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'Fat Duc' O2 manipulator preliminary results.

Penis Rotor

GT Godfather!
Joined
Oct 28, 2008
Messages
2,833
Location
Bungendore, NSW Australia
OK. First things first. This product is NOT one that is going to give you any sort of wonderful increase in performnce. Nor is it going to make you be able to circle the globe on two litres of petrol. All it is a variable resistor that alters the signal the ECU recieves from the O2 sensor so that when the ECU is operating in closed loop some minor adjustments can be made to the AFR.

I *believe* that the system is operating in closed loop up to about 40% throttle although I'd imagine that this is also dependent to a degree on RPM. At what points engine speed wise it goes open loop I don't know, perhaps Todd has a better idea on this.

This product will NOT address any of the fuelling issues during the time that the system is running open loop, so f'rinstance on my Griso where at WFO once you are above about 6500RPM the poor thing overfuels to the point it should be pouring out black smoke and the Fat Duc can do nothing about it.

Moving on from there when I purchased it through Dan I was not expecting anything much at all in terms of improvement. My 8V Griso runs pretty damn well, most likely because i just set it up right and then have resisted the temptation to f@ck about with it simply for the sake of f@cking about. The only modification to stock as far as the motor is concerned is a Guzzitech Rx exhaust can that to be honest I find too loud but it looks great and I can live with the noise as i wear ear plugs and live in the country. Whether my neibors could live with it if I lived in the city is another matter! One of the reasons I have been unwilling to muffle it though is the absurd richness of the top end. If I were to muffle it it would simply make it richer still which is the last thing I want!!!

So on to the Fat Duc.

Installation is mindlessly simple. Remove the starter motor cover. Disconnect the O2 sensor and plug in the Fat Duc into the coin. It has the correct plugs on either end. Then it is simply a matter of positioning it and cable-tying it so that the adjuster is accessible and the loom isn't fouling anything. A ten minute job.

Adjustment was carried out by the time honoured 'Suck it and See' method. I found out where maximum and minimum input were by turning the screw and then set it about half way. Fired the bike up and went out for a good flog to warm it up.

Because of the engine temperature sensor location and the crude and inadequate temperature compensation mapping I wanted to get the bike well up to operating temperature before making any observations about positives or negative so I went for a good 20Km run. On returning to town it was obvious that the widget was having a quite useful effect. One of the biggest issues my 8V has always had is that at low RPM, low throttle openin, when hot it won't do what I would describe as 'Surging' but it will miss and hunt a bit and 8-stroke. This has the unfortunate effect of causing lash in the entire driveline and one of the things that had always worried me was that I could HEAR the pinnions in the box rattling back and forthe, loading up one way and then the other. Given that the ONLY shock absorbers in the driveline are the anti-rattle springs in the clutch friction plate and the silentblock type rubber insert in the driveshaft itself, (Which is pretty unforgiving!) I'd always been concerned about hammering of the pinnion faces. Right from the get-go it was apparent that this was GREATLY improved.

A few more stops and enrichment adjustments an I'd managed to get it to the stage where it would quite happily pobble along on a whiff of throttle at 2,200RPM in any gear and simply by gently opening the throttle it would pull cleanly without hesitation and none of the previous 'Hammering' was apparent. That for me has proved unequivically that the tool has merit.

Now the Caveats! I have tried this on precisely ONE bike. My 8V Griso and it has done what I wanted it to do, even though I didn't expect it to. As mentioned above it is NOT an alternative to something like the PCV and that will be my next modification with a view to addressing the weightier issues elsewhere in the map but it HAS helped significantly at the bottom end. You can feel the engine is happier! No it hasn't been done very scientifically, I'm not looking for an ideal, I'm looking for an easy, practical sollution to a problem that can be felt in the seat of my pants while riding.

Where I suspect it could be very useful is for people who suffer badly from the 'Popping on the over-run' so prevalent in some motors, most specifically the Norge, but as yet I have NO evidence to back this up.

The stepper motor seems to cope perfectly adequately with the mixture change as well and idle speed was maintained.

Somebody asked me to measure the resistance of the component so they could fabricate their own. Sorry, I feel a bit uncomfortable doing that. The bloke who produces the product has taken the time and the trouble to work that stuff out as well as having sourced the plugs and assembled the product, prepared it for sale and marketed it. I feel it would be dishonourable of me to simply short-circuit, (as it were.) his product by releasing wht I find publicly. If others feel OK about that? That's also fine, but my conscience won't allow me to do it. Sorry.

So? Am I happy? Surprisingly, yes I am. Very happy. I was really not expecting it to really do anything much but it does, at least on my bike. I'll do a bit more experimentation and next time I'm near an AF Dyno I'll fling it up and have a bit of a play with an EGA up the pipe but as it stands it has made a significant and pleasant improvement tothe rideability of the machine. It's also very cheap really. Yes the resistor is probably only a $5.00 part, (I have no idea!) but the plugs, wiring and assemble all have to be taken into account and if you buy it it just plugs in and comes with a money back gaurantee. I can't really see a downside!

I WILL re-itterate once more it is NOT an alternative to a *real* map modifier but it does address one issue rather well. I'm not a believer in snake oil. If I thought it was doing nothing I'd say so and I, as I said, wasn't expecting it to work. I've been pleasantly surprised.

Pete
 
Pete, thanks for the post. I would encourage you to go to your AFR dyno guy and see where it's at after a few miles. If you read, I watched the fueling go flat-line at >10:1 in short order. It did not flag the warning light either. If/when you do, have him hold steady throttle in closed-loop (if in fact it's running at the AFR you think it should be), run up into open-loop, that back down in closed and hold.
 
Yup, will do. It'll be interesting. I've only been out for a few tens of Km so far as I said the big thing it has addressed is the obvious driveline abuse, there is a lot of testing to go and it is NOT a wonderful panacea for all ills but I think it does have the potential to be very useful.

Time will tell.

Pete
 
Oh, another thing. While it was obviously changing the mixture significantly it wouldn't on my bike trigger the 'Service' alarm. Now it must be in line and delivering a signal as there is nothing showing up as faulty in the OBD. Note that this is an 8V with different mapping to that used on any of the 2VPC motors. I'm assuming Todd that your experimentation was done using your Norge?

Pete
 
On my 8V the service light comes on when I try to set it "richer" then halfway.
My bike has improved but is still running to lean especially when hot.
 
OK. And what pipe are you running? stock? I'm not expecting to be able to offer any stunning insight here, we are all flailing about with one arm tied behind our backs and a bunch of leprechauns playing hop-scotch on our todgers, but the more points of refference we have the better.

Pete
 
Probably still more restrictive than the Guzzitech pipe which is essentially a nicely made tube! That might have in impact. Are all the joints on the system gas tight? If air can get in then it'll throw everything to hell in a handbasket!

Pete
 
Pete,I have been waiting to hear your results after testing the fat duc.I am quite sure the mapping on the 8v verses the 4v are very different and it would be expected that the results may vary from bike to bike.My bike as stated previously is a 4v with canister removed stepper blocked off and an open minstal can which is pretty much a straight through pipe without the furnished baffle.With the baffle in my bike would set a code at alittle over the half rich setting,with baffle out I could move the fat duc to a more rich setting of what the manufacturer would describe as being about 13.4 afr.Just thought you might be interested.I feel for low rpm running in closed loop the fat duc truly improves ride-ability.At least on my bike.
 
Pete and Klaas

I've been following the PCV thread and have one on order. Tho not as knowledgable as Pete on whats going on with my 1100 4v, what he is describing by way of general symptoms sounds very close to what I'm finding. This has made me very keen to look further into the Fat Duc.

Is there another thread my search isn't throwing up that will give me more info on getting hold of one of these. As both of you have seen improvements, one on a 4v and one a 8v it does offer hope for me and if its cheap enough its a gamble well worth taking on improved running (pending PCV/ECU/Autotune/crossover....)

As Pete points out (and this applies to the replacement ECU/PCV deal also) and I'm with him on this... thankfully somebody has put in the time to help sort out our problems and they deserve some payback (I see it as reducing their loses rather than them making a profit as I'm sure they dont put $$$$ on the long hours they spend on it).

One more thing I'm a big fan of making one change at a time then checking the outcome. At the moment my only change is the can. This does seem to have opened up the breathing (30k run).I have yet to get back on the dyno but i think its safe to assume it will have brought the overfuelling at higher revs back a bit ..
 
Cool stuff!
I'm very interested in the outcome of this thread...
I have a stock 06 Breva that will be fitted with a Mistral can this weekend. I've not noticed any pinging or popping, but may have felt slight surging at low rpms. It isn't real noticable or pronounced anyway.

THis product seems to give a way to dial out the possible occurance of that surging.

Thanks to all involved in this!
 
pete roper wrote:
Probably still more restrictive than the Guzzitech pipe which is essentially a nicely made tube! That might have in impact. Are all the joints on the system gas tight? If air can get in then it'll throw everything to hell in a handbasket!

Pete

Yeah everything is gas tight Pete, but maybe my bike needs balancing and TPS reset.
The VDSTS software is on it's way and ECU swap + PC-V are ordered so I'm not worried about the results with the Fat Duc. It will be for sale in a while anyway.
 
duc wrote:
With the baffle in my bike would set a code at alittle over the half rich setting,with baffle out I could move the fat duc to a more rich setting of what the manufacturer would describe as being about 13.4 afr.Just thought you might be interested.I feel for low rpm running in closed loop the fat duc truly improves ride-ability.At least on my bike.
That probably explains the service warning on my bike, thanks duc.
 
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