Airbox and Manifold air temp observations

Discussion in '80-Series Tech' started by alia176, Oct 15, 2007.

  1. alia176

    alia176

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    I had a chance to take some measurements of the airbox temps and compare that to the OBD-II reading of the Intake air temp (IAT) on a long trip this past weekend. The numbers are astounding to me. Obviously, these #s are not very accurate and there were lots of variables (vehicle speed, cross wind vs head wind, etc). Let's not dwell on the exact numbers but the relative delta between them.

    Outside temps: X

    Air box temps: X + 40 degrees :eek:

    IAT temps (OBD-II): X - 7 degrees. Interesting to note that the air gets cooler as it travels on the plastic air intake tube. That surprised me.

    My IAT temps often reached 140* while traveling at 70 mph with an ambient outside air temp of around 74* (A/C on or off). I was climbing lots of hills and the water temps often reached 200*. I had lots of head and cross wind.

    While on the return trip home, the IAT was around 110* while the ambient was around 70*. Lots more tail wind and fewer hills.

    Air box temps went up during higher engine RPM operation vs lower RPM (hills).

    Air box temps sky rocketed while in 4low with the aux electric pusher fan on or off. :crybaby: It hit 150* at times. I then moved the temp reading device to a bone stock 80 in front of me and he reported 120* to be the highest temps he was seeing.

    I have the usual mods: bumper, winch, lights, york, extra battery, 4" lift, 7,000 cst clutch fluid, 4.56 gears, 315s. I was towing a 1500# trailer on this trip.

    Obviously a snorkel would help with cooler air going into the engine. But, an immediate concern of mine is how to evacuate the hot air that's under the hood. Hood louvers may be a solution. I should also remove the side skirts from the fender well area to see if that helps. Perhaps drive around with no hood to see if that really helps!
     
  2. 96r50

    96r50

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    What about insulating the air filter canister as per Landtank a while ago? I've been thinking of this myself, but I'm not sure what to use. Ideally something with a reflective surface so it "bounces" the heat off the canister. I'll probably wait until the spring though, as I'm not sure if the engine will like really cold (0*F) winter air without the preheat effect (I have no basis for this idea, but then again, when do I ever?):cheers:

    So, yeah, what about insulating the canister?
     
  3. KCCruiser

    KCCruiser

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    Would this go towards the argument that a snorkel not only brings in more air but cooler air? Just a thought and I don't mean to open a can of worms here. I know the snorkel/performance issue is a hot topic as of late.

    Cheers
     
  4. Hayes

    Hayes

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    I think the recent snorkel thread showed that snorkels do generally deliver cooler air.
    Seems logical--the factory airbox intake is right next to/in the toasty warm engine bay.

    I wonder if even a reflective coating on the air delivery plumbing would make a difference...
     
  5. corsair23

    corsair23

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    I'm confused on your numbers...It appears that you noted IAT temps LOWER than outside temps in one spot but then state IAT at ambient + ~70F in another spot :confused:

    I don't have a way to measure my air canister temps but I have seen similar temperatures (higher) like you on my IAT temps per my Scangauge II. How to address those higher temps is the question (and one Romer has been looking into as well)...My thoughts are wrapping the canister and louvers or similar to evacuate the hot air from the engine compartment.

    Ever notice on your 80 that when you vent in outside/fresh air that it seems way warmer than the outside air temp? Every car I have ever owned will usually blow in cool outside air (when outside temps are relatively cool - say 60-70F) but not so in my LX...It will blow warm air on you.
     
  6. corsair23

    corsair23

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    I've been thinking about looking into a way to use some of this stuff:

    Automotive Heat Sound Insulation (ebay if link no longer works down the road)

    4'x10' so you should be able to do at least a couple vehicles with one roll. Not sure how to attach it to the air canister though :confused:
     
  7. FirstToy

    FirstToy

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    Ali,
    On the freeway grades, I will hit 200*-207*WT and 140-150*IAT (around 3000rpm, kicking up to 4400rpms when it downshifts)
    it will immediately go back down to 192-195*WT after the climb.

    Offroad, anywhere from 183-193*WT. 140ish*IAT
    The engine did not seem stressed in these situations

    the biggest concern for me is going up a freeway grade, AC on, loaded w/gear. This seems the most stressful event- constant load, high rpm.

    The airbox is all metal- would heat soak eventually bring the temp back to un-insulated range within a few hours of driving?

    this is also an idea why things are getting hotter in a lifted truck-
    https://forum.ih8mud.com/showpost.php?p=2583266&postcount=13
     
  8. LX_TREME

    LX_TREME

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  9. FirstToy

    FirstToy

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    hehe, in this case, aerodynamics might be on your side Harry
     
  10. Darwood

    Darwood

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    Is this offroad in 4lo, or a combination of 4lo 4hi? I found that when I had a partially clogged radiator that the truck loved 4lo for cooling off road in Death Valley. 4lo seemed exert the least stressful load on the engine compared to both 4hi off road and highway travel, which makes sense when you think about it.

    I really haven't had my 80 off road since the new radiator... and I replaced the radiator about a year ago :crybaby:
     
  11. FirstToy

    FirstToy

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    Derek, it was in 4Lo. I was surprised but temps remained low even w/ AC on. Those freeway grades really made the temp swing up...
     
  12. Darwood

    Darwood

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    I think it might be due to the fact that 80's are just happier off road in 4lo ;)
     
  13. Dusty

    Dusty

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    you should see how hot mine airbox gets with the turbo. I need a shield
     
  14. alia176

    alia176

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    I can only imagine!

    No doubt that a snorkel will deliver fresh air but if the air box is so efficient at heating it up, I wonder if the benefit will be maximized. A 40* temp rise in such a short distance is amazing to me.

    I like the idea of insulating the air box and maybe circulate windshield washer fluid around it as a heat sink? :eek: Kidding...
     
  15. LX_TREME

    LX_TREME

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  16. Hayes

    Hayes

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    OK.
    Let's assume one can get cooler air to the box with a snorkel. And assume that the box and intake tube could be insulated enough to realize some effect there as well.

    Would the result yield any noticeable gain for a naturally aspirated 1FZE?
     
  17. Tools R Us

    Tools R Us

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    Alia do you have a second battery mounted on the right side? My observation is, there is a cooler, closer to ambient temp air flow, from the headlight area back along the right fender well. When the truck is stationary everything pretty much heat soaks to fan output temp, as the truck is driven faster this cooler airflow gets cooler and covers a larger area. Adding a battery to the right side would block some/most of this flow, it appears to come from the holes behind the headlight and some flows behind the side marker light into the fender cavity. I will bet that Toyota knew about this cooler flow (may have designed it?) and that’s why the air intake, injector resister, etc are mounted over there?

    Insulation is most of the time good stuff, but in this case, with heat soak it may not be very effective. I would look at making some simple ducting to flow cooler air past the filter can, that approach maybe more effective?
     
  18. Jacques Villeneuve

    Jacques Villeneuve

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    Has that truck ever left your living room? :D

    - How about using silver reflective tape used to tape together silver colored bubble wrap like insulation on hot water heaters? This stuff is at Home Depot, Lowe's, etc.
     
  19. cruiserdan

    cruiserdan SupportingVendor Emeritus Moderator

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    It looks like you are getting ready to barbeque a chicken.........:eek:
     
  20. Romer

    Romer fatherofdaughterofromer Moderator

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    Man you could eat off of that engine.

    I still have that scoop sitting on my shelf. I need to do the test with the yarn to see how the wind flow is on the top part of the hood and evaluate if I want to do the scoop or not.

    The snorkle took care of the intake temps now I have the same concern you have with the underhood temps. With the JDM fan Its a controllable problem as long as everything stays in good shape, I would like to drop the underhood temps 5 deg or so and thats why I am looking at the scoop.

    When I run the Yarn test on the hood, I will take video and post a link. Maybe this weekend if I can stop driving my new to me Z4 enough to do it :D
     
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