Lowest idle
891 rpm
High Output coils
Highest RPM
10,461
Compact coils, map #4 at 12V
Best maps
#0 & #4
Lowest idle, sharpest throttle
MCU input
10–12V
Never above 12V
Both coil types started easily and idled steadily when hot, with no failures in any test.
About the Cison LS V8 MCU Ignition
The Cison LS V8 is a real gasoline miniature engine leading the way in miniature engine design and technology. This engine utilizes multi-coil ignition paired with engine temperature and an MCU unit to precisely control the Cison LS ignition for optimal engine performance. The MCU comes with 5 throttle maps to get the most from the ignition coils.
The technology required to manufacture the coils used for the Cison LS V8 is impressive. Each coil is made with copper strands thinner than a strand of hair. The smaller compact coils have 3 coil windings per coil pack, allowing for a quicker pulse rate and engine RPM — perfect to get more performance out of your model.
The larger coils have 4 coil windings per coil pack, allowing for a fast pulse rate but also producing a stronger spark — perfect for a stable lower idle when looks and sound are most important for your scale model, or as a beautiful display conversation piece.
Either way you decide to go, small coil or large coil, the Cison LS V8 is a high-revving, very strong engine that produces amazing power and torque.
New to MCU ignition? Key terms explained
- MCU: the small computer that controls the ignition. It reads engine position and coolant temperature, then decides when each spark plug fires.
- Coil-on-plug: each of the 8 spark plugs has its own ignition coil, instead of one coil shared through a distributor.
- Throttle map: a preset ignition program stored in the MCU. The LS-52 MCU has 5 (#0–#4), and each one makes the engine idle, respond and rev a little differently.
- Rev limiter: a maximum RPM set by the MCU. When the engine reaches it, the MCU cuts the spark briefly to keep the engine from over-revving.
- Hall sensor: the sensor that detects crankshaft position and tells the MCU when to fire. Moving it changes the ignition timing, which is why Jamie kept it in the same place for this test.
- MCU input voltage: the voltage from your battery or power supply to the MCU. Cison specifies 10–12V.
The Test
The Cison LS V8 was put through a rigorous high-speed running test to specifically test both the large and small coils through the different MCU throttle maps, input voltages, and engine temperature ranges, as well as to figure out which coil can idle the lowest and most stable.
Conclusion
There was no clear winner, as both coils performed extremely well through all the tests, and I experienced no failures or issues that needed addressing.
The Cison LS V8 ran perfectly. In fact, both coils worked so well the engine had no trouble starting when hot. The LS V8 holds a stable idle even when hot — no fluctuations or erratic loss of power. This is the first engine I've seen that can do this; the multi coils are not affected by engine temperature.
Changing the input voltage improved the ignition coil performance, but only a small gain of RPM and a slightly quicker throttle response. I found an MCU input voltage of 11 volts performed very strong; going to 12 volts gives that extra little bit. Going higher than 12 volts risks damaging the MCU unit.
The only difference was that the smaller coils have a more responsive throttle and the highest RPM, but the large coils did really well too. In the high RPM there was not a huge difference between the coils.
When performing the low idle test, the clear winner was the large coils with a stable idle at 891 RPM. The small coils idled at 1,152 RPM but would not hold as stable as the large coils.
Personally, I like them both so much I have both, but it is really awesome that Cison gives users a choice.
Testing Criteria
- First tested the small coils all at once, then retuned the engine and tested the large coils all at once.
- Max RPM tested through all 5 throttle maps at 10 volts, 11 volts, and 12 volts.
- The carburetor settings stayed the same.
- To keep the coil test as equal as possible, the Hall sensor stayed centered in the same placement throughout, with the mounting capscrew in the middle of the Hall sensor board's adjustment space — except during the low RPM test, when the Hall sensor needed repositioning.
- The fuel tank always had more than half a tank.
- The outside temperature was 20°C, and humidity stayed the same throughout coil testing.
Stirlingkit Note
Jamie retuned the carburetor before switching coil sets — and that step matters. Each coil type needs its own fuel mixture. If you plan to swap coils on your own LS-52, follow our Before You Change Your Coil – LS-52 Carburetor Tuning Guide first.
Test Results
Both coil sets were run through all 5 throttle maps at 10V, 11V and 12V. Tap below to see every result.
Show full RPM data (all 5 throttle maps)
Max RPM unless noted. The higher result in each row is highlighted.
| Throttle map | MCU input | Small coils | Large coils |
|---|---|---|---|
| Map #0 | 10V | 10,140 | 10,080 |
| 11V | 10,140 | 10,140 | |
| 12V | 10,407 | 10,220 | |
| Map #1 | 10V | 9,940 | 9,780 |
| 11V | 10,040 | 9,790 | |
| 12V | 10,140 | 9,830 | |
| Map #2 | Low idle | 1,152 | 891 |
| Rev limiter | 8,500 | 8,500 | |
| Map #3 | 10V | 9,940 | 9,798 |
| 11V | 9,980 | 9,860 | |
| 12V | 10,080 | 9,768 | |
| Map #4 | 10V | 10,227 | 10,120 |
| 11V | 10,314 | 10,280 | |
| 12V | 10,461 | 10,226 |
Small coils = Coil-on-Plug (Compact – Clean Layout). Large coils = Coil-on-Plug (High Output – Stronger Spark). Values in rpm, as measured.
The 5 MCU Throttle Maps Explained
After extensive testing, this is my observation of the 5 throttle maps:
| Throttle map | How it runs |
|---|---|
|
#0 and #4 My favorite |
The best of the five, with the lowest stable idle and a very responsive throttle. These two maps yielded the highest possible RPM during this coil test. |
|
#2 Pretty solid |
The idle was lower and more stable, and the throttle was very snappy — capable of reaching the 8,500 RPM rev limiter almost instantly. |
|
#1 and #3 Least favorite |
Very similar to each other and don't run as well as the other three. The idle needed to be a bit higher RPM and the throttle acted more sluggish, with the lowest max RPM — almost 500 RPM less than maps #0 and #4. |
— Jamie RCBlock
Which Coil Should You Choose?
Stirlingkit summary based on Jamie's results
Choose it for display running, a slow idle and engine sound.
- Lowest, most stable idle: 891 rpm
- Peak RPM in test: 10,280
- Coil size: 13 × 11.5 × 11 mm
Choose it for powering models, chasing RPM and a cleaner layout.
- Highest RPM in test: 10,461
- Slightly quicker throttle response
- Coil size: 9 × 8.5 × 8.5 mm
Can't decide? Jamie runs both — and the gap at high RPM is small either way.
FAQ
Which coil idles lower on the CISON LS-52?
The High Output (large) coils. In Jamie's test they held a stable idle at 891 rpm, while the Compact coils idled at 1,152 rpm and were less steady.
Which coil revs higher?
The Compact (small) coils reached the highest RPM in the test, 10,461 rpm on throttle map #4 at 12V. The High Output coils peaked at 10,280 rpm, so the gap at high RPM is small.
Which MCU throttle map is best?
In Jamie's testing, maps #0 and #4 performed best, with the lowest stable idle, the most responsive throttle and the highest RPM. Map #2 is a solid choice with a snappy throttle and an 8,500 RPM rev limiter. Maps #1 and #3 were his least favorite, with a higher idle, a more sluggish throttle and about 500 RPM less at the top end.
Do I need to retune the carburetor when switching coils?
Yes. Jamie retuned the engine before testing the second coil set. See our LS-52 carburetor tuning guide for step-by-step needle adjustments.
What MCU input voltage works best?
Cison's MCU documentation specifies an input voltage of 10–12V — do not exceed 12V. In Jamie's test, 11V performed very strongly and 12V gave only a small extra gain in RPM and throttle response. A fully charged 3S LiPo reads about 12.6V, which is above the limit, so use a voltage regulator. Jamie runs his set to 11V.
Does the LS-52 start and idle well when hot?
Yes. With both coil types, the engine started easily when hot and held a stable idle with no fluctuation or loss of power.
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