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Hood scoop pressure too much on big end. SSAH Type #1616513
05/05/14 02:46 PM
05/05/14 02:46 PM
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Richmond, Tx. (Houston)
GTSDave Offline OP
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Looks like I may have issues with my hood scoop working too well. Last outing on the big end my hood was wanting to lift up at the rear in the center. I was up in the 135mph range with a head wind.

Car is a 68 Barracuda FB with SSAH type HEMI scoop molded into a fiberglass hood. No carb / hood seal plate, just blowing down into the engine compartment.

What have you done to relieve pressure on the top end with your hood scoop? What do you suggest? What has worked for you in the past?

-Dave


PLEASE Pray for our brothers and sisters in harms way.

If you are the owner of a GTS us at the GTS Registry www.gtsregistry.com
Re: Hood scoop pressure too much on big end. SSAH Type [Re: GTSDave] #1616514
05/05/14 03:05 PM
05/05/14 03:05 PM
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Bend,OR USA
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Cab_Burge Offline
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Bend,OR USA
Those cars(A bodys) are noterous for that regardless of the scoop type or size, it is the air pressure from the front end coming into the engine compartment trying to blow the hood off, not the air coming into the scoop Put a carb. plate on it to seal the air from the bottom of the engine compartment and see if that helps, I would block the air from coming in from the grill, it will come in from behind the bumper and up from the K member area also A good spoiler mounted in front of the radiator core support will help also My tube chassis 1970 Cuda has issues also but I have not installed a spoiler or carb sealer yet It trys to blow the hood off at 135+ MPH also on the throttle stop it is worst at 145 MPH off the throttle stop I need to block the grill off and install a spoiler also

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Re: Hood scoop pressure too much on big end. SSAH Type [Re: Cab_Burge] #1616515
05/05/14 03:12 PM
05/05/14 03:12 PM
Joined: Jan 2003
Posts: 3,048
Richmond, Tx. (Houston)
GTSDave Offline OP
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I don't think the class rules (NSS) would allow me to add a spoiler. Was thinking of a belly pan instead of an engine diaper. Maybe I can kill two birds with one stone.

Pretty sure I cant block off the radiator area either.

-Dave


PLEASE Pray for our brothers and sisters in harms way.

If you are the owner of a GTS us at the GTS Registry www.gtsregistry.com
Re: Hood scoop pressure too much on big end. SSAH Type [Re: GTSDave] #1616516
05/05/14 03:39 PM
05/05/14 03:39 PM
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Thumperdart Offline
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Drill holes in the back of the scoop..............


72 Dart 470 n/a BB stroker street car `THUMPER`...Check me out on FB Dominic Thumper for videos and lots of carb pics......760-900-3895.....
Re: Hood scoop pressure too much on big end. SSAH Type [Re: Thumperdart] #1616517
05/05/14 04:24 PM
05/05/14 04:24 PM
Joined: Feb 2003
Posts: 991
Addison,IL
OUTLAWSSAA Offline
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Addison,IL
Dave, there's only one way to fix that problem. I had the same thing happen. You have to put in 8 pins. Three on each side of the hood, and that will take care of it.

Re: Hood scoop pressure too much on big end. SSAH Type [Re: GTSDave] #1616518
05/05/14 06:52 PM
05/05/14 06:52 PM
Joined: Jan 2003
Posts: 6,531
Jacksonville, FL
Chris2581 Offline
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Fastest I've gone was 116 and my hood does the same thing,although it now lifts against the hood pins.I have 3 pins across the back and 3 across the front.71 Demon with snorkel scoop.


Nautilus Racing-
We use Superformance gaskets and Turbo Action converters/products.
Re: Hood scoop pressure too much on big end. SSAH Type [Re: Thumperdart] #1616519
05/05/14 07:14 PM
05/05/14 07:14 PM
Joined: Aug 2008
Posts: 4,071
Mo.
racerx Online work
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Quote:

Drill holes in the back of the scoop..............


^^^This^^^ I'm thinking of trying with my 5"T/A hood.

Re: Hood scoop pressure too much on big end. SSAH Type [Re: racerx] #1616520
05/05/14 07:27 PM
05/05/14 07:27 PM
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State of confusion
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Thumperdart Offline
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Quote:

Quote:

Drill holes in the back of the scoop..............


^^^This^^^ I'm thinking of trying with my 5"T/A hood.




Plus it really helped w/my O2 #`s WAY more solid probably due to helping w/the turbulence..........


72 Dart 470 n/a BB stroker street car `THUMPER`...Check me out on FB Dominic Thumper for videos and lots of carb pics......760-900-3895.....
Re: Hood scoop pressure too much on big end. SSAH Type [Re: GTSDave] #1616521
05/05/14 08:07 PM
05/05/14 08:07 PM
Joined: Jun 2003
Posts: 52,972
Romeo MI
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Block of the front... dont let the air in

Re: Hood scoop pressure too much on big end. SSAH Type [Re: OUTLAWSSAA] #1616522
05/06/14 01:30 AM
05/06/14 01:30 AM
Joined: Jan 2003
Posts: 3,048
Richmond, Tx. (Houston)
GTSDave Offline OP
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Quote:

Dave, there's only one way to fix that problem. I had the same thing happen. You have to put in 8 pins. Three on each side of the hood, and that will take care of it.




Thanks Outlaw,

I am no where near as quick as you guys. I run a low deck wedge with a Jerico. Still launching fairly easy, but the thing is making great power so we are slowing it down until we get it tuned the way we want. We built it to run FX Classes. The MPH has me worried with the scoop the way it is because it is already trying to pull of the car on the big end and we don't have it turned up yet. It will only get worse.

Right now we have brackets glassed in and we are using the factory style hinges with no springs. Up front one dutz in the center with two pins in stock location.

I may end up drilling the holes in the back of it, and probably adding more pins. With the hinges pins wont work because of the angle it opens at, but it is worth looking into. I am not sure how it would work with airflow across the carbs if we drill the holes. I use a heavily modified STR intake with dual eddy 800's inline configuration.

Thumper do you have any pics of yours you willing to share? What are you running for cabs, and did the holes make that much difference in your O2 readings?

-Dave


PLEASE Pray for our brothers and sisters in harms way.

If you are the owner of a GTS us at the GTS Registry www.gtsregistry.com
Re: Hood scoop pressure too much on big end. SSAH Type [Re: GTSDave] #1616523
05/06/14 02:53 AM
05/06/14 02:53 AM
Joined: Feb 2007
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fresno ca
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mikeysmopars Offline
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fresno ca
Although i'm no authoraty. I made a base and sealed it except for the front edge about 3/4". mine has run 135 and i also have 6 pins, Three in front and back. I've never had a hood issue....Unless you count the time the pins we not in it.

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Re: Hood scoop pressure too much on big end. SSAH Type [Re: mikeysmopars] #1616524
05/06/14 02:54 AM
05/06/14 02:54 AM
Joined: Feb 2007
Posts: 1,608
fresno ca
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Base

8135609-DSCN1747.JPG (163 downloads)

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Re: Hood scoop pressure too much on big end. SSAH Type [Re: mikeysmopars] #1616525
05/06/14 02:55 AM
05/06/14 02:55 AM
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fresno ca
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Hood

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Re: Hood scoop pressure too much on big end. SSAH Type [Re: mikeysmopars] #1616526
05/06/14 08:35 AM
05/06/14 08:35 AM
Joined: Mar 2006
Posts: 9,843
MI, usa
dvw Offline
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I've run nearly 148 with this one, 4 pins. It does move around some.
Doug

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Re: Hood scoop pressure too much on big end. SSAH Type [Re: dvw] #1616527
05/06/14 10:52 AM
05/06/14 10:52 AM
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Windsor ,Ca.
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My '68 RR with a glass 6 pack hood raised up 1-1/2" every pass for years with no ill effects to the hood, some were I have a video of it, see if I can find it. My Challenger hood raises up about a inch as well it has a big pro stock type scoop and I drilled 4 - 1-1/4" holes in the back which had no effect so I just let it do it's thing as well as doesn't seem to hurt it either.

Re: Hood scoop pressure too much on big end. SSAH Type [Re: GTSDave] #1616528
05/06/14 12:41 PM
05/06/14 12:41 PM
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Posts: 19,317
State of confusion
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Thumperdart Offline
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Quote:

Quote:

Dave, there's only one way to fix that problem. I had the same thing happen. You have to put in 8 pins. Three on each side of the hood, and that will take care of it.




Thanks Outlaw,

I am no where near as quick as you guys. I run a low deck wedge with a Jerico. Still launching fairly easy, but the thing is making great power so we are slowing it down until we get it tuned the way we want. We built it to run FX Classes. The MPH has me worried with the scoop the way it is because it is already trying to pull of the car on the big end and we don't have it turned up yet. It will only get worse.

Right now we have brackets glassed in and we are using the factory style hinges with no springs. Up front one dutz in the center with two pins in stock location.

I may end up drilling the holes in the back of it, and probably adding more pins. With the hinges pins wont work because of the angle it opens at, but it is worth looking into. I am not sure how it would work with airflow across the carbs if we drill the holes. I use a heavily modified STR intake with dual eddy 800's inline configuration.

Thumper do you have any pics of yours you willing to share? What are you running for cabs, and did the holes make that much difference in your O2 readings?

-Dave




There`s an old post about "Thumperdarts scoop and ? photos" from several months ago but what I did was evenly space 5 tear drop holes across the back to release pressure and my scoop is trying to rip off the car above 135+ mph and the w/b is rock solid now w/other changes to the carb also.


72 Dart 470 n/a BB stroker street car `THUMPER`...Check me out on FB Dominic Thumper for videos and lots of carb pics......760-900-3895.....
Re: Hood scoop pressure too much on big end. SSAH Type [Re: Thumperdart] #1616529
05/06/14 01:19 PM
05/06/14 01:19 PM
Joined: Jan 2003
Posts: 3,048
Richmond, Tx. (Houston)
GTSDave Offline OP
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Thumper,

Couldn't find that thread, but did find one where you had a couple of pics. Looks like they didn't need to be very big at all. Do you think they would work without the pan, or does it need the pan to work?

https://board.moparts.org/ubbthreads/show...amp;Search=true


mikeysmopars

Love your car. Thanks for the pics. It gives me some ideas for where to mount additional pins.

Thanks again to everyone who replied. It gives me some ideas to work with. Depending on the weather, we are planning to run in St. Louis this weekend, and if all goes well again over Memorial day for the Dave Dual Classic.

-Dave

8135862-img002.jpg (89 downloads)

PLEASE Pray for our brothers and sisters in harms way.

If you are the owner of a GTS us at the GTS Registry www.gtsregistry.com
Re: Hood scoop pressure too much on big end. SSAH Type [Re: GTSDave] #1616530
05/06/14 02:14 PM
05/06/14 02:14 PM
Joined: Jul 2004
Posts: 19,317
State of confusion
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Thumperdart Offline
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State of confusion
Quote:

Thumper,

Couldn't find that thread, but did find one where you had a couple of pics. Looks like they didn't need to be very big at all. Do you think they would work without the pan, or does it need the pan to work?

https://board.moparts.org/ubbthreads/show...amp;Search=true


mikeysmopars

Love your car. Thanks for the pics. It gives me some ideas for where to mount additional pins.

Thanks again to everyone who replied. It gives me some ideas to work with. Depending on the weather, we are planning to run in St. Louis this weekend, and if all goes well again over Memorial day for the Dave Dual Classic.

-Dave




That`s it...............


72 Dart 470 n/a BB stroker street car `THUMPER`...Check me out on FB Dominic Thumper for videos and lots of carb pics......760-900-3895.....
Re: Hood scoop pressure too much on big end. SSAH Type [Re: Thumperdart] #1616531
05/06/14 05:54 PM
05/06/14 05:54 PM
Joined: Aug 2004
Posts: 2,128
sweden
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sshemi Offline
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sweden
Sorry to highjack but what gains can be expected going from a stock Hood to a glass with hemi scoop on a -68 barracuda?
Anyone ever did a somewhat fair back to back test on this?

Re: Hood scoop pressure too much on big end. SSAH Type [Re: sshemi] #1616532
05/06/14 08:52 PM
05/06/14 08:52 PM
Joined: Sep 2005
Posts: 1,551
baldwinsville new york
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a493demon Offline
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baldwinsville new york
I had to put a dzus at the back of mine .
it was lifting enough at the back that I could see the carb.

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