Ram Air Does Work...did Some Playing Around
03-29-2008, 07:22 PM
#1
Ram Air Does Work...did Some Playing Around I got tired of everyone doubting that ram air actually works at the speeds we see...yeah it might not be alot but it is something...more than i thought actually...
I did two test one with the car in stock form (breathing from the 1inch slit infront lid) and one with the ram air...The pressure was read using a monometer i jacked from work for the weekend...the tube was placed inside of the lid after the filter...see pics
The test consisted of setting the cruise control and waiting for the monometer to balance out around a given pressure in inches of H20...
There is an excel sheet for the ram air, but the stock form which is kind of obvious showed no increase in pressure inside of the air box when it balanced out at a given speed...But what about WOT???
This was the interesting part i did three runs for both tests and saw that the ram air had the same basic increases in pressure as the speed increased...But for the stock form under WOT it had a constant VACUUM of 5 inches of H20 throughout all three runs...So on the top end of the track 1/8-1/4 my car car traps 97-123 so we can use an average of 110mph which would be about 6 inches of H20 from the graph...So my car is gaining 11inches of h20 over a stock car that does not have a RAM AIR setup for half of the drag strip!!!
really over all of the drag strip it has a benefit but the faster you go the more gain you have...
FYI...11 inches of H20 is .809 in Hg...and for me every 800 ft is 10hp or 1 tenth...using an online DA calculator and only changing the alt. setting gives 918 ft...so i am gaining just due to the RAM effect 11.5 rwhp...So add the cold air effect of not breathing from the engine bay and you probably have around 20rwhp over stock...
My ram air is similar to a FTRA but to the extreme...
Also the tests were done in the same direction with a tail wind because when i tried on run the other way at 100 it was 2 inches higher...but i figure the gained pressure is negated more by the aerodynamics the car has to over come...aero> ram air effect (my guess)
Enjoy man that is a long thread...
I did two test one with the car in stock form (breathing from the 1inch slit infront lid) and one with the ram air...The pressure was read using a monometer i jacked from work for the weekend...the tube was placed inside of the lid after the filter...see pics
The test consisted of setting the cruise control and waiting for the monometer to balance out around a given pressure in inches of H20...
There is an excel sheet for the ram air, but the stock form which is kind of obvious showed no increase in pressure inside of the air box when it balanced out at a given speed...But what about WOT???
This was the interesting part i did three runs for both tests and saw that the ram air had the same basic increases in pressure as the speed increased...But for the stock form under WOT it had a constant VACUUM of 5 inches of H20 throughout all three runs...So on the top end of the track 1/8-1/4 my car car traps 97-123 so we can use an average of 110mph which would be about 6 inches of H20 from the graph...So my car is gaining 11inches of h20 over a stock car that does not have a RAM AIR setup for half of the drag strip!!!
really over all of the drag strip it has a benefit but the faster you go the more gain you have...
FYI...11 inches of H20 is .809 in Hg...and for me every 800 ft is 10hp or 1 tenth...using an online DA calculator and only changing the alt. setting gives 918 ft...so i am gaining just due to the RAM effect 11.5 rwhp...So add the cold air effect of not breathing from the engine bay and you probably have around 20rwhp over stock...
My ram air is similar to a FTRA but to the extreme...
Also the tests were done in the same direction with a tail wind because when i tried on run the other way at 100 it was 2 inches higher...but i figure the gained pressure is negated more by the aerodynamics the car has to over come...aero> ram air effect (my guess)
Enjoy man that is a long thread...
03-30-2008, 01:24 AM
#6
Your results seem reasonable, but I think you are misinterpreting them. I don't see the validity of comparing them to an airbox that has vacuum at WOT, as nearly zero vacuum can be achieved without ram air. The .2psi at 100mph is definitely something, but well within the limits of "not much at speeds we see". If you managed to test at 200mph, you might well see one whole psi or more.
03-30-2008, 08:53 AM
#7
Your results seem reasonable, but I think you are misinterpreting them. I don't see the validity of comparing them to an airbox that has vacuum at WOT, as nearly zero vacuum can be achieved without ram air. The .2psi at 100mph is definitely something, but well within the limits of "not much at speeds we see". If you managed to test at 200mph, you might well see one whole psi or more.
I mean do you think a custom ram air setup would add 20rwhp over stock...most people would not believe that is true but that is about what mine gained...(obviously for the 1/4 racing)
Bottom line this trype of ram air setup from getting air from either infront of the car or beneith is far superior to any other setup...if you have a zero pressure filter on the intake...you are still missing out on the RAM AIR effect and also the cold air...leaving hp on the table...etc...
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03-31-2008, 06:44 PM
#13
yes it is common sense in the way that we know the phenomenon occurs. what's important here is this dude is trying to quantify the effects. granted, it would be nicer if he did it in more useful units like kPa, correlated it with manifold vacuum or manifold absolute pressure from a scanner, etc...
I saw an article in some bike mag like a year ago where they measured ram air effects too, and what they found is that while it does occur, the effects were marginal, and they were only clearly visible above 150mph. but this is cars not bikes, so it might be quite different, and until someone measures it (kudos!) we wont know.
I saw an article in some bike mag like a year ago where they measured ram air effects too, and what they found is that while it does occur, the effects were marginal, and they were only clearly visible above 150mph. but this is cars not bikes, so it might be quite different, and until someone measures it (kudos!) we wont know.
03-31-2008, 08:56 PM
#14
Fantastic however I'd like to see some more data. The pressure behind the filter would depend on what the engine is doing.. so if you compare 4700 RPM @ 50mph it wouldn't be comparable to those at 6000 RPM @ 100 mph.
I have personally tested a vararam by running the car up to say 100 mph and killing the ignition and plotting the decel (in neutral) by intake manifold pressure. This elminiates what the engine is doing. I was able to see around .15 inHg
I have personally tested a vararam by running the car up to say 100 mph and killing the ignition and plotting the decel (in neutral) by intake manifold pressure. This elminiates what the engine is doing. I was able to see around .15 inHg
what about mass air flow?
04-01-2008, 11:59 AM
#17
Fantastic however I'd like to see some more data. The pressure behind the filter would depend on what the engine is doing.. so if you compare 4700 RPM @ 50mph it wouldn't be comparable to those at 6000 RPM @ 100 mph.
I have personally tested a vararam by running the car up to say 100 mph and killing the ignition and plotting the decel (in neutral) by intake manifold pressure. This elminiates what the engine is doing. I was able to see around .15 inHg
I have personally tested a vararam by running the car up to say 100 mph and killing the ignition and plotting the decel (in neutral) by intake manifold pressure. This elminiates what the engine is doing. I was able to see around .15 inHg
04-02-2008, 02:15 PM
#18
Bottom line this type of ram air setup from getting air from either infront of the car or beneith is far superior to any other setup...if you have a zero pressure filter on the intake...you are still missing out on the RAM AIR effect and also the cold air...leaving hp on the table...etc...
Was there or is there a way to compare manifold pressure before and after?
Because at wide open throttle if you are not seeing a positive pressure inside the manifold then in my definition of ram air you're not getting any ramming and any increase in power you got was from freeing up an airflow restriction, or providing colder denser air.
any change in air velocity will result in a pressure change so to take a valid measurement I think you'll want to be well inside the intake, past the throttle blade. I think by having you're measurement before the throttle blade, you have a larger cross sectional area flowing into a lower cross sectional area of the throttle body and it's providing a misleading reading.
Ram Air 
1 in H2O = 0.036127 psi