carb conversion/fuel lines, which is correct? |
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carb conversion/fuel lines, which is correct? |
nycchef |
Oct 1 2008, 08:46 AM
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#1
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mechanical moron Group: Members Posts: 952 Joined: 28-November 05 From: new york city n.y. Member No.: 5,202 Region Association: None |
i am finishing my 2.0 installation. have a cb performance fuel pump 3 1/2 lb, no regulator (maybe later) so here's the question. i will be blocking off the old 7mm return line at the tank and using the 9mm to feed the pump, which is under the tank. i still have the 7mm and 9mm lines running to the engine bay, which would be better to feed a set of dual weber 40"s?
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Mark Henry |
Oct 1 2008, 11:34 AM
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#2
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that's what I do! Group: Members Posts: 20,065 Joined: 27-December 02 From: Port Hope, Ontario Member No.: 26 Region Association: Canada |
i am finishing my 2.0 installation. have a cb performance fuel pump 3 1/2 lb, no regulator (maybe later) so here's the question. i will be blocking off the old 7mm return line at the tank and using the 9mm to feed the pump, which is under the tank. i still have the 7mm and 9mm lines running to the engine bay, which would be better to feed a set of dual weber 40"s? You wan't to feed with the original feed line as it has the brass in tank screen, but I thought that was the 7mm line. I could be wrong about the 7mm line, but you do want the feed line. A 2.0 won't have enough Hp to need a larger than 7mm line. |
r_towle |
Oct 1 2008, 11:37 AM
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#3
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Custom Member Group: Members Posts: 24,577 Joined: 9-January 03 From: Taxachusetts Member No.: 124 Region Association: North East States |
You probably want the pump in the rear so it sucks instead of pushes the fuel...
Pumps can only push so far. Get a regulator, 3.5 lbs can be to much for carbs and you will have issues tuning them. Rich |
URY914 |
Oct 1 2008, 12:14 PM
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#4
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I built the lightest 914 in the history of mankind. Group: Members Posts: 120,725 Joined: 3-February 03 From: Jacksonville, FL Member No.: 222 Region Association: None |
Actually fuel pumps are made to push, not pull. Pump should be near the tank.
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Joe Ricard |
Oct 1 2008, 12:21 PM
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#5
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CUMONIWANNARACEU Group: Members Posts: 6,811 Joined: 5-January 03 From: Gautier, MS Member No.: 92 |
Word
pump under the tank, regulator in the engine compartment. 5/16" line is enough for 150 HP for sure. I know Paul at one time had 3/8" and I will probably upgrade as well to 3/8" when the time comes to plumb the white car. |
r_towle |
Oct 1 2008, 12:26 PM
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#6
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Custom Member Group: Members Posts: 24,577 Joined: 9-January 03 From: Taxachusetts Member No.: 124 Region Association: North East States |
Considering the stock location is lower than the tank and alot easier to get to once the cheap pump dies, and it will, IMHO its the best place to put it.
Agree, the regulator should go in the engine bay in plain sight, possible with a gauge inline to verify. I have not seen alot of accurate setups so a gauge is a good way to verify everything. Rich |
brant |
Oct 1 2008, 04:36 PM
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#7
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914 Wizard Group: Members Posts: 11,625 Joined: 30-December 02 From: Colorado Member No.: 47 Region Association: Rocky Mountains |
circulatory fuel systems are better than non circulatory ones...
fi or carbs I run a return on carbs brant |
nycchef |
Oct 1 2008, 04:49 PM
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#8
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mechanical moron Group: Members Posts: 952 Joined: 28-November 05 From: new york city n.y. Member No.: 5,202 Region Association: None |
thanks guys all done ,pump under tank 7mm line will put in a regulator when the budget allows. i left the 9mm line tucked away in case . how do you run a return anyhow?
rich |
Root_Werks |
Oct 1 2008, 04:56 PM
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#9
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Village Idiot Group: Members Posts: 8,321 Joined: 25-May 04 From: About 5NM from Canada Member No.: 2,105 Region Association: Pacific Northwest |
Good time to note: I thought the return line was also a tube that run up higher than the suction line anyway. So you'd still read something in the tank via the fuel gauge, but be sucking air if you used the return line? No? (IMG:style_emoticons/default/idea.gif)
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Root_Werks |
Oct 1 2008, 04:58 PM
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#10
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Village Idiot Group: Members Posts: 8,321 Joined: 25-May 04 From: About 5NM from Canada Member No.: 2,105 Region Association: Pacific Northwest |
thanks guys all done ,pump under tank 7mm line will put in a regulator when the budget allows. i left the 9mm line tucked away in case . how do you run a return anyhow? rich Like has been said, run pump under tank, 7mm line has supply to first carb then out to second carb, then out to pressure regulator then to 9mm return line. |
nycchef |
Oct 1 2008, 05:17 PM
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#11
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mechanical moron Group: Members Posts: 952 Joined: 28-November 05 From: new york city n.y. Member No.: 5,202 Region Association: None |
Good time to note: I thought the return line was also a tube that run up higher than the suction line anyway. So you'd still read something in the tank via the fuel gauge, but be sucking air if you used the return line? No? (IMG:style_emoticons/default/idea.gif) i connected the pump to the regular suction line. i was wondering about the lines that went thru the tunnel from the old fi. does anyone know where to buy an adjustable fuel pressure regulator? |
peetzinc |
Oct 1 2008, 05:33 PM
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#12
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peetzinc Group: Members Posts: 60 Joined: 30-November 07 From: Salem, Oregon Member No.: 8,396 Region Association: None |
I am curious here as I see what, I think, is contradicotry information. The fuel pump I have says it is a pusher, so under the tank would be good but I have spoken with a few folks that say mount it where the FI pump was. Easy here as the wiring is right there.
I am in the process of doing exactly the same. 40 IDF's, fuel pump and I bought an .009 Pertronixs electronic distibutor. I have to rebuild the carbs yet and then set it all up. I am looking for a definative on the location for the pump. The fuel pressure regulator sounds like a great idea. Where would one get an adjustable one...with a gauge would be great? |
SGB |
Oct 1 2008, 05:43 PM
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#13
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just visiting Group: Members Posts: 4,086 Joined: 8-March 03 From: Huntsville, AL Member No.: 404 Region Association: South East States |
It should be up front. There is no problem achieving the required pressure. I've had my pump in front for 20+ years, using the 9mm line. no return line, and no pressure regulator. (IMG:style_emoticons/default/smile.gif)
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nycchef |
Oct 1 2008, 05:46 PM
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#14
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mechanical moron Group: Members Posts: 952 Joined: 28-November 05 From: new york city n.y. Member No.: 5,202 Region Association: None |
It should be up front. There is no problem achieving the required pressure. I've had my pump in front for 20+ years, using the 9mm line. no return line, and no pressure regulator. (IMG:style_emoticons/default/smile.gif) good answer (IMG:style_emoticons/default/piratenanner.gif) do you think mine will be o.k with the 7mm line? i still have the 9mm laying in the car. planned on leaving it there after i put in the engine in case i.m wrong. |
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