Author Topic: Straight or angle fuel line, methanol?  (Read 3815 times)

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Offline Dave Haller

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Straight or angle fuel line, methanol?
« on: January 12, 2007, 11:08:35 AM »
I have a new A/FL that will be running Methanol. The line from the tank is a -12. The line coming out of the tank has a 45 degree bend to miss a major frame rail. It runs back to the pump mounted low on the engine. It is a Rons Fuel Injection pump. The in side on the pump is down at about a 45 degree angle. To clear the belly pan panel at that point I need to install another 45 degree -12 male/female fitting. I am hearing from a couple of different sources that the fuel line from the tank to the pump needs, exphasize needs, to be straight. Something about this being very critical for fuel flow. Can anyone enlighten me on this point. What might I experience with these two angle fittings in the main line to the pump?
Thanks for any help,
Dave Haller 93 A/FL

Offline POPS

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Re: Straight or angle fuel line, methanol?
« Reply #1 on: January 12, 2007, 02:03:43 PM »
Dave,
It's best to keep the suction line straight as possible.  Instead of using restrictive fittings can you put 45 deg bends in the tubing?  If you are using braided line use XRP fittings because the have the biggest IDs.  The key thing to avoid is causing a vacuum at the pump inlet.  My only experience with a Ron's pump was on a sprint car and it flowed 2.5 gpm on my bench.  So this flow is small compared to the 3/4" suction line and the fittings will probably be OK.  If you have a data acquisition system, hook a vacuum transducer to the bottom of the pump.  If you get a vacuum when running the car I'll guarantee it will be lean.  If you are a number guy the ideal suction line speed is less than 1ft/sec.  On most nitro drag cars we can get away with 3 ft/sec due to the acceleration.     
Pops

Offline Dave Haller

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Re: Straight or angle fuel line, methanol?
« Reply #2 on: January 12, 2007, 03:36:57 PM »
Thanks very much. I will look into what you have shared. I may be able to just use the line like you say. I will also try to locate the xrp fittings and see if that solves it. I'm kinda old school and have no data aquisition stuff on the car as of yet. That may come over the next few years. I have some youngsters helping and I know they would be into that stuff.
Thanks again,
Dave Haller

Offline Harold Bettes

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Re: Straight or angle fuel line, methanol?
« Reply #3 on: January 12, 2007, 06:40:26 PM »
Points listed are very good from knowledgeable folks. Some good rules of thumb on any liquid system is to NOT use any drilled 45 or 90deg fittings. Think smooth and the result will always be fewer bubbles generated in the system. Aeration in the fuel system OR the oil system is nasty. The formed tubing type fittings (large radius) 45 or 90s are by far the better choices. I think that one of the best treatises on fluid fittings and plumbing is Crane paper 410 (as I recall) which was done a long time ago, but certainly still applicable.

Regards to All,
HB2
If it was easy, everybody would be doing it.

As iron sharpens iron, one man sharpens another.

Offline Freud

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Re: Straight or angle fuel line, methanol?
« Reply #4 on: January 15, 2007, 12:32:47 AM »
When you see Tom Bryant at the Bonneville Northwest Reunion, ask him. He has just gone thru that drill. As I remember he rotated his fuel tank so he could use a straight fitting.
I don't know if he has run since he made the change.
I'll see you and your family Feb 17th.

FREUD
Since '63

Offline Dean Los Angeles

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Re: Straight or angle fuel line, methanol?
« Reply #5 on: January 15, 2007, 01:07:23 AM »
In case you want a copy of Crane Technical Paper No. 410
http://www.tp410.com/tp410.htm
Well, it used to be Los Angeles . . . 50 miles north of Fresno now.
Just remember . . . It isn't life or death.
It's bigger than life or death! It's RACING.

Offline goldleaf

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Re: Straight or angle fuel line, methanol?
« Reply #6 on: January 15, 2007, 12:09:34 PM »
dave, why dont you give the pump dept. at rons a call.  520-573-6890  ask for john or francis. we are both into land speed racing. we have apump dyno and test stand that can duplicate your system

Offline Dave Haller

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Re: Straight or angle fuel line, methanol?
« Reply #7 on: January 15, 2007, 12:24:35 PM »
Great advise from all. I will be redoing the line so it is straight as possible and will give Rons a call. Thanks again all, looking forward to August and running a non door slammer.

Offline promachine

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Re: Straight or angle fuel line, methanol?
« Reply #8 on: January 15, 2007, 12:38:18 PM »
Also, make sure your vent is large enough to displace the fuel exiting the tank.
2.5 gallens does`nt sound all that big for a -12 line.
Dirty 2 driver-nitro junkie-H.P. peddler