An idea for added airflow in 1FZ engine

[tech_dog]

mount a fan underneath your hood (mount the fan to the hood itself) pushing the air UP thru the new vent ??

I'm thinking more like blowing down from below the hot exhaust manifold and out through the open bottom of the vehicle, possibly with a cowling at the back botton edge of the engine bay, creating a low pressure point at the PS bottom of the firewall.

 

[landtank]

Hell, why not take the shroud off and see if what they are saying is true.

I was thinking this as well. In the "Blue clutch mod" thread, CDan noted increased engine temps while idling parked and this was corrected by opening the hood. My first thought was that everything was crowding the shroud and with out some vacuum from driving the truck it would restrict the air flow enough to allow the engine to run hot.

With both Sumotoy and Christo having good cooling results from having no shroud, I'd take the thing off and see what happens.

But then again, I'm only looking for a stable reliable piece of equipment and not so much driven by maximizing it's performance like SUMOTOY seems to be.

 

[Tools R Us]

Those temps were in the air filter itself - right?

so if there was a significant heat transfer to the intake air thru the 3 gallon metal bucket the filter sits in, or the rubber hose that runs over the top of the exhaust manifold (or even in the large aluminum intake manifold) then the air temps that the engine gets are even higher - right?

is there some way to get your probe into the intake manifold itself?

if so, and if you happen to insulate the intake system (filter can, hose, and manifold) and recheck the temps - I would gladly buy you a beer the next time you are in South Carolina.

The probe is between the pleats of the air filter, so takes into account the heat transfer from the biggest part of the can. The 4.5L motor turning at rpm makes a serious shop vac, that air is moving at a good rate and I doubt that much temp transfer takes place. Thought about putting one probe in the intake and the other at the air inlet to see.

oh, and by the way - you are the man!!

No idea where that came from!

In full disclosure my truck is pretty much stock, a 5" over stock lift and 295 tires, that will change the airflow around the truck and may affect airflow out from under it at some speeds and a old style blue hub fan clutch that is modded. The older blue hub has more shearing area that may make it transfer more torque and it has 10000 cst fluid in it, making for very much improved airflow. The 10000 cst fluid is probably overkill and isn't recommended due to possible fan interference issues, 5000-8000 cst is looking like the sweet spot, but more testing is needed to confirm.

 

[cruiserdan]

Dan, with a snorkel AND a supercharger, you would be the next logical one to post some airbox data.

Scott Justusson

In order to get comparable numbers, what should I use to measure it with?


Re your comment that you do not care for snorks, I found that my vehicle did change a bit when I added the snork. The throttle reponse is "crisper" than it was before. It could be placebo effect perhaps but it "felt" real.

 

[Grench]

Something for the extreme <ahem> file?

Has anyone considered boring 4" holes through the fenders just in front of the firewall and then venting out the side using boating deck vents?

Might look funny or mean depending on the viewing angle and ports selected... The big curved stainless ones would be kind of cool in that car-toons sort of way.

http://www.westmarine.com/webapp/wc...ct/10001/-1/10001/144699/10001/12407/12406/12

Now picture them coming out at just under mirror level from the upper rear of the fenders with the exhaust end slightly down and back...

 

[Tools R Us]

Hell, why not take the shroud off and see if what they are saying is true.

The 80's cooling is overkill for the needs of most, what other car or for that matter truck holds 4 gallons of coolant. Can you remove the shroud and have it work, yes many have on many types of vehicles, because you can get away with it doesn't make it better. If your cooling airflow system is comprised, removing the shroud may improve over the comprised system, but will require lots of mods and careful engineering to equal the performance of a properly functioning stock system.

To get an idea of what I am talking about lets look at how the system works. This maybe old news to most and I am not an engineer, but will try to explain it so that maybe some can make sense of it?

The coolant enters the top tank, (the thing that we lean on when working on the truck) It functions as a distribution manifold, the coolant spreads out and greatly slows down. Then flows through the cooling tubes into the bottom tank, a collection manifold, where the coolant from all of the tubes is mixed and pumped back to the engine. A unit of coolant only flows through one tube on each pass through the radiator, it's only chance for cooling.

In the tube the coolant gives up heat to the metal tube and air flowing past the tube and it's fins remove some of it. It's simple to measure, touch a temp probe to the top and then the bottom of a tube to see how much heat is removed. For this argument we will call it 200F in and 160F out and the tube is 14" long, or about 3F of heat transfer per inch of travel. With even airflow all of the tubes perform close to the same and when mixed the output coolant is close to 160F.

Now we remove the shroud and for the sake of a simple argument put on a 14" contact type fan and assume that the truck is stopped, with no additional airflow. The tubes centered to the fan are fully in the airflow and perform the same. The ones half the way out on the blades are only under the fan and getting good airflow for half of their length, so they only give up 20F of heat, the ones further out on the fan are even less cooled and the tubes in the other 10" of the radiator that isn't covered by the fan aren't getting any airflow at all, so hot coolant is just squirting right through. So when all of the coolant from the tubes is mixed in the bottom tank the output is more like 185F.

Yes this is a simplistic overview, even with no active airflow there will be some cooling due to convection, etc., the front tubes are more efficient than the rears and a bunch of details. The point is to think of a single pass radiator as a collection of individual cooling units (tubes) working together. Then the importance of even airflow to each tube, no matter how you get it, big fan with shroud, bunches of smaller fans, ram air, etc. becomes apparent for maximum cooling efficiency.

 

[SUMOTOY]

Yes this is a simplistic overview, even with no active airflow there will be some cooling due to convection, etc., the front tubes are more efficient than the rears and a bunch of details. The point is to think of a single pass radiator as a collection of individual cooling units (tubes) working together. Then the importance of even airflow to each tube, no matter how you get it, big fan with shroud, bunches of smaller fans, ram air, etc. becomes apparent for maximum cooling efficiency.

All good points, however, vortex can massively affect if that pressure is even. Which means specifically, an improperly designed shroud, can actually create more turbulent vortex, massively offsetting the efficiency of shrouding the fan.

The work of Chako et. al in "Numerical Simulation for Improving Radiator Efficiency by Air Flow Optimization" put more importance on sealing the airflow around the radiator, and ducting air to equalize pressure on the radiator face for a 34% increasse in air velocity through the core. Radiator, radiator fan and radiator shroud were constants.

My shroudless comparo would certainly support the fact that a lot of airflow happens at low vehicle speed, high rpm, since I had maximum aero blade deflection. If it was stalled or vortexed, blade deflection wouldn't follow exactly that of a shrouded fan. My conclusion is the same as Christos. I don't believe it does what shrouds are known to do, because there is too much turbulent vortex in a narrow shroud to give ideal pressure distribution.

TRU, I'm familiar with how shrouds work, and frankly my results surprised me. I encourage you to take the thing out and run some tests. It appears to have no effect on low speed cooling, and ram air speeds will be better anyhow. Give it a shot, it's an interesting experiment for sure. Long term it appears to work well, for both me and Christo, since he did the delete long before I did.

SJ

 

[ashooter]

Did anybody ever come to a solid conclusion about whether the engine cools more efficiently with the fan shroud present or absent???

 

[jlbuk]

Did anybody ever come to a solid conclusion about whether the engine cools more efficiently with the fan shroud present or absent???

x2 (sorry, I know it's an old post, but I'm busy prepping one car for shipping to far hotter climates)

 

[PDoyle]

Did anybody ever come to a solid conclusion about whether the engine cools more efficiently with the fan shroud present or absent???

Bump.

 

[Tools R Us]

Did anybody ever come to a solid conclusion about whether the engine cools more efficiently with the fan shroud present or absent???

The cooling system is far more efficient with the shroud in place.

 

[treerootCO]

I was running around without a hood the last few weeks and the truck overheated every chance it could. Once the hood was back in place, the truck only overheats on long uphill climbs under full throttle. My thought is the more air you can push/pull through the radiator the better. The last thing you want is a high pressure zone under the hood or behind the radiator.

 

[PSI-EFI]

our engine bay gets really hot with the chev.. back when we were having over heating issues (towing).. we decided to make some changes.. so we moved the front spotties to the side and we ripped off the airconditioning condenser.. allot cooler now..
since we got twin throttle bodies we might even extend the piping were the pods go onto.. even thinking of getting twin snorkels..
were also gonna remove the stock air cleaner as it takes up too much room.. using it as a tool box for now. lol

BTW were running au falcon twin thermo fans with a 4 core radiator.. and a ford 460 v8 thermostat

 

[PSI-EFI]

The cooling system is far more efficient with the shroud in place.

i second that.. without the shroud, its nearly useless.. most cars will guarantee to overheat with out the shroud..

 

[treerootCO]

https://forum.ih8mud.com/80-series-tech/238896-hood-louvers-retro-fzj80.html

I ran without the hood and proved that, without airflow through the radiator, the engine will overheat. Adding the louvers does appear to eliminate heat from the top of the engine compartment. I'll take a temperature reading with them covered and uncovered to confirm. Driving around with a piece of yarn taped to the hood proved that the airflow is correct. The air is being forced out of the louvers from the engine compartment and airflow above the louvers would indicate the Bernoulli's principal is at work.

 

[Romer]

I have been driving without the shroud for a while now with no issues. Mine was a forced test as I accidently broke it getting it out

I likely will replace it though

 

[landtank]

nice job on the louvers. Where they placed there for the best flow or to get around some bracing underneath? I've seen a lot of hot rods at the local car show and have been meaning to find out where they get it done.

 

[treerootCO]

nice job on the louvers. Where they placed there for the best flow or to get around some bracing underneath? I've seen a lot of hot rods at the local car show and have been meaning to find out where they get it done.

Placement was mostly due to the under hood bracing; however, fit within the area I felt would provide negative pressure so it was a win win. No guillotine created by modding the structure of the hood and lower engine temps. The hot rod guys use a punch but most don't offer anything bigger than 3". This was done by a hot rod shop that still had a pullmax machine and a craftsman that knew how to operate it.

 

[landtank]

This was done by a hot rod shop that still had a pullmax machine and a craftsman that knew how to operate it.

That's the key right there. They are a dieing breed unfortunately.

 

[voorland80]

airflow

I just went out and sipping a beer had an idea on increasing airflow, supercharger or not. More airflow is good no matter what you are running.

The 2nd battery tray is blocking air flow. The radiator overflow blocked some before the tray was there. I do notice it being hotter in the engine bay.

So, here is what I am thinking:
1) Move the Radiator overflow to the drivers side in front of the primary battery. Lots of room to do this.
2) Trim the battery tray so that it is only 7" from the fender to the end. Still need to figure the best way to do this and provide the protection of the tray.
3) Turn the battery 90 deg up against the Fender. Build a mount to hold it in place.

This will open up a clear path of 4 inches across for airflow from the fender well to the hood around the pass side of the radiator. I think this is more than before the 2nd tray was installed due to the overflow bottle. In fact, the 2nd battery now won't be blocking any additional airflow based on the airfilter being next in line. The new location of the overflow won't be block any additional flow due to the primary battery tray. I have a Yellow Top in the Primary tray and there is lots of room there.

Again, this for any application, stock engine, TRD or Supercharger.

I also think wrapping the exhaust is a good idea.


Thoughts?

Romer, I think you are spot-on with your observations, with one possible exception. In addition to all the modern ancillary purposes, the exhaust manifold serves two important functions: First and foremost, it expels the exhaust. Second, it helps to dissipate the heat generated by the exhaust gases. Wrapping might help to protect external components located along the exhaust path, but could wreck havoc with the various systems tied to the exhaust. The exhaust manifold should receive all the relatively cooler air it can get. Proper venting and added airlflow help achieve this. That said, anyone here wrap the exhaust manifold (not including non-efi engines, non-computerized engines) in their 80 without any problems? Gotta love the louvered hoods!
Everyone, thanks for all the great ideas and info!