I'm not sure if this is the right forum for this or not but it seems to make sense that it go here. Here's the debate:

Some friends and I were discussing cold air intakes and actual access to a cold air source. I recently installed an '84 T/A hood but do not have the "flapper" that came with it that opens with some vacuum pressure to allow air into the duct and to the engine.

The debate started when one gent claimed that the formy hood was cosmetic only due to the fact that the air opening was too far away from the base of the windshield to be much use. In other words, air does not get into the engine through the vent like it should because the design does not faciliatate that flow of air. The opening is too far away from the low pressure area near the windshield to be effective (maybe).

Does anybody have any data on this? Click here: Picture for reference.

Regardless, I like the look of the hood over my LO3 (obviously not focusing on performance) and if anything, I am actively venting hot air off the engine through this hole. I'm still curious about this for you formy/TA guys.

as far as I know this occured when the hood was ditched after 1984 and re-appeared in 1987 on the Formula. I don't think I've ever seen a formula hood functional even on LG4 cars (where as the T/A hood 83-84 WAS functional with an LG4). Can someone confirm?

It's my understanding the shaker hood on the 2nd Gen T/A's were not useful because htey were too far away fomr the base of the windshield to be functional. Then, they closed off the plates and were totally cosmetic.

The early 3rd gen's were functional. They had solenoids connected to the engines for the Trans Am's to open them up at full throttle, regardless of G,H or X engines.. (L69 305, LG4 305 or Cross Fire fuel injected 305)

I thought the later formulas were TPI engines with the air intakes up front- making the hood's opening useless.

Cadillac- I have extra hood "flapper" units if you're interested. Let me know.

I have seen maybe two of these setups over the last few years. Basically they were both on trans am l69 cars. The first setup I saw was very neglected and the plastic housing for the hood was broken so I left it where it was. The second I saw a month ago and I managed to snag the air cleaner lid with hood seal, but the rest of it was trash and broken. Now that I think about it I will probably never use this item but just bought it for novelties sake. If you are trying to piece one together I will let the air cleaner go for what I paid for it.
-SmallTires

The L69 engine codes were "7" in 1983, "G" 1984-1986, The LG4 was always "H" in thirdgens, and the LU5 CFI 305 was a "7" in 1982, and "S" in 1983....just to let ya know. There was no "X".

:-)

On my 91 I removed the blanking plate and replaced it with the chicken wire mesh one from an earlier car where it worked.

Its not for air in, but it helps get air out.

later
Jeremy

That's mighty nice of you and I am interested! I'm a tad curious about how I rig that up to my LO3 though.

So far I think this thread hasn't really answered the question. Maybe the only way to really answer the question is with a wind tunnel and not many folks have that handy. The odds of seeing data like that from the 80's are nil too. Fun to talk about though...

it basically gives the motor an extra inlet to suck in air. you would need to valve thingy that go's on the hood and the air cleaner assembly w/ lid. works like the old cowl induction set up.

Hum, a couple of days ago, I saw a dual snorkel air box with a rubber seal off-set in the lid in a TA or Firebird. Is this apart of the set-up?

JamesC

84L69TA- thank you for the corrections. My apologies to everyone for quoting wrong info.

Cadillac- Let me get you some pics. they're up in my rafters so I have to get them down, etc..

I don't know if you're aware of this site- but I found this and it may be of help to you:

http://www.goingfaster.com/spo/cold_...r_the_l03.html

Note that I only have the upper part that bolts to the hood. (the part you referred to as flapper)

The factory air breather had a hole (with rubber seal) in it to accept this and I don't have one of those. I see them regularly on ebay, though. there's also a rain/ water catch that bolts to the hood. I don't have extras of those either. It's helpful for keeping water off the engine.

Thanks,

-BV

The dual snorkel that I speak of above had this lid? Possible? Or would the Camaro dual snorkel even fit under the hood?

JamesC

If you have a TPI Formula with the hood bulge cover removed, hold your hand by the opening for a minute or two after driving.

You will see that is helps by venting quite a bit of heat. I ran mine open for years with no problem.

Here's the setup on ebay right now...

http://cgi.ebay.com/ebaymotors/Trans...QQcmdZViewItem

Thanks again, BV.

I'm not 100 percent into doing this other than to protect the the engine in the rainy season. Like 'formula8!!' mentioned, I can see a lot of heat escaping from this opening in the hood when I drive around the city. I can figure a way to cork the opening in the winter in San Francisco and get by but having the original hardware would be cool.

You've got a PM.

~C

I had both setups, one for a Crossfire Injection car, and one for a carbed car. Sold both of them on Ebay recently. Right now my cowl is open, but it was originally a Crossfire car anyway. I don't think the engineers would go through all the trouble to produce the parts if they didn't work. Eventhough the cowl is in the back, that is how all the 2nd gen's were also...

If I could ever find a complete CFI setup I would put it back on...however some have shown that dual open elements gives the engine a little power than through the cowl induction unit, even if the air is hotter just due to more air breathability.

I'm sorry, I read through all of this and I still don't know exactly what's being asked?

The location of the opening in the hood is fine, for air going in or going out. When its connected to a carb or TBI it'll suck air through the hood a lot easier then the necked down horn on the stock aircleaner. When it's left open as is popular with TPI Formula's the air coming up from under the car will push heat and fumes out of the opening thereby lowering underhood temps.

The CFI and Carb setups are completely different, they share design theory and some parts but overall they're different. The CFI setup is pretty much useless for anything except a CFI car since its got a diamond shaped outlet on the bottom of the hood that wouldn't mate up with an aircleaner without a lot of trouble. The Carb setup however would hook up to a TBI or carbed formula with minimal fabrication and would be a huge step up from the stock aircleaner.

The Gateway to all that is Black Echo link is a riot. That toolbag was on here for years day dreaming about this and that, mostly about making TBI cars fast. When it was all said and done all he did was post rediculously long rants. I don't remember him ever even posting a time slip.

FWIW with a TPI formula there isn't much reason to try to make the hood functional. It would require a bunch of fabrication and wouldn't be any better then a cold air intake. I've run mine open, or with a fabricated screen, and finally with a factory screen since 1999 in all kinds of South Dakota weather with zero problems. I've got a factory block off plate, but its never touched the car. It was gone when I got it and I've never felt the need to install it.

Also, that setup on ebay is missing all the wiring, the solenoid, the solenoid clamp, the vacuum operated actuator, aircleaner, etc. If anyone is putting a setup together I've got a carbed aircleaner lid with the offset hole and rubber seal along with the stock lower aircleaner and ducting with snorkle. $50 +shipping

heres the air cleaner setup

top of the lid


bottom of the lid

Thanks Drew. Outside of seeing a wind tunnel test showing a stream of smoke going directly into the engine through the cowl opening this is the response I was fishing for.

Want to sell that block off plate? Is it still around?

Cheers!

I've still got it but I plan to hold onto it. It's just a thin sheet metal plate cut to the shape of the opening with mounting tabs across the bottom. I think it might even still be available from the dealership, it was the last time I checked (couple years ago)

I'll look into that but am not holding my breathe it will be available still.

Thanks again.

~Caddy

Pls post part num if you find out...

Classic Industries listed the block off panel in the Firebird catalog as recent as 1999 or 2000. It's funny cause they list 82-84 Trans Am with one part number, then they listed 87-92 Formula with the same part number right below.

Classic Industries listed the block off panel in the Firebird catalog as recent as 1999 or 2000. It's funny cause they list 82-84 Trans Am with one part number, then they listed 87-92 Formula with the same part number right below.

Dragging this one out of the depths...

It's been raining lately in the Bay Area and now I know for a fact that air is being forced into the engine bay through the cowl. I know this because I can see water being forced into the engine bay when I am at speed! I guess that is the closest thing to a wind tunnel my hood will see.

Anyway, I still haven't been able to locate the block off panel but I really haven't looked real hard for it either. At this point I need it though. I'll come back if I find it or would appreciate any clues if you guys know part numbers.

I have the block off plate...I removed it from my hood because it needs to be painted. But, I now like having the scoop open, as I believe it helps keep the engine bay a bit cooler, and I don't mind a little water getting in there.

I found 2 part numbers

COVER, Hood Orna (Exc Turbo) 10024254
COVER, Hood Orna (W/Turbo) 10023479

Mind you this is from my '82-'83 Parts catalog, so I don't know if GM changed part numbers over the years or what. They might be able to cross reference the numbers if they were changed.

I'm guessing that the number w/turbo is for the screen, while, the one excluding the turbo is the block off plate. Also, I am not positive if you could get the "Turbo" hood without the hood induction in '82-'83. I know you could only get the Turbo hood with the TA. Regardless there are 2 numbers for the hood cowl plate so I am guessing one is the screen and one is the blockoff plate.

Hope this helps.

Awesome. Using those parts numbers and Google, I located this site:

Puritan Pontiac-Gmc/NEW GM PARTS

I have the block plate coming from there for 30 bucks. Sure I could have fabbed something (I already did with plastic sheet) but I'll feel better about this.

Thanks!

I have this on my 82 trans am which now has a TBI motor. to make it functional all the time simply pull the flapper out then cut the ends off the flapper and silicone them back into the bushings where they were to seal those holes.

as for rain issues the factory put several good points for water to drain out and not get into the motor. If I can run my car through a car wash and the motor never dies the drains work

OK, here is my .02. The Formula hood is functional not because the ram air effect but because it is a less restrictive air flow path. In fact most hood scoops (factory installed anyway) are more of a "suck air" set up than ram air because the scoops are too low. The scoops either need to be forward on the hood or about 6" high to get out of the boundry layer of air clinging to the sheetmetal. That is not to say that these set ups are not effective, but they are effective because they allow the engine to draw in cool air in a "straight shot" with out snaking around the engine bay.

On a side note the 2nd gen TA shaker hood was never designed to be in the high pressure area of the cowl, it is too far foward. It was put there to homolgate the hood with a hole in it for racing. The race teams wanted to run a high rise intake, but did not have hood clearance and the rules at the time would not allow them to cut the hood. The shaker hood from 70 - 72 was functional with a flapper door which opened at WOT, allowing the engine to draw in cool air directly into the air cleaner rather than the heated air from the snorkles under the hood. The shaker was sealed in 73 due to drive by noise restrictions, not because it was not effective.

this is a Longshot but do you still have the hood flappers?

I saw one of those on ebay awhile back after watching a cool youtube video of a guy who converted a later formula hood to functional. Its still available

https://www.ebay.com/itm/Firebird-82...-/254447225409

I have the hood parts for the CFI and a carb setup. One of them has a broken mount for the electrical

I'm such a sucker for stuff like that.

Same here, it’s fun to check eBay over for old parts. Also If I had a car with that style hood I would try that mod.

I've had a few bits of both the carbed and CFI setup laying around over the years. In all cases, I couldn't see any way to make it worth the trouble with TPI, and I couldn't see that it'd flow enough air to really be worth the trouble on a carbed or TBI setup that it'd work well with. There are always easier and more efficient ways of getting more air into the engine, albeit less golly gee whiz bang gimmicky ways.