measuring air pressure |
Post Reply |
Author | |
Mark W.
Member Sponsor Member Joined: 09 Nov. 2014 Location: Silverton, OR Status: Offline Points: 7986 |
Post Options
Thanks(0)
Posted: 30 Mar. 2019 at 1:15am |
OK so those who follow my Project thread know I have created a forced fresh air intake. This intake picks up fresh air from in front of the Radiator and just below the hood and behind the grill. This area while at speeds above say 20 mph create a high pressure area similar to what is found at the base of a windshield like on a 68-69 Chevelle. Which GM used to feed the Cowl induction intake used on High performance Chevelles. My ducting is approx. 2 times the flow capacity as the stock air horn on a Carter WO on a 134L I'm curious with the way I have my air intake and air cleaner system set up if my intake can actually create boost. Now before you shoot me down think about it if you feed air through a funnel at say 40mph will not the air coming out of the small end of the funnel be denser and moving faster then the air entering at the large end? IE BOOST SO I am thinking about picking up one of these gauges to see if I can actually measure that pressure. Or if there even is any pressure or if the engine still has to suck in its air. The gauge should tell me if there is even an 1/8 of a pound of boost (granted 1/8 of a pound will do nothing for performance) But I think it would be fun to see if there is some. And if at say 40mph I'm getting a couple pounds that would certainly be a boost to my HP. And since this is something setting CHUG on a Chassis Dyno will not show unless I some how did it while in a wind tunnel which ain't happening on my budget or anywhere around here. So now shoot me down save me $28 bucks. Interesting I just worked through a couple Boost estimators on line. I am assuming with my engine improvements and reduced parasitic drag I am going to have an 80HP engine with 20 HP going to the drive train as shown by dyno tests on other 134L powered CJ-2A's I'll have 60HP at the rear wheels at 4000 rpm. Anyway just 1lb of boost according to these calculators will result in almost 5 lbs of additional HP. Be interesting to see how it all comes out. Edited by Mark W. - 30 Mar. 2019 at 1:25am |
|
Chug A Lug
1948 2A Body Customized 1949 3A W/S 1957 CJ5 Frame Modified Late 50's 134L 9.25"clutch T90A D18 (1.25") D44/30 flanged E-Locker D25 5.38 Since 1962 |
|
mbullism
Member Sponsor Member x 4 Joined: 29 May 2015 Location: MA Status: Offline Points: 4783 |
Post Options
Thanks(0)
|
Go back to work
|
|
Those who do not learn from history are doomed to repeat it... Welcome to 1930's Germany
|
|
Bruce W
Member Joined: 29 July 2005 Location: Northeast Colorado Status: Offline Points: 9651 |
Post Options
Thanks(0)
|
If you want to mount another permanent gauge so you can watch it all the time, maybe $28 is worth while. On the other hand, if you just want to see what it shows and then disconnect it, why not use your vacuum gauge that you use to test fuel pumps and tune the engine? They show low pressure as well as vacuum. BW
|
|
It is NOT a Jeep Willys! It is a Willys jeep.
Happy Trails! Good-bye, Good Luck, and May the Good Lord Take a Likin' to You! We Have Miles to Jeep, Before We Sleep. |
|
Mike F
Member Joined: 12 Aug. 2018 Location: Longview wa Status: Offline Points: 684 |
Post Options
Thanks(0)
|
Mark, simple wind force developed would be at the typical 1/2mv^2 calculation. A google calculator puts it at 44 mph you would have about 5 psf of wind pressure. But there is a lot more to it than the simple calculation. A thorough study would get into fluid dynamics. But simply put 5 psf would be 0.035 psi. If you could run it through a cone and compress it by say a factor of 4 then you would be looking at 0.14 psi.
|
|
Bob W
Member Sponsor Member x 4 Joined: 08 Aug. 2005 Location: Monticello, NY Status: Offline Points: 1691 |
Post Options
Thanks(0)
|
Make a water manometer.
|
|
Mark W.
Member Sponsor Member Joined: 09 Nov. 2014 Location: Silverton, OR Status: Offline Points: 7986 |
Post Options
Thanks(0)
|
Thats interesting Mike. I only know that if I can get the air intake from one that feeds the engine by suction to one that is either equal pressure or a positive pressure it will improve performance. In the Chevelles with cowl induction you could feel the increase in performance when the little cowl doors opened. Numerous articles on line about how drawing fresh COLD air from intakes with higher then normal air density (Like the base of the Windshield front of the Grill/Radiator) increases performance. I'm just curious how much the Fancy Air Intake I have designed and built will do for my overall engine plan. Might not be able to quantify it out but I'm still curious.
|
|
Chug A Lug
1948 2A Body Customized 1949 3A W/S 1957 CJ5 Frame Modified Late 50's 134L 9.25"clutch T90A D18 (1.25") D44/30 flanged E-Locker D25 5.38 Since 1962 |
|
Mike F
Member Joined: 12 Aug. 2018 Location: Longview wa Status: Offline Points: 684 |
Post Options
Thanks(0)
|
I would think a Willy’s goes through the air like a brick. A flat topped building would be a good would be a good model for air flow around it. There are wind load calculators online that would serve as a guide for where to expect higher and lower pressure areas to occur.
One would think that right in front of the grill. Pressure would be higher. But then that’s where the radiator is. Any pressure there will will be relieved by escaping through the radiator. Still if you forget to latch the hood down at about 25 it will start to come up. (Don’t ask me how I know). There is not enough pressure yet to overcome gravity but I would think by 30 you’d have trouble seeing around it.
Edited by Mike F - 30 Mar. 2019 at 4:01pm |
|
Greaser007
Member Joined: 16 Jan. 2018 Location: Anderson, Calif Status: Offline Points: 850 |
Post Options
Thanks(0)
|
Mike, if he gets a '46 hood that someone cut a hole in for an F134, he could look through the hole beyond the speed of 30mph :)
The funnel idea or a velocity stack may help compress the air. The stuff we dream of doing to our Willys is amazing. hahaha |
|
Post Reply | |
Tweet |
Forum Jump | Forum Permissions You cannot post new topics in this forum You cannot reply to topics in this forum You cannot delete your posts in this forum You cannot edit your posts in this forum You cannot create polls in this forum You cannot vote in polls in this forum |