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Bracket Talk Bracket Talk Forum Tech Talk - by Abruzzi Belt drive fuel pump questionGo | New | Find | Notify | Tools | Reply | |
| Belt drive fuel pump question | Login/Join |
DRR Sportsman |
I run a door car with a carbed BBC with a belt drive pump. Present setup has poppet valve on return line set at 9#. car idles at 6# and stays at 9# with rpm up. Been running this setup for about 2 years Started having occasional flooding when go on brake. Question is am I deadheading the pump at 6#? Friend suggested I take spring and piston out and just run a jet, that the pressure needs to be about 1-2# at idle. Or do I need a return regulator at the carb? Anyone with experience with this setup flame away Dave | ||
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| DRR Top Comp |
I really like my Aeromotive return style regulator. Stays at about 7.5 lbs. down track according to the Racepak. There are several ways to skin a cat. Clowns to the left of me, Jokers to the right. Here I am....... | |||
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| DRR Sportsman |
Have you weighed your floats lately? | |||
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DRR Top Comp |
I think you are on right track there. Check out needles and seats, floats and verify fuel pressure at the carb. Too much fuel pressure or needles and seats / floats are bad. Also if float level is too high it can cause issues. https://postimg.cc/gallery/np3zpruo/ "Dunning-Kruger Effect" -a type of Cognitive bias where people with little expertise or ability assume they have superior expertise or ability. This overestimation occurs as a result of the fact that they do not have enough knowledge to know they don't have enough knowledge. Before you argue with someone ask yourself, "Is this person mentally mature enough to grasp the concept of a different perspective?" If not there is no point to argue. 4X NE2 CHAMPION. 2020 TDRA NE2 Champion | |||
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| DRR Sportsman |
That's what l thought. New floats and needle & seats both ends, lasted 4 runs and done it to me again, in the semi final Dave | |||
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DRR Sportsman |
The spring handles your idle pressure. The jet controls the high end pressure. No, you are not deadheading it. Pump is capable of over 200 lbs at rpm. The only way you could over pressure and you would see it on your gauge is if the return check valve was stuck or the hose plugged up. Nothing like that? It's a carb issue. Dave Koehler - Koehler Injection - http://www.koehlerinjection.com Fuel Injection - Nitrous Charger - Nitrous Master Software - Balancing 99% of fuel injection problems are electric. | |||
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| DRR Trophy |
Might want to check area in the bowl where the o ring on the needle and seat seals for pitting or corosion. | |||
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| DRR Sportsman |
Are your inlet and bypass lines the same size? | |||
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| DRR Sportsman |
Pump inlet -10, line to carb and bypass both -8. I did change primary bowl about month ago due to stripped inlet. Forgot rule #1. Undo whatever you did last will probably fix it Dave | |||
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| DRR Sportsman |
Two more questions, 1. Do you use a starting line enhancer or do you control when it goes wide open? 2. Is this an alcohol carb? | |||
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| DRR Sportsman |
No SLE, E85 Dave | |||
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| DRR Sportsman |
When it goes to 9 psi the floats aren't controlling the fuel level any more. Since you have one needle and seat per bowl this is a band aid to prevent fuel starvation (on methanol). When you go on the brake you are dumping a large amount of fuel in the carb which the floats can't fully control, hence your occasional flooding. You could try the following to alleviate it: --a SLE to prevent additional time on the brake dumping fuel --adjusting the floats and/or fuel pressure since e85 doesn't need as much fuel as methanol | |||
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| DRR Top Comp |
If the poppet valve is set at 9 PSI then it probably has some small shims in there to increase pressure. Remove one or two of the thin ones to lower pressure to maybe 8 or so. If you are sure the carb is good then go back and look at fuel pressure. Yes, you should always run a return style regulator but your poppet valve is your return regulator here and you can adjust it. https://postimg.cc/gallery/np3zpruo/ "Dunning-Kruger Effect" -a type of Cognitive bias where people with little expertise or ability assume they have superior expertise or ability. This overestimation occurs as a result of the fact that they do not have enough knowledge to know they don't have enough knowledge. Before you argue with someone ask yourself, "Is this person mentally mature enough to grasp the concept of a different perspective?" If not there is no point to argue. 4X NE2 CHAMPION. 2020 TDRA NE2 Champion | |||
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| DRR Sportsman |
Sorry Curly, That won't work. It has a really weak spring in there and the poppet is wide open as the rpm comes up. The jet dictates the high pressure. Bigger jet, lower high pressure. You did note the 9 lbs that I missed in the first post. Isn't 9 lbs the traditional max for a carb if one is lucky and the gauge doesn't lie? As I remember history the 9 lbs came around due to not having the pumps we have available today. Speed. Drop it to 8 lbs. Dave Koehler - Koehler Injection - http://www.koehlerinjection.com Fuel Injection - Nitrous Charger - Nitrous Master Software - Balancing 99% of fuel injection problems are electric. | |||
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| DRR Sportsman |
Thanks for the advice. This is my first belt drive so I'm learning. No shims in poppet valve. Plan is to change out bowl again and enlarge jet to lower fuel pressure. And you're right Dave, over 50 years messing with this stuff I thought 9# was the magic number going down the track Thanks again Dave | |||
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DRR Sportsman |
I've had similar problems in the past. Here is my .02 As rpm increases so does fuel pressure. 9# is fine under WOT but when you lift, it floods over and pushes past the needle and seat. This is because the rpm is dropping gradually, once the pressure drops below the N&S threshold it should clear up. I would increase the bypass pill .010 to reduce the pressure at WOT to 8 or less. I run mine at 7.5 lbs now with no issues. 72 Nova "Hooptie" | |||
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| DRR Sportsman |
I just remembered another old trick for improved fuel delivery on a carb. You know those windows in the needle and seat where the fuel comes in? Try to line those up with the incoming fuel hose. Observation. I have always been impressed with how those dual needle and seat bowls solve a lot of the usual issues with alky or gasoline carbs. When you get down to it, available volume without frothing in the bowl is the key to effective tuning and not so much the pressure on the incoming side of the needle and seat. Dave Koehler - Koehler Injection - http://www.koehlerinjection.com Fuel Injection - Nitrous Charger - Nitrous Master Software - Balancing 99% of fuel injection problems are electric. | |||
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| DRR Sportsman |
You said you are on e85. My little experience with it is that e85 foams easily at higher pressures. On my car I had issues at anything above 6.5lbs. Lowered pressure to 5.5 used .130 stainless steel needle and seat the lined up the inlet Windows like Dave said and got much better results. I am however useing a magnfuel 500 electric pump with a aeromotive a2000 bypass regulator. #10lines in and out of regulator with #8 to the bowls. | |||
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| DRR Sportsman |
Thanks guys. Bigger jet lowered fuel pressure to 8# max, float level set at bottom sight glasses, try it tonight if weather permits. Dave | |||
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| DRR Sportsman |
Saturday morning, it's raining, the European finals from Santa Pod is streaming and this happened. Carb pondering. IF large fuel bowls could contain enough fuel to complete a run would this eliminate the need for a fuel pump? Could this also eliminate floats and needles and seats? Dave Koehler - Koehler Injection - http://www.koehlerinjection.com Fuel Injection - Nitrous Charger - Nitrous Master Software - Balancing 99% of fuel injection problems are electric. | |||
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Bracket Talk Bracket Talk Forum Tech Talk - by Abruzzi Belt drive fuel pump question
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