JB4 Thread for Lotus Emira AMG i4 (M139 Engine) – Tuning, Setup, Results & Support

[ManuelB]

Hi everyone,

I noticed that most JB4 discussions here are mixed between the V6 and the AMG i4 engines, which can make it difficult to find specific info for each setup. To help keep things organized and easy to access, I’m starting this dedicated thread for everything related to the BurgerTuning JB4 on the Lotus Emira AMG i4 (M139 engine).

Installation Guide (PDF):
For a step‑by‑step installation process, please refer to BurgerTuning’s official guide:
https://www.jb4tuned.com/instructions/Lotus-2.0T-JB4-Install-Guide.pdf

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Let’s use this topic to discuss:

• Installation process, tips & photos for the i4
• Map selection and custom mapping for the M139
• Dyno results and real‑world performance gains
• Troubleshooting, error codes, and solutions
• Which wires/connectors are used on the Emira i4
• Experiences with different fuel types and blends
• Integration with other mods (intake, exhaust, etc.)
• General impressions, pros & cons

Please keep posts relevant to the AMG i4!
This way, info stays easy to find for everyone looking to tune or get the most out of the 2.0 L M139 engine with the JB4.

If you’ve already installed a JB4 on your Emira i4, please share your setup, experiences, photos, and dyno charts!

Thanks to everyone contributing – let’s make this a helpful resource for all current and future Emira i4 owners.

Cheers!

 

[ManuelB]

For anyone interested in official numbers, here are the dyno results published by Burger Motorsports for the JB4 on the Lotus Emira AMG i4 (M139):

Dyno Results:

• Baseline (91 Octane): 387.5 hp / 311.5 lb-ft
• JB4 Map 1 (91 Octane, IAT Spoof): 422.9 hp / 354.9 lb-ft
• JB4 Map 2 (93 Octane): 439.2 hp / 351.6 lb-ft
• JB4 Map 3 (93 Octane): 444.3 hp / 355.4 lb-ft
• JB4 Map 4 (E30 Blend): 456.9 hp / 371.3 lb-ft

Here’s the dyno chart provided by Burger Tuning:

And for those who want to see the full testing process, check out this video from Burger Motorsports with all the dyno runs and data:
JB4 for Lotus Emira AMG i4 Dyno Results & Testing – YouTube

 

[Emira Fan]

[Baseline (91 Octane): 387.5 hp / 311.5 lb-ft]
With a parasitically loss multiplier of 12.5 % for a rear engine DCT, that suggest stock config is over 430 HP, which would be inline with C&D 0-60 figures of 3.4s

JB4 map 2 comes in around 500HP. 60 to 70 HP is a good amount of HP to pickup. Will be nice to see how everyones cars handle the additional heat from the extra 6-7 psi of boost.

 

[Kaz]

Mine will be installed in next couple of weeks alongside methanol injection and it'll be run on the dyno at DRS. I'll ask them to do baseline, meth+91 and possibly meth+100 since I have a station right next to me with 100 in Pasadena. Also be good to get a different set of dyno numbers to compare so we can get the actual percentage gains (since all dynos are relative to one another and not 1:1)

 

[Lotus F1]

Mine will be installed in next couple of weeks alongside methanol injection and it'll be run on the dyno at DRS. I'll ask them to do baseline, meth+91 and possibly meth+100 since I have a station right next to me with 100 in Pasadena. Also be good to get a different set of dyno numbers to compare so we can get the actual percentage gains (since all dynos are relative to one another and not 1:1)

To be honest it would be better to do the runs without the meth because very few people will have that

 

[Lotus F1]

For those of you that want to run E30 blend I have a calculations done here

 

[ManuelB]

For those of you that want to run E30 blend I have a calculations done here

Thank you!! I believe you’ve already tested E30 on the Emira — mind sharing which JB4 map you used for it?
Also curious to know:

• Any noticeable performance gains?
• Did you log fuel trims or AFRs?
• How’s the cold start and driveability?

Would be great to know how the M139 reacts to E30 on the stock fuel system with JB4.

Thanks in advance!

 

[Lotus F1]

Thank you!! I believe you’ve already tested E30 on the Emira — mind sharing which JB4 map you used for it?
Also curious to know:

• Any noticeable performance gains?
• Did you log fuel trims or AFRs?
• How’s the cold start and driveability?

Would be great to know how the M139 reacts to E30 on the stock fuel system with JB4.

Thanks in advance!

Yes, it feels like the fastest map. I also like the chemical cooling Ethanol provides.
I did not log but I can. I am on Map4
The car started and runs with no issues at all thus far. You wouldn't know anything different.

I have the blended 100 octane in there now but will return the E30. Apparently, it's safer than blending 93 octane with VP Booster to make 100, not to mention the added savings.

 

[675430VME]

[Baseline (91 Octane): 387.5 hp / 311.5 lb-ft]
With a parasitically loss multiplier of 12.5 % for a rear engine DCT, that suggest stock config is over 430 HP, which would be inline with C&D 0-60 figures of 3.4s

JB4 map 2 comes in around 500HP. 60 to 70 HP is a good amount of HP to pickup. Will be nice to see how everyones cars handle the additional heat from the extra 6-7 psi of boost.

Map3 is an additional 4.5 psi which is good for 98 ron fuel. Map4 is 5.7 psi which I have tried with just 98 Ron fuel but wouldn't work and fall back to Map3. Problem now is the calibration for measuring boost is inaccurate, I hope JB4 will fix that soon.

 

[675430VME]

Map3 is an additional 4.5 psi which is good for 98 ron fuel. Map4 is 5.7 psi which I have tried with just 98 Ron fuel but wouldn't work and fall back to Map3. Problem now is the calibration for measuring boost is inaccurate, I hope JB4 will fix that soon.

Making a correction, after I read more closely on the log for Map 4, it does kinda work with just 98 Ron fuel but it does not hit target boost as consistent as in Map 3 and runs a little rich AFR at 10.6 & TRIMS at 34.0.

 

[ManuelB]

Making a correction, after I read more closely on the log for Map 4, it does kinda work with just 98 Ron fuel but it does not hit target boost as consistent as in Map 3 and runs a little rich AFR at 10.6 & TRIMS at 34.0.

LTFT at 34% ??? God... that's a lot! How much more boost is it making?
I'm currently waiting for the JB4 to arrive so I can run some tests. In the meantime, I've been checking the wiring and I’m planning to tap into the CAN bus near the engine bay instead of running a cable all the way to the OBD port.

 

[TurboTambo]

Can we make our own adjustments, or run our own maps on the JB4?

 

[675430VME]

LTFT at 34% ??? God... that's a lot! How much more boost is it making?
I'm currently waiting for the JB4 to arrive so I can run some tests. In the meantime, I've been checking the wiring and I’m planning to tap into the CAN bus near the engine bay instead of running a cable all the way to the OBD port.

STFT at 34, around 5 psi out of target 5.7. It's not too bad running the wire from the wheel arch to the cabin, I am afraid if you tap into the can bus wire in the back you might have more warranty concern.

 

[675430VME]

Can we make our own adjustments, or run our own maps on the JB4?

Yes, minor adjustments, but you have to know what you are doing.

 

[Kaz]

This post has absolutely no value other than showing the back of my car naked lol. Shop is about to start installing the methanol kit - when they did my Alfa 4C they made the entire thing invisible other than the tank in the trunk. They'll not modify a single thing on the chassis or car, everything will be reversible if needed and inside the body panels. They should be tuning with Burger Motorsports some time next week I think is the plan.

 

[Emira Fan]

Great pictures. Keep those coming, not many pictures out there of chassis without the skin.
Any idea if the plastic vents in the second picture release air into the bumper skin cavity and release air into the rear black ports? I noticed there are very small vents at the top of the ports.

 

[TurboTambo]

Yes, minor adjustments, but you have to know what you are doing.

But you can't fully build your own map???

 

[TurboTambo]

This post has absolutely no value other than showing the back of my car naked lol. Shop is about to start installing the methanol kit - when they did my Alfa 4C they made the entire thing invisible other than the tank in the trunk. They'll not modify a single thing on the chassis or car, everything will be reversible if needed and inside the body panels. They should be tuning with Burger Motorsports some time next week I think is the plan.

View attachment 67983View attachment 67984

wow.... that seems like a lot of hard work. Looking forward to seeing the gains.

 

[Milk242]

This post has absolutely no value other than showing the back of my car naked lol. Shop is about to start installing the methanol kit - when they did my Alfa 4C they made the entire thing invisible other than the tank in the trunk. They'll not modify a single thing on the chassis or car, everything will be reversible if needed and inside the body panels. They should be tuning with Burger Motorsports some time next week I think is the plan.

View attachment 67983View attachment 67984

Where are you injecting and what adapter or product did you buy and also will this be pre or post intercooler injection?

 

[Kaz]

Where are you injecting and what adapter or product did you buy and also will this be pre or post intercooler injection?

I bought the pre-bunged Weistec charge pipe to save some time, here is the pipe compared to stock. It's always post intercooler with methanol injection to not only chemically cool but to clean the combustion chamber, valves, piston heads. I am using the pump and tank from Snow Performance, and the rest of the kit and electronics comes from Burger Motorsports as the JB4 will control the system. So I'll be able to run stock, 91, 93 etc and also those maps + methanol (super handy) which means if I'm in a trip and don't want to bring methanol I can just run whatever map.