2019 C43 JB4 performance
 

First, this is in no way a review or put down of BMS or JB4. I think it is a great system, and think that there might be something either specific to my car, my JB4, my Dragy, or my location in Germany. So, I am wanting to gauge other 2019 C43 owners and their experience with JB4s. I have had mine on for a couple of weeks now, and am sort of disappointed. My fastest times are below. Both times were the straight 0-60 (not 1 foot rollout):
JB4 Map 0 (stock) 0-60: 4.38 (1/4 tank)
1/4: 12.67
JB4 Map 1: 0-60: 4.44 (full tank)
1/4: 12.62

Some points to make:
1. I only have had Map 1 on for about a week. More time with the map should yield better results.
2. These have been brake boost, so there is a possibility of inconsistency (even if only milliseconds).
3. Overall 1/4 mile did improve by .05.
4. I logged and did see an increase in boost to ~19lbs. I could be reading the data wrong.
5. I don't know how much satellite visibiltiy is affecting the Dragy accuracy.

I have switched to Map 2 in hopes that I see some improvement. I am also contemplated dead stop runs , after a couple of weeks with map 2, to get a real gauge in the differences between the maps. I think the times might be more consistent. Anyone have any observations that they have had with their 19s?

That is definitely slow. my GLC43 did 12.7 in the 1/4 Mile on Dragy with a JB1 and 2 extra passengers. And Taiwan is super humid.

What fuel do you use? I would think the difference between stock and map 1 on a 2019 would be very little since it has the most boost in stock form.
12.6 is a good time stock, whats the trap speed looking like? Any wheel spin? Do you have any log of the run?
Not sure how accurate draggy is for 0-60 times if it isnt connected to obd2 for mph readout, but i would expect sub 4.0 times with map 2 and a good launch.

FWIW, when i got my JB4 i skipped map 1 and went straight to map 2, but im in a C400 so that basically brought me to where a 2017 C43 is stock lol.

Trap speeds were ~112-113. No wheelspin. We get 98 RON (3 equivalent) over here. I do buy it on post, currently, so there is a posbility that it is not Top Tier. I do not know who supplies AAFES with their fuel. I have been watching some vieos and it appears as some are able to get a good build of boost prior to releasing the brake. It is something I will be looking at. Also, one video I watched the driver only had his DSC to Sport not fully off. I have been going fully off.

You should be seeing better times than that if you're hitting 19psi, but would need to see logs to get the whole picture. Your DA is only currently ~700ft, so that should be helping you. I would move on to map2, do some logging and investigate fuel options. It's only anecdotal at the moment, but Boostane and octane boosters haven't yielded the best results when compared to quality fuels. The most power is being made with E30 blends and car/region/user specific maps. Munaj's fastest map6 deployed in Toronto did not yield the same results for me in Nebraska. I spent a few weeks tweaking from there and figuring out optimal fuel blend.

Re: launch, the best established brake boost protocol is to BB and while RPMs are still swinging up, release at 1500rpm. Any higher and there's a higher chance of the car pulling boost until 2nd gear is fully engaged.

WHat is your time in other maps

I have only ran the two map (0,1) so far. Attached is a full run and its 4th gear.
https://cimg2.ibsrv.net/gimg/www.mbw...3143d23d14.jpghttps://cimg4.ibsrv.net/gimg/www.mbw...e0b18ef440.jpg

Among the JB4's great features is internal diagnostics. So post the JB4 log of the specific run in question and lets see where your missing horsepower is! We need the CSV file itself not a photo of the log as we also check internal settings and other parameters not included in your photo.

In terms of performance it's very launch dependent. The best way to make a performance comparison is doing 1/4 mile runs on map0 and map2, and comparing the trap speeds. 1mph of trap speed is around 10hp.

While braking, I have:
Nailed it to 1500-2000 and released braked
Feathered to 1500-2000 build boost..
Fathered and then nailed it..
All have never reached hicher than 1/4 on the boost gauge..
Got it, its not as accurate as vaccum boost gauge. Anyone have simialr results?

I can get you that. Understand in regards to traps speed. I am going to give Map 2 a chance, since it should be a non-negligible measurement. About how long does the learning process take for the maps?

You cannot say you are not saying gains without using the other maps. Map 1 is just a 3 psi boost increase over stock. You would still feel it, just not that much.

Well the stock times were faster, and 1/4 was only .05 over stock with map 1. Negligible. I am not trying to get into some debate, because I am pretty sure there is an extremely valid reason. That's why I asked about how others are brake boosting. Maybe it's me, the dragy, or the car? I specifically am trying to see if anyone else with the 19s has tried out a JB4. I would like to see what gains they have had. I am contemplating just flat 0-60s and 1/4s with no brake boost with all of the maps for consistency. Maybe a week with each.

It does take some time to adapt. I dunno if it takes as long as a week. But my JB1 started to feel slightly faster and faster every day I drove it for like a week.

I have a 2019 with a JB4 and I was able to get a 4.10 on map 2. I can also tell you that I know I can do better as I was not doing a great job launching. I let it go to like 2200rmp and build up. This is not the best way to do it. I also did a 4.0 on map 2 but that was on a slight grade so was not technically valid. I would bet I will hit below 4 soon just need to do better launches. I also had BMS review my logs and they confirmed I am making good power compared to stock. I am now trying to run some E85/93 Octane mix to make even more power. Going to be trying to run map5 and see how I can do. I know my JB4 is making much more power than stock just need to get better at launches.

Do 100-200kmh runs instead. You will get a more accurate and consistent performance baseline to compare.

For your reference my best 100-200kmh runs in different stages:

11.92 Stock with 98ron
9.82 JB4 Map2/6 with 98ron
9.37 ECU tune with 98ron
8.93 ECU tune stack JB4 with 98ron + octane booster

JB4 shaved off full 2 seconds compare to stock... one mighty piggyback~ :naughty:

Is this Map0 or Map1?

Map 1. I have some new runs and a .csv that I will be sending to BMS. Thanks to all that have provided some valuable insight.

Attached is this morning's .csv (Day 3) of a Map 2 run. Sorry, it is a little long, but I have to start it whne I leave for work. Not a lot of time, typically, when I get to the wide open portion of the road.

Here are this morning's 2 runs (Map 2) separated into 2 .csv files

Man... nice cold weather u got there.. im jealous~ :cool:

Honestly, the only thing I see of concern is the trims. You can easily resolve with the green plug. BMS/Terry will give u better guidance... they're pretty responsive and helpful.. good luck!

Would love to see a Map0 log or graph if u got one :D

I can geto ione once is all settled. Do you have either email? Their site is blocked at my work.

You can email me or Terry and we'll review the logs. Easier and quicker to go through that way.

Payam@burgertuning.com
Terry@burgertuning.com

Not sure how you can claim only 0.5 faster than stock when you don’t have any map 0 runs. I guarantee you won’t run a 12.7 in THAT car on map 0.

What are you talking about? It has already done a 12.67 on Map 0. That is stated in the original post. Don't understand your "THAT" reference.