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

[675430VME]

Update on my JB4 + WMI setup for the AMG Emira. Been logging a bunch in Sport and Track.

TLDR: 490hp, car RIPS

After about 700 miles of testing so far I have settled on some settings that are stable. I might lower the boost additive to 40, will test that soon just to see if it tames overboost near redline. The methanol is providing exceptional cooling and anti-knock...I'm seeing on average IAT 10-15F above ambient after repeated pulls and hours of canyon driving. There's no observable heat soak and engine water temps are low.

Setup

• JB4 on Map 7 custom tuned at DRS with Terry's remote help
• Boost Additive set to 45 (this is how much boost is requested as methanol spray ramps up)
• Burger WMI kit, 100% flow at WOT, methanol ramps up at 15 psi
• High-flow cat, Weistec charge pipe, Aerie exhaust

Boost by Mode

• Sport: ~30–31 psi sustained
• Track: ~32–33 psi sustained

Power (SuperFlow Dyno) - usually the shop uses a 20% loss on their dyno which is verified with all the cars I have used there (Elise, Alfa). To be conservative I also show 15% loss. So let's call it averaged, the tune is making around 490HP. My car stock (charge pipe+hi flow cat+exhaust) was showing 342 whp on this dyno for reference, and is probably making around 415hp stock. A pick up of around 66whp/80hp -
Pump 91 Cali gas + map 7 (methanol on)

• Wheel: ~407 whp / 370 wtq
• 15% loss: ~479 hp / 435 ctq
• 20% loss: ~509 hp / 462 ctq

Intake Air Temps (IAT) with WMI

• WOT median IAT: ~83–91°F across recent logs (ambient 75-80F)
• IAT stays flat under load once WMI is active, no heat-soak climb
• Meth flow = 100% at WOT, consistent across pulls

Timing / Knock Health

• Average timing under load: typically low-teens to high-teens
  ~12-18° average with clean recoveries
• No pattern of sustained timing pull, and no throttle closures under boost

Notes

• Rear O₂ (P2270/P2271): shows up intermittently because of the high-flow cat + WMI. ECU trips lean or rich codes from the cat, previously before the JB4 it was showing rich only and the normal efficiency code.
• Stock my car was giving me overboost code when we installed the Weistec charge pipe and hi flow cat. We will recheck boost sensor connection but everything seems to be working fine with the JB4. I get overboost code in Track mode if I trip the rev limiter for longer than a couple seconds so I have been intentionally short shifting around 6500. With the dash delay and the car just sounding like it's going to explode at that point I feel more comfortable short shifting a little, power curve shows no real benefit maxing out revs each gear.
• Engine Oil Temp channel does NOT work in my JB4 app when I have live gauges going, anyone else see engine oil temp active?
• updated bluetooth module and app do not start live connection until the wheels are moving (might just be weird glitch on my car)

I'll take some photos of the methanol system and post the same data in a separate thread since V6 owners will get great benefit from this as well.

Very good number for your setup, nice!

 

[Kaz]

Very good number for your setup, nice!

methanol plus forced induction always a great thing! basically it's just running race gas all the time you can just crank up timing, since we don't directly control that with JB4 it's just boost request against methanol spray ramp up. With the new ECU flash you are doing they can control everything now, really exciting! Based on what the AMG A45 S guys get with methanol and stage 2 we should see 500+ easy on the I4. And if they can control wastegate we can start experimenting with hybrid turbos (!)

 

[Ryan_929]

Just want to give another perspective on the install. I’m not very mechanically inclined; other than changing the oil or brake pads and basic bolt on mods. That being said. I did the install in my garage on ramps. It took about 2 hours and a lot of that time was spent tracking down the right tools. The instructions from burger were straight forward and accurate. The concept of the installation was super easy. Getting access to the bottom sensor was the only difficult part. I didn’t use any special tools and if I had to do it again I would. ALTHOUGH, I would recommend trying to get access to a lift. It was definitely cramped under the car just using ramps. Trying to maneuver my hands and arms into the correct position to access sensors and bolts was the biggest pain of the entire install. Moving/prying the intercooler forward made a big difference. I used a long flat head to reach and disconnect the stock sensor. The stock sensor had enough slack to pull down and plug into the jb4. I worked the other end of the jb4 into place as best I could with my hand and pushed it the rest of the way with the screw driver until it “clicked in place. If you’re into DIY I would say it’s worth giving it a shot, but I highly recommend trying to get it on a lift to do it.

 

[Ryan_929]

On another note, can anyone advise on sending logs to burger? I’m plugged into the OBD and connected to Bluetooth. I’ve stored three logs so far and I can’t seem to email them to myself. I’ve tried multiple times to two different emails and they never come through to my inbox or spam. I’m using the jb4 mobile app that cost $.

 

[Lotus 2024]

I just sent my logs to myself, pay app worked fine. I would reach out to them. They are very responsive

 

[Kaz]

On another note, can anyone advise on sending logs to burger? I’m plugged into the OBD and connected to Bluetooth. I’ve stored three logs so far and I can’t seem to email them to myself. I’ve tried multiple times to two different emails and they never come through to my inbox or spam. I’m using the jb4 mobile app that cost $.

I'm only using the new bluetooth module and using the new free app and logs just stay in the log tab by date created and I can access and email from there even if the phone isnt connected to the car. Paid app might operate differently, but yeah they are highly repsonsive