2020 C43 AMG JB4 questions - MBWorld.org Forums

Mar 13, 2021 | 10:00 PM

HelloSon

Thread Starter

Newbie

Joined: Mar 2021

Posts: 7

Likes: 0

2020 C43 AMG

2020 C43 AMG JB4 questions

Hey all! New here, but excited to start digging in to the platform!

I’ve got a couple questions as far as the JB4 goes, with accompanying pieces. From the quick bit I’ve read, having a ‘19+ it’s recommended that I get the JB4, BT and BCM to maximize the gains/accessibility of the JB4, correct? Second question is that I’ve seen that Map 2 recommends 93 octane. Would it be a disservice to run it on 92? Or would I be limited to running Map 1 only?

Furthermore, I don’t plan on modding any further past this as it’ll be plenty of power for a daily. Maybe downpipes at some point, but my short list just includes this and lowering.

Thanks for any help that you guys provide!

Mar 14, 2021 | 07:08 AM

Howyalivin

Member

Joined: Mar 2020

Posts: 199

Likes: 75

Acura TL-SH, among others

Quote:

Originally Posted by HelloSon

When it comes to either tunes or piggybacks, always err on the side of additional octane. You wouldn't "do a disservice" to the JB4 on map 2 by running it with lower octane, you would endanger your engine. That's the same thing with a tune. When you're running more boost, there's more pressure, more heat, and a definite need for protection against detonation. No forced induction motor is "OK" with lower octane than recommended, and deciding to go that route is the surest way to cause engine damage, even in stock form.

I would normally recommend higher octane fuel, or a quality octane booster like Boostane, but I don't think you have the right mindset for it. Never cheap out on going fast, especially in these cars, because if you damage the motor, you're likely looking at a 20K plus repair.

As for your first question, if you want the most from the JB4 on a '20 car, then the BCM is a requirement. Don't do either though if you're not going to run at least 93 on map 2, and much higher on other maps. Here's a list of maps on the JB4, from BMS:

JB4 Map Guide as of v6 firmware:
Map 0: Disables tuner
Map 1: Up to 4psi over stock peak, suitable for all 91 octane+ fuels
Map 2: Up to 5psi over stock peak, suggested for 93octane+
Map 3: Up to 5.5psi over stock peak, slightly more aggressive version of map2
Map 4: Up to 6psi over stock peak, suggested for E30+ or unleaded race gas mixtures
Map 5: Up to 7psi over stock peak, holding more boost to redline, suggested for E30+ or unleaded race gas mixtures
Map 6: User definable map, boost over stock entered on user adjustment page
Map 7: WMI (water/meth injection) progressive map for BMS FSB integration
Map 8: Low boost VALET map

Reply Subscribe

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)