Recommendation on where to get hood cut

[Romer]

Thanks Gary

I will ponder this some more.

 

[corsair23]

Romer,

Here is what you need to do...get some yarn and tape (blue painters tape). Cut the yarn into 2-3" long pieces and tape them to the hood in strategic places. Then go for some test drives and see how the wind flow affects the yarn (i.e. flowing straight back, going all over the place, etc.)

I know it sounds stupid/silly but it should give you an idea of the general flow of air across the hood as YOUR LX is setup now with the ARB etc.

P.S. I'm digging the hula hoops - You should bring those to the next meeting

 

[waggoner5]

That is a great way to see air flow.

 

[farnhamstj]

This is kind of what I was thinking

 

[wesintl]

The snorkel has done an awesome job in lowering the intake temps by 20 degrees at least on a hot day.

I'm not sure I buy that... How was that measured pre and post snorkel install. Or are you just measuring the temp at the snorkel inlet and old intake inlet?

 

[Uncle Ben]

I'm not sure I buy that... How was that measured pre and post snorkel install. Or are you just measuring the temp at the snorkel inlet and old intake inlet?

His data prolly came from his OBDII reader, which would be reading the data stream from the mass air sensor.

 

[wesintl]

His data prolly came from his OBDII reader, which would be reading the data stream from the mass air sensor.

I thought he always had a snorkel. But looking back in the members bios i guess that wasn't the case.

That's pretty impressive. I wonder what the Difference in the average 80* day...

 

[Romer]

His data prolly came from his OBDII reader, which would be reading the data stream from the mass air sensor.

That is exactly correct reading the OBD Air Intakle sensor. I meassured it for a day prior to install and it averaged 135 deg F and after the install same drive similar conditions 115 deg F, some times even down to 98 deg F when driving quickly as the ambient air temp went into the high 80's. This was measured using my real time OBD II reader so I watched during the entire drive.

My understanding is that the air at this sensor is the important one for air/fuel misture and the supercharger. I also notice max boost has increased from approx 6 to about 7.5 psi. This is per my analog boost gauge in the cab.

edit - Per wes's new question, the above reading were taken on a +90 deg day back in July

 

[wesintl]

Thanks.. I guess I believe now

 

[Hulk]

Crap, now I want a snorkel.

/Never wanted one before.

 

[Romer]

Thanks.. I guess I believe now

The stock air input location on an 80 is the inside of the fender. The temperature is hot from being near the engine and the flow is fairly constant even when driving.

The snorkel air input starts higher and away from the engine and the faster you drive the more air is forced into the pipe. As I was researching, it provided 3 beni's other than water crossings

1) Cooler air
2) More air flow
3) Cleaner air - Dust off trail is thicker under the wheel well typically than at the snorkel level.

The drawback I have noticed is that it's an idiot magnet

"say whats that thing there."
A snorkel
"no really"
A snorkel
" No I really would like to know"
It's my custom tailpipe
"Then why does it say snorkel on it?"



Back to the thread. I have taken care of the intake temps. It's the underhood temps I wanted to reduce with the scoop.

On a day like today with no AC, coolant temp is about 190 deg

On a 95-100 deg day with AC, the coolant temp is between 195-200 when not using any boost. No Aux fan

On a 95-100 deg day when I use boost e.g. highway driving with AC temp climbs to 205. I then turn on the aux fan and it comes down to about 195-200

on a 95-100 deg day mtn driving with lots of boost and AC temp with aux fan on I get temps down to 200-210. If the fan was off it would go to 215 to 220 unless I turned off the AC.

Once temp gets above 200 in either of the last two conditions, stopping at a stop sign or driving in slow traffic makes the temp climb a few degrees to 205 even with the fan on.

The above actually shows my system is running fine and the aux fan is doing it's job. Could also turn off the AC as a backstop if needed.

What I wanted to do with the scoop is lower the last few conditions by 5-10 degrees. Heat is an enemy to longevity, especially electronics.

 

[Red_Chili]

FWIW, Terry at CIM can install your scoop in whatever direction you want and can paint it to match (friends don't let friends do non color matched scoops ). $20 on fleabay, eh? Stinker.

The area around the scoop is a fairly low pressure area though. Backwards would definitely draw out air from the engine compartment.

The problem is, it puts it right about where your cowl air intake is for fresh air. You'll likely be using your air conditioning just a tad more where before fresh air would have been just about right. This I discovered with a hole in my hood, much less a scoop facing rearward (which would evacuate a bit more air). It wasn't a biggie.

No worries on weather via louvers, you will have no issues.

 

[spincycle]

1st: noob alert for this forum, although a long time Toyota driver & current owner of a much-modded '07 FJC.

2nd:
Having just installed a supercharger, and given the intake's (silly but unavoidable) location in the very forward position in the engine bay, I've been looking at a combination of a) forward-facing ram duct just above the SC air intake to help with feeding it cold air, and b) rear-set louvers to help with engine bay hot air removal removal.

Thoughts on this setup?

 

[Romer]

Romer,

Here is what you need to do...get some yarn and tape (blue painters tape). Cut the yarn into 2-3" long pieces and tape them to the hood in strategic places. Then go for some test drives and see how the wind flow affects the yarn (i.e. flowing straight back, going all over the place, etc.)

I know it sounds stupid/silly but it should give you an idea of the general flow of air across the hood as YOUR LX is setup now with the ARB etc.

So if I do this what should I be looking for relative to consideratiuon of a scoop? If it's flowing straight back at that location is the correct thing to look for I would assume.

Again, I am not trying to lower intake as the Snorkel already does that. Just want to lower underhood temps 5-10 deg F on a hot day while driving. I know it won't do anything going slow or standing still.

 

[corsair23]

So if I do this what should I be looking for relative to consideratiuon of a scoop? If it's flowing straight back at that location is the correct thing to look for I would assume.

Pretty much. That should indicate that the airflow is good and relatively "stable" wherever the yarn is blowing straight back. If it is dancing around or tending to flow forward then you'd know putting a scoop there definitely won't "catch" much air and force it into the engine bay.

Again, I am not trying to lower intake as the Snorkel already does that. Just want to lower underhood temps 5-10 deg F on a hot day while driving. I know it won't do anything going slow or standing still.

I hear you on that, although whether a scoop will accomplish that I dunno . If you have good air flow into the scoop then it stands to reason that you'd be mixing realtively cooler outside air with hotter engine bay air and should see some benefits. Thinking of where the hottest part under the hood is though I'm thinking that maybe a centered scoop wouldn't be as beneficial as an offset scoop (toward the PS over the exhaust). Not sure how that would look though

IMO a combination of getting more air in while being able to provide a path to extract hot air out would give you the most benefit. I watched my intake air temp on the way up to Steamboat on Friday and typically, even on the highway, the IA temp was a good 50F+ hotter than ambient air temps. Often it was much higher even when running on the highway . Say for instance the WT (water temp) was running 198F, I would see IA temps in the 150F range, running at 60+ mph, with an ambient air temp probably in the high 70s to low 80s. The only time I would see a significant drop is coming down hills with the engine basically coasting.

On the MUD thread I sort of half joked about ceramic coating the air filter canister (I think Spike called that akin to killing a roach with a grenade ) since ceramic coating headers seems fairly popular. Landtank spoke on the trial he did with a winter coat wrapped around the air filter canister. Got me to thinking that maybe a simple approach would be to use some heat wrap like this

Not sure what you'd use to "attach" it, but it should IMO reduce some of the exhaust heat affect on the IA temps.

Other thoughts would be to do some sort of bumper "ducts" to allow more cool air in. And of course there are those on MUD that have modified the hood to space it up in the rear which per them helps to reduce temps under the hood as well. Personally, I don't think Toyota put much thought into venting the hot air out of the engine bay as this is the first vehicle I have owned where when I switch to fresh outside on the HVAC controls I tend to get pretty warm/hot air blowing in my face, even on relatively cool days.

Sorry for the long winded answer . I know you stated you weren't looking to lower you IA temps as the snorkle is doing that but in my brain under hood temps and IA temps seem to sort of go hand in hand. If you can lower your under hood temps then the IA temp should also drop.

 

[Romer]

Hood Air Flow test

I finally got around to doing the Yarn test. The video is in two phases. In the first part, the Yarn is about 5" long. Got concerned the Yarn itself might be too heavy so I cut it in half to 2.5". The yarn on the far right isn't moving much because it is stuck to the tape. The hood scoop (If I go with it) would go like shown in the below picture. Another alternative is to put it on back wards facing the windshield to pull hot air out.

Here is the link to the video with the string tests. I went higher res so you could see the yarn

http://www.risingsun4x4club.org/uploads/Romer/Yarn.wmv

Seems like the flow is pretty good infront of the windshield washer dimples.

Thoughts?

The goal is not to reduce intake temp, but reduce under hood temps.

 

[BogusBlake]

Cool test!

I like that your camerawoman is calling out "70, 75, 80" as you're passing 55mph signs!

 

[acon40]

let me know when you get your hood cut. I want to do mine the same day. I have just been sitting back waiting for the final word...

 

[Red_Chili]

Cool test!

I like that your camerawoman is calling out "70, 75, 80" as you're passing 55mph signs!

Yeah... and you are still getting passed!

 

[Uncle Ben]

let me know when you get your hood cut. I want to do mine the same day. I have just been sitting back waiting for the final word...

So basically Romo's 80 is getting it's Brit Milah! Interesting.....