around the air cleaner to seal with the hood and see if I can get better gas mileage and if I don't, I'm happy with 12-14 mpg

 

Al, I would like to know if your mileage changes when you seal up to the hood .The flange I used was for a 70 -72 Chevelle cowl induction air cleaner with the Olds foam for the seal to hood

 

Tom, from your engine compartment picture it shows that your air cleaner foam is squash a little so you should be getting a good seal, my question is do you know how tall is the foam? Do I need a different air cleaner base to be able to put foam on it? Or will the foam fit mine, I ask because from the top of my air cleaner to the hood when the hood is shut it looks like I have about 6" inches in between so I feel I need to customized one so it will seal good to the hood

 

Wait 7-8 mpg ? What kind of modifications to the actual engine. I'm getting between 7-8 but I have a pretty built up 355 and a holley double pumper with 3.73 gears. I get that kind of mpg with a lead foot. Even back when I had a mild 350 with 3.73 gears I got. 12-15 mpg. I don't mind the crappy fuel milage but I don't think the ram air effect is enough to lean out the engine to the point to double your mpg. Most stocker set ups avg. In teens and low 20's mpg range.

 

I'm betting your engine didn't sound as cool with the OAI ducts blocked so you weren't getting on it as much

 

"I'm betting your engine didn't sound as cool with the OAI ducts blocked so you weren't getting on it as much "
Well we know besides not sounding as cool, it sure doesn't look as cool with those chunks of foam stuck up the ducts..... seriously if you think it gets better mileage that way, why don't you just replace the OAI air cleaner lid with the non OAI style. That way it still looks good.......

 

After running another tank of fuel I got 12.7 MPG , there was probably 3 hours of cruising at idle thru the fair ground and hotel parking lots so not a fair comparison . I plan on getting up to Norwalk at the end of the month so that will be a better check.

 

Why don't you just install a factory lid with the vacuum operated door?

 

I have the air cleaner top but with the Edelbrock intake the hood clearance is too close

 

Hey tom, I know it's taken a while but I finally got my air cleaner flang like the one you got and after a lot of searching I finally found a foam tall enough to seal against the hood, I need help on what's the best glue to use to glue on the foam, do you remember which one you used on yours? Or those anyone have one they recommend? After I get it installed I will do a mileage check and see if it improves or not, I will also see if I get better performance or not

 

3M spray adhesive will work just fine...no need for the heavy duty spray either

 

I knew a guy 25 years ago who took his 70 Cutlass and made a wire screen mesh thing for it. He had it under the carb somehow and heated it. He swore on a stack of bibles that he got about 50% better mileage. Never asked him about performance, but he was not the lying type of person. He wanted me to do it on my car, but it seemed too weird at the time.

 

Al , I just used weather strip adhesive on my foam . The spray trim will work just as well. After a few more road trips there IS a big change in fuel mileage with the foam inserts. Going to Norwalk (110 miles )14.9 MPG . 70 miles with out the inserts on the way home 9.8 MPG. Almost identical driving conditions both ways other than 15 degree temp. difference.

 

Thanks on the adhesive advice, I had some double face tape and it seems to stick on pretty good but ill have the spray type ready just incase this peels off, so tom you are saying that you got better gas mileage with the foam inserts that sounds wierd tomorrow I will take the car out for a test drive and see if I get better performance as for the gas mileage ill have to wait till this weekend for a longer drive and see if it gets better or worse, I hope it get better if not at least I love this look

 

my 82, 2.8 s10 had a similar set up from the factory. dont know if it helped or not it was so anemic.

 

I wonder if the improvement in mileage is related to less wind resistance. Looks like the air may now go up and over instead of getting trapped?

 

This thread just makes baby jesus cry. Driving down hill with a tail wind would help too.
No way you doubled your mileage by installing foam in your hood. Better check to make sure your friends aren't putting gas in your tank at night when no one notices

 

X2

 

If you add a few of these, you'll soon have to start siphoning the excess gas OUT of your tank...

 

Foam in the snoots will have no appreciable effect on drag of the car.

Source: Mechanical engineering as a profession.

 

Please send me some of what you have been smoking. What a load!

If you really believe that this doubled your fuel economy I feel sorry for you.

 

Funny...I was just thinking how that "Type-Bil Kompressor" fuel saving device that Joe P. posted looks like something you'd see for sale in a head shop.

 

I guess I don't know what I'm talking about . I have been a certified master ASE auto tech. since 1979 and have owned my own auto repair business for the last 5 years . All I know is the math shows a drastic improvement and I have no other changes between the checks. Since most here think I'm on crack , I will no longer post what I feel is helpful information .

 

I wouldn't go that far. But double kind of seems out the window. I would guess maybe 2 mpg at most since you are not running highway all the time. Maybe a mix of both. Don't get so exited about posts that don't go your way. Just follow up and give the results after some more driving.

 

Toms Vista, I did not get a chance to run my car with the new foam,that double face tape peeled right off with the engine heat,my wife is bringing some 3M spray adhesive later and I hope that bonds good they say let it dry for at least 24hrs then ill see if I get better performance,as for better gas mileage ill have to do the test, first with out the air cleaner foam then with the air cleaner foam finally ill try plugging the hood vents, im curious what the results will be

 

" Almost doubled my fuel mileage"
Something seems to good to be true about that statement. I do know car manufactures spend hundreds of millions$ trying to meet new fuel consumption regulations. Mazda had to kill the rotary engine because they can't meet that and new emmission standards. If such a simple restriction, redirection, increase, decrease in air flow could achieve the stated results well......... It just doesn't make any sense. I think there is an error in calculations.

Mike

 

Seemed just as logical as foam under the hood doubling the milage

 

Agreed. To clarify, what happens on oddball cavities in an airflow is air gets trapped there and circulates (ie, leaves in your pickup truck bed). You get a boundary layer over that rotating pocket which would be a line from the hood in front of the snoots to the top of them. Now, with air intake running, you will be replenishing that air some, so it will disrupt the boundary layer to a certain extent, but it won't be noticeable at all. It would be like hanging your elbow out the window.

 

Look, as a certified master ASE auto tech, you should know that what you are suggesting should NOT "double the gas mileage" on a car that is properly jetted and tuned. Is it possible for this to work on one specific vehicle that may have been jetted too lean or otherwise not optimized? Sure. Just don't think this will work on EVERY car.