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Fuel Filter Location - before or after mechanical pump?
#1202972
03/25/12 02:15 AM
03/25/12 02:15 AM
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Joined: Jan 2010
Posts: 1,442
NW Chicago suburban area
Mopar Mitch
OP
pro stock
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OP
pro stock
Joined: Jan 2010
Posts: 1,442
NW Chicago suburban area
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I have a s/b Chall T/A that I use for auto-x and hi-speed road course lapping sessions, as well as a little street/hwy driving. My ~25 yrold mechanical pump has just sprung a leak, so, I'll be replacing the pump. I've always had the filter BEFORE the pump (I know that's not stock, but neither is the car). Does it realy make any difference if the fuel filter is positioned BEFORE the mechanical pump, or, is there a better reason for it be positioned AFTER the pump (between the pump and the carb... maybe only for easier install/removal?)?
Also, any thumbs up/down on using the Carter race-mechanical pump (~$80-90) instead of an OE-type pump (~$40)? I never had any problems with the OE-type mechanical pump (and the filter being installed just before the pump).
Thanks ahead!
Mopar Mitch
"Road racers and autocrossers go in deeper and come out harder!"... and rain never stops us from having fun with our cars... in fact, it makes us better drivers!
Check out MOPAR ACTION MAGAZINE, August 2006 issue for feature article and specs on my autocross T/A!
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Re: Fuel Filter Location - before or after mechanical pump?
[Re: Mopar Mitch]
#1202973
03/25/12 02:25 AM
03/25/12 02:25 AM
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Joined: Jan 2003
Posts: 27,467
So Cal
autoxcuda
Too Many Posts
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Too Many Posts
Joined: Jan 2003
Posts: 27,467
So Cal
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I run the hi po non race pump. Whatever that is. One above stock I guess. I ran 3/8" fuel line and sending unit. Tim Herren has said he has run fuel starved at the end of the long straight at the race track. I also ran fire sleeve over everything near heat to keep from fuel percolation. 
Last edited by autoxcuda; 03/25/12 02:35 AM.
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Re: Fuel Filter Location - before or after mechanical pump?
[Re: autoxcuda]
#1202974
03/25/12 02:31 AM
03/25/12 02:31 AM
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Joined: Jan 2010
Posts: 1,442
NW Chicago suburban area
Mopar Mitch
OP
pro stock
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OP
pro stock
Joined: Jan 2010
Posts: 1,442
NW Chicago suburban area
|
Hi Steve, Thanks for the reply. I see the pump (that's the one I'm thinking of installing) on your pic... and the different routing of the fuel line up to the carb, along with the top-mounted filter. nice pic!
Mopar Mitch
"Road racers and autocrossers go in deeper and come out harder!"... and rain never stops us from having fun with our cars... in fact, it makes us better drivers!
Check out MOPAR ACTION MAGAZINE, August 2006 issue for feature article and specs on my autocross T/A!
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Re: Fuel Filter Location - before or after mechanical pump?
[Re: Mopar Mitch]
#1202975
03/25/12 02:45 AM
03/25/12 02:45 AM
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Joined: Jan 2003
Posts: 27,467
So Cal
autoxcuda
Too Many Posts
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Too Many Posts
Joined: Jan 2003
Posts: 27,467
So Cal
|
Quote:
Hi Steve, Thanks for the reply. I see the pump (that's the one I'm thinking of installing) on your pic... and the different routing of the fuel line up to the carb, along with the top-mounted filter. nice pic!
The concept of the fuel line routing is to avoid turbulent fuel flow from sharp turns and avoiding heat sources.
When you run the stock routing between the alternator and motor I would have had to run a 90 degree fitting of the fuel pump. And our theory (could be wrong) was that liquid fuel making a sharp 90 degree turn out of the pump could cause fluid cavitation, causing airation, then more tendency to cause vapor when heated.
Also the fuel line has smoother more gradual curves up to the carb.
Running the fuel line around the outside of the alternator gets it away from the that heat trap between the alternator, block and water pump housing. Also on the outside you get some air flow past the line, where as with the stock routing air flow is stopped by the block.
I could get away with running the line around the alternator because it's that mini Nippondenso alternator off a Suzuki Samauri.
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