Vented L-88 hoods
Tech Contributor
Joined: Jun 2004
Posts: 20,910
Likes: 962
From: I tend to be leery of any guy who doesn't own a chainsaw or a handgun.
I've been contemplating doing that. Been working on some ideas to assist the airflow from the radiator up to the hood vent, but haven't got the saw out yet to cut open the hood.
There's a guy on another site (he might possibly be on here too) that has opened his up. It looks very nice visually too.
There's a guy on another site (he might possibly be on here too) that has opened his up. It looks very nice visually too.
Le Mans Master
Joined: Apr 2007
Posts: 7,353
Likes: 72
From: Graceland in a Not Correctly Restored Stingray
Taking a long look at opening mine up too, but before going from serious contemplation to commitment I wish to verify that there's sufficient pressure drop between the initial rise and primary bulge - not likely to happen any time soon seeing that my shark is in pieces awaiting additional funding. (Mike, I'm surprised you haven't already cracked that nut open yet.)
In any event, it might be worth noting that the area in question sits pretty much on top of the radiator, as well as that the main bulge that trails it also sits higher in the air stream. So, it could take more than simply opening up the rearward facing panel aft of the initial rise to create more than a rudimentary extractor, and the reason I'd prefer checking the differentials before breaking out any cutoff tools.
FWIW, the adaptation of a C7 extractor done on the Jimmy Johnson SEMA 'vette looks pretty dang good IMHO.
In any event, it might be worth noting that the area in question sits pretty much on top of the radiator, as well as that the main bulge that trails it also sits higher in the air stream. So, it could take more than simply opening up the rearward facing panel aft of the initial rise to create more than a rudimentary extractor, and the reason I'd prefer checking the differentials before breaking out any cutoff tools.
FWIW, the adaptation of a C7 extractor done on the Jimmy Johnson SEMA 'vette looks pretty dang good IMHO.
Melting Slicks
Joined: Dec 1999
Posts: 2,116
Likes: 156
From: Mid West
Cruise-In III Veteran
Melting Slicks
Joined: May 2002
Posts: 2,717
Likes: 121
From: Sulphur LA
St. Jude Donor '05-'06,'11,'13-'14,'16,'18,'19,'24, '25
I opened mine up,
My car is no show car and I had been fighting heating issues for a good while so I gave it a shot.
I don't have an L88 hood, I have a stock hood with an L88 scoop mounted on top.
I really didn't notice any change in my heating issues after opening it up but can say that I tried many things to resolve my heating issue and none worked until I added the oil cooler so I can't say one way or the other if the L88 hood venting will help with cooling, it is sound physics and should work.
Neal
My car is no show car and I had been fighting heating issues for a good while so I gave it a shot.
I don't have an L88 hood, I have a stock hood with an L88 scoop mounted on top.
I really didn't notice any change in my heating issues after opening it up but can say that I tried many things to resolve my heating issue and none worked until I added the oil cooler so I can't say one way or the other if the L88 hood venting will help with cooling, it is sound physics and should work.
Neal
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Melting Slicks
Joined: May 2002
Posts: 2,717
Likes: 121
From: Sulphur LA
St. Jude Donor '05-'06,'11,'13-'14,'16,'18,'19,'24, '25
I'll have to take a shot of the vents after church and get them posted for you.
This is the scoop mounted to the hood:
[/URL]
This is the underside of the hood:
[/URL]
I drilled the holes in the hood just ahead of the radiator,
I had to add a wall in the scoop to separate the filter area and the vent area,
right now the scoop is bolted on,
Neal
This is the scoop mounted to the hood:
[/URL]This is the underside of the hood:
[/URL]I drilled the holes in the hood just ahead of the radiator,
I had to add a wall in the scoop to separate the filter area and the vent area,
right now the scoop is bolted on,
Neal
Le Mans Master
Joined: Apr 2007
Posts: 7,353
Likes: 72
From: Graceland in a Not Correctly Restored Stingray
Shouldn't affect it at all if you don't compromise the air box (assuming you have or plan on a proper CAI box). That said, short of a full duct, at a minimum some sort of baffle might be a good idea to help manage water that does find its way into the opening. I'm more concerned about wet accessories, so figuring on eventually molding something up from ABS.
Melting Slicks
Joined: May 2002
Posts: 2,717
Likes: 121
From: Sulphur LA
St. Jude Donor '05-'06,'11,'13-'14,'16,'18,'19,'24, '25
It was a complete hood skin and I cut it down to fit. They raised the scoop to 5" for me so it would work. I had a filter pan at one point so the air would come from the windshield area and not from under the hood (air would flow between the hood and scoop).
Neal
[/URL]
[/URL]
Tech Contributor
Joined: Jun 2004
Posts: 20,910
Likes: 962
From: I tend to be leery of any guy who doesn't own a chainsaw or a handgun.
Taking a long look at opening mine up too, but before going from serious contemplation to commitment I wish to verify that there's sufficient pressure drop between the initial rise and primary bulge - not likely to happen any time soon seeing that my shark is in pieces awaiting additional funding. (Mike, I'm surprised you haven't already cracked that nut open yet.) I've been a bit slow at this particular mod due to a couple reasons. I don't mind pulling heavy parts off the car and welding up lighter stuff. If it works, great. If it doesn't, I just keep modifying/improving the part until I'm happy. My last option, and thankfully I haven't had to do it yet, is that I can always put the factory part back on. I'm a bit slower when it comes to modifying the bodywork. I like stockish styling, and after doing the 'glass work and painting on the car years ago I'm just reluctant to jump into cutting up any bodywork, no matter how small, that I'm going to have to reglass and paint in case I made a mistake. So, I'm still working out the details first.
In any event, it might be worth noting that the area in question sits pretty much on top of the radiator, as well as that the main bulge that trails it also sits higher in the air stream. So, it could take more than simply opening up the rearward facing panel aft of the initial rise to create more than a rudimentary extractor, and the reason I'd prefer checking the differentials before breaking out any cutoff tools.
FWIW, the adaptation of a C7 extractor done on the Jimmy Johnson SEMA 'vette looks pretty dang good IMHO.
In any event, it might be worth noting that the area in question sits pretty much on top of the radiator, as well as that the main bulge that trails it also sits higher in the air stream. So, it could take more than simply opening up the rearward facing panel aft of the initial rise to create more than a rudimentary extractor, and the reason I'd prefer checking the differentials before breaking out any cutoff tools.
FWIW, the adaptation of a C7 extractor done on the Jimmy Johnson SEMA 'vette looks pretty dang good IMHO.
Haven't been able to get back to measuring the differential pressure on each side of the hood as I prefer doing the high speed measurements during a track day, and the gauges are currently installed in my '84 for some turbo plumbing "efficiency" measurements (inlet and outlet pressures of the turbine and compressor sections).
Not fancy, but the setup works.
Once I get done with the '84 testing I'll get back to taking some measurements on the '69. Here's an old concept/test fit of some aluminum sheet to help direct some of the radiator exit air up to the area that I'm contemplating cutting open (if the differential pressure measurement is significant enough to warrant the bodywork modification).
I also need to measure the pressure differential across this deflector to calculate the bending forces and make sure that the final attachment bracketry will be strong enough to withstand the air pressure against it at speed. Unless I come up with a better plan I was just going to ramp up my peak speeds while taking notes of the gauge pressures, and then just doing some math.
For those with good eyes, the fan is temporarily out as I recently moved the steering rack location to improve the steering geometry, and the fan and rack were competing for the same real estate. Over the winter I'll make some hopefully simple changes to be able to get the fan back into the picture.
Oh, and the big empty space under the radiator is normally sealed up with the bellypan, removed while I was reinstalling the rack.
