Larger Fuel Filter ?

[milkboy]

I have noticed a number of people with superchargers using fuel filters that are larger than OEM to prevent a lean a/f condition at WOT.
If I understand the reasoning correctly, it is supposed to increase fuel flow rate at WOT and provide a larger reservoir of fuel (in the filter) that's available during short high-RPM bursts.

Opinions ?

 

[horse123]

A well-designed engine doesn't need that.

 

[gathermewool]

The filter represents a flow restriction, with a pressure drop from the inlet to the outlet. Size doesn't necessarily matter, but restriction and pressure drop does. If the larger filter has more filtering area, but is no more restrictive than stock or if the larger filter has media that flows better, the pressure drop will be lower and there may be benefits if you're pushing the fueling system beyond it design. It's very case-specific, though, because some systems may be injector-limited well before the fuel pump runs out of capacity.

My ol STI was known for nearly maxing out the injectors with mild bolt-on parts and a tune, for instance.

The filter isn't, however a reservoir of pressure for short duration bursts of additional fuel. It's a solid can, not a bladder or gas-loaded accumulator.

 

[Popsy]

A bit unrelated but I see a difference in my turbocharged diesel between old filter and new filter. Maybe the mechanical pump is a bit tired, but it has always done that. In fact the owner manual advises to replace the filter if the idle becomes erratic and/or if there are loss of power (or every 15/20000Km)...they don't do such precise manuals anymore!

 

[Olas]

The slight reduction in pressure drop may help an old fuel pump, and if your tank is full of crud the extra capacity could help, but otherwise it's neither here nor there.

 

[UltrafanUK]

Originally Posted By: milkboy
I have noticed a number of people with superchargers using fuel filters that are larger than OEM to prevent a lean a/f condition at WOT.
If I understand the reasoning correctly, it is supposed to increase fuel flow rate at WOT and provide a larger reservoir of fuel (in the filter) that's available during short high-RPM bursts.

Opinions ?


Might be you do not need a fuel feed pump if a less restrictive filter is fitted. Weight is very important in race cars, so if a bigger filter weighs less than a fuel feed pump, then it's a plus.