Air Dam & Splitter attachment Points & COA [Archive]

tom91ita

07-21-2009, 11:43 AM

I could note find your quote. What I did find was the statement that the design wa illegal because he had unducted openings.

What did I miss? :shrug:

my quote was from the last sentence of the facts in brief portion.

Greg,

I think it is interesting that within the description of the air dam / spoiler / splitter they say that the following;

Multiple components may be joined to create an air dam, whose shape is unrestricted - thus allowing a “splitter” lip which must not protrude beyond the body when viewed from above.

if the shape is "unrestricted" why can't there be openings?

i do not have this device on my car but the one i had started making was going to be supported by more than the front cross-member and front tie-down clips. and now i am wondering about the comments regarding attachment to the body OR bumper cover in the decision section;

The panel must be attached to the body or bumper cover (if the car is so equipped)

Xian

07-21-2009, 11:47 AM

I could note find your quote. What I did find was the statement that the design wa illegal because he had unducted openings.

What did I miss? :shrug:

It's there... right above "Decision" and toward the bottom:

Mr. Moser’s design incorporates unducted openings, and is therefore non-compliant.

Just a guess here but I'm betting that he designed something with an "unducted opening" that could have fed air to the area where there used to be a Cold Air Intake. It'd be easy enough to make a legal airbox above the hole in the unibody that leads down to the fender area... the fender area would be enclosed by the fender liner and fed by the opening. Definitely a good idea but still not legal.

Christian

Greg Amy

07-21-2009, 11:58 AM

if the shape is "unrestricted" why can't there be openings?
At the risk of sound flippant - I don't mean to - there can't be openings because they're specifically disallowed.

If your question is, "why does the rule disallow openings" I can't offer the specific reason, but I suggest it's to eliminate the possibility of someone fabricating a wing and hanging it off the car. Allow airflow under, around, and through an airdam and I can guaran-damn-tee a wing will be made (easily.) Look at the intorturation of the original airdam that got us splitters!

...was going to be supported by more than the front cross-member and front tie-down clips. and now i am wondering about the comments regarding attachment to the body OR bumper cover in the decision section.

Well, I'm as guilty as anyone on this; the rules specifically state the airdam shall be mounted to the "body". I think a lot of us - myself included - glossed over this and used attachments to the crossmember, engine clips, etc - and we're wrong.

GA

tom91ita

07-21-2009, 12:15 PM

i don't think we are guilty of the attachment methods since their use of "or" does not appear to be correct. per the GCR it does not say "shall" but "may"

the front spoiler or airdam may be attached to the bumper cover[/qutoe]

however, now i am wondering about laying the plywood on the ground and taping a marker to a rod and drawing the outline. is that the "body" or the "bumper" as noted below?

[quote]
A front spoiler/air dam is permitted. It shall not protrude beyond the overall outline of the body when viewed from above perpendicular to the ground, or aft of the forward most part of the front fender opening. This body outline does not include bumpers or bumper mounts. The spoiler/air dam shall be mounted to the body, and may extend no higher than four (4) inches above the horizontal centerline of the front wheel hubs. It shall not cover the normal grille opening(s) at the front of the car. Openings are permitted for the purposes of ducting air to the brakes, cooler, and radiator. Dealer installed or limited production front/rear spoilers/air dams/wings are prohibited. The spoiler shall have no support or reinforcement extending aft of the forward most part of the front fender wheel opening.
NOTE: Integrated bumper assemblies are defined as those designs where an external non-metallic bumper cover completely encloses the primary energy-absorbing bumper and where this cover could be installed in its normal position with the underlying bumper removed. On cars with integrated bumpers, the front spoiler or airdam may be attached to the bumper cover.
Where an air dam/spoiler is used, two total openings may be cut in the front valance to allow the passage of up to a three (3) inch diameter duct leading to each front brake/rotor assembly.

spnkzss

07-21-2009, 12:16 PM

Well, I'm as guilty as anyone on this; the rules specifically state the airdam shall be mounted to the "body". I think a lot of us - myself included - glossed over this and used attachments to the crossmember, engine clips, etc - and we're wrong.

GA

I'm glad I DIDN'T buy those fancy brackets and mounted it directly to my bumper cover. ;)

Greg Amy

07-21-2009, 12:23 PM

per the GCR it does not say "shall" but "may"
Tom, I think you're cherry-picking. Copying from your quote above, here are the important bits:

...The spoiler/air dam shall be mounted to the body...On cars with integrated bumpers, the front spoiler or airdam may be attached to the bumper cover.

Bottom line, nothing in there allows attachment of the airdam to anything other than the body or the integrated bumper cover.

is that the "body" or the "bumper" as noted below?Integrated bumpers are included in the "outline" and vertical viewing. - GA

tom91ita

07-21-2009, 12:34 PM

if i get my air dam done, it will be mounted most likely like everyone elses. it would be interesting to do a straw poll at the IT fest and see how we have been doing this.

my immediate goals are annual tech of my car and a head gasket in my daughter's daily driver.

JLawton

07-21-2009, 01:17 PM

Maybe Andy B can give us some advice on attaching air dams??

(he, he, he)

.

JeffYoung

07-21-2009, 02:59 PM

I'm not the quickest when it comes to rule interpretation, but is anyone else reading this to say you can cut holes in your splitter to duct air to the RADIATOR?? The decision specifically mentions brake ducts and oil coolers, but what about an opening between the attachment points in the bumper cover and the "vertical plane" for radiator air?

Or is it saying ALL air must be ducted so that none of it spills over into the engine compartment?

tom91ita

07-21-2009, 03:02 PM

radiator is Prego (its in there).

i did an edit to highlight in the section from the GCR up above.

JeffYoung

07-21-2009, 03:09 PM

Thanks Tom...so next question, does the ducting have to be "air tight" so that no air spills into the engine compartment? That's what I am reading the decision to mean.

I've got my air filter in a different location so that the air that misses the radiator is not getting to it, but I certainly don't have air tight ducts to the radiator/oil cooler...the opening in the spoiler/splitter just fart in their general direction......

tom91ita

07-21-2009, 03:33 PM

i think i better understand your question.

my intention was to add a plywood "splitter" using the bumper/cover as my outline and attach that to the factory tie-down points with maybe a vertical rod or two from the front bumper.

then bridge the gap from the factory body work to the plywood with some thin aluminum (4" gutter). i was not doing anythng higher up than that.

Andy Bettencourt

07-21-2009, 03:46 PM

Maybe Andy B can give us some advice on attaching air dams??

(he, he, he)

.

That's why they blow up dude! Just attached to the bumper cover. The poblem with the ones I run (ran) is that when you go off, there is no flexibility. New and simpler design coming soon.

quadzjr

07-21-2009, 05:19 PM

The poblem with the ones I run (ran) is that when you go off, there is no flexibility. New and simpler design coming soon.

Problem solved... don't go off:D

Care to clue us in on what is the basis for your better more flexible yet efficent design?

shwah

07-21-2009, 05:39 PM

Mine just bent the heck up when I went off. Downside being that one side was right at, middle 1/2" over and the other side 1/4" under legal height afterwards. I'm waffling on making a stronger one that won't deform, or a weaker one that will deform but bounce back - leaning towards the latter.

I never considered extra openings for radiator flow, but also never considered not fully ducting the radiator so that all the air has to go through it. This made a bigger improvement in cooling than any other single thing on my car.

tom_sprecher

07-21-2009, 05:53 PM

...the opening in the spoiler/splitter just fart in their general direction......

I've been contemplating using this fart technology you speak of. How big of a fart and how close dare you be to the orifice?

Yes, I am serious. The stock radiator ducting had some pretty good size holes in it and I wanted to relocate my air filter closer to those holes, and when I say closer I mean hover right beside and over them.

Is that not legal?

seckerich

07-21-2009, 07:23 PM

Actually this ruling specifically allowed the attachment points to the body. Anything above the floor pan licked by the airstream is fair game. If it is on the outside of the car it gets licked.:D The ruling was that the openings in the air dam were not used for legal purposes. The first ruling on the attachment points was just to get it to the COA for a definitive ruling. That was overturned and the attachment specifically defined as legal.

tderonne

07-21-2009, 10:48 PM

I'm confused on this ruling.

I've always read the airdam rule as allowing me to add as much or as little airdam as i want as long as I stayed inside the x,y,z, dimensions allowed.

If my car is 5' wide, and I put a 3' spoiler in the middle do I have 2 1' unducted openings at the sides? I don't think so. The ruling talks about a horizotal plane. If I have a splitter that has a "U" shape when viewed from underneath is the inside of the "U" an unducted opening? Again, I don't think so.

The rule is written kind of dumb. It basically allows any airdam. It then goes on to allow openings for DUCTING air to a couple things. They were already allowed under any airdam. I don't follow how they then starting talking about "unducted openings". Must my airdam also now be sealed to the bumper and/or body? Are those leaks unducted openings?

JeffYoung

07-21-2009, 10:59 PM

Tim, EXACTLY -- that is exactly my confusion as well. It seems to suggest you can only have an opening in the air dam if you use it to duct air to the radiator, oil cooler or brakes, and also seems to suggest that you have to have a perfect "seal" so that no unducted air gets to the engine compartment.

That's not right. But I'm pretty sure that is what it says.

I suspect Moser (the guy asking for the ruling) was using the splitter/air dam to duct air to his air intake and that is what the CoA was trying to prohibit, but the language they used went way too far.

Andy Bettencourt

07-21-2009, 11:58 PM

I think we need to see the pictures.

Z3_GoCar

07-22-2009, 01:32 AM

I'm considering making a good "airdam" for the Z3, along with several other parts. I'd love to see what's not legal on this airdam.

Greg Amy

07-22-2009, 07:03 AM

The rule is written kind of dumb.
If you read this in the context of its original design, that being the early 1980's, you'd understand how we evolved here. Do a search on this forum for "splitter" and "airdam" and you'll find a long discussion on its history, which may assist in understanding its spirit.

If, in today's context, it makes no sense, then design and recommend a re-write. But be aware: this forum can tear a rule to shreds in microseconds and leave your ego panting on the doorstep of reality...

dickita15

07-22-2009, 07:09 AM

But be aware: this forum can tear a rule to shreds in microseconds and leave your ego panting on the doorstep of reality...

And therein lays one of the greatest assets that this forum provides. Using a forum like this gives a far better chance of anticipating unintended consequences that any small committee, no matter how smart, can do.

Racerlinn

07-22-2009, 08:23 AM

My guess is that he was adding a conventional splitter as we all know it, but did not fully fill the front "gap" between the top of the splitter and the bottom of the stock bumper cover (what we would normally consider the extended air dam). So the splitter kind of just "hung" beneath the front bumper. And then perhaps some vanes or other items of some sort were added to the top of the splitter to direct air upward or towards a specific spot...

tderonne

07-22-2009, 08:52 AM

They should never had said openings are allowed.

Follow this logic:

If it doesn't say you can, you can't.

You CAN add an airdam, but it CAN'T go past x,y,z dimensions, and it CAN'T cover existing openings.

Saying that you CAN have openings doesn't follow the "if it says you can" premise. The only thing you can say after a CAN is CAN'T. If there is something that an airdam CAN'T do, it needs to be spelled out somehere. (There can be an illegal functions called out elsewhere too.)

It's like saying you can use any wheel, and you can use blue wheels. If they can't be red, it has to say that.

seckerich

07-22-2009, 09:03 AM

Actually the rule is pretty clear in use. It allows us to have an airdam/splitter that redirects air around/under the car. It is allowed to help performance by reducing drag,providing downforce on the front of the car. It is specifically allowed to have openings to not block stock grill opening and allows very detailed use of any air that passes through any other openings. Anything else is covered by allowed modifications performing a disallowed function.

Knestis

07-22-2009, 09:27 AM

Evidence of why we've never done an airdam of any kind on Pablo. I can NOT imagine one lasting 12 hours in the real world and the carnage would undoubtedly take out something else - PS belt (which is RIGHT there), cooling hose, brake line.)

Interesting info in the finding though...

K

Greg Amy

07-22-2009, 10:31 AM

I can NOT imagine one lasting 12 hours...
Try 45 minutes... :sadbanana:

http://lh4.ggpht.com/_ujKKwlok5l8/Rze8EbxLu1I/AAAAAAAAHh0/YZj5WRfGCsw/s720/DSC_1701.JPG

titanium

07-22-2009, 12:56 PM

Try 45 minutes... :sadbanana:

http://lh4.ggpht.com/_ujKKwlok5l8/Rze8EbxLu1I/AAAAAAAAHh0/YZj5WRfGCsw/s720/DSC_1701.JPG

Wow, you went so far off course you hit some guy fishing. I see the line from his pole caught up in your airdam.:D

rhygin

07-27-2009, 10:53 PM

Sorry Greg... thought the fishing comment was good enough that I almost shot beer out of my nose...

Is this the pic y'all have been fired up about? Looks like a 2007 pic. No comment as the pic is from a long way away and not sure if this is the car in question. is there a gap between the splitter and the engine bay....?

Xian

07-28-2009, 08:56 AM

From what I remember, the splitter/airdam on the car at that time didn't have the extra holes referenced in the appeal. I really think their intent was to find a way to duct outside, cool air into the air intake and gain back some of the advantage they lost (up until 08 they were running a cold-air intake that was ruled illegal at the 08 ARRC).

jimmyc

07-28-2009, 06:16 PM

from an aero stand point, that provides no advantage adds some drag and probably creates a ton of turbulence...

seckerich

07-28-2009, 09:23 PM

from an aero stand point, that provides no advantage adds some drag and probably creates a ton of turbulence...

You hold that thought.:rolleyes:

jimmyc

07-31-2009, 04:55 PM

You hold that thought.:rolleyes:

holding and waiting to hear a counter to it...

Z3_GoCar

07-31-2009, 07:55 PM

According to Simon McBeath, the generation of vorticies may act as a side skirt.

What I want to know is, since my bumper cover has a round under side, can I add dive planes as long as they're below the side profile and no further out that the side of the tire?

WRXRacer111

07-31-2009, 08:08 PM

http://www.flatout-motorsports.com/catalog/images/DSC00185.JPG

If that's legal... why not?:shrug:

Z3_GoCar

07-31-2009, 10:13 PM

Exactly:eclipsee_steering:

lateapex911

07-31-2009, 11:12 PM

seckerich

07-31-2009, 11:33 PM

holding and waiting to hear a counter to it...

Without going into a long drawn out explanation there is a reason we put our GA cars in a wind tunnel. There is also a very real reason we are limited on the size and overhang of our splitter lip. It is not because they are afraid we will create too much drag and disrupt airflow. Boundry layers and their height off the pavement are very real and have a big affect on drag. The air dam also allows you to better manage the air that enters/goes around the nose and its path. Small changes can alter the lift/downforce difference. But thats just my guess.:D

Andy Bettencourt

08-01-2009, 10:33 AM

But be careful, that one blows up! ;-)

jimmyc

08-01-2009, 01:33 PM

Without going into a long drawn out explanation there is a reason we put our GA cars in a wind tunnel. There is also a very real reason we are limited on the size and overhang of our splitter lip. It is not because they are afraid we will create too much drag and disrupt airflow. Boundry layers and their height off the pavement are very real and have a big affect on drag. The air dam also allows you to better manage the air that enters/goes around the nose and its path. Small changes can alter the lift/downforce difference. But thats just my guess.:D

Umm that was a FAIL on my point...

I was speaking directly too the spliter on the orange CRX and the angle it has along with the openings.

I agree with you on everything else.

It my understanding that something like a splitter doesn't actually create downforce, it simply (can) reduce drag and reduce lift.

Z3_GoCar

08-01-2009, 01:43 PM

I've thought about stuff like that (not for my own car) and wondered if the extra downforce needs to be balanced in the rear? I suppose it depends on how efficient the thing is, and I'd think that there would be some tradeoff vs drag.

That's a definate concern I have, I don't want to make my car any more aero-loose. With proper control of the air flow around and under I should be able to reduce some of the lift on the front and back.

rhygin

08-02-2009, 11:42 PM

A well planned splitter does a few things... namely reducing drag (dues to reduced turbulance under the car) and clear delineation of above and below air flow. A few minutes on google will outline the importance of the horizontally flat aea behind the leading edge of a splitter.

As I see the regulations... there are three challenges/specifics of importance... a) height... should be no lower than the rim in ITA, b) allowable horizontal plane... needs to map the trajectory of the front fender, c) attachement... not sure how to do a good splitter without something fairly ridig to which the unit will attach.

Used to have a GREAT set up for track days... but it ended up in the recycle bin since the racing problem started!