Fuel-X Lite Review: Plug-in Fuel Injection Optimizer

[sacbiker]

I ordered a FuelX Lite for my bike.
The reason why I don't use the 390 much these days is because it is a pain to ride it in the city in lower revs.
Experts say that this is due to the unusually lean AFR set by the OEM in lower revs to meet emission standards.
I was initially planning to get the Powertronic V4 ECU, but then it is too much wiring and tinkering around! I also do not seek any more power from this bike.
Plus, I am 100% sure that I will keep playing with custom maps and screw up the engine ultimately. So I decided not to get the Powertronic piggyback ECU.
Race Dynamics was running an Independence Day sale with 10% OFF,
Decided to go with the FuelX Lite version as it would suffice my use case of a stock bike. It is told that even minor mods like a free-flow air filter and exhaust mod can also be handled by the module.
Got it for Rs. 5841.
The shipping got delayed due to the Independence Day holiday. Still waiting for the delivery.
If all the reviews from Youtube are to go by, the module will make the 390 rideable from 2000 RPM onwards. (It idles at 1800).

Expected behavior after the mod.

• The engine will run cooler/healthier/richer while in a closed loop.
• A slight reduction in FE due to a richer mixture. (This might not be the case as the engine will be running at lower RPMs)
• Torquey in lower RPMs.(Can shift to 6th gear in 3500 RPM)
• No more infamous 390 jerks in lower RPMs.

FuelX for Duke 390 works by modifying the signal from the Lambda sensor which goes to the ECU.
It is a simple principle. There are other devices like booster plug which does the same by modifying the intake air sensor values.
The FuelX Pro version comes with a switch that can be used to toggle between 10 settings to choose from 10 levels of AFR.
They say that it'll autotune the AFR based on the number we choose. Very confusing as there are a lot of variables and I want it as fuzz-free as possible.
The FuelX Lite doesn't need any of this, it's plug-and-forget.
I am not writing a step-by-step installation here since it is already well-versed in their official manual.
I will go for a ride after the mod and update my experience here.

 

[sacbiker]

It is well-designed and packed. Proud to see such a world-class product from India.
The connectors and wires are of high quality.

Contents

• FuelX Lite module
• Cable
• Stickers, Zip ties, and a keychain
• Warranty Card (2 years)

Module in hand.

Connectors to bypass the lambda sensor.

Installation
The installation was straightforward.
I followed the instructions from their manual.

• Remove the ignition coil to access the lambda sensor connector and bypass it using the wiring kit.
• Route the cable carefully avoiding hot areas by zip-tying it to the frame and also making sure that it's not getting pinched anywhere.
• Connect the ground cable to the negative terminal of the battery,
• Connect the other end of the wiring kit to the Fuel X module and place it under the rear seat.
• Reconnect the Ignition coil and its ground to the frame of the bike.

Changes post FuelX Lite mod.

• The change was so evident from the moment I started moving in first gear. The jerk in lower RPMs was gone, it was acting more like a Duke 250.
• Smoother clutchless upshifts.
• The bike is stress-free at speeds below 10 kmph in 1st gear.
• The bike can move without jerking in 2nd gear without any throttle input at 14 kmph.
• The engine heat is definitely lower as the fan did not kick in throughout the ride.
• The bike is a joy to ride at 40 kmph in 5th gear without stress. Can be shifted to 6th in 50.
• FE is not affected.
• Lesser clutch use.

I rode the bike at speeds under 40 kmph and I got 35 kmpl. I believe these are respectable figures for a 390.
My long-term average is 25.5 kmpl before the mod. I will update it after riding 1000 km.

Final Thoughts
My only regret is that this was not installed earlier.
From BS4 onwards, the 390s had better rideability than before at low speeds, yet it never felt natural to ride the bike below 4000 RPM.
FuelX lite has solved this issue for me. For BS3 models, the change would be far better.
I also believe that this mod goes a long way in improving the engine health of a 390 as the factory fuel map at low RPM is so lean (source1, source2).
This makes the bike extremely hot when ridden in lower RPMs. As per my understanding, they have done this to satisfy emission norms.
I am sure that the clutch plates will last more since their use is reduced now.
I am planning to go for longer rides in the 390 now and I will share the updates in this thread.

 

[sacbiker]

I rode the bike at speeds under 40 kmph and I got 35 kmpl. I believe these are respectable figures for a 390.

I used to get 39-40 kmpl if I tried to ride the bike under 40 kmph before the mod, but the engine ran terribly and I never really rode that way. I did that run before the mod to get a sense of before and after.
After the mod, it's 35 kmpl, but the engine runs healthily without any jerks or overheating.


Here is an explanation of the working principle behind FuelX from their support.

If the sensor has a voltage less then 0.4 or greater then 0.5 (lean/rich) regard less,FuelX always tends to keep the AFR/voltage at the same level according to the map available on the FuelX ECU

Every single map has its own value according to the AFR set at each map and the FuelX monitors and keeps making changes that keeps the fuel ratio at the same level according to the map (afr kept at each map),
The voltage of the O2 sensor output signal values stored in stock ECU for rich or lean settings are not exceeded by the FuelX as it operates between the same operating temperature
FuelX is a fuel optimizer that is focused on refining and enhancing the motor to ensure it runs smooth and is happy. It autotunes the engine to its best optimal parameters constantly monitoring, learning, and adapting to the conditions of the engine like wear and tear, riding style, mods like exhaust/air filter as well as external weather conditions and altitude. It can control the AFR completely, as well as reduce stalling, jerking, and bogging in the initial throttle range and provide a better throttle response.

FuelX has complete control in Closed-loop and partial control in Open loop to a certain limit. As a result, the engine will be running in an optimal condition, much cooler operating engine temperature and lesser gear shifts incidentally resulting in performance gains at the lower RPM and throttle percentage region. This initial response helps the engine to eventually pushes more at higher revs and throttle percentages and provides overall performance.

 

[vijesh_360]

FuelX lite has solved this issue for me. For BS3 models, the change would be far better.

This is tempting. Will wait a little longer for your updates and decide.

 

[sacbiker]

This is tempting. Will wait a little longer for your updates and decide.

Sure. I'll keep the thread updated.
It's this review which made me finalize my mind.

 

[sacbiker]

Made some time to route the cable efficiently and discreetly.
As per their manual, it needs a lot of part removal and especially in the newer 390, it's a pain to remove the cross bar under the seat.
So, I found a better way to route the cable with minimal part removal. Just loosen the rear bolt of the tank.

 

[sacbiker]

Update.
Never got a chance for a long ride. The bike's one-touch start did not work and I had to keep it pressed to get it started. Once the battery is charged up, the one-touch start is working.
The battery was above 12V. Do not know if this is a battery issue or a starter motor issue.
Took a short ride to the nearby beach (Varkala) for 30kms.
FE is 27 kmpl when ridden normally.
The 6th gear can be engaged after 55kmph and the bike gives 30 kmpl if continuously ridden in 6th like that.
It now pulls cleanly from 20 kmph in 3rd gear. The need for clutch slipping in lower gears has gone down by 50%.
1st and 2nd gear crawling can be done without using the throttle or slipping the clutch.
Another noticeable difference is the smoothness in clutchless up and downshifts. I guess it's due to the smoother RPM modulation.

Location: Black Beach, Varkala.

 

[sacbiker]

FuelX Lite for Duke 390 is on sale on Amazon for Rs.4965.

 

[sacbiker]

My long-term average is 25.5 kmpl before the mod

Long term average increased to 27.9 kmpl.
2.4 kmpl increase in a span of 360km after the FuelX mod.

 

[sacbiker]

My long-term average is 25.5 kmpl before the mod

View attachment 314701
Long term average increased to 27.9 kmpl.
2.4 kmpl increase in a span of 360km after the FuelX mod.

 

[sacbiker]

Update
Since the bike is mostly used in urban conditions nowadays, it rarely sees the 6th gear and therefore, the long term average went down a bit. Notice that the average speed also went down.
No other issues were faced related to the FuelX.

 

[sacbiker]

3300 km completed with Fuel X lite.
The bike runs normally and returns and average of 27 - 28 kmpl if ridden sanely. With frequent acceleration, it drops to 26.
No other complaints and the bike runs flawlessly. In urban conditions, I always cruise at 40-50 kmph in 4th and 5th gear.

I've been noticing a white compound formation on the spark plug after the fuel x lite mod. This generally means the spark plug is overheating.
I have raised this concern to Race Dynamics twice, once a few months back and one time recently. Their support is extremely poor.
In the recent one, they didn't even bother to respond. So, I guess it's safe to conclude that their after sales support is bad.
Keep this in mind before you get any Race Dynamics item.

 

[Redex]

Hi,
assuming you are not using any fuel additives, this looks like a plug that is running too hot or an engine that is running too lean. You could try running on 95 or 99 Octane. Alternatively run a plug one step cooler. Sometimes white spotty deposits are just well burnt oil deposits, indicating a small amount of oil leaking by a piston or valve stem seal. Neither are a problem and possibly some oil leaking past the top piston ring is actually providing good lubrication to the ring.
In my early days of motoring (50 years ago), we added a shot or two of Redex upper cylinder lubricant into the fuel tank,( at the fuel pump). White deposits were normal then.
Either way there is nothing desperately wrong with your plug. Most likely the engine is running lean and slightly hotter than intended.
Lean mixtures run hotter anyway. That is why the carb on the rear cylinder of an air cooled "V" twin has a slightly larger main jet. The rear cylinder runs a little richer to keep it cooler, because it doesn't get the same amount of cooling air as the front cylinder.

 

[sacbiker]

. Alternatively run a plug one step cooler.

Turns out that I am running a cooler plug.