Fuel Filter In Front or Behind Pump?
Thread Starter
Pro
Joined: Oct 2016
Posts: 684
Likes: 62
From: Ogden, Utah
Fuel Filter In Front or Behind Pump?
I'm restoring my '74 with original Q-jet, stock intake and cowl induction. I noticed someone cut the fuel line years ago for the Holley which is now sold. I'm planning to buy a new fuel line but then thought I may need to cut the pipe to put in an in-line fuel filter. Should I put the filter in front or before the fuel pump? What was the stock setup?
Le Mans Master
Joined: Oct 2006
Posts: 7,123
Likes: 433
From: Gladstone MO
C3 of Year Finalist (appearance mods) 2019
Generally, fuel pumps are not real happy trying to pull fuel thru a filter. No problem pushing thru one. THE stock filter in the Q-Jet would be the way to handle this one.
Dr. Detroit
Joined: Mar 2012
Posts: 10,097
Likes: 4,027
From: New Braunfels Texas
NEVER run a regular filter before the pump........
The only time this is a consideration is if you are in a jam with a tank full of crap and have to get to a destination......
Jebby
The only time this is a consideration is if you are in a jam with a tank full of crap and have to get to a destination......
Jebby
Tech Contributor
Joined: Aug 1999
Posts: 14,380
Likes: 6,391
From: At my Bar drinking and wrenching in Lafayette Colorado
Never run a fuel filter on the suction side of a mechanical fuel pump - that is a sure way to induce vapor lock and fuel starvation at elevated rpm. Just run the stock, in-carb filter on the Q-Jet - it works quite well. Do not run a second filter on the pressure side of the line. If you decide, for whatever reason, to run an in-line filter between the pump and the carb, remove the stock in-carb filter.
Instructor
Joined: Oct 2014
Posts: 144
Likes: 9
Never run a fuel filter on the suction side of a mechanical fuel pump - that is a sure way to induce vapor lock and fuel starvation at elevated rpm. Just run the stock, in-carb filter on the Q-Jet - it works quite well. Do not run a second filter on the pressure side of the line. If you decide, for whatever reason, to run an in-line filter between the pump and the carb, remove the stock in-carb filter.
Racer
Joined: Apr 2016
Posts: 493
Likes: 65
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Tech Contributor
Joined: Aug 1999
Posts: 14,380
Likes: 6,391
From: At my Bar drinking and wrenching in Lafayette Colorado
Lars
Last edited by lars; Feb 20, 2017 at 10:51 PM.
Safety Car
Joined: Apr 2006
Posts: 4,057
Likes: 421
From: BC
When running a stock mechanical pump, the pressure drop through 2 filters will often cause fuel starvation at wide open throttle - it usually occurs near the top end of 2nd gear. I can't count the number of times I've seen the problem, and it's always solved by removing one of multiple filters installed. 2 filters does not gain you any more protection than 1 filter: you get the filtering protection of whichever filter has the smallest millipore size, but you get the pressure drop associated with two filters. Generally not a good idea, and it gains you nothing.
Lars
Lars
