Does the larger radiator cover either of the stock knockouts for the air inlet?
CK5
Register an account today to become a member! Once signed in, you'll be able to participate on this site by adding your own topics and posts, as well as connect with other members.
Air intake options
- Thread starter Bent77
- Start date
The 89 crew cab didn't come with the knock outs. It had a contraption that bolts next to the radiator and gets air indirectly from the core support area. I had to put the coolant overflow tank where the intake contraption was. There is no factory provisions for it on the driver side of the radiator and the extra width of the diesel radiator is all to that side so I don't think there's room between the radiator and the second battery I have mounted on the driver side.
The picture above is not the diesel radiator.
The picture above is not the diesel radiator.
I'll know when I put in my '91 core support. But I think there's room on the passenger side. Not an ounce of room on the driver side for sure.
This is definitely a build your system solution. I did a bunch of calcs and calling around to find actual filter flow rates years ago. With real filters. Get some silicon bends, and some straight plastic tubes, attach a Volant 61509 (Donaldson powercore with volant's own rubber end to attach to tube) in a little fabbed up box plumbed to the big opening your going to cut on the core support. Then sit back and pour a glass of scotch.
It took 2 calls to volant for them to give me actual flow rates of the filters. When I finally got one of their guys to let me say cfm numbers and he would say yes or no. Bottom line was it flows over 1060cfm brand new with decent dust capacity vs "H2O. I was able to find what I deemed a comparable graph based on donaldson catalog back then. To match my engine cfm requirements at 7k rpm the filter would be at 75% total tested capacity. Now in the real world and on the trail I have no idea what that capacity looks like without a flow bench. But so far its doing damn well and I just change it out every year.
So, silicone bends, plastic straights, round air box for the volant 61509, into your core support, and you're set. That's my .015.
It took 2 calls to volant for them to give me actual flow rates of the filters. When I finally got one of their guys to let me say cfm numbers and he would say yes or no. Bottom line was it flows over 1060cfm brand new with decent dust capacity vs "H2O. I was able to find what I deemed a comparable graph based on donaldson catalog back then. To match my engine cfm requirements at 7k rpm the filter would be at 75% total tested capacity. Now in the real world and on the trail I have no idea what that capacity looks like without a flow bench. But so far its doing damn well and I just change it out every year.
So, silicone bends, plastic straights, round air box for the volant 61509, into your core support, and you're set. That's my .015.
I guess its still net positive when considering the energy needed to run the a/c?
Am I understanding that correctly: a single 6.5" tube will supply more air than two 4" tubes? That doesn't seem right.
But then again, neither does most of what comes from our President, so who knows?
That’s figuring surface area of the circle
www.omnicalculator.com
Area of a Circle Calculator
The area of a circle calculator will compute the surface of a circle using a radius or a diameter.
www.omnicalculator.com
Oh, you're right on the math, of course. I'm just wondering if velocity would make a difference. Given the vacuum the engine is creating, can it pull enough air through a 4" pipe to equal the amount in the 6.5" pipe, it would just be moving faster? Way out of my comfort zone with this stuff, but I'm sure you must be right or someone would have piped up by now. I also know the filter presents an obstacle to the air moving quickly through the tube, which is also going to impact velocity. The factory intake tube on my 90 5.7 appears to be 4", and where it enters the air cleaner it gets smooshed down quite a bit. but I'm thinking the outside measurements remain the same, so the tube conducts the same amount of air. Just one of those things that doesn't seem right...seems like 2 four inch pipes would be bigger than one 6.5"....like an inch and a half bigger. But they aren't. Biggest take away is that the 5.3L intake I stripped out of a truck at the yard is not going to be sufficient for the 7.4L I had intended to use it on. I'll need a second!
Velocity absolutely matters. That’s why I have only the surface area to reference, I have no way to generate a CFM number on these systems since we don’t have air speed numbers. With the engine pulling under vacuum would also be different then if it was being forced in. I’m hoping the “ram air” effect actually works, and is capable or generating more power due to the positive pressure at the front of the radiator support
Single best way to “real world this” I actually plan to do. That is, put a fitting in to the existing air cleaner and measure the pressure +/-
Then with the changed filter box, repeat the experiment, and hopefully also take readings inside and outside of the filter. I’d suspect the element itself changes the flow. From there I could plug one tube to see how a single 4” also does. Added bonus, I have good digital gages to do this with
Because math is great theory. Actually testing it on application is really what matters
Will you be able to measure A/F ratio as well?
Definitely curious to see performance the difference. Hopefully its noticeable.
Definitely curious to see performance the difference. Hopefully its noticeable.
Yes, running a PF4, so I can get the numbers off of the tablet as I drive.
I was just sitting here trying to figure how I can record this in real time data to capture the changes under acceleration. Static numbers at 30/50/75 mph should be easy
Does the pf4 measure incoming airflow like a oem setup with a MAF? I can monitor the MAF from torque as I drive.
Pressure only, no MAF
Figured without a maf it would be speed/density based.
I have one of the Specter housings for a 14” round 4” tall filter. Comes with a single 4 inch inlet. Going to cut that off and graft in 5” aluminum tubing that will run to the core support.
Couple of things to keep in mind......
First, as always, Bernoulli rules. Or I should say his rule rules.
Where you measure the pressure matters, as you can see from this article.
www.khanacademy.org
And, as to the difference between one large hose and two smaller hoses, you also have to consider the type of flow.
Laminar flow will always move more air than turbulent flow. So, except for when you are trying to mix air and fuel, you usually want laminar.
So, multiple hoses with larger area than one large one will still flow less than the large one if the large one is laminar and the smaller ones are turbulent.
But, its hard to predict unless you do the math. Often larger pipes have turbulent flow when smaller pipes don't.
This is the last week of turkey season, so I may have all that backwards...... I'm having problems telling a Reynolds number from the Instapundit right now.
First, as always, Bernoulli rules. Or I should say his rule rules.
Where you measure the pressure matters, as you can see from this article.
What is Bernoulli's equation? (article) | Khan Academy
Learn for free about math, art, computer programming, economics, physics, chemistry, biology, medicine, finance, history, and more. Khan Academy is a nonprofit with the mission of providing a free, world-class education for anyone, anywhere.
And, as to the difference between one large hose and two smaller hoses, you also have to consider the type of flow.
Laminar flow will always move more air than turbulent flow. So, except for when you are trying to mix air and fuel, you usually want laminar.
So, multiple hoses with larger area than one large one will still flow less than the large one if the large one is laminar and the smaller ones are turbulent.
But, its hard to predict unless you do the math. Often larger pipes have turbulent flow when smaller pipes don't.
This is the last week of turkey season, so I may have all that backwards...... I'm having problems telling a Reynolds number from the Instapundit right now.
Whatever the reason, if the large hole in the center of the core support can still be helped by a fan at 60mph, to me it seems unlikely there is a large amount of pressure at the core support. I'd guess that air "backs up" as it can't exit as fast or easily as it can enter. If that is what's happening inlet air to the engine from the core support will probably not be experiencing much outside push.
At some point I'd like to flag the engine bay and use a gopro to see exactly what goes on at speed in there for airflow. I think it's more complex than people assume.
Wish I had kept it, I saw some numbers on ram air setups via video I believe, they were quite minimal and really didn't do much until very high speeds. Like 100+. Cold air is better regardless, so certainly not advocating against it, just that ram air seems pretty gimicky for street use based on the numbers I saw.
At some point I'd like to flag the engine bay and use a gopro to see exactly what goes on at speed in there for airflow. I think it's more complex than people assume.
Wish I had kept it, I saw some numbers on ram air setups via video I believe, they were quite minimal and really didn't do much until very high speeds. Like 100+. Cold air is better regardless, so certainly not advocating against it, just that ram air seems pretty gimicky for street use based on the numbers I saw.
Spectre in-line filter, through blower motor hole, grabbing fresh air from cowl. No rain issues. Constant ~5* difference between outside air temp and what the intake sensor was reading. With the filter open, in traffic I would see 155+ IAT. With this it wasn’t higher that ~5*. No interior cab noise either, since it was all closed up.
(Powder coated black after this picture)
(Powder coated black after this picture)
