[longstrokeclassic]

Has anyone considered fitting an AFR modulator on their EFI? something like this -
http://www.dimsport.it/en/rapidbike Easy
 Seems a slightly more elegant solution to changing the AFR than fitting a PowerCommander (unless you're chasing performance).

[tooseevee]

Has anyone considered fitting an AFR modulator on their EFI? something like this -
http://www.dimsport.it/en/rapidbike Easy
 Seems a slightly more elegant solution to changing the AFR than fitting a PowerCommander (unless you're chasing performance).

           Read the whole website and it seems good to me, but can find no unit for Royal Enfields. Luckily and thankfully I don't need one.

[Bert Remington]

I found this topic yesterday while researching ECU tuning options and it cut to the core question: closed loop or open loop?  This is going to be a long, technical and probably controversial discussion.

My 2016 C5 is tuned closed-loop using an AFR adjuster (AF-XIED configured for Alpha-N BMW R1100 ECU) with a loud "cocktail glass" muffler (I can't bring myself to call it a silencer) and Peter's dual-fin intake manifold.  I was getting what I consider excessive popping and backfiring on overrun/coasting throttle to the extent I usually pulled the clutch in when coming to stops in urban settings.  And low throttle transitions weren't consistent but having ridden Amal-equipped British singles a half-century ago, my old habits compensated.

This particular post will address why I was now researching ECU tuning options.  First, Peter the cam guy says an open-loop Power Commander (ie, PCV) must be used.  Second, I recently purchased a 2010 C5 that included a PCV in its box.  Third, in the process of relocating the EVP canister behind the engine, I temporarily blocked the TB's Purge port and then rode both mountain-to-sea level and at sea level.

With no other changes, the popping and backfiring were gone and throttle transitions were smooth and consistent.  I might get a little chuff on full throttle closure but I've chuffed louder myself.

This is very distressing.  I was always bothered that the RE EVP design did not include an ECU-activated valve in the circuit like all other motorcycles and cars that I've examined.  Instead they used a 3-port valve under the gas tank together with a tee in the Purge circuit that included the TB and EVP canister that looked iffy to me.  And Yes I checked the connectivity against both markings and the airbox diagram.  And now removing the EVP circuit from the air-fuel equation I get normal engine operation.

Well not quite.  Peter has asked for performance information but I've delayed while the motorcycle is breaking-in (2.6K miles now).  Now that I'm comfortable running at 55mph (60 indicated) I have a mile-long test hill with a mild slope for the first third then steepens for the last two thirds.  I enter in 5th at 60 (indicated) but when the hill steepens more throttle is required.  About two thirds up the hill I'm at full throttle and am losing speed.

After blocking the TB's Purge port, I easily rode up the hill at steady 60mph (indicated).  Air temperature was within 5F of previous runs.

I can accept the possibility of AF-XIED+loud muffler+EVP canister leading to air-fuel mixture popping/backfiring issues but I can't accept the apparent EVP-caused power loss.  EVP doesn't work that way.  The circuit is closed from the air-fuel mix except when the ECU commands a purge under certain conditions that don't affect power and drivability.  Except on an RE.  As Kevin Mahoney explained, he had to find the EVP solution and then drag a reluctant RE into producing it.  Which they did, obviously poorly.

The story continues with the next post.

[Bert Remington]

I lied about making no changes when blocking the TB Purge port.  I relocated the rectifier-regulator at the same time which included temporarily disconnecting the battery negative wiring (which was reconnected exactly as before).

And I forgot to mention the first ride (mountain to sea level) included several idle-hunting incidents at traffic light stops.  They don't seem be occurring with subsequent rides.  Which brings up the following questions:

(1) does the RE Keihin ECU have a long-term trim capability?

(2) if so is the trim stored in volatile or non-volatile memory?

(3) if so is a TPS reset protocol included, ala the BMW Motronics ECU?  (The BMW reset after battery reconnect is turn ignition on, fully open and close throttle several times, and turn ignition off.)

With all this in mind, let's examine two the AFR FI tunings the ECU might use.  I'll begin with a longish quote from a Triumph forum:

----------
[Per ANFA under the heading:] The alpha speed principle (αlpha N)

The theoretical approach is identical except that the load is no longer determined by the engine speed and manifold pressure, but by the throttle position and engine speed. The coefficient of loss will be of the form: K2 (αlpha, N).  The disadvantage of this system lies in the accuracy of the throttle position information because it is a much less accurate than the manifold pressure. However, for transitory operation, the rate of throttle opening is interesting information which reduces the response time of the motor by adjusting the injection time

In reality, manufacturers use two systems:

• p, αlpha, N: Pressure manifold, throttle position and engine speed.

• αlpha, N: Throttle position and engine speed

[Note: p is 'pressure' as in manifold air pressure; alpha is 'angle' as in throttle plate angle; and N is 'number' as in number of crankshaft revolutions per minute.  Ya gotta know those math codes.]

The system p, αlpha, N uses two separate maps to determine the mass of air admitted.

• The first uses the manifold pressure and engine speed for low loads.

• The second throttle position and engine speed for high loads.

The system thereby combines the advantage of the accuracy of the pressure sensor at low loads and the low response time of the throttle position sensor for rapid load changes.

Today, the system αlpha, N tends to disappear in favor of p, αlpha, N which offers better drivability and does not require detailed settings.

----------

Per the forum, Triumph's Keihin ECUs use p, αlpha, N system with two AFR mapping tables: F and L. The F (low load) table uses the p, alpha,  N system and L (high load) table uses the alpha, N system.  Its a closed-loop system that includes an O2 (lambda) sensor.  It also includes an EVP canister with an ECU-controlled valve (just like all other EVP systems I'm aware of).

The RE Kiehin ECU seems to be a p, alpha, N system as follows:

MAP (p): provides air density
TPS (alpha): provides engine operating mode; PCV connects to this
CPS (N): provides engine speed and timing; PCV connects to this
fuel injector: fixed pressure* on-off valve; PCV connects to this
ignition coil: energy storage inductor; PCV connects to this
HEGO (lambda): voltage generator; AF-XIED and Rapid Bike Easy connect to this; except for 2017, PCV replaces with their "O2 Optimizer"

* the fixed pressure is a nominal 40psi controlled by in-tank regulator working in a sealed variable-pressure tank (ie, with no correction relative to intake manifold vacuum and with a off-on vent valve that takes several psi to open).  Does the ECU also use the MAP or HEGO to adjust fuel injector duration (pulse width) to maintain atmospheric-to-intake differential at all elevations and throttle openings?  And what about the varying gas tank pressures -- HEGO corrected?

Next post: the mystery of the RE Keihin ECU plus the AF-XIED, RB Easy and PCV.

[Bert Remington]

I like closed loop systems.  Perhaps due to those Navy fire control engineers forming my brain at a tender age.  But I also learned, sometimes painfully, доверять, но проверить.  Your sensors are going to lie and your actuators are going to ignore you.  And both are expensive so choose and use them for maximum ROI.

Based on its size, pin count and contemporaries I expect the RE Keihin ECU is a sophisticated p, αlpha, N system with dual AFR mapping table and long-term trim capabilities.  But does RE fully use those capabilities like Triumph apparently does?  Certainly there seems to be no equivalent to Triumph's TuneECU feature although this warrants further investigation.

Let's explore this using fuel injection pressure correction possibilities.  The fuel pump is in the sealed gas tank, which is common for fuel injection as the higher pressures typically require a fuel-cooled pump.  The in-tank piping includes a nominal 40psi pressure regulator and the tank itself is vented through a 3-way valve whose closed-open activation pressure seems to be 1-2psi.  The ECU controls the closed-open fuel injector valve with a single, variable-width pulse.  The fuel injector is working into the varying intake manifold vacuum.

Is this tank-to-intake variance significant?  In my experience, external return-to-tank pressure regulators include a hose to the throttle body to provide a consistent injector-to-intake pressure differential.  I'm not sure how this differential is maintained, or even if it is, for non-return-to-tank systems like the RE.  But my research leads me to believe it is significant and that modern systems provide some means to adjust for the varying injector-to-intake pressure differential.

If the RE ECU does provide this adjustment, then two methods are available: MAP feed-forward and HEGO feed-back.  The MAP method is a simple and direct atmospheric-to-intake measurement but it doesn't compensate for tank venting events of 1-2psi.  Since the bottom port of 3-way valve is connected to the TB Purge port, perhaps the intake vacuum is reducing the events to fractions of psi so no compensation is needed.  The HEGO method is more complex (what is the cause of the AFR change?) but in all cases enables correction for all causes.  For both MAP and HEGO the correction is increased or decreased fuel injector pulse width.

Let's step sideways for a moment and examine the AF-XIED and RB Easy AFR modifiers.

My specific AF-XIED, which I borrowed from my BMW, is configured to the R1100's Motronic αlpha, N system (more modern AF-XIED configurations are available).  While having two cylinders, the BMW fuels and sparks like the RE: every rotation which means alternating "dead" and "live" fuel and spark events for each cylinder.  It has a potentiometer to vary the AFR.

An example RB Easy for the KTM 390 (https://rapidbike.us/products/rb-easy-ktm-390-duke-rc-2012-2017) which likely to be a modern p, αlpha, N system.  The Easy has two controls, a multi-position switch for a specific make/model configuration and a potentiometer to vary the AFR.

Since both are in the post-combustion feedback loop, I don't think the difference between the αlpha, N AF-XIED and the p, αlpha, N RB Easy will be significant.  But then again I could be wrong.

Returning to the main path, what does this mean for choosing AF-XIED or RB Easy vs PCV?

If RE's programming of the Keihin ECU is as crude as it appears on the surface, then the open-loop PCV is the better, albeit more complicated, choice.

If RE's programming of the Keihin ECU is more capable including long-term trim, TPS reset protocol, tank-to-intake differential compensation, etc then the closed-loop AF-XIED or RB Easy are the better and simpler choice.

Which almost answers the initiating question.

So how crude/capable is the RE programming of the Keihin ECU?  I'll search the Triumph forums for more clues.

And returning to my infuriating EVP experience, let's just say I'm not going to be in a hurry to mount the canister behind the engine.

That's all for now.  What are your thoughts?

[Haggis]

My thoughts, you have too much time on your hands and your brain is in hyperdrive.
Other than that I think you overestimate the complexity of the RE EFI.
The tank on my 2016 C5 has an internal breather pipe that vents to atmosphere so there are no pressure changes within the tank.
The pump runs continuously once the engine starts and delivers fuel at 40psi controlled by a relief valve on the pump.
There is nothing in the system to measure any change in pressure.
I have tried an Amal carb conversion which was very easy to do and the bike ran extremely well.
Lovely smooth connection between throttle and engine. Dyno at 21rwhp.
I now have a PCV fitted which gives more power, 25rwhp, but does not have to creamy smoothness of the carb.
Personally, closed loop fueling is a pain in the butt. It's only function is emissions and does cause problems by weakening the AFR until engines can barely run.
At least with the carb and the PCV I can choose AFR.

[Rattlebattle]

We are fortunate in that we don't have charcoal canisters on our REs (unless the Euro IV ones do, I wouldn't know). I put a carb on mine too, but I've just taken it off and put back the EFI. Mine ran well enough with the Amal, but I've always had a nagging concern about why the earlier carb conversion kits were a lot more expensive and came with a replacement generator and ECU, rather than mine which only had the hardware for the carb mounting and control and the carb itself. What exactly is the ignition curve doing? Is it still active? Is the ignition now fixed? Who really knows? Frankly I got bored with the loud noise from the first "silencer" I fitted. It seemed a bit OTT to me to be making all that racket yet hardly moving. Having fitted a nice stainless silencer made by Motad, courtesy of Hitchcock's it now produces a sound reminiscent of an old Brit single - loud but muted if that makes sense. With the removable baffle in I doubt that it's far out from the original, not enough to warrant a PCV etc anyway. Amazingly (to me) the EFI worked fine when refitted. It must have a zillion stored fault codes given the disabling/disconnection of nearly every sensor during its pre-historic period (carb fitted). Yet the MIL extinguished normally as if nothing had happened.
Personally I like EFI; going back to a carb was interesting but frankly it's a lot easier tuning EFI than dismantling a carb to change needle position or jetting. The slide is scored already at 2,500 miles use, even with an air filter. Twas ever thus; you can get a Mikuni conversion now....It is years since I had a bike with a carb. For me fuel injection started with the K series bikes. Never touched the FI system; never needed to. Next came BMW oilheads. Some fiddling around with tps voltages, throttle body balancing and cat code plug changes to get rid of surging. Quite informative, loads of info on oilhead forums about relatively simple system. Enjoyable to learn and play with. BMW F800GT came next. Full-blown EFI with can bus system. Never touched it, never needed to. Honda Deauville 700cc. Same. Triumph Sprint GT SE. Same again, though had I kept it beyond warranty I would have used TuneEcu to service it. No need to flash the ECU to remap; it was spot-on from the factory. Current Triumph Thruxton 865cc. Extensive use of TuneEcu to service the bike (easy peasy). Also to remap it. No need to fiddle with fuelling myself as I bought a dyne tested map that was designed specifically for the stage 1.5 mods I have done on my bike. It's like night and day compared to the anaemic performance of the emissions junk cluttered factory bike. Sounds superb too and is now easily the best fuelling bike from ticker to full bore I've ever owned. The thing is that there is such a wealth of info about what works and what doesn't on these Triumph air/oil cooled twins - not really the case with the RE kit, which IMHO is good kit spoiled by poor implementation and options for tweaking, even by dealers. To those who like to fiddle with them I say good luck, but at the end of the day unless you're into cam timing and cylinder head mods etc and want to seriously tune them IMHO it's a waste of time. You can't turn a slug into a racehorse just by tweaking the EFI.

[Haggis]

I don't think there any major problems with the ignition timing when fitting a carb.
My bike was making more HP with the carb than with EFI, no other changes.
If the timing was off in some way then the performance would have been adversly affected.
Various bikes owned in the past like Yamaha ttr250, GasGas 250 Cami had carbs with ecu ignition and they managed their ignition curve just fine.
Not looking to turn it into a racehorse but that does not mean living with a donkey.
Its reasonably easy to have the engine run at optimal performance and enjoy it for what it is without the intrusion of ECU intervention, just like you and I did with the early BMW sytems.
They are good fun though and always raise a smile.

[Bert Remington]

Rattlebattle -- my motorcycle experience matches your until the oilhead and then I went in the RE direction.  I concur with your ECU conclusion.

Haggis -- yep I'm retired and am spending too much time in front of the computer because world events are just so fascinating.  I wanted to give the RE a chance so researched its FI and shared my findings in hopes someone might see and say: "Try this, it worked for me."  But I doubt that's going to happen.  Rattlebattle nailed it with "...not really the case with the RE kit, which IMHO is good kit spoiled by poor implementation and options for tweaking, even by dealers."

With the TB Purge port plugged, the popping and backfiring are essentially gone and throttle transitions are more consistent.  The EVP canister is ready to mount at the back of the engine and once I sort things out that's where it will go.

I'll bypass the AF-XIED and, if there aren't any changes, back to the BMW it goes.  When the PCV arrives late August I'll install both it and Peter's cams.  And while I preferred closed-loop solutions, I also learned sometimes open-loop is the right choice.

[Rattlebattle]

Haggis: You may well be right re the ignition timing, though my point is really about partial throttle opening. Mine was certainly as pokey once revving ie when it would be on full advance anyway. Maximum power isn’t what I meant. I know that on the Triumph the ignition curve can be altered as well as fuelling. Most bikes pre EFI had electronic ignition and advance curves, as did the home market bikes with a carb. Why did the older conversion have a different generator? Was the trigger that fired the ignition in a slightly different place? Who knows? What I do know is that EFI systems accept different fuels more readily. How can a carb tuned for fuel containing say 5% ethanol automatically adjust for fuel with 15% ethanol in it, given the different stoichmetric ratios of petrol and ethanol? It can’t. Nor can it adjust for significant altitude differences.
I bought my conversion simply because it was a lot cheaper than a PCV. As I’ve now no intention of tuning the engine anyway I’ll stick to the EFI, crude though it is. My choice.
Bert R: The thing I forgot to mention is that I don’t use the O2 sensor. I blanked this off not long after I bought the bike and put a resistor in the O2 sensor socket. These bikes have a cheap narrow band O2 sensor rather than a wide band one. Hitchcock’s reckon the Euro IV EFI is a lot more sophisticated than that on the earlier bikes and that the O2 sensor should remain in place even with a PCV. I’m not sure anyone had really cracked the differences between the two systems yet. Maybe it has a wide band sensor and doesn’t need remapping for a different exhaust as it is self-learning? Does anybody actually know?
Wish I’d kept my 1100RS. There’s one for sale with only 7,000 miles on it - a late model (2002) so one with the best gearbox. Tempted I am....

[Bert Remington]

Rattlebattle you know the BMW Pluses: performance, protection and Minuses: weight, it's still a Getrag.  My BMW is kinda lonely...until it gets colder and wetter.  I think you need one too.

[gashousegorilla]

   Bert , why not use a wide band o2  sensor and auto tuner with that PC-V you are getting or may have already  ?   You would be running "closed loop " then.      They WERE a little pricey, but a little snooping around Ebay... particularly from the California seller's... the prices have come down quite a bit from list price.  It seems they may throw a guy in jail or heavily fine him for doing a little tuning on his bike out there  .     Anyway.. they may not ship to California residents.   But I'll tell ya ... I was skeptical about using them in the past.  But since trying one out for the last 6 or 8 months or so , on bikes with different configurations or whatever I throw at it.  It does the job nicely and is snap to use.    A windows laptop or PC is a must though.   create lean maps  or rich maps or switch between the two...  or whatever suits you. 

[Bert Remington]

GHG -- dang I should have seen that.  I knew the AutoTune included the wideband HEGO (properly UEGO) but this EVP canister thing has affected my thinking.

I've found a new, privately-owned combination PCV+AT-200 for a modern multi-cylinder motorcycle for about the price of an AT-200 only.

This means sensor-actuator connectors are different from RE but that's easily fixed.

My big concern is sensor-actuator device mapping.  The PCV for RE has four; the PCV for the other motorcycle seems to have six.  Not only is the count different but the device characteristics might be different (eg, Kettering vice CDI).

DynoJet provides excellent capabilities across a wide range of motorcycles.  To achieve this flexibility at reasonable cost, I would expect the PCV's sensor-actuator interfaces to have programmable device characteristics.  Therefore when you load an  map, those characteristics are included along with the AFR mapping thereby allowing the same PCV electronics to be used for all motorcycles, albeit with different wiring harnesses.  Do you have any opinions on this?  Should I ask DynoJet?

I know you located your UEGO by your kickstarter but I'd like to use the stock HEGO location.  I feel dumb asking but I'm not at my workshop: are the UEGO and HEGO the same size M18x1.5mm thread?  The bung angle and distance seem to match DynoJet requirements.

[gashousegorilla]

  Honest answer Bert ?   I ain't sure if you can use that PC-V off of that multi-cylinder bike.  But my gut tells me no.  And my buddy around the corner , who is Dynojet dealer and tuner has told me no in the past.   He was told by a dynojet rep some time ago.. that there are issues with resistance values of the injectors on various different bikes.  One example would be ... if i am remembering correctly ?...  Dynojet offers a PC-V for a Triumph Bonneville, but NOT for a Triumph Scrambler ?   You would think they gotta have the same EFI systems ?!    But evidently not... different injectors .

 Anyway , I HAVE  used a PC-V for a Suzuki LT-R 450 on my bikes.. without issue . But it does not have ignition control.   That is not a must with these bikes,I have found ... BUT you can gain a bit more with some judicial timing advances , depending on how your motor is set up.   The plugs are the same, at east for the earlier bikes.  And you would need the o2 sensor "optimizer"  or cheater for the  Enfield Model PC-V.    Or make your own, I'm sure.   But obviously, if you are using the auto tuner , you don't need the o2 cheater.

 Dynojet has EXCELLENT tech support I have found.   Even to the point where they will remotely get onto your laptop, if you want them to, and start tuning your bike a little bit to check things out and etc. ... update your hardware and software and etc.  For me.. the PC-V and the auto tuner has been WELL worth the money.   I would most definitely give them a call and see what they say.

[hpwaco]

Wish I understood any/all of that! ! ! !.   What's a TB purge port? ?