milowilli

Has anybody thought of opening up the hood scoop on the 4Runner? I have tried it on two 4Runner sports. The hood scoop was designed initially for the Turbo diesel model sold in other parts of the world to cool the intercooler. It is on the Sport Edition for looks only. When opened it cools the Aluminium intake manifold which gets very hot due to the hot air from the radiator cooling fan. As you might know..hot air reduces the efficiency of the engine by hot air having a less charge of oxygen than cooler air. With the hood scoop opened the temp of the intake drops enough for you to hold it with your bare hands. Closed, it it is very hot and one cannot toutch it for more than a few seconds. Most modern engines have taken this into account and are making plastic intake manifolds which cut down intake temps.The 1GR-FE on the new Tacomas, 4Runners and FJ has a plastic intake manifold. I am sure opening the hood scoop to allow airflow over the manifold is a good idea even though i have not tested the effect in full detail. Water and rain entering the engine bay does not affect the engine at all....LETS KNOW WHAT YOU GUYS THINK.

gilby4runner

good thinking...anyone tried it? RAM AIR would be nice....lol

midiwall

If only there was a search mechanism! Oh wait... there is!

https://www.yotatech.com/forums/f2/scoop-sr5-change-57547/

Ironmike4x4

:bigclap:

crackerjack

once again ditto the Iron man:bigclap:

QSVeilside

How do you open up the hood scoop? After a search I found that some people have cut it out, others have said that it is a removable insert. I'd rather remove it without damaging the scoop or the insert. After looking at the underside of the hood, there are four bolts. Not sure if that secures the scoop to the hood or the insert to the scoop.

QSVeilside

Opened up the hood scoop tonight.

Tools needed:

10mm wrench
Sharpie pen
Dremmel tool or handheld rotational saw

1. Unbolt the four nuts on the underside of the hood. This unbolts the insert within the scoop.

2. Push the bolts straight up and you will see the insert move on the top of the hood. There is a single clip located in the middle of the two inner bolts. It is secured by a phillips screw. This clip secures the insert to the hood. I managed to break one side of the clip, (I didn't see the screw, and anyways the clip is not really necessary since there are four bolts securing the insert). Be careful if you would like to retain this clip, or unscrew it.

3. Continue to push directly up and maneuver the bolts to remove the insert from the top of the hood.

4. In order to minimize water seepage, I decided to cut out only the rear TOP HALF of the insert. This leaves a nice lip to catch water. Use a sharpie to draw the lines following the curve of the scoop before going at it with the saw. I believe some folks have cut out the entire rear, which allows water to drain down the scoop directly onto the intake manifold/supercharger. If the bottom of the insert is left untouched, it will act as a lip that will catch water and drain out the two small holes on the sides of the insert as it normally does stock. You could possibly run hoses to divert the water elsewhere so that it does not contact the intake manifold or supercharger.


Results:


The scoop is located over the supercharger, and not suprisingly the charger is louder outside of the truck when reving the engine. I don't necessarily believe that the convection alone is significant enough to create an increase in performance. However, the sound when in park reving past 3500 rpm is nice.

After going on an errand tonight and shutting the truck down, the scoop now vents a significant amount of heat. I don't know whether this translates to a faster cool down time. The underhood heat definitely escapes much better.

Tonight it was also raining. With the way I cut the rear of the scoop, there was only a small increase in water seepage.

Pics to come.

QSVeilside

Confirmed. And my intake pipe is aluminum.

QSVeilside

These are small due to the forum requirements.

QSVeilside

Last Picture

MTL_4runner

If you went that far I'm not sure why you wouldn't just cut the entire back off the scoop insert? I mean water seepage isn't really an issue on the motor since you aren't linking the air intake to the scoop at all. The engine would get a heck of alot more water splashing around just going through a big puddle on the highway than you'd get driving rain through the scoop at highway speeds.

Good pics of what you did anyway.....there are also free pic hosting sites so you can make your pics alot bigger.
www.webshots.com
www.photobucket.com
www.imageshack.com

QSVeilside

True. You can't really do much about the puddles! The amount of rain we get in Hawaii is enough to consider leaving the bottom intact. As you mentioned, ideally, you would cut out the entire rear. Additionally, you could add a vent in the back towards the windshield, (or raise the rear of the hood), so that the hot air evacuates immediately after the cold air is drawn in through the scoop.

I did not end up keeping the stock airbox. I went with a cheap $15 cone intake from ebay. Getting underhood temps down was/is somewhat of a goal for me.

Thanks for the free hosting links. I'll keep those in mind next time.

surf4runner

i did it over a year ago. https://www.yotatech.com/forums/show...ght=hood+scoop

QSVeilside

Surf4runner, by any chance are you supercharged?

Yesterday I took the truck out to run errands, (city driving), and found the cone filter was warm and the intake pipe adjacent to the charger hot but bearable.

Today I took the truck out on the freeway and did some 3rd gear pulls. It felt like the truck was pulling harder than normal, and in my enjoyment, I ended up driving all the way to the end of the freeway in Kahala. After pulling into a side street, I opened the hood and was surprised to find that the intake cone was cool to the touch. Not warm, cool. The aluminum intake pipe at the junction of the cone filter was also cool. The pipe was only warm where it joins the supercharger. It was not hot whatsoever. Before modifying the scoop, on any drive, city or highway, the cone filter and the intake pipe would be hot to the touch. Adjacent the supercharger, unbearable.

These supercharged engines are apparently very temperature sensitive. In a recent post, I mentioned that when my truck's clutch fan comes on it actually adds power, (morning or after running errands doesn't matter. When that thing is roaring, there's more throttle response). The only explanation I could come up with: Cooler intake temps = more power. Now that the truck is breathing in ambient 75 deg air instead of mixed heated air probably around 100 deg, it's running how it should be.

midiwall

Right on the 2nd part. The first part is a bit sideways - It's not that the SC engines are specifically sensitive to the heat, it's more that the SC generates more heat and higher exhaust temps. Then, the air intake on the 3.4L's are in horrible spot, that airbox loves to absorb the heat from the engine compartment and thus heat the incoming air.

That's the power rob...

A "cold air intake" is nothing new as a way to get more power into an engine, but doing a _proper_ one in these trucks is just insane. The K&N/Airaid solution is bunk. An hour of driving and the air at those intakes is just as hot as a stock airbox.

One of the most creative solutions I've seen is that someone opened up the port underneath the passenger headlight and snagged air from there. That works pretty well, but it brings up issues of what to do in water crossings.

What you've done is basically given the trapped heat someplace to go, and as such created an updraft through the engine compartment which further lowers the heat build-up and temps. That in turn reduces the temp in the airbox, and... voila! cooler/denser air which can absorb more fuel which provides more power.

Now, if you search here you'll find that someone once tried running flex tubing from the scoop into the airbox. Outside of the issues pointed out in that thread about the capacity of the flex tubing being less than the stock airbox opening, I would venture a guess that would NOT be as productive as what you did. That solution didn't allow for the heat to escape, which means the airbox is still warm.


Bottom line - Nice job.

QSVeilside

Thanks for the response and explanation Mark.

Right now I'm running an FIPK knockoff, (cone filter, aluminum pipe, heat shield), which as you mentioned, is complete crap. After thinking about what was happening with the clutchfan, (I even asked if it's possible to have the clutchfan running all the time), I knew that I needed to do something to reduce underhood temps, or go back to the stock airbox.

I couldn't find info on how to open up the scoop, (I missed surf4runner's post on the back page of that thread - it would've helped!), so I decided to do a mini-writeup under a thread that would be sure to come up on opening the hood scoop / functionality search.

95FourRunner

I'm going to have to look at mine this evening. Living in Florida, any way to cool off the engine would help tremendously

surf4runner

unfortunately, no. just crazy.

i never checked the temp before i opened up the scoop, but the plastic (not AL) tube is only luke warm after a 2 hour drive.
part of the reason i opened it was to provide a flushing effect of the hot air out of the engine bay. i think it works well.

only being 2wd and not much water over here, ive not seen any mud end up on the cone, even when the lights are muddy. anybody serious would though.
dirt/dust build up in the bay is minimal and easy to clean. i did see a lot of sand collect this past week or two of heavy winds.


if someone without any of these mods could verify temps at the air box/engine bay, i would measure mine for comparison.