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Thread: aerodynamics

  1. #21
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    My old ITC Honda presented the same dilemma. A/C cars had the condenser beside the radiator; non-A/C cars had a bolted-in block-off plate. I just took the plate off one of my non A/C parts cars and put it on the race car. The sourcing of the air was not a problem, because it originally came from the left-side headlight surround. I just "upgraded" the original, and left it at that. Besides - how much air does it take to run 65 WHP??

  2. #22
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    You guys are wrong... Theirs a way to get a ruling from Topeka, It costs $250.00 but tonight when I get home I will check it out. It is outlined in section 13.9 of your GCR.

    BTW: This ruling from Topeka in a 13.9 is confidential for the competitor only and can be presented at any time especially when he/she gets protested. This is the only documentation that holds precedence in a protest. (He or she may share the info at his/her discretion; SCCA will not share it in Fast Track or anywhere else). One thing to note though is that it is only good until December 31 of that year as when the new GCR comes out it may or may not have changes that supersede any prior rulings.

    The other way you guys mentioned is to get protested and find out the results. Unlike in our US legal system, prior rulings on a protest done in Topeka or locally does not have any precedence.

    Raymond

  3. #23
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    Bill, not picking a fight here, just curious -- where do you see an intent that "engine compartment" be defined as behind the radiator?

    I think (for what that is worth) that the rule allows you two choices:

    1. pick up air from the stock location OR

    2. anywhere in teh engine bay, which is bounded by the hood, the firewall, the inner
    fenders and the radiator.

    That make sense?


  4. #24
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    Based on past conversations, I expect that you'll get little disagreement on the hood (easy if there are no holes in it), firewall (very easy since they tend to be sealed up), and maybe the inner fenders.

    However, the line at which the engine compartment ends and the outside world begins is harder to define out the front, and out the bottom of the car. Interpretations will vary a BUNCH.

    For example, how far down may I go with my snorkle/intake thingie? Into the airflow under the car?

    K

  5. #25
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    Originally posted by charrbq:
    As an example of what I meant. I've seen a duct built that attached to the inside of a car's grill and had an hose running from it to the front of the air filter element. It was not attached to the filter or the carb...simply blew cooler air onto the element. It was protested in impound and allowed as there was no ram air effect, not enclosing the carb, and no new or additional holes were made in the body work for its application.
    However, everyone is aware that different tech inspectors and stewards view things differently.

    I would call this illegal for sure. Air to the intake must be sourced from inside the engine bay. Clearly not the case the way you describe.

    AB

    ------------------
    Andy Bettencourt
    New England Region, R188967
    www.flatout-motorsports.com

  6. #26
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    Kirk, I agree. The definition of "engine compartment" gets real fuzzy out the bottom (who would want to pick up air down there though, with all that crap?) and near the front. So, I'm going to a safe spot that is (and most people don't realize this) THE best place to get air.

    Ram air is way overrated and the studies I read showed it doesn't really work below 130-150 mph or so. But, picking up cool air at the low pressure zone in front of the windshield a la a Winston Cup car is the way to go for us IT guys.

  7. #27
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    Originally posted by Andy Bettencourt:
    Air to the intake must be sourced from inside the engine bay. Clearly not the case the way you describe.
    AB

    this brings up the problem. if the duct is attached to the grill you can say the air is being sourced outside the engine compartment. but if it is back 2 inches from the grill it is ok. how about 1 inch. 1/8 inch.
    because of this i am thinking that if the duct is inside the engine compartment it is legal.
    dick

  8. #28
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    Actually, Jeff that should be a *high* pressure area in front of the windscreen. How would the air get into the engine compartment, though? Most "cowl induction" systems that I've seen have either a rearward-facing hood scoop, cowl louvers (like I have for AC/heater air intake), or a hood that's propped up somehow. My hood is actually sealed with a gasket at the back - what's the TR like?

    K

  9. #29
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    I really appreciate the input. I have really tried to keep my car legal from the first time I started to build it into an IT car, as I knew one day I would start winning and would be protested. I had heard of a guy named Kaz Busch who raced a swift in the NE, winning often, and getting protested so much he quit racing.
    The opening beside my radiator, which is a stock radiator, was where the A/C condensor sat at one time.
    I plan to put a sheet metal plate, about the size of my old A/C condensor to fill the hole, but will leave a small peice missing next to the intake filter. I will then put another sheet metal peice between the air filter and the headers, to keep the heat away from the air intake.
    After this, building an air dam, maybe out of fiberglass, not sure yet, will complete my aerodynamic work.
    Maybe result in another second or two.

  10. #30
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    Zoo, with a "low" hp car (relatively speaking), do some testing with teh air dam. You might actually lose some time on the trackes with longer straights. A buddy who raced a Spitfire in G Prod or U Prod or someting was faster without his air dam.

    Kirk, the car draws air into the vents via some grating in the rear of the hood (high pressure, high pressure, that's right...). I was going to put the box directly under that, riveted to the firewall. Grates are decent size -- about 30" or so across, maybe 5-6" deep.

    Sounds like on Pablo there's no real way to do it?

  11. #31
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    No way at all, on the Golf.

    Zooracer - you are describing a couple of things that would leave room for another ITB racer in the SE (hmmm?) to protest your modifications.

    Unless you can show which rule lets you put a sheet over that grill opening, that's paper-bait. You are going to want to make sure that your heatshield is attached to the exhaust system, too.

    But then, IANATI.

    K

  12. #32
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    Originally posted by Knestis:
    Unless you can show which rule lets you put a sheet over that grill opening, that's paper-bait.
    Unless, like I said, you can find a non-A/C car and get the stock block-off plate from it.


  13. #33
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    Originally posted by Knestis:
    You are going to want to make sure that your heatshield is attached to the exhaust system, too.

    But then, IANATI.

    K

    How about this from the ITCS ?

    "Any exhaust header and exhaust system may be used. Exhaust shall exit behind the driver, and shall be directed asay from the car body. Original exhaust system heat shields may be removed. A suitale muffler may be necessary to meet sound control requirements (see GCR Section 12)." para g on page 6

    Heat shields, We don't need no stinking heat shields!




    [This message has been edited by jhooten (edited June 22, 2005).]

  14. #34
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    Jeff brought up something you should really consider when doing things that may be pushing the rules. What performance gain if any is there to be had? A while ago I had some similar questions and was a bit surprised with the answers that I received. There are also several well known magazines and tuner books (hey, I do have a Honda) that have done research on the cold air intake. I have not seen anything that indicates, or better yet actual proof, that there is a benefit to doing this with our cars. So why do this then? I'm not saying don't do anything such as a air box that is attached to the filter if that gives you a mental edge but I really wouldn't push it especially if you will be running up front. Just be sure to weigh the possible benefit versus all of the b.s. you might have to go through. As a minimum when people look in your hood at your creative rules interpretiation and wonder what else have you done? How much would it suck to win your first race and get protested with something in such of a grey area as this?

    ------------------
    Dave Gran
    NER ITB #13
    '87 Honda Prelude si

  15. #35
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    "2. anywhere in teh engine bay, which is bounded by the hood, the firewall, the inner
    fenders and the radiator."

    Jeff, are you disagreeing w/ me or just looking for rules authority? Because your definition appears to be the same as mine - the "engine bay" does not include the area between the radiator and the grill. Actually, it's just common sense - if anyone thinks otherwise, please tell me what part of the engine is in that area? If the engine bay includes the area forward of the radiator, what then would NOT be a legal source for air other than outside the car?

    Andy, you are overlooking the "stock location" part of the rule. If the car in stock trim sourced air from in front of the radiator or outside, it can do so in race trim. Now, fabricating a custom box for it is another matter. But, back to my RX-7 example, I think you probably could run a duct from in front of the radiator to your air box since the stock air box did the same.

    Raymond, where are you getting all that info re advisory rulings? No one said you could not get one, just that it wasn't worth much. An SSC driver got one at The Runoffs re stainless brake lines but I heard that other competitors were told that it would not necessarilly protect THEM if they used them.



    ------------------
    Bill Denton
    87/89 ITS RX-7
    02 Audi TT225QC
    95 Tahoe
    Memphis

  16. #36
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    Bill, I think we got our wires crossed, sorry. I was saying I intend to pick up air in the engine bay on teh firewall right below some existing openings in the hood.

    I agree with you on your definition of engine bay.

    Kirk, let Pablo breathe, let him breathe!

    Here's another question for the team -- since hood fasteners are free, what if I put big old rubber washers on my hood pins (which are located at the back of the hood) so that it sticks up an 1" and more air can get to the box??? Sounds technically legal, but a "spirit" violation.

    Zoo, agree withteh others on the blanking plate....be careful with that.

  17. #37
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    Bill,
    Email me re: RX7 airbox's

    Jim
    jcohen at wdi dot com

  18. #38
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    Bill,

    Not overlooking it, just not mentioning it as other posters have and it is only applicable to a very few cars.

    AB

    ------------------
    Andy Bettencourt
    New England Region, R188967
    www.flatout-motorsports.com

  19. #39
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    "Raymond, where are you getting all that info re advisory rulings? No one said you could not get one, just that it wasn't worth much. An SSC driver got one at The Runoffs re stainless brake lines but I heard that other competitors were told that it would not necessarilly protect THEM if they used them."

    As someone on the SOM at times it is worth a win in a protest against YOU. The YOU part is correct as it is a ruling for you and only you, however I am sure that if you were to share the approval with your friends that it would hold up for them as well. I would anyway. IE: If that SSC driver copied the letter saying that stainless steel lines were ok on his car and gave it to a friend who was protested for it, then I would say it was ok on his car also (same make/model/year). I would have a hard time arguing that what was good for one was good for the other, and I think that Topeka would have a hard time arguing that also if it went to appeal.

    Raymond

  20. #40
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    Originally posted by JeffYoung:
    Bill, I think we got our wires crossed, sorry. I was saying I intend to pick up air in the engine bay on teh firewall right below some existing openings in the hood.

    I agree with you on your definition of engine bay.

    Kirk, let Pablo breathe, let him breathe!

    Here's another question for the team -- since hood fasteners are free, what if I put big old rubber washers on my hood pins (which are located at the back of the hood) so that it sticks up an 1" and more air can get to the box??? Sounds technically legal, but a "spirit" violation.


    How about this quote?

    "D. Authorized Modifications
    The following modifications are authorized on all Improved Touring Catagory cars. Modifications shall not be made unless authorized herein. No permitted componant/modification shall additionally perform a prohibited function."

    You can modify the mounts but not take advantage of the modification to duct cold air.

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