I changed my OEM fuel filter and my supplemental frame-mounted Pre-OEM Racor R60S fuel filter over the weekend. In the OEM position, I installed one of the new and improved Racor "Dual Pleat" filters. I took a couple of measurements at the fuel system test port, using a Kent-Moore Vacuum-Pressure gauge, to see what the differences in fuel system vacuum were between the two filters in the OEM position (original OEM Racor and new/improved "Dual Pleat" Racor).<o:p></o:p>

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There was virtually no difference in fuel system vacuum between the two filters. With the old original style OEM Racor installed, the measured vacuum at the test port was 2.5 inHg. With the new "Dual Pleat" Racor installed, the measured vacuum was still 2.5 inHg. (Note: the old style Racor that was installed prior to the filter change was hardly used, maybe a 1/2 inch circular band at the bottom of the filter.)<o:p></o:p>

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The picture below is the fuel system vacuum (engine idling) with the "Dual Pleat" Racor installed in OEM position along with a Racor R60S supplemental fuel filter installed on the frame rail. Those running their trucks with a supplemental filter should be able to use the new "Dual Pleat" Racor OEM filter and not worry about fuel system vacuum levels. Just remember to change the filters in a routine interval.

That's good news.

kennedy had me worried when he said he found 1" hg and then someone remarked that that was a significant amount of added restriction.


I haven't done any detailed studies, but it wouldappear that the dual pleat adds a solid 1"hg pressure drop on an idling Dmax. Nothing severe, but if you are marginal already it could have an effect. This is why I chose such a large element for my Mega filter. With the new synthetic media it will only be better!

Don't know what to tell you,, I did a before and after check and measured virtually no difference at all. I know the Mega Filter System itself adds about a 1 inHg of insertion loss to the fuel system (do to the way it is mounted and the effects of gravity, not the filter itself).

Mine was an off the cuff observation going by memory, and I did not do anything scientific, but from experience, I don't trust the Kent Moore gauge to be very accurate.

Not sure what the actual absolute accuracy of the Kent-Moore gauge is. However, if placed on the same location of the vehicle (I used the front driver side battery), it does give consistent and repeatable results (and I have been using this gauge for 2 years now). The answers this gauge produces seem to be consistent with others who have measured the fuel system vacuum at the test port. Not the best product, but sufficient enough for the measurements taken (in my opinion ,,,, and I realize you sell a better product, it just wasn't available when I bought my gauge 2 years ago!!)

What we are looking for with this test is a difference measurement. Measure a filter with the gauge installed on test port, replace fuel filter with a new filter, prime system and take another measurement. I would expect the difference measurement to be fairly accurate. For conversation, lets say the repeatability is within 0.25 inHg (and I expect that to be the worst case). Then that says the filters are within at least 0.25 inHg of each other. This is a good thing for people who want to upgrade to the new Racor design and who have a supplemental filter installed that creates extra demand on the fuel system!!

I think I was the one that commented that 1 Hg was a large increase to the suction head and I seriously doubted it when I read the statement. I knew Allen was going to install a new filter shortly and would give us some data. It doesn't make any difference if the gauge is very accurate as long as it is repeatable. Most vacuum gauges from the cheap $6 ones to $600 ones will usually repeat. One of the reasons I chose the Racor 660R2 was the very low vacuum drop. .1 for the new filter would be a reasonable number. Thanks Allan. Later! Frank

I run the new dual pleate with my nicktane, and im not having any problems