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Old 11-14-2017, 12:12 PM   #22
142 guy
Board Member
Join Date: May 2014
Location: Saskatchewan, Canada


I was running a slightly different version of the Aeromotive FPR on my 142 with the original B20E engine.

My take is that the primary difference is that this regulator has an optional spring which allows lower operating pressures.

Like others, I noticed that on shut down the regulator would allow loss of fuel pressure very quickly. The bigger problem I encountered was irregularities in fuel pressure, particularly spikes in fuel pressure and a lot of noise from the FPR. In particular the FPR seemed to have a lot of valve chatter anytime the FPR was by-passing lots of fuel. When driving, if you lifted the gas pedal quickly the FPR would howl - being mounted on the firewall made for a great sounding board and lots of noise.

By experimentation, I discovered that this Aeromotive FPR is acutely sensitive to back pressure on the fuel return line and it has a problem managing pressures at low flow (high by-pass) rates. I improved operation slightly by making sure that all the bends on the discharge were very large radius >15cm. Aeromotive's technical support suggested that the problem was that the return line was too small. In their technical documents the minimum recommended return line is 3/8" and the stock return line on the 142 E is 5/16". I ultimately solved the problem by using an FPR for a Nissan 280 ZX. Non adjustable, does not look as trick; but, provides consistent reliable operation.

As an observation. If your regulator is chattering it will cause accelerated wear on the control orifice and other problems. Depending on how you have the FPR mounted you may not notice the valve chatter. Also, if you have large fuel return lines you may not encounter the back pressure problem.
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