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Tech / General EngineIs your car making a strange sound or won't start? Thinking of adding power with a new combination? Need other technical information or engine specific advice? Don't see another board for your problem? Post it here!
If there's something I hate it's fake air scoops, fake everything in fact... What's the point? I love American cars but the majority of them from the muscle car era and all the way up to the 90's have fake air scoops, what the heck, may as well inject saline into your biceps and walk around pretending you're strong. The thing is, I've always wanted this car specifically because I like the way the induction hood looks, I know that back in the early 80s (82-84?) the Trans-ams had an HO engine that actually had a functional hood scoop but my under 20k mile 1990 formula of course had the usual blank off plate fake nonsense... So what to do?
From a distance it looks okay, but up close it's pretty obvious that it's just a cheap and useless shadow of a former feature that this car never had (nice from far, but far from nice!). Enough, I had to make a plan! I started to look at photos of engine bays online and to my surprise it looked as if it would take little to no fabrication to get this cold air setup to fit on my weaksauce 305 TBI, here's a picture of my engine bay:
And here's a picture of a random internet search showing a functional induction hood setup:
To my eye it looks like if I could just get a hold of the air cleaner and the hood scoop bits I could just bolt it right in, so I went on ebay and spent a stupid amount of money buying an old but complete set:
Sooo, yeah, $440 for a gross old box of rusty bits, but it was all there!
I started by mocking things up, turns out the the air cleaner housings are almost identical! (the original cowl induction one has a slightly different vacuum tube setup since the older engines were more primitive) so why replace the whole thing I thought, let's see if the lid fits... and sure enough, the lid fits with absolutely no modification other than having to use a nut as a large washer to fasten the wingnut down... Awesome, let's clean it up! (I will be at some point giving it a proper sand blast and re-paint, but I'm too excited to wait):
A bit of wire wheel later and some header paint (high heat) and it looks way better!:
More importantly I can actually make out the directions on how to mount this properly, it has marks to tell you where the snorkel of the air cleaner should be in relation to the lid (I couldn't see this before because of all the surface rust and flaky paint):
Next I had to make sure the rubber grommet was still okay and to my surprise it was actually fine! A bit of a clean up using armourall protectant and it was shiny and looking like good healthy rubber!
Next step, remove that lame blanking plate from the hood, easy enough.. four bolts, I took the ebay hood scoop thing apart and first installed the chicken wire looking screen (only attach it by the two inner bolts, the two outer bolts attach the actual hood scoop unit and also mount the drip tray)
Next of course was the whole hood scoop assembly (once I had cleaned it up and looked for cracks (no cracks surprisingly) and even more of a surprise is that all the mounting points and holes are actually still on this hood even though it was never meant to see a functioning scoop, so happy days it bolted right in!
Here you can see I have some test wires hooked up to the actuator motor and yes if I supply it with 12v the actuator opens the door, allowing that sweet sweet cold air to flow in... this could be a cool party trick at a later stage, I could install a switch to "activate induction" or some such nonsense, but to be honest, why would I want it to be closed anyway? I live in California, it's not like it snows or gets too cold or anything so I just ended up tastefully jamming it open with a discreet cable-tie.
with everything in place and the lid now on aligned as it should be according to the markings, I stuck a go-pro under the hood and slowly closed it to make sure that the rubber grommet was indeed sealing up and contacting where it should and again to my surprise it was! How is it possible that this conversion would be so easy? I've never had anything work out this way... Now time to test it:
I started it up in my garage and I could feel the air getting pulled into the scoop, I have a short video here:
Honestly I wasn't expecting much of a difference and I just wanted to do it so that I wasn't driving around with a fake scoop, but there is a significant difference in throttle response, it starts easier and it has a lot more pep! Also the sound is of course better as I can hear the induction when I have the windows down.... All in all the most reward with the least amount of work!
Not only does it look cool when sitting in the car, but I'd wager that I now have the only 1990 Firebird Formula with a full original and functional hood scoop! I know this would be a massive hassle on the formula 350, but if like me you have a 305 TBI, give it a shot, you won't regret it!
The screen should be black FWIW. The anodizing or whatever coloring fades in the elements, that's why the other surface of the screen is black. Kinda looks cool in bare aluminum, but OEM OCD bugged me every time I looked at mine before repainting it.
You can always get a vacuum operated switch and wire up the solenoid to kick on when vacuum drops (aka WOT). Biggest issue I'd worry about is the monster 70's tech solenoid deciding to burn down.
The screen should be black FWIW. The anodizing or whatever coloring fades in the elements, that's why the other surface of the screen is black. Kinda looks cool in bare aluminum, but OEM OCD bugged me every time I looked at mine before repainting it.
You can always get a vacuum operated switch and wire up the solenoid to kick on when vacuum drops (aka WOT). Biggest issue I'd worry about is the monster 70's tech solenoid deciding to burn down.
Nicely done!
I suspected as much! I'm pretty happy with the aluminium look but I may paint it black as it was intended in the future, the idea of a complicated way to make my engine breathe better rather than letting it breathe better all the time is not very appealing, I'll look into it if I find a need, but for now she breathes better and runs better and all round is better so I'm happy and can enjoy my beer better than before!
Nice job. So much the better that everything actually was bolt on. No fabricating involved.
Now why couldn't GM have done that?
I was honestly taken by surprise! I didn't expect any of this to fit but it worked perfectly, anyone with a **** 305 TBI like mine can get the old transam 305 HO hood scoop stuff and make it work! And it really does make a massive difference
Had this setup on my car when I bought it. PO had it all setup. Mine was wired to a switch. I changed to open air cleaner but left vented scoop. While the cold air setup looks cool and all I can assure you the open element draws in much more air.
A carb could be made faster than a stock TPI, but probably not while breathing through an 84 air cleaner. To each their own, but there's nothing sexier under a thirdgen hood than a TPI. Maybe if you shoehorn a LT5 or MPFI BBC...
Think thats totally cool woulda done the same myself. Best part is it looks factory....that fake scoop stuff irks me also but probably for liabilty reasons they didnt. Some idiot would run a hose in it and turn in a warranty claim for an engine. lol
Cool air may not make a huge difference but why not if its there in front of you!
There's a historical event known as "the Robo-Wash incident". Specifically the functional hoods in 82 ran into problems the first time someone drove thru an aggressive drive-thru car wash. The supposed fix was to add drains and baffles, with mixed results. By the time someone thought to bring back the Formula hood for 87, the functional idea probably met with strong disdain from the bean counters that had to clean up the earlier mess. The cool of a functional hood was trumped by the lame of a CFI 305 full of soapy water.
I just bought one of these induction setups for the 4 bbl version and after inspection, it looks like the air door never completely seals due to the depression on the bottom to the rain vent. So much for cold starts!
I just bought one of these induction setups for the 4 bbl version and after inspection, it looks like the air door never completely seals due to the depression on the bottom to the rain vent. So much for cold starts!
Im looking for the rubber seal that goes between the hood unit and the air cleaner lid. Who has ideas for what I can use?
If there's something I hate it's fake air scoops, fake everything in fact... What's the point? I love American cars but the majority of them from the muscle car era and all the way up to the 90's have fake air scoops, what the heck, may as well inject saline into your biceps and walk around pretending you're strong. The thing is, I've always wanted this car specifically because I like the way the induction hood looks, I know that back in the early 80s (82-84?) the Trans-ams had an HO engine that actually had a functional hood scoop but my under 20k mile 1990 formula of course had the usual blank off plate fake nonsense... So what to do?
From a distance it looks okay, but up close it's pretty obvious that it's just a cheap and useless shadow of a former feature that this car never had (nice from far, but far from nice!). Enough, I had to make a plan! I started to look at photos of engine bays online and to my surprise it looked as if it would take little to no fabrication to get this cold air setup to fit on my weaksauce 305 TBI, here's a picture of my engine bay:
And here's a picture of a random internet search showing a functional induction hood setup:
To my eye it looks like if I could just get a hold of the air cleaner and the hood scoop bits I could just bolt it right in, so I went on ebay and spent a stupid amount of money buying an old but complete set:
Sooo, yeah, $440 for a gross old box of rusty bits, but it was all there!
I started by mocking things up, turns out the the air cleaner housings are almost identical! (the original cowl induction one has a slightly different vacuum tube setup since the older engines were more primitive) so why replace the whole thing I thought, let's see if the lid fits... and sure enough, the lid fits with absolutely no modification other than having to use a nut as a large washer to fasten the wingnut down... Awesome, let's clean it up! (I will be at some point giving it a proper sand blast and re-paint, but I'm too excited to wait):
A bit of wire wheel later and some header paint (high heat) and it looks way better!:
More importantly I can actually make out the directions on how to mount this properly, it has marks to tell you where the snorkel of the air cleaner should be in relation to the lid (I couldn't see this before because of all the surface rust and flaky paint):
Next I had to make sure the rubber grommet was still okay and to my surprise it was actually fine! A bit of a clean up using armourall protectant and it was shiny and looking like good healthy rubber!
Next step, remove that lame blanking plate from the hood, easy enough.. four bolts, I took the ebay hood scoop thing apart and first installed the chicken wire looking screen (only attach it by the two inner bolts, the two outer bolts attach the actual hood scoop unit and also mount the drip tray)
Next of course was the whole hood scoop assembly (once I had cleaned it up and looked for cracks (no cracks surprisingly) and even more of a surprise is that all the mounting points and holes are actually still on this hood even though it was never meant to see a functioning scoop, so happy days it bolted right in!
Here you can see I have some test wires hooked up to the actuator motor and yes if I supply it with 12v the actuator opens the door, allowing that sweet sweet cold air to flow in... this could be a cool party trick at a later stage, I could install a switch to "activate induction" or some such nonsense, but to be honest, why would I want it to be closed anyway? I live in California, it's not like it snows or gets too cold or anything so I just ended up tastefully jamming it open with a discreet cable-tie.
with everything in place and the lid now on aligned as it should be according to the markings, I stuck a go-pro under the hood and slowly closed it to make sure that the rubber grommet was indeed sealing up and contacting where it should and again to my surprise it was! How is it possible that this conversion would be so easy? I've never had anything work out this way... Now time to test it:
I started it up in my garage and I could feel the air getting pulled into the scoop, I have a short video here: https://youtu.be/QBSF3Ar70_M
Honestly I wasn't expecting much of a difference and I just wanted to do it so that I wasn't driving around with a fake scoop, but there is a significant difference in throttle response, it starts easier and it has a lot more pep! Also the sound is of course better as I can hear the induction when I have the windows down.... All in all the most reward with the least amount of work!
Not only does it look cool when sitting in the car, but I'd wager that I now have the only 1990 Firebird Formula with a full original and functional hood scoop! I know this would be a massive hassle on the formula 350, but if like me you have a 305 TBI, give it a shot, you won't regret it!
Im looking for the rubber seal that goes between the hood unit and the air cleaner lid. Can you suggest something? Or advise me on a good replacement? Your video inspired me to do the mod on my own car. As you know, parts are kind of rare or worn out. Thanks!
Im looking for the rubber seal that goes between the hood unit and the air cleaner lid. Can you suggest something? Or advise me on a good replacement? Your video inspired me to do the mod on my own car. As you know, parts are kind of rare or worn out. Thanks!
If you can't find one on Ebay I'd say it's actually pretty easy to just make one using any sort of rubber gasket, look around the house or look at other similar applications, all it needs to do is create that seal, I can get some measurements for you but honestly you could probably even do something like get a trunk weather seal, cut it up and glue it onto the lid of the air cleaner, it's not complicated, as long as it give a seal.
If you can't find one on Ebay I'd say it's actually pretty easy to just make one using any sort of rubber gasket, look around the house or look at other similar applications, all it needs to do is create that seal, I can get some measurements for you but honestly you could probably even do something like get a trunk weather seal, cut it up and glue it onto the lid of the air cleaner, it's not complicated, as long as it give a seal.
Winston I solved that issue. I used a rubberized flexible toilet gasket, yes that's right. I also had to hand fabricate the air cleaner cover because I just could not find it anywhere, Here are some photos of my set up. The cap and gasket were adhered together with Gorilla glue brand heavy duty construction adhesive. Our cars are not "Worthless whips", cheers! TBI lid cut for air flow. TBI lid refinished. Cap for the air cleaner before the circular hole was cut for the gasket. Air cleaner cover finished with gasket installed. Installed 100% functional!
02-16-2020, 02:56 PM
When a hood is popped open, I expect to see an air cleaner. 
