PCV/AT and FAT DUC compared!

[Spaceclam]

Well, ladies and gentelmen, i have done a side by side comparison, thanks to my buddy Eldo Jon. His griso is equipped with a mistral, fat duc and home brew open airbox, while mine is equipped with a GT muffler and airbox ring, as well as the PCV/AT/ECU reflash. We traded bikes and drove around for a little bit.

My impression?

there is NO excuse to have a stock bike. at $70, AT LEAST buy the fat duc. It DOES help, and for the money, not a bad buy. It still pops, still pings, but it pops less so, and it's more powerful than stock, just all around better. $70 well spent.

Todd's solution however, is far better. It's smoother, more powerful, and a little more intuitive than the fat duc. Power delivery is much more linear, it revvs better, and just all around blows the fat duc out of the water. But it's also a chunk of change. (worth it IMO). The one piece, no need to modify anything airbox lid is a great design, and sure beats drilling holes. No inrush sound either.

I would reccomend the PCV/reflash kit over the fat duc by a big margin.

 

[guzzi jon]

What Andrew says, his Griso runs like a perfectly dynolinked PCIII, which is the gold standard. His torque curve and hp were linear and strong, I could not get one hiccup out of his bike, it worked flawlessly. It made it clear that the fat duc does clean up areas of the rpm/throttle position range, but the full solution changes the bike. I'm sold on it, it ran as well as my 02 Lemans and felt just as fast (85 bhp on the dyno)

 

[GTM®]

I would reccomend the PCV/reflash kit over the fat duc by a big margin. But if you just cant pony it up, do yourself a favor and buy the fat duc, unless you just plain dont care.

Caveat emptor on the FatDuc resistor... as I've stated before, I've watched it do ugly things during testing on the A/F dyno.
Jon, what kind of fuel mileage are you getting? I recommend pulling the plugs to ensure they're not wet, or you may be facing a premature top-end failure on the valves & guides. Just a heads-up.
Clam, how's the pre-detonation?

 

[Penis Rotor]

Todd, while it may of indicated it was doing strange things on the Dyno the fact is that in everyday use it is a cheap, easy and moderately succesful modification that can adress a lot of the 'Driveability' issues that people are experiencing.

Neither Jon or I are saying that it is a cheap alternative to the PCV-Autotune combination but for many, especially in the current financial climate, that simply isn't an option. If they're lucky they'll be able to hang onto their bikes, never mind tipping an extra grand into 'em!

The fact is that as a way to make the CL area work better the Fat Duc does work, no matter what horrors the EGA and dyno may reveal and enough people have been using them for long enough now that I think that your comments about top end wear are not only unsubstantiated but also a bit paranoid.

I am really looking forward to getting the PCV set up on the Chatanooga Choo-Choo next year but at the moment the Fat Duc is serving me well. It is a long way from perfect, on my 8V as soon as the ambient temp gets above a certain point in the high twenties centigrade the O2 sensor obviously moves it's signal outside the ECU's parameters and it throws up the 'Service' icon. It did this with bothe the GT-Rx pipe and with the Termi so there is obviously a problem with the EGT, especially at low load/throttle opening but the plugs are looking good, fuel mileage hasn't got appreciably worse, (Or better!) but a lot of the nasty CL issues have been adressed and the machine is a lot more pleasant to ride.

For people without bottomless pockets it is a worthwhile consideration. I understand that you are probably hunting 'Perfection' but for many of us simple driveability and general enjoyment are more important than obsessing about dragging every last bit of *whatever* out of the machine. Just sayin'......

Pete

 

[GTM®]

The least favorite EPROM person still has bikes fueling, however there is pretty solid data that I've collected linking top end failures. Since the FD resistor is adjustable, just need to put it out there. The above opinions are just that, and not shown/proven on the Dyno. I know what I witnessed, and for the record I wouldn't personally run one unless I was running a AFR guage to assure it's operation.

Yes I sell a pricey alternative that I can assure works as promised, and I've invested a great deal of time and money to the project. As I read above, it states that the FD resistor works as a cheap/viable alternative. I simply disagree based on above.

 

[Spaceclam]

Pinging..... It's still random. It comes and it goes, but it's SO much better than it used to be, especially in warm weather. Im still gonna check my squish here when school gets out

Fat Duc:
having compared it back to back, i wouldnt call it "dragging every last bit out of the machine". It's not night and day for sure, but for sure significant. Maybe it depends on your riding. I wouldnt call it an alternative. Band-aid is a better description.

I dont doubt the strange things the Fat Duc does on the AF dyno, but i think Todd also had a particularly bad experience. But it drives better than stock, and i would highly advise, if you cant get a PCV/AT, to AT LEAST buy the fat duc. Since some areas are leaner than others, you will never achieve *good* fueling, so probably better to set it on the lean side so you dont go over rich. Eliminating the popping requires 60%+ additional fuel in areas. If you get rid of the popping completely, you are WAY too rich everywhere else. However, just that extra bit of fuel, in the always lean closed loop area helps.

Call it bare minimum. It does work, if only somewhat. But for $70... it's a lot of bang for your buck.

Had i known this product actually functioned in our bikes, i would have bought one until i got my PCV. Kind of a mute point now though.

 

[GTM®]

Again, unsubstantiated... show evidence provided by a A/F dyno, and you'll see too. It seems that no one here can prove otherwise as to what I witnessed on the dyno, and I wouldn't call it a "bad experience" rather a witnessed huge downside to the product. Band-aid perhaps, but one with very poor adhesive, even if it "seems" to work OK. inch:

 

[guzzi jon]

Todd,
First of all, your system totally changed spacelams griso, it was superb in all aspects and besides fueling perfectly at lower throttle and rpm's seemed to have an extra 10bhp on top. I have an exhaust gas analyzer which I will be doing some garage only testing as I've lost the 12 volt adapter to carry it on the bike, but I am interested in what it shows. I have set mine to the leaner side just to make sure, but it does reduce the poping and make the bike run better. I thought I had the sweetest running griso around, then I rode spaceclams.....

 

[GTM®]

Thanks Jon, I would for sure test it based on my earlier outline, hate to see anyones motor compromised. If i didn't witness what I did, I'd have nothing to say.

 

[duc]

Well,only a quick note,as previous posts I have been messin around with resistors and the fat duc for a few months now.If I had the cash to spare or were looking for perfection I would go with the pcv and auto tune but neither works for me at this time.The fat duc has been on my bike now for several months,open air box open exhaust with the tps set a little higher than standard.The bike runs well,setting the icon depending on temp,but no overly rich exhaust nor lean looking at plugs and tailpipe.It isnt perfect like my duc with full exhaust and tuned pciii but it sure beats nothing!

 

[jlburgess]

For the guys going for bang for the buck, I'll give ya the lowdown on the PC V only option - no ecu or autotune changes. I'm running it on an 8V with the open airbox and a Zard pipe. It has a Stelvio map loaded in it currently, but I'm off to the dyno room on saturday.

Knowing the mapping isn't correct, I can say that closed loop mapping seems to be vastly improved. No popping and very little surging noticed.

I am guessing that the O2 sensor can only make some changes, not massive one's like the +80 map numbers I saw in the yet to be loaded 8V map Todd emailed me. I'll post up some dyno numbers this weekend. I'd say the bottom line is that it works pretty well without closed loop elimation or fat duc mod.

 

[GuzziMoto]

I am guessing that the O2 sensor can only make some changes, not massive one's like the +80 map numbers I saw in the yet to be loaded 8V map Todd emailed me. I'll post up some dyno numbers this weekend. I'd say the bottom line is that it works pretty well without closed loop elimation or fat duc mod.

As delivered by Todd the PCV can not change more then 20 from the base map, but once you accept the changes the process begins all over. So yes, with a few rounds of that it can change the fueling that much or more if needed. To me the best thing about the AutoTune is that it will keep fine tuning the map as air temp and pressure and whatever else throw off the fueling due to the correction factor the stock ecu applies not being perfect. With a set map, even a well made map, there may be times when it is really hot, really cold or you are riding up a 10,000 ft mountain, where the fueling will be slightly due to the ecu not adjusting the fueling to compensate for the change in conditions correctly. Is it a major problem? No, not really. But it is nice to know that the bike will run as near the same as possible regardless of conditions. And after all the $$$ spent on the rest of the ecu/PCV kit the AutoTune was not much more.

 

[jlburgess]

I'd be good with 1 map that works right. Way back in the good old days ;>) when carb's used to rule, almost every bike got 45 mpg and could be adjusted in a few hours with $10 in parts. Now we get 32 and massive techno wrinkles to iron out. I'd take a couple of flatslides in a heartbeat it that was offered!

PS is that your no crash pic?. Looks like you kept your eyes pointed where you wanted to go...

 

[Spaceclam]

JLburgess,
the PCV option alone doesnt touch the closed loop, unless it was improperly configured. IN which case, the 02 sensor will just continue dropping the fuel until the total amount the bike sees (including the increase in the PCV) is the lean mixture it wants to see.

Or, perhaps your TPS is a little messed up and telling the computer to add more fuel.

I think what you are experiencing is called the placebo effect.

You are right though. Fuel injection was designed to crap all over carburators, but instead, manufacturers and the EPA just use it as an effective method of pollution control. Most people dont have the tools to undo this, and thus, carbs crap all over OEM supplied EFI

sad.

 

[GuzziMoto]

PS is that your no crash pic?. Looks like you kept your eyes pointed where you wanted to go...

No, I'm too old. I couldn't bend my leg up that high anymore. Hell, I have to wear a knee brace now when I race to keep my knee from popping out of joint. I am a reasonably fast guy at my local grassroots level, but my days of pro racing and putting it on the line like that are long gone.

 

[jlburgess]

Clam,
I'll have to disagree with the placebo effect. I believe the maps Todd has sent out are built with auto-tune, so all mapping cells are changed from stock. Without the ECU mod, the O2 sensor will fight against the PC V, but ultimately, the PC V is connected directly to the injectors, so I suspect the tendency will be a pulse duration closer to the intended PC V mapping than not, especially when rpm or throttle position is not constant.

My bike doesn't pop on decel anymore either.

Another thing I noticed when viewing the 8V map is that a lot of zeroes are present at high rpm. It's extremely unlikely that the stock mapping is that good, so for some reason the auto-tune didn't make any changes there. Maybe the test bike hasn't been run up to redline enough. Another reason I'll give the dyno a try.

 

[GuzziMoto]

Clam,
I'll have to disagree with the placebo effect. I believe the maps Todd has sent out are built with auto-tune, so all mapping cells are changed from stock. Without the ECU mod, the O2 sensor will fight against the PC V, but ultimately, the PC V is connected directly to the injectors, so I suspect the tendency will be a pulse duration closer to the intended PC V mapping than not, especially when rpm or throttle position is not constant.

My bike doesn't pop on decel anymore either.

Another thing I noticed when viewing the 8V map is that a lot of zeroes are present at high rpm. It's extremely unlikely that the stock mapping is that good, so for some reason the auto-tune didn't make any changes there. Maybe the test bike hasn't been run up to redline enough. Another reason I'll give the dyno a try.

The stock map tends to be lean in the low to mid rpms and ok to rich up top.
The PCV with out the AutoTune/ECU O2 delete will only adjust the fuel a set amount from what the ECU is trying to do. If the ECU decreases the amount of fuel to inject at a certain rpm and throttle postion due to the O2 sensor saying that it is too rich at that point (due to the PCV adding extra fuel) , the PCV will not add more fuel to maintain the original amount of fuel. Plus, the ECU will keep removing fuel to get back to the 14.7:1 that it wants to see. Eventually, either the O2 sensor will win and the air fuel ratio will be maintained at or near 14.7:1 or the ECU will trip the service light since something must be wrong as it is maxed out on how much fuel it can take away and the mix is still to rich. That is why if you dial in too much with the FatDuc unit it can trip the service light. It is not a function of exhaust temp but rather the ECU has maxed out its correction factor and the mix is still too rich. Yes the O2 sensor may not react quick enough to correct the extra fuel when the rpms are changing quickly, but those are mostly the times when the ECU is in open loop mode and the O2 sensor is not a factor (but the PCV is).
Yes, without an AutoTune, building a map is the next best thing. But its effects and ability to improve the performance in the closed loop parts of the fueling will be pretty limited. That is why DynoJet did not introduce a PCV for the CARC Guzzis until Todd came up with this package. Without removing the O2 sensor DynoJet saw limited improvement and issues caused by the O2 sensor.

 

[jlburgess]

I'll buy that. The best way to avoid closed loop issues other than the ECU mod is to never ride in closed loop. It's a lot more fun too ;>)

 

[Spaceclam]

when i removed the stepper motor, my bike ran fantastic for about 50 miles. Then the o2 sensor figured out that the mix on decel was too good, and soon after, it corrected to run like crap again. Could it be that you havent ridden much since the install?

Basically, the short story is, the o2 sensor will eventually win on closed loop, because it feeds back to the ECU. you can add fuel with the PCV, and the effects WILL be noticeable until the o2 sensor leans it out again, undoing what you just did.

the ECU reflash actually disables the input for the o2 sensor, so that cant happen.