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DIY O2 manipulator

Hagaik

Hagaik

Just got it firing!
Joined
Jul 14, 2015
Messages
16
Location
Israel
I just finished building and installing 2 O2 manipulators on my V7II. They're basically "fatduc" style - a simple voltage divider circuit.
Did around 200Km since installing them - the engine feels "rounder", less prone to hesitation in opening the throttle and smoother deceleration. Also feels like it's running a little cooler, but I have no way to measure this. No "check engine" light.
All in all - a very nice upgrade for very little money - bought enough components for building 4 of these puppies for about 30$ US.
Cheers
Image Image
 
Are you going to let is into the secret of the resistance ratio? I was told that a particular type of diode in the line would work, but it brought up the service light.
 
Early on I put a schottky diode in my Breva , it bought up the service light but it went out as soon as the bike warmed up. It seemed to fix the popping on decel and the weak mixture. I had it in for about a year, its all back to original now. I've got about 60,000Kms on the bike and it runs sweet as.
 
Brian UK said:
Are you going to let is into the secret of the resistance ratio? I was told that a particular type of diode in the line would work, but it brought up the service light.
Click to expand...
I used a diagram I found online - I can find the link later this evening and post it.
 
this is the diagram I used - found it here:
apriliaforum.com/forums/attachment.php?attachmentid=204446&d=1349343861&thumb=1

attachment.php
 
The older 15RC (sign216 link above) and the MIU used on the newer V7 are not the same, and won't work correctly. I would be sure what you built in for the newer ECU.
02-sensor foolers are band-aids, and while occasionally can work, most feel the step from closed to open loop more pronounced.
I offer a version that is more then a simple resistor; https://www.guzzitech.com/store/product/gt-02-optimizers/
 
Hagaik said:
Actually I did see your tutorial - very nice and helpful, thank you!
I had the resistors laying around so only had to get the trimmers - but your solution with the diode looks very simple and certainly easier to do.
Click to expand...

Fatduc uses a trimmer like yours, so it's all just different ways for the same goal; lower the signal voltage.
 
sign216 said:
Fatduc uses a trimmer like yours
Click to expand...
FatDuc uses a simple variable resistor. Mine uses an actual powered circuit board. FatDuc does not work on the 5AM or MIU.
 
I can see why an O2 spoofer is a "band-aid" solution, compared to a properly mapped ECU.
But all things considered - I can't see how one voltage-regulator circuit is fundamentally better than another (e.g Fatduc vs Schottky diode vs LM317). There are different practical advantages to each (diode is dead simple, Fatduc is continuously adjustable, LM317+DIP switches has stepped voltage control) - but they all eventually fulfil a very simple role: lower the signal voltage coming from the lambda sensor.
Am I missing something here?
 
Hagaik said:
Am I missing something here?
Click to expand...
It's never as simple as one may think, because the newer ECUs are more intuitive than the older 15RC; The FatDuc delivered off the scale rich conditions at low speed throttle, and never returned for several minutes (while being tested on the dyno) on both the 5AM (Big block Guzzi) and the MIU (V7). I would highly recommend having your air/fuel data checked on an A/F dyno if you tinker with home built devices.
 
can somebody explain how to install the Fat Duc on the v7ii? thanks
i can't find instructions online!
 
Mate I haven't used one but it looks fairly simple to install.
You will have to find the two 02 leads (plugs) the one on the left gear lever side is behind the side cover and the one on the right is behind or just in front of the right hand side cover rear brake side.
Unplug the 02 leads and plug the fat duc in.
 
frnco said:
can somebody explain how to install the Fat Duc on the v7ii? thanks
i can't find instructions online!
Click to expand...
Does anyone ever read anything I write? I really wonder how much of a waste of time I spend posting these days. See below or above. Good luck.

GT-Rx® said:
It's never as simple as one may think, because the newer ECUs are more intuitive than the older 15RC; The FatDuc delivered off the scale rich conditions at low speed throttle, and never returned for several minutes (while being tested on the dyno) on both the 5AM (Big block Guzzi) and the MIU (V7). I would highly recommend having your air/fuel data checked on an A/F dyno if you tinker with home built devices.
Click to expand...
 
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