BB hood fresh air induction
#1
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BB hood fresh air induction
.com/user/Bluestripe67/media/DSCN3676_zps6b089fb5.jpg.html][/URL]
I know some of you guys have talked about making the BB hood functional. Since I have mastered the photo thing here on the CF, here are the shots of what I made for my car and the details. SB w/Edelbrock Performer intake, Edelbrock 625CFM carb, dropped base air filter, 3" filter, and standard GM distributor/cap/wires. The hood is a GM issued replacement. Look at the shot of the backside of it and you can see the specific ribbing/reinforcements around the perimeter. I removed the three ribs at the back side (see the yellow tape markers) so the air would have a smooth entry path. I do not know about modifying a production hood. I guess you can do the same cut, but you will have to close the open ends, no big deal. First effort I mocked the unit up with cardboard to get height numbers (used modeling clay) for hood clearance. Second effort I got some scrap sheet metal and did the mockup and finally with all the specs and fit just right I took it to a sheet metal fabricator for the final that you see in the engine shot. The foam was bought at the Army/Navy surplus store and cut to fit. This fresh air induction made a big difference in performance and drivability. You will need to re-jet your carb due to the nice cooler air coming in. Dennis
I know some of you guys have talked about making the BB hood functional. Since I have mastered the photo thing here on the CF, here are the shots of what I made for my car and the details. SB w/Edelbrock Performer intake, Edelbrock 625CFM carb, dropped base air filter, 3" filter, and standard GM distributor/cap/wires. The hood is a GM issued replacement. Look at the shot of the backside of it and you can see the specific ribbing/reinforcements around the perimeter. I removed the three ribs at the back side (see the yellow tape markers) so the air would have a smooth entry path. I do not know about modifying a production hood. I guess you can do the same cut, but you will have to close the open ends, no big deal. First effort I mocked the unit up with cardboard to get height numbers (used modeling clay) for hood clearance. Second effort I got some scrap sheet metal and did the mockup and finally with all the specs and fit just right I took it to a sheet metal fabricator for the final that you see in the engine shot. The foam was bought at the Army/Navy surplus store and cut to fit. This fresh air induction made a big difference in performance and drivability. You will need to re-jet your carb due to the nice cooler air coming in. Dennis
#2
Melting Slicks
Or you could bond in the L88 airbox from Ecklers like GM did for cowl induction back in the day:
http://www.ecklerscorvette.com/corve...hood-1967.html
You would also need the L88 air cleaner base setup (below on my 69) which means your air filter goes up inside the airbox.
http://www.ecklerscorvette.com/corve...hood-1967.html
You would also need the L88 air cleaner base setup (below on my 69) which means your air filter goes up inside the airbox.
Last edited by Marks69BB; 05-12-2013 at 01:44 PM.
#3
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Marks69BB, your installation deals with factory components where mine are aftermarket integrated parts resulting in the custom build. The principal of function and results remains the same...free HP. Dennis
#4
Le Mans Master
So you can't use it with the ignition shield?
It doesn't look like you could squeeze a whole lot of air through that small area above the cowl in the back. And of course you recognize that a factory BB hood is nothing like that on the underside.
It doesn't look like you could squeeze a whole lot of air through that small area above the cowl in the back. And of course you recognize that a factory BB hood is nothing like that on the underside.
Last edited by toddalin; 05-12-2013 at 02:47 PM.
#5
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toddalin, I stated the difference in hoods in my OP. True...you can't use it with shielding! I have no way of knowing the CFM flow from the opening. I can tell you that it must be enough. It made a very noticeable difference in low end torque because when I went to the track (previous runs 13.5, 13.6) a second time I couldn't get the tires too hook through 1st into 2nd and turned 14.1, 14.3. That proved my point of free HP/TQ from the fresh air induction. Dennis
Last edited by Bluestripe67; 05-12-2013 at 02:58 PM.
#6
Melting Slicks
Dennis: I agree this is all factory stuff; just another option for those who have original 67 BB hoods but the airbox could be integrated into any aftermarket hood with some fab work to get the benefit of cowl air induction. It made a huge difference on my 69 with the 555!
Here's a pic of a real 67 L88 hood compliments of an older JohnZ post:
Before bonding in the airbox, the stock BB hood whould have to be cut out above the rear support for cold air cowl induction.
Before bonding in the airbox, the stock BB hood whould have to be cut out above the rear support for cold air cowl induction.
#7
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That's a great shot of an orig. BB/L-88 hood. Is it fun playing with these cars or what? Dennis
#10
Burning Brakes
My 63 had a BB hood with the front cut out to allow air flow.It was OK , but not totally functional. Has the car painted last year so I bought a new BB hood. I found a part in Ecklers cat, called " fresh air induction". It has to be molded to the under side of the of the hood and it fits pretty tight around the air cleaner. It looks great and works great. If I ever figure out how to take pictures, I'll post a few.
#11
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If I ever figure out how to take pictures, I'll post a few.[/QUOTE]
Ren, Go to the latest post up top in the stickies section about posting pics. Thats how I learned and succeeded on this post. Trick was using the tutorial on my laptop beside the desktop PC. Dennis
Ren, Go to the latest post up top in the stickies section about posting pics. Thats how I learned and succeeded on this post. Trick was using the tutorial on my laptop beside the desktop PC. Dennis
#12
Le Mans Master
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you can't just slide the air box back.
Last edited by magicv8; 05-13-2013 at 03:10 PM.
#14
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of the rubber A-C hood seal, when the hood is down. The screen is needed to minimize incoming
bugs. No holes were drilled to mount the aluminum panels. It made an incredible difference, since
the heat coming from the A-C unit in front of the radiator was no longer entering the carburetor.
Last edited by magicv8; 05-14-2013 at 11:38 AM.
#16
Safety Car
The screened hole at the front of the center aluminum panel is in the high pressure area in front
of the rubber A-C hood seal, when the hood is down. The screen is needed to minimize incoming
bugs. No holes were drilled to mount the aluminum panels. It made an incredible difference, since
the heat coming from the A-C unit in front of the radiator was no longer entering the carburetor.
of the rubber A-C hood seal, when the hood is down. The screen is needed to minimize incoming
bugs. No holes were drilled to mount the aluminum panels. It made an incredible difference, since
the heat coming from the A-C unit in front of the radiator was no longer entering the carburetor.
I'm not smart enough to follow what you did, though.
#17
Safety Car
My 63 had a BB hood with the front cut out to allow air flow.It was OK , but not totally functional. Has the car painted last year so I bought a new BB hood. I found a part in Ecklers cat, called " fresh air induction". It has to be molded to the under side of the of the hood and it fits pretty tight around the air cleaner. It looks great and works great. If I ever figure out how to take pictures, I'll post a few.
#18
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The steel rain shields for the hood grilles were exchanged for aluminum pieces that also let cold air in to the air cleaner.
Cardboard templates were cheap and the aluminum was bent on the edge of my work bench.
Last edited by magicv8; 05-14-2013 at 11:52 AM.
#19
Race Director
can also remove the rubber flaps over the A frames and plumb cold air there(inside the wheel well).. not so good on dirt roads or in a downpour making sharp turns imo.
#20
Safety Car
I made a cardboard template, then took a piece of sheet aluminum and bent a double step in it to step over the hood frame. At the front of the hood is a hole to let cold air get in. The A-C hood seal hits the aluminum just in back of the hole when the hood is down. At the other end the cold air comes out of the 3 inch gap between the aluminum and the hood, right in front of the air cleaner.
The steel rain shields for the hood grilles were exchanged for aluminum pieces that also let cold air in to the air cleaner.
Cardboard templates were cheap and the aluminum was bent on the edge of my work bench.
The steel rain shields for the hood grilles were exchanged for aluminum pieces that also let cold air in to the air cleaner.
Cardboard templates were cheap and the aluminum was bent on the edge of my work bench.
The hole in the front of the hood sounds good. Like a modern Z06.
I'll keep that scheme in mind.