Engine Under Shield - Enhanced Efficiency - DIY (1 Viewer)

[Bambusiero]

Here is a design for a DIY fabricated "Engine Under Shield" or lower radiator air dam for radiator air flow control.

The purpose is to block heated radiator cooling air from recirculating back around into the radiator at low speed, and probably to create more of an engine compartment vacuum at high speed, enhancing air flow rate. This design seals to the frame better and extends further back, to the frame cross member, so the air flow control has enhanced efficiency compared to the stock design (I think).

I've been having engine overheating issues (another story), so the whole air flow thing has my attention lately.

Check that all of the airflow control devices are in place, ... and the tin plate above the steering stabilizer...

Tools R Us has mentioned this kind of thing more than once, I believe, but my truck didn't have any such thing, so I didn't know what to think. Searching for "airflow control" and "air dam" and such did not give much of use. I now know that the official terminology is "Engine Under Shield", and searching for that will show you pictures of the factory solution.

But I still didn't have one... so I made my own. Here it is.

Materials:
6061 T6 aluminum sheet, 12" x 48" x 0.032"
This thin gauge is fine if stiffened with rolled beads, but go with 0.062 or 0.080 if going flat.
Poster board or something for pattern making.
M8 x 1.25 x 15 bolts & washers - 4 each. (from my old radiator brackets)
M8 x 1.25 x 20 bolts & washers - 2 each.
M8 x 1.25 x 20 set screws - 2 each.
M8 x 1.25 extruded sheet metal nut - 2 each.
1 1/4" Hose clamp, vinyl or rubber padded - 2 each.
Self etching primer.

 

[Bambusiero]

Some more pics.

Frame fit on the passenger side:

Frame fit on the drivers side:

Bottom view:

Top view:

 

[Bambusiero]

Here is the overall layout, with a couple of details missing.
I would suggest drawing out your own layout with straight edge & square, rather than blowing up this photo. Might be distorted.

Steering stabilizer bolt clearance hole added, and some corner details.

For the side wing hole locations, insert the M8 x 1.25 set screws into the side frame threaded holes, mount the sheet metal in place (side wings already bent), and tap with a hammer to make hole location marks. Then drill.
As for the back edge holes for the hose clamps, figure it out as a best fit last step.

Have fun fabricating!

 

[DARKNESS]

Cool idea. Any numbers on how much it helped?

 

[jwilliams]

That looks really good. Skills I don't have

Toyota Makes a part for that piece.

Check out my thread about it:
Is there a lower engine cover for the fzj?

(1) Engine Under Cover (Splash Shield) 51441-60190
(4) Bolts/Washers 90119-08863

 

[SmokingRocks]

So it's called a splash sheild.. I would tend to believe that the cooling gains are a byproduct and probably minimal.

 

[Tools R Us]

So it's called a splash sheild.. I would tend to believe that the cooling gains are a byproduct and probably minimal.

Agree, minimal, but mine works in the desert, so will take all I can get. People put hood vents, so cut holes in the hood, and the ones we have worked saw zero real/usable benefit.

That looks like a bunch of work to avoid buying a $60 part? There are likely used ones around? Also it has to come off to service stuff down low, looks like much more work than stock?

 

[Kernal]

Nice work, is the design available in a digital format so that others could print it out?

 

[Qball]

Very nice work! But I agree with some that gain in cooling is minimal if any. If you want better hot exit points just take out the side baffle in the wheel wells.

Properly tuned fan clutch, properly sealed fan shroud and snorkel will help in high heat situations.

 

[SmokingRocks]

I'm also going to heat wrap my headers and down pipes. I imagine this will make the biggest difference in under hood temps.

 

[Tools R Us]

... If you want better hot exit points just take out the side baffle in the wheel wells.

On a relatively stock configuration rig, this is overall counter productive. May help a tiny bit at idle, but they blow outwards when there is pressure under the hood, so likely if there is any change, minuscule. At speed, the suction under the rig, pulls air out of the engine compartment behind the axle. The side skirts and splash shield help in making as much as possible come in through the grill.

... snorkel will help in high heat situations.

Coolant temp,,, surely you jest.

 

[Qball]

On a relatively stock configuration rig, this is overall counter productive. May help a tiny bit at idle, but they blow outwards when there is pressure under the hood, so likely if there is any change, minuscule. At speed, the suction under the rig, pulls air out of the engine compartment behind the axle. The side skirts and splash shield help in making as much as possible come in through the grill.

Interesting point, not sure about at speed but at speed the 80 usually don't have as much cooling issue. PO did say this might help with slow speed cooling. I'm sure Mr T put them there for a reason but I think they are more for prevent splash of much and crud into engine compartment from tires but I could be wrong. The side skirts are missing on one side of my 80 and when I walk by that side with engine idling on a hot day I can feel the hot air pouring out to the point I can't really stand there because it's so hot.

temp,,, surely you jest.

No it doesn't do anything for coolant temp but does help a lot with intake temp which makes engine run better with more air/more oxygen. I only said helps with high heat situations, not necessarily just for coolant, in fact the factory snorkel is designed for the middle east desert and the outbacks. Surely you are fully aware of that.

 

[Rivman1243]

How will it help with IAT's? I ask because I've been noticing that mine will crawl up pretty high. Sometimes as high as 170° and that's while driving!

 

[Qball]

How will it help with IAT's? I ask because I've been noticing that mine will crawl up pretty high. Sometimes as high as 170° and that's while driving!

The factory location for air intake is in the passenger fender and for the most part is closed off except for one section to the engine compartment. So as temp under the hood rise the intake temp will go up because a lot of the air is actually from the engine compartment. That's great for water crossing without a snorkel but not good in hot weather. In summer the air is actually hotter near the ground because of the heat reflected and radiated from the hot ground, so by having a snorkel and pull air as high as possible you will get the coolest air possible and also least amount of dust.

 

[Rivman1243]

That's what I keep reading. .... I need a snorkel to get the IAT down. Seems like the temp should go down when I get on the interstate. Also if I stop and run in the store when I restart the engine the maf gets heat soaked really bad. If I can keep the IAT from getting hot it will stay ok but once it gets hot it stays there.

 

[Qball]

That's what I keep reading. .... I need a snorkel to get the IAT down. Seems like the temp should go down when I get on the interstate. Also if I stop and run in the store when I restart the engine the maf gets heat soaked really bad. If I can keep the IAT from getting hot it will stay ok but once it gets hot it stays there.

Yup! Once the MAF is heat soaked that also means the entire engine bay is heat soaked and factory intake will suck up the hot air. After snorkel my IAT is consistently between 5-10 degrees over ambient temperature regardless of the speed. Even after MAF is heat soaked the IAT temp drop back to the normal 5-10 above ambient quickly.

Given the little power we got, having such hot air will rob even more power from our poor little....er big engine. Cooler temp = denser air = more oxygen = power suck less.

 

[Rifleman]

One of the easy, and cheap items that helped the cooling on my truck, was the replacement of all the old foam sealing tape used around the radiator. When i took my radiator out to have it cleaned, i took the time to clean off all the old factory sealing foam tape that goes between the radiator header, radiator, and fan shroud. Most of the foam on my 22 year old truck just fell apart in my hand when i removed the radiator. I went to home depot and bought all new sealing foam tape from the AC department, they have alot of different sizes for use with window AC units. Make sure you don't forget to replace that factory 2X2 inch foam seal that goes between the bottom of the radiator and the radiator header. If you forget that seal it leaves about a 1 1/2 inch gap for the air to slip pass the radiator. Sealing all those air gaps forces all the air through the radiator core for max cooling. I think i spent about 10 bucks on all the foam tape i used to seal my truck.

 

[Rivman1243]

One of the easy, and cheap items that helped the cooling on my truck, was the replacement of all the old foam sealing tape used around the radiator. When i took my radiator out to have it cleaned, i took the time to clean off all the old factory sealing foam tape that goes between the radiator header, radiator, and fan shroud. Most of the foam on my 22 year old truck just fell apart in my hand when i removed the radiator. I went to home depot and bought all new sealing foam tape from the AC department, they have alot of different sizes for use with window AC units. Make sure you don't forget to replace that factory 2X2 inch foam seal that goes between the bottom of the radiator and the radiator header. If you forget that seal it leaves about a 1 1/2 inch gap for the air to slip pass the radiator. Sealing all those air gaps forces all the air through the radiator core for max cooling. I think i spent about 10 bucks on all the foam tape i used to seal my truck.

You don't happen to have any pictures of the foam do you?

 

[Rifleman]

I'll have to call my daughter, and have her bring my camera back, once i have it I'll take some photos for you.

 

[Tools R Us]

Interesting point, not sure about at speed but at speed the 80 usually don't have as much cooling issue.

Maybe just us, but one of the biggest challenges is highway speed climbs in the heat. If it will do that well, the rest is pretty much gravy.

PO did say this might help with slow speed cooling. ...

It could, one of the problems is hot air recirculating, so pushing the exit further back can help.

The side skirts are missing on one side of my 80 and when I walk by that side with engine idling on a hot day I can feel the hot air pouring out to the point I can't really stand there because it's so hot.

Agree, internal combustion engines waste most of the energy that they make as heat, should run around 200F, so when running, will push out air that is uncomfortably hot to most people.

... in fact the factory snorkel is designed for the middle east desert and the outbacks. Surely you are fully aware of that.

IIRC, dorkels were designed to allow military vehicles to operate in water. True, Toyota supplied them in places where users would be more likely to use rigs for other reasons than going to the mall. I have never seen any documentation other than being designed for fording.

There a slight advantage in dust. But the stock filter system is well designed. As long as the tuna can is dumped as needed, mine goes ~30-40K miles before the filter needs cleaning. I wheel in the desert, like 100+ days a year, if not would go twice as far or more. Who runs their filter that long, so what real world difference does it make?