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Thread: "The Confines of the Engine Compartment"

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  1. #1
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    Default "The Confines of the Engine Compartment"

    GCR 9.1.3.D.1.a.4 says, in part, "Air intake source shall be within the confines of the engine compartment or stock location." Define "the confines of the engine compartment".

    GCR Technical Glossary (Appendix F) defines "engine compartment" as:

    Engine Compartment – The loosely defined volume, nominally enclosed
    by panels on top and sides, which is the normal location of the engine in
    a car.

    "Loosely defined", indeed. Question is, how loosely?

    "So where's he going with this?" you may ask. I had an email exchange with someone, asking about the compliance to the ITCS of the Jackson Racing intake system for the Miata. He had seen it in other Miatae for sale and wanted to know if he could install it on his own car. Photo, installed:

    http://www.miataturbo.net/attachment...as-2u5q0ox-jpg

    This appears to pull intake air from above the radiator support. At first glance, I'd call it non-compliant, however nowhere is there a clear delineation of "engine compartment" for the front or bottom, and in this particular case the "top" is the hood, and this parts sits under that.

    We briefly touched on the subject in the 2008 discussion of the ARRC CRX fender well intake protest. Within that, we recognized that there was some ambiguity, but never truly delved upon it.

    Stock 1.8L engine compartment:
    http://carphotos.cardomain.com/ride_...ata_engine.jpg

    Stock 1.6L engine compartment:
    http://www.practicaltech.ca/jpg/auto...engine-bay.jpg

    Since the top of the "engine compartment" is inferentially defined by the Technical Glossary as the bottom of the hood, and this part fits within that without modification, isn't anything under the hood part of the "engine compartment"? If so, where does that allowance end in the forward direction?

    And what about "prohibited function"? The regs clearly indicate that pulling air from outside the "engine compartment" is clearly prohibited, and the regs further clarify that you cannot run a minimal radiator to make open space to route air to the engine intake. But what if you are not modifying anything to grab air from that area?

    About the only thing I can suggest is that it's non-compliant because the "engine compartment" definition in the Glossary states "the normal location of the engine in a car", and there's no way that the area above and in front of the radiator is a normal location for the engine. But it's not clear where that "normal location" definition ends, nor is it clear if that definition changes based on make/model (and if it does, then any space that the engine does not "normally" occupy - basically all the clear space around the engine - would not be allowable places from which to source air.)

    Is it the aft edge of the radiator? Does that change with the allowed radiator design change? Is it the aft edge of the radiator support? Of the forward edge of the rad support? And if that part were trimmed back an inch to that plane, but still pulled air from above the radiator and radiator support, would it then be compliant?

    I'm torn. Without using much intorturation, I see how this could be allowed, as-is.

    I'm sure no one else on this board will have a strong opinion on it, but figured I'd ask anyway...

    GA

  2. #2
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    Default

    I must admit i am uncomfortable with the intake breaking the plane of radiator.
    dick patullo
    ner scca IT7 Rx7

  3. #3
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    Default

    Quote Originally Posted by dickita15 View Post
    I must admit i am uncomfortable with the intake breaking the plane of radiator.
    Fair enough. So look at that photo of the item installed again. Note that the piece that extends well past forward of the radiator is the mounting system, and there's no limits to the mounting system for the air intake, only limits to where the air is sourced. If he were to trim back the top of that item, where the initial opening of the air source is, to a point right at the vertical plane of the aft edge of the radiator, would that not satisfy the letter (and potentially the intent) of the reg?

    GA

  4. #4
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    <johnbishop> It's illegal. Period. </johnbishop>

    Kirk (who freely admits that combining obtuse references to both html and '70s-era IMSA is probably leaving pretty much everyone out of the joke)

  5. #5
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    Quote Originally Posted by Knestis View Post
    <johnbishop> It's illegal. Period. </johnbishop>
    Wish we could....but then there'd be all kinda arguments over how come *I* got to be John Bishop...

  6. #6
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    Default

    I have no problem with it. Unless you are going to mandate bone stock air filters and housings, it works.

  7. #7
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    I don't mean to complicate the issue, but it reminds me of the stock airbox/ramair setup of the S5 RX7.
    It seems to me that if none of the fast RX7 guys utilize these stock parts, it probably isn't worthwhile.
    What I do know is that we toyed with it, and we determined that its volume flow restriction would likely
    outweigh any possible (and doubtful) pressurized advantage

    red 1991 (10).jpg
    Last edited by lawtonglenn; 06-12-2014 at 09:34 AM.

    Glenn Lawton
    GSMmotorsports
    #14 ITS RX7
    NARRC ITS Champion 2012
    NERRC ITS Champion 2013 12 11 10 09 08
    NERRC STU Champion 2010

    __________________

  8. #8
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    Default

    In this case, this intake was included on a Miata driven by an extremely talented driver (I'm almost certain - Price). I never would have protested him because he could drive circles around me and I would have known it sure as heck wasn't the intake.

    Andy - what's your take on the performance of that intake versus say an ISC?
    Dave Gran
    Real Roads, Real Car Guys – Real World Road Tests
    Go Ahead - Take the Wheel's Free Guide to Racing

  9. #9
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    Quote Originally Posted by lawtonglenn View Post
    I don't mean to complicate the issue, but it reminds me of the stock airbox/ramair setup of the S5 RX7.
    It seems to me that if none of the fast RX7 guys utilize these stock parts, it probably isn't worthwhile.
    What I do know is that we toyed with it, and we determined that its volume flow restriction would likely
    outweigh any possible (and doubtful) pressurized advantage

    red 1991 (10).jpg

    Go back and look again, you missed something.
    Steve Eckerich
    ITS 18 Speedsource RX7
    ITR RX8 (under construction)

  10. #10
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    Default

    The rules are pretty clear about no 'ram-air' and this would put the air intake into an area of higher pressure than it would normally have in it's stock location. You have to remove the plastic trim for it to work.

    Two strikes, you're out.

  11. #11
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    Agreed. No plastic piece and no air intake there? Cool (IMO). No plastic piece AND intake there? Too far.

    Now I need to go find one of those plastic pieces. Agree with Andy on using it to keep temps down.
    Dave Gran
    Real Roads, Real Car Guys – Real World Road Tests
    Go Ahead - Take the Wheel's Free Guide to Racing

  12. #12
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    Quote Originally Posted by seckerich View Post
    Go back and look again, you missed something.
    ok Steve ... we still have the parts ... six pack of lager for some hints?

    Glenn Lawton
    GSMmotorsports
    #14 ITS RX7
    NARRC ITS Champion 2012
    NERRC ITS Champion 2013 12 11 10 09 08
    NERRC STU Champion 2010

    __________________

  13. #13
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    Default

    PM me and I will send you a picture.
    Steve Eckerich
    ITS 18 Speedsource RX7
    ITR RX8 (under construction)

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