New MPS diaphragm kits - Tangerine Racing, Rebuilt and road tested with excellent results Options

[JeffBowlsby]

I spent some of my remaining vacation time with a new Chris Foley MPS diaphragm kit today. A week ago I installed the kit in a core MPS and it seemed to work well but I didnt have time to test it fully before a trip out of town. Got home and put it through its paces today. I compared it with 2 NOS and 2 other known good, used, unopened MPS's that I own as well as other data I have collected from others, to calibrate it. Interestingly, each MPS is factory sealed, with original factory settings. While the calibrations are slightly different between them they each work perfectly on my bone stock 50KMI 74 2.0L. The MPS with the new diaphram kit was road tested and put through its paces, in all load settings, testing idle, hills, highway, WOT, deceleration, and the transitions between all RPMs. It behaved perfectly, as anticipated. I don't have an exhaust gas analyzer or other sophisticated equipment or instrumentation so that is a caveat. YMMV. I then reopened the MPS to inspect the diaphragm and saw no visible damage or other indication of failure, distress or unusual wear. Chris has done a exceptional job with these diaphragm kits, they appear to match factory specifications and performance in every respect, and the kits also include 3 new gaskets to prevent air leaks.

Mounting the kit is easy enough, but there are two challenges in rebuilding them and in determining costs:

1.) Cleaning up the outer cases of cores may take alot of effort, or not, depending on the condition of the specific core. Most of the dozen or so cores I have are going to take some effort to make nice, I may need to look into getting a buffer. Cleaning and detailing the MPS case could easily take more effort than just getting it functional again.

2.) The bigger issue is in detemining the exactly correct calibration for a specific engine, which to a large extent depends on that engines particular mechanical, fuel injection and ignition systems (and their components) characteristics and conditions, including wear and state of tune. A factory stock new engine is easier to get right than modified or worn engines, at least using the calibrations we know about. Brad Anders mentions this on his site, to the extent that each MPS may have been adjusted specifically to the exact equipment used on each specific car and its specific nuances, most likely using exhaust gas analyzer equipment to perfectly tune it. I can get these close to what I understand to be 'factory calibration' using the inductance meter, but it needs to be emphasized that each MPS may need more refined calibration using an exhaust gas analyzer by a mechanic if its not spot on for your car.

One way that the calibration could be correct for a particular car, is if the known good MPS from your current car is sent along with the core and then the calibration could be matched exactly, especially if the MPS has been previously recalibrated.

I have calbration specs for the 1970-73 1.7L, 1973 2.0L, 1974-76 2.0L and 2056, using the LCR inductance meter.

I think I'll determine a fixed cost to install a new diaphragm kit and calibrate an MPS to known settings, and leave the case cleaning for its owner. I will also just put a dot of epoxy to hold the outer screw in place, not a full embedment, to make it easier for others to access the adjustment screws if necessary

Does this seem like an acceptable approach for now?