MFI Pump - Open Heart Surgery

[356RS]

You will need to replace the complete arm assembly, or try to clean up and polish the tip.

[Peterfrans]

I have run into some question while rebuilding my mfi pump. The dimension "f" for this pump is 22.75mm. The thermostat, once fully warmed up only comes to 22.40mm (a second spare is the same). Obviously, I can achieve 22.75 with a set screw, but that will never be reached under normal running conditions. What is the correct approach here:
1. use a set screw to 22.75mm, then adjust the stop (8,9,10) accordingly and then proceed to set dimension "c"
2. use the maximum length provided by the thermostat and use that as "f"

[philippeF]

I don' t think that 22.75 is a good value, What is your pump ?

[Peterfrans]

2.7RS.

I have the burgess book that provides 22.75 as "f" for most pumps (exception the very early 2.0 pumps).

My bosch documentation states:
+15 - -15 C "f" = 19.60-16.90
+50 - +20 C "f" = 22.75-20.05

with f at 22,75 I cannot get "c" to 0,8mm without excessive shimming of the barometric cell.

Second question is adjusting the transmission ratioe with the excenter on the correction lever. The handbook provides a basic adjustment and a procedure to adjust using an unobtanium tool. Any idea what the effect of turning cw or ccw would yield?

[philippeF]

Peter
I won't advice to play with the ratio screw, you will offset the entire map area, then have the pump to flow uncorrectly ...

[356RS]

Peter, 22.40 is close and you should be able to get your 0.8mm "c" with the 2mm baro spacer plus a few 0.10mm to 0.35mm shims. If you can't, then you can adjust the threaded base & shaft nut #8 to get your "c". You will not need very much of an adjustment. Is your baro cell in good shape?
About the eccentric nut on the "c" balance bar, adjusting this will change the main rack ratio a small amount. I would just leave that one as is.

[356RS]

Peter, if you do attempt to adjust the spring shaft, don't forget to loosen the shafts base nut first before adjusting #8 nut.

[Peterfrans]

Thanks Mark,

the baro is in good shape, shows the same extension as a spare I have (the same for the thermostat btw). I think I will focus on "c" and adjust f accordingly by the #8 nut.

[Eisenbrandt.eu]

Hi injection pumps fans.
We are a german company and our profession is MFI.
On the subject of individual MFI mapping we developt several technics.
Transfer maps on spacecams for road and race is important.
For the desired map engine-mapping in dyno is required. We`re using electronic control unit, a so called Master pump.











This map is from a 3.0-liter engine with 360 hp.
The mapping of a 3.0 RSR MFI with space cam 109 is not to compare with the required mapping.

Through the well-tuned mapping the engine reaches an unexpected performance.

With the obtained data, we calculate a complicated process a space cam.
These data are to mill the basis of a 5-axis milling machine, a space cam ..
We use only the 18 mm wide version.



What is discussed here often is sampling a scam with a dial indicator.
That's not easy, it needs at any angle and at any value are accurate.
Accuracy in hundredths of a millimeter is important.



To reproduce Spacecams we have built a fully automatic measuring machine.
We have surveyed and digitized all Porsche cams, so that we have remade every Spacecam and in stock.

I look forward to your opinions and questions.

Best regards

Joerg