HELP PLEASE hood scoop and carberatour problems?????
 

I put a new scoop on the roadster over the winter and went racing this weekend and had a lot of problems with the air pulling the fuel out of the vent tubes on the carberatour. The carberatour sits about 2 inches from the top of the new scoop and the front vent tube sits about 3/4 of an inch from the top and the rear vent tube sits about 1/4 of and inch from the top. the first run the car surged in and out from about half track on and only went 9.67 @ 157mph in super gas trim. Then i made some changes and no improvement. I run a under the carb dedenbear stop and took it off and that gave the carb about 1 inch to 1 1/2 inches of more clearance. the first pass ALL OUT it went 7.84 @ 167 then i used a piece of rubber hose and put it on the vent tubes with a small notch in the middle and the car went 7.77 @ 171.40. Im trying to figure a way to use my under the carb stop for super gas without having to cut the new scoop out and installing another one. Any ideas would be greatly appreciated.

Re: HELP PLEASE hood scoop and carberatour problems?????
 

is the back of the scoop open in any way ? seems to me there would have to be a inlet and a outlet for it to draft. the hood/scoop could actually be dropping down on the run and closing off the vents....... if so, make a stand and install it in the center stud of the carb. (air cleaner stud )

And are you useing a tray to seal carb to the hood/scoop..... this is a must too !



hope this helps ...

let us know

Rick

Re: HELP PLEASE hood scoop and carberatour problems?????
 

Ryan, I have seen people put 90* spark plug boots over the vent tubes to fix that problem.

BB

Re: HELP PLEASE hood scoop and carberatour problems?????
 

Had a similar problem several years ago.
Venting the bowls outside the scoop had a result similar to what you saw.
A friend who is involved with Pro Stock carbs suggested a couple of 1" holes in the scoop tray,adding or removing plugs untill the pressure sweet spot was found.
2 1" holes made a huge difference, but eventually raising the scoop to allow 4" over the carb was far more effective.

Re: HELP PLEASE hood scoop and carberatour problems?????
 

Rick Greg risk is coming tonight to measure to make a pan for the scoop but he doesn't seem to think it will cure the problem.

Re: HELP PLEASE hood scoop and carberatour problems?????
 

X 2, i think it would clear without cutting, worth a shot, and as for your other post, under carb t-stop the only way to go, IMO

Re: HELP PLEASE hood scoop and carberatour problems?????
 

If you are running this set up without any kind of pan to seal it off, I have seen where the air going around the carb into the engine bay will pull fuel out of the carb. Had a friend with a simular problem years ago, I had him put a scoop plug in and he picked up 6 mph. The next week he had an air pan installed.
Chuck

Re: HELP PLEASE hood scoop and carberatour problems?????
 

Ryan..... I think the dimension is 6 or 7 inches from the throttle plates....but they all act a little different.....mine is very close and seems to work fine sealed or not....but put something on the vent tubes....I have a hose on ours....and a plate stop is a better choice....7.77 seemed stout but the speed seemed slow....something is not as happy as it could be...probably got to try a few things....use tape and test a little....unfortunately you probably want to race next weekend....better test on Thursday and have a backup plan.....can you run it without the scoop for the weekend....just a suggestion....

Rock....

Re: HELP PLEASE hood scoop and carberatour problems?????
 

I should be there Thursday if ya need anything I would be glad to help.

BB

Re: HELP PLEASE hood scoop and carberatour problems?????
 

Well here's what im doing i have to get a in line stop for this weekend and im sealing the hood. Probably going to get a taller scoop and mount it separate from the hood that way i can go back to using my base plate stop. thanks for the suggestions and help i will probably make an all out run Thursday first and see what the car does compared to this past weekend then make the runs to figure out a ratio. one question i have always tried to keep my coast speed at 4000 can i make it about 3000 or lower and still be consistent? Im trying to not be on the stop for a long time with this in line deal.

Re: HELP PLEASE hood scoop and carberatour problems?????
 

Ryan,

You will have the inline stop today. I had the same issue with my truck with the carb being to close to the hood. I had plug boots on mine & only when I installed the scoop on my truck did it resolve the problem. I installed a simple Lexan scoop & pick up 6 MPH running SG.

Marc Erickson
www.dedenbear.com
www.autometer.com

Re: HELP PLEASE hood scoop and carberatour problems?????
 

Thanks mark i will let you know how it goes. what do you mean a little lexan scoop?

Re: HELP PLEASE hood scoop and carberatour problems?????
 

Like Barney said,
I'll be there Thursday about 11:00 or 11:30 if you need help...

Re: HELP PLEASE hood scoop and carberatour problems?????
 

I cut a hole in the hood & bolted a Lexan scoop directly to the carb.

Re: HELP PLEASE hood scoop and carberatour problems?????
 

So, did you fabricate the scoop, or did you purchase it from somewhere. I seen your scoop and I might have to do the same thing. Been looking for scoops, but have not finalized a purchase. Looking at options.

Re: HELP PLEASE hood scoop and carberatour problems?????
 

I had the same problem , 90 degree spark plug boots worked on my Corvette roadster for me as well.

Re: HELP PLEASE hood scoop and carberatour problems?????
 

You can run lower rpm with the inline stop but I would stay around 3500.

Re: HELP PLEASE hood scoop and carberatour problems?????
 

spell it carburator.it will run better

Re: HELP PLEASE hood scoop and carberatour problems?????
 

Ryan check your PM's

Re: HELP PLEASE hood scoop and carberatour problems?????
 

did you get this issue fixed?, curious to know what you did and the results...

Re: HELP PLEASE hood scoop and carberatour problems?????
 

I am curious as well.
I have been experienceing a similar problem ever since I changed my hood scoop last year on my door car. The old scoop I had sealed off with a pan and foam to the top of the scoop. The new scoop is much larger which I have not sealed off and lost at least 2 mph and have gained an occasional engine miss during the pass. EGT is showing lower than normal as well indicating a richer condition.
I have tried it with the pan (Pan only no seal) and without and see no difference other than the motor wants to stall when I click neutral with the pan on. I am suspicous that there is air turbulance causing the MPH loss and the stalling deal on top end. (unless ironically other problems have cropped up that I am not seeing ie electrical or motor)
I am going to try my next race to seal off the scoop with the pan a huge piece of foam and see if that makes a difference. Any suggestions or comments would be appreciated.
BTW the new scoop is open in the back and the old one was closed.