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Thread: How badly does a intake manifold heatsoak on a 8 valve?

  1. #21
    Supporting Member Turbo Mopar Contributor
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    Re: How badly does a intake manifold heatsoak on a 8 valve?

    Has anyone tried to coat the inside of the IM to reduce thermal transfer to the charge? Just an idea
    Regards,
    Miles

    DD '87 Sundance T1, SLH with rear disks
    '87 CSX #432 2.5 CB TII, SLH

  2. #22
    Super Moderator Turbo Mopar Staff contraption22's Avatar
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    Re: How badly does a intake manifold heatsoak on a 8 valve?

    You have to wonder how much heat transfer actually takes place from the manifold to the charge air at high RPM.
    Mike Marra
    1986 Plymouth Horizon GLMF "The Contraption" < entertaining sponsorship offers
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  3. #23
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    Re: How badly does a intake manifold heatsoak on a 8 valve?

    Quote Originally Posted by wheming View Post
    I thought I was?! Lol. It's like any other time folks even vendors have tried doing things. Everyone is interested until they realize its not free! What's another 70 bucks into my setup....
    you and me both. 70$ is nothing. its a nice dinner out. no big deal.
    HONESTLY . if you really want it. you can buy the material yourself for about 20-40$
    i measured needing a 15x4 inch piece to cut up myself. 3/8ths inch thick.
    The "holes" can be done with a drill press and hole saw/bit.
    so can the mounting holes. wouldnt be too hard.
    but i went from building a engine on free time for a long term swap.
    to a "need to put it in to keep the car running"..
    The place that was going to do it was going to use a special blend to withstand 450 intermittent heat, 300 continuous.
    and then CNC it for me. I was going to need to order 100$ (70x100 =7,000)
    I was trying to get a vendor to go in with me on 30-50 of them. but didnt happen at that price range.
    you COULD use two smaller pieces and make 2 seperate
    like this picture below.
    https://scontent-ort2-1.xx.fbcdn.net...74&oe=5AAB6851

    I had my 2 piece lower ceramic coated in and out ( wasnt supposed to be coated inside)
    http://www.turbododge.com/forums/att..._190110-1-.jpg

    Seems more to trap heat in the aluminum. more than it does prevent heat from the turbo getting to it.
    Also had the exhaust coated in and out. and a sheet of insulation between them bolted to the fuel rail bolts.
    http://www.turbododge.com/forums/att..._190138-1-.jpg
    the intake still gets very hot.


    check out the stock below

    https://www.google.com/shopping/prod...ASEQ8wII7wIwAg

    https://www.ebay.com/i/202013315225?chn=ps&dispItem=1

    https://www.ebay.com/i/252985617117?chn=ps&dispItem=1

  4. #24
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    Re: How badly does a intake manifold heatsoak on a 8 valve?

    Quote Originally Posted by contraption22 View Post
    You have to wonder how much heat transfer actually takes place from the manifold to the charge air at high RPM.
    Wonder? I have logs that show faster the engine speed, the lower the intake air temperature. Doesn't that imply very little heat transfer take place between the HOT intake manifold and the CHILLED inter-cooled air?

  5. #25
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    Re: How badly does a intake manifold heatsoak on a 8 valve?

    Quote Originally Posted by chromguy View Post
    Has anyone tried to coat the inside of the IM to reduce thermal transfer to the charge? Just an idea
    Or just WOT when you want your intake air temperature to be lower....

    The only heatsoak intake issue I have is hot restart, car wants to run super lean, but I can tune that out.

    Honestly, heatsoak intake is not an issue for me while I am boosting as you can see, faster I go, cooler the intake air temperature gets.

    When I am not boosting, do I really care how hot the air intake temperature is? Actually, I take that back, the hotter the intake air temperature while I am cruising the better, I can get better MPG!
    Last edited by tryingbe; 10-25-2017 at 08:23 PM.

  6. #26
    Supporting Member II Turbo Mopar Contributor Shadow's Avatar
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    Re: How badly does a intake manifold heatsoak on a 8 valve?

    Quote Originally Posted by tryingbe View Post
    Wonder? I have logs that show faster the engine speed, the lower the intake air temperature. Doesn't that imply very little heat transfer take place between the HOT intake manifold and the CHILLED inter-cooled air?
    Bingo!

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  7. #27
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    Re: How badly does a intake manifold heatsoak on a 8 valve?

    Quote Originally Posted by tryingbe View Post
    Wonder? I have logs that show faster the engine speed, the lower the intake air temperature. Doesn't that imply very little heat transfer take place between the HOT intake manifold and the CHILLED inter-cooled air?
    Yep, a graphed curve will illustrate the diminishing returns that your logs show. Still, I wonder if an isolator, simple and cheap, at the head would offer a benefit at the base of the curve, if only in spool point? The plastic intake manifolds on new cars offer more than just a lower production cost, they also reduce heat transfer to charge air.
    Last edited by johnl; 10-25-2017 at 03:47 PM.
    John Laing

    "The sole condition which is required in order to succeed in centralizing the supreme power in a democratic community, is to love equality, or to get men to believe you love it. Thus the science of despotism, which was once so complex is simplified, and reduced . . . . to a single principle."
    -- Alexis de Tocqueville

    "One of the methods used by statists to destroy capitalism consists in establishing controls that tie a given industry hand and foot, making it unable to solve its problems, then declaring that freedom has failed and stronger controls are necessary."
    --Ayn Rand

    "To evolve, you don't need a Constitution. All you need is a legislature and a ballot box . . . . things will evolve as much as you want. All of these changes can come about democratically; you don't need a Constitution to do that and it's not the function of a Constitution to do that."
    -- Justice Antonin Scalia

  8. #28
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    Re: How badly does a intake manifold heatsoak on a 8 valve?

    My 87 ShelbyZ underhood temps were always pretty hot on those 100+ degree days we get up here during the 1st week of august. When I made an upper plenum for my 2 piece I put a phenolic spacer under it. On those days you could get out and rest your hand on the plenum while you looked under the hood right after shutting the car off. Most of the time it was cool to the touch from the cold air coming out of the i/c.

    There's a few of those plenums and phenolic spacers floating around the community. If you're going to do phenolic at home make sure you use plenty of water and a mask while cutting it. As a machinist I hate the crap. Destroys the coolant in the machine, but I guess it's better than me breathing it. I'm not sure how thick a spacer you'd have to go to be able to move the intake mounting holes enough to have meat in the head to hold raised stud locations so the runners line up off the top of my head.

  9. #29
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    Re: How badly does a intake manifold heatsoak on a 8 valve?

    I just realized something.

    For maximum MPG, intake air temperature needs to be HOT when cruising.

    For maximum power and less chance for knock, intake aor temperature needs to be cool when boosting.

    It would seem I somehow unknowingly stumbled upon the best of both worlds for a street car?

    For my last tank of E54, I got 27.56 mpg.
    Last edited by tryingbe; 10-25-2017 at 11:30 PM.

  10. #30
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    Re: How badly does a intake manifold heatsoak on a 8 valve?

    one way to keep the intake and plenium cooler is to simply paint them black

    - polished metal retains heat thus things like chrome oil pans are not so cool - no pun intended

    have you leaned on your black valve cover and noted the bare aluminum fins are hot enough to almost brand the palm of your hand but the painted surface is only just nice and warm ?

    painting the tanks on the intercooler should help too but not the fins as that would reduce the efficiency of the fins
    painting the tanks should help move the heat from the tank material into the tubes to cool also

    I don't think much of the heat in the intake is going to be from the head - simple airflow through the ports should help draw any heat away from the intake as might the water outlet at the front at the t stat
    more so the heat radiates up from the turbo .. and I've seen my turbo get really hot after a hard pull
    so much so that 1-2 min later the turbine housing and s/v housing are cherry red .. still , and probably were hot enough to see through moments before

    I don't think heat soak of the intake is an issue or ever was much of one even with the old log motors but I do think it would be nice if the fuel rail , injectors and regulator weren't heat soaking along with the intake
    I've thought a few times a small scoop under the crossmember and a small duct leading air up the firewall and out somewhere might help as you might be able to direct the air where you want it with a little thought.. maybe a couple of holes in the side of each strut tower ?
    - some air movement management around the turbo might help the most

    perhaps our next step forwards in intake manifolds should look to 3D printing a new plastic one
    - if that were simply a modded two piece bottom we would be off to a good start
    (though I'd imagine the knock sensor might need to be moved off the intake)

  11. #31
    Super Moderator Turbo Mopar Staff contraption22's Avatar
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    Re: How badly does a intake manifold heatsoak on a 8 valve?

    Quote Originally Posted by Dr. Johny Dodge View Post

    I don't think heat soak of the intake is an issue or ever was much of one even with the old log motors but I do think it would be nice if the fuel rail , injectors and regulator weren't heat soaking along with the intake
    I'd figure the fuel system would be even less susceptible as it constantly has cool fuel from the tank circulating through it.
    Mike Marra
    1986 Plymouth Horizon GLMF "The Contraption" < entertaining sponsorship offers
    Project Log:
    http://www.turbo-mopar.com/forums/showthread.php?69708-The-Contraption-2013-14&highlight=

  12. #32
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    Re: How badly does a intake manifold heatsoak on a 8 valve?

    not so much as the tank gets warmer the longer you drive - thus one of the reasons for a returnless system

  13. #33
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    Re: How badly does a intake manifold heatsoak on a 8 valve?

    https://www.amazon.com/HM-FC-Titaniu...SIN=B01A6F02TW

    $27 turbo wrap


    As for ducting, isn't the base of the windshield a point of high pressure when moving? And, aren't there low pressure points under the car? So .. . duct pickup from the cowl directed down onto the hot side, swing valve, and downpipe?
    John Laing

    "The sole condition which is required in order to succeed in centralizing the supreme power in a democratic community, is to love equality, or to get men to believe you love it. Thus the science of despotism, which was once so complex is simplified, and reduced . . . . to a single principle."
    -- Alexis de Tocqueville

    "One of the methods used by statists to destroy capitalism consists in establishing controls that tie a given industry hand and foot, making it unable to solve its problems, then declaring that freedom has failed and stronger controls are necessary."
    --Ayn Rand

    "To evolve, you don't need a Constitution. All you need is a legislature and a ballot box . . . . things will evolve as much as you want. All of these changes can come about democratically; you don't need a Constitution to do that and it's not the function of a Constitution to do that."
    -- Justice Antonin Scalia

  14. #34
    Slugmobile & MeanMini Caretaker Turbo Mopar Contributor wheming's Avatar
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    Re: How badly does a intake manifold heatsoak on a 8 valve?

    Anyone that wants one of those, i have one! It didn't fit with my setup.
    Wayne H.

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  15. #35
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    Re: How badly does a intake manifold heatsoak on a 8 valve?

    And then there's a corrugated stainless/ceramic/stainless sandwich.

    http://www.thermalcontrolproducts.co...-heat-shields/
    John Laing

    "The sole condition which is required in order to succeed in centralizing the supreme power in a democratic community, is to love equality, or to get men to believe you love it. Thus the science of despotism, which was once so complex is simplified, and reduced . . . . to a single principle."
    -- Alexis de Tocqueville

    "One of the methods used by statists to destroy capitalism consists in establishing controls that tie a given industry hand and foot, making it unable to solve its problems, then declaring that freedom has failed and stronger controls are necessary."
    --Ayn Rand

    "To evolve, you don't need a Constitution. All you need is a legislature and a ballot box . . . . things will evolve as much as you want. All of these changes can come about democratically; you don't need a Constitution to do that and it's not the function of a Constitution to do that."
    -- Justice Antonin Scalia

  16. #36
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    Re: How badly does a intake manifold heatsoak on a 8 valve?

    Quote Originally Posted by johnl View Post
    You must not have BMF intake manifold.









  17. #37
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    Re: How badly does a intake manifold heatsoak on a 8 valve?

    And then there's a corrugated stainless/ceramic/stainless sandwich.

    http://www.thermalcontrolproducts.co...-heat-shields/

    THAT could be a winner ^

    especially for the log motor guys that almost all need something to replace the old o-e heat shield under the fuel rail

    I made a shield for my log motor long ago from a piece of mirror plate stainless - it had been cut to fit flat in a dart/duster cluster to mount custom gauges but had never been cut for the gauges it made the perfect shaped and sized heat shield for my log motor
    I simply added two L shaped brackets that I riveted to it so I could bolt it to the manifold at the stock heat shield mount points
    then I drilled the fuel rail where the clips hold the o-e shield to the rail , drilled the piece of stainless to match and put two screws in to hold it all together

    two pieces of stainless like mine with something to sandwich in between would be really cool

  18. #38
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    Re: How badly does a intake manifold heatsoak on a 8 valve?

    something to keep in mind is the idea of a shield that cannot soak up gas if you have a fuel leak
    - but something that can keep the fuel from dripping directly on the exhaust also is good to consider
    on my log motor , the first time I drove it I had am O ring on the injector leak (no heat shield)
    every time the injector fired it shot a little stream of gas directly at the swing valve housing where it instantly vaporized
    one of those "I'm glad I caught that deals" lol

  19. #39
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    Re: How badly does a intake manifold heatsoak on a 8 valve?

    Quote Originally Posted by johnl View Post
    And then there's a corrugated stainless/ceramic/stainless sandwich.

    http://www.thermalcontrolproducts.co...-heat-shields/
    you can get tons of that at the junkyard. just look under newer cars.. even the the focuses have that.
    almost all BMW do. even older. jags and lexus.

    You could get a 5 foot by 3 foot piece in a 10 minute trip.
    Last edited by masterjr33; 11-01-2017 at 07:49 AM.

  20. #40
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    Re: How badly does a intake manifold heatsoak on a 8 valve?

    Relocated the MAT sensor to right after the intercooler. Temp is much more stable.




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