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Kaefer Kaefer is offline
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Join Date: Sep 2004
Location: Central Va
Posts: 3,589
Quote:
Originally Posted by Reanimotion View Post
Scott,

The standard MicroSquirt firmware will not work to control the Frequency Valve properly.
The FV requires a constant frequency of around 100 cycles per second regardless of engine speed and an on/off ratio of +/- 50%, the staged injection is a timed squirt per revolution of the engine so the frequency varies with speed and the ratio is therefore too hard to control and too jumpy below 6000 rpm.
The FrankenCIS firmware has the fuel control required for both the FRV and eWUR and also does not need the eWUR at all if you are only interested in controlling the lambda circuit.

So start with FrankenCIS firmware from day 1, we've also written the firmware changes so you can switch the system between CIS modes and Normal EFI if you do feel the need to experiment.
This is great info. Isn't the 50% on/off ratio just the ratio that the lambda computer defaults to when it's not seeing a signal from the stock O2 sensor?

Quote:
Originally Posted by Reanimotion View Post
regarding the lambda control
From post 423 in this thread


replicating the static tests Eddie did with your 930 would be fairly simple, and safer than with a running engine on the road.
Stock operating range is 15% to 90% on time - so short periods of 12v or 100% wont hurt.
Gotcha.

Quote:
Originally Posted by Reanimotion View Post

The stock Lambda computer only has a limited range of activity and will disable itself under full load or extended marginal operation, so trying to fool the stock system would have the very high risk of the thing turning off at the wrong moment.

Also note the 044 pump and the stock CIS pumps have the same pressure and flow curves. The only difference being the different inlet on the 044 and the 044 is generally cheaper. There is a Bosch test results PDF link earlier in the thread, obviously a good new 044 might be better than a worn stock pump, but for the messing around I'd personally stay with a new stock replacement or change to the true 8bar motorsport pump from Bosch and not the 044.
You're again correct. However it's easy enough to change the input parameters to the stock lambda computer and get it to work in a non stock manner. I won't be going this route however as I want to learn the FrankenCIS/MS system to implement full control over my CIS system.

I did not realize the 044 pump and the stock CIS pumps have the same pressure and flow curves. Do you have a link to the 8bar motorsport pump?

Thanks again for all your help!
__________________
-Scott
1987 911 turbo
In the past - '71 T, '77 S 3.6, '80 SC, '88 3.6 cab
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