aerodynamics

Z

zooracer

New member
I did a search, but didnt see anything, so here goes.
I want to do a few things.
The air filter is an open element K&N and I want to build a box or sheild to keep heat from the headers. I then want to put a shield to stop air from entering the engine compartment through a large opening I have next to the radiator. I could even direct some air from this opening toward the air filter?
Wondering about the legality of this...
 
IANATI but you are allowed to build a box for the air filter, as long as the entire thing is inside the engine compartment. If that box is in front of a hole in the grill - a hole that is there for a legal reason - and the box is open so that air goes into it, I'd have a hard time finding a problem with that.

My biggest question is about that hole and why it's there. That isn't typical practice for a manufacturer.

K
 
Great! I am going to work on it today.
The hole is more like an open space behind the grill next to the radiator.
I have a hard time remebering, but I think the A/C condensor was filling this space at one time.
At first I was going to block it off, so that more air would hit the radiator, rather then blowing against the headers.
But then I thought about making it so some of that air funneled into the air intake filter.
Now I just need to figure out how to make a splitter/air dam...
 
You can pretty much design anything you want to direct air to the intake as long as you don't cut holes or build something that would pressurize the carbs at speed. You can use all sorts of "blocking panels" and air ducting devices to get cool air to the intake. Just don't cut holes or use something like a headlight bucket or turn signal, etc.


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Chris Harris
ITC Honda Civic
 
I'm going to voice some caution about "pretty much design anything."

If I just put a panel over a big gap in the grill opening, left by the installation of a slightly smaller radiator for example, I'd be doing so without a rule leg to stand on.

If I were looking to protest you, I'd expect that your "airbox" would all be one piece. If you had a panel, not mounted to the box, that turns air to where you want it, I'd ask you to show me which rule allows you to do it.

K
 
Please also show me where you can "duct" or 'direct' air to the intake. I think MANY people take EXTREME liberties with these rules.

Your "BOX" that you create around the filter must be attached to the filter and it would be legal under the open filter rule. If it isn't - it isn't. Ducting air to the air intake - don't see any provisions for it, and frankly I see a few rules that specifically disallow it.

Break out your GCR's and bring it on!

AB

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Andy Bettencourt
New England Region, R188967
www.flatout-motorsports.com
 
What about the heat shield to keep the hot air from the air filter???

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Evan Darling
ITA Integra
 
Show me some rules that allow what you are talking about....but I will play:

A heat sheild attached to the header (free) is legal. It can not however duct air to the intake. An allowed mod can not in turn facilitate an illegal one (GCR). Rules like: Air must be sourced from inside the engine bay, Ram air systems being illegal, holes created from fitting alternate radiators must not be used to provide air to the intake, etc are all in place to dissallow such ducting.

AB

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

My question: My carbs were originally fed by two hoses that attached to a plastic duct in the lower left and lower right front fender. The hose then ran to a bi-valve that was itself connected to the stock manifolds. When cold, the car drew air off the manifolds for emissions purposes. When warm, the car had a crude ram air system to the front fender holes.

NOW, I want to move the air intake point from the "ram air" inlets (which are crap, and pick up all kinds of crap), to the low pressure zone right in front of the windshield.

I intend to build an air box to hold a K&N filter and rivet it to the fire wall, and then run the EXISTING stock hoses to the air box.

Legal? I'm using a stock hose, but I'm running it to an air box that is NOT connected to the "stock" filter location -- in fact, I've moved the filter location in its entirety to the base of the windshield.

I THINK that because I am using essentially the stock setup -- hoses drawing air to the carbs -- moving the filter and the box to a new location within the engine bay is legal.

Thoughts?
 
Just make sure your air box is 'part of' the FREE filter. Otherwise, you have created something that nobody will be able to find in the rules that says you can...

"Ram Air" set-ups are prohiobited unless fitted as original equipment...sounds like you fall under that OEM disclaimer...

AB

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Andy Bettencourt
New England Region, R188967
www.flatout-motorsports.com
 
2005 gcr definitions, pg 166

"Ram Air - A type of induction systemin which the incoming air is obtained from an extension into the airstream outside the body work."

the term Ram air does not apply in this discussion.

itcs 17.1.4.D.1.c (pg5) "..air intake hoses, tubes,pipes, resonators, intake mufflers, housings, ect., located ahead of the air metering/measuring device (i.e. air flow meter, mass air meter) may be removed or substituted."
I think this gives you quite a bit of flexability in designing a airbox/filter structure. as long as you stay withing the engine compartment and make no new openings. i disagree that the "ducting" you want to ad has to be attached and one piece, but i understant the argument and you can easly design your airbox to blunt that objection.

I would however be very very sure of the history of the opening next to the radiator that you can't quite remember what it was for. most of us would love to have such an opening so we will be jealous.

dick patullo
 
Thank you....very clear what can be done there...it is amazing what can be found in that book
smile.gif


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Evan Darling
ITA Integra
 
Jeff Young, ITCS 17.1.4 D.1 c. ...."Air intake source shall be within the confines of the engine compartment OR THE STOCK LOCATION"........ If it did not pull air from in front of the windshield before, it cannot now, you cannot make a hole for it to pull from in that area. You can still pull it from the left and right sides low where it pulled it from the factory. Pull it there and filter it.

Zooracer, ITCS 17.1.4 D. 3. a. ..."No new openings created by fitting an alternate radiator may be used for the purpose of ducting air to the engine."....
ITCS 17.1.4 D. 3. e. "Air conditioning systems may be removed in whole or in part."
ITCS 17.1.4 D. ...."No permitted component/modification shall additionally perform a prohibited function."

If the hole beside your radiator was not there before you removed your air conditioning I think that you would have to fill that hole to block the air flow into your engine compartment, as it is now a "new" hole that did not exist before you performed an allowed modification. You are not allowed to take advantage of that new source of cold air. If that hole is there, unblocked, in non-air conditioned versions of your car, have at it.
That is how I read what the book says.
 
Renault, by under the windshield I mean under the hood in the engine bay right in front of the windshield. Legal I think, if I follow Andy's advice and make it part of the filter.
 
Originally posted by JeffYoung:
Renault, by under the windshield I mean under the hood in the engine bay right in front of the windshield. Legal I think, if I follow Andy's advice and make it part of the filter.
Click to expand...

Also read Dick's quote above...you should be able to make a box...

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Andy Bettencourt
New England Region, R188967
www.flatout-motorsports.com
 
to take this to the extream we might be able to get clear opinions...

Can you legaly build an air box that collected all of the air entering the front of the engine compartment???

A) Your not leaving the engine compartment not even for the fastners to attach such a "box".
B) we don't care about the fact that we need to duct the radiator also or we will overheat (ignore the fact that the grill area is mainly used for the radiator).
C) Their is space (behind the grill area and infront of the radiator) to fit such a box, and you will make the box funnel into an air filter contected to the original air metering/measuring device.

Now I know a lot of cars might not fit such a thing... but would it be legal if your car could???

I think that we/you will find that some tech stewards feel that this is Ram Air and or goes beyond some part of the intent of the rules... we have debated this for a few years now and the only answer we get is it is up to interpretation.

The best thing to do is submit your desing to Topeka, however you will need to do that every year if you want to be sure that it is legal.

Raymond "Just cause one person says it is legal doesn't mean another one will" Blethen
 
Originally posted by RSTPerformance:

I think that we/you will find that some tech stewards feel that this is Ram Air and or goes beyond some part of the intent of the rules...
Click to expand...

again raymond ram air has a speciic definition. if it is not outside the bodywork it is not "ram air" even if rams air.
dick
 
Originally posted by RSTPerformance:
... The best thing to do is submit your desing to Topeka, however you will need to do that every year if you want to be sure that it is legal. ...
Click to expand...

While it would be nice if this were the case, there's no provision in the rules for anyone in Topeka to establish a legal precedent. The best you could hope for from there is an opinion that might sway someone's opinion but, push come to shove, you are still at the mercy of the protest process.

A slightly more effective approach would be to have it protested, be found out of compliance, appeal it, and then have it found to be legal. Even THAT doesn't actually set a true precedent but it's a close as you're going to get.

K
 
I've seen more than one case of someone calling/writing Topeka for a ruling on an item and try to use that ruling in a protest only to find out that it wouldn't hold water.
I forgot how cautious I've got to be in choosing my words on this site. I flagrantly used the word "ducting" without taking in consideration the consequences of my words.
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.

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Chris Harris
ITC Honda Civic
 
My understanding of the rule justification for air boxes has been the same as Dick's - that you can do just about anything forward of the metering device as long as you collect air from the engine compartment or stock location. Most of the ones I have seen over the years have NOT been connected to or made part of the filter or tube.

Raymond, as to where the air can be taken, I think the intention of "engine compartment" (poorly defined in the Glossary - no surprise there) is behind the radiator. So your theoretical box would not be legal unless the car in stock trim took air from forward of the radiator. I have seen some 240Zs w/ air tubes extending through the radiator bulkhead and the filter right in the air flow. I guess there is some stock precedent for this.

Interestingly, although I don't do it, I think an argument could be made that air can be taken forward of the radiator in 2nd Gen. RX-7s. The stock air box is fed by a flat duct that extends along the top of the radiator, turns 90 degrees toward the front, and has what looks like a little "ram air" scoop!

As for establishing precedent, Knestis is right - there is no judicial precedent in SCCA. Every advisory ruling, protest outcome, and even COA opinion is authoritative only in the case at hand. I think that COA opinions should absolutely be binding precedent, should be catalogued, indexed, and searcheable. If you agree, write your Director.

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