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BMS VW GTI JB4 info thread

shortyb

Drag Racing Champion
Location
Upstate SC
Car(s)
A band from Boston
What determines the FOL setting? Default looks to be 45. Is it ok to just leave it there on Map 2 and 3?
FOL is Fuel Open Loop setting and affects fuel trims. Its what drives fuel delivery when given demand. Generally, on a GTI running E-blends, the trims go high (>40) to add extra fuel to compensate for the lower fuel density of ethanol. Rail pressure also goes down and injector pulse width widens because it is trying to keep up with the fuel demand and has limitations. When these limits are critical, you get CEL and lean fuel conditions (no bueno). Raising the FOL to around 60 helps E-blend cars that are on the edge fueling-wise provide an additional cushion of headroom and helps avoid this condition. FOL is a "global" setting and applies to all maps, ie; you don't have to change it when changing maps. Hope this helps a bit.
 

Fugner

New member
Location
Denver, Colorado
Hello! I've been running the JB4 on my Mk7.5 GTI for 6-ish months now and I love it. However recently I've noticed that it's been throwing these two fault codes:

3BEF 15343 P2099 Boost Pressure regulation not reached
3AE5 15077 Idle control system RPM higher than expected

It drives just like it always has and nothing feels off. Other than the JB4 I just have a drop-in filter with the snow guard removed. No other mods. Here is a map 1 log from earlier today: https://datazap.me/u/fugner/map-1-gear-3?log=0&data=1-4-11

Does anyone have any ideas?

Thanks!
 

Yungaxel3

New member
Location
SF Bay Area
Car(s)
'19 GTI DSG Autobahn
Sorry if this was asked many times before.

I drive a 2019 Mk7.5 GTI w/ DSG with the stock air box mod and a TCR muffler. I also live in California and don't have easy access to anything more than 91 octane gas. It looks like Map 1 is the only way to go for me? Will I need to posi tap the AFR wire if I'm only running Map 1 on the Mk7.5?

Thanks!
 

Chogokin

Drag Racing Champion
Location
So Cal
Car(s)
GTI Sport | Audi A3
Sorry if this was asked many times before.

I drive a 2019 Mk7.5 GTI w/ DSG with the stock air box mod and a TCR muffler. I also live in California and don't have easy access to anything more than 91 octane gas. It looks like Map 1 is the only way to go for me? Will I need to posi tap the AFR wire if I'm only running Map 1 on the Mk7.5?

Thanks!
If you're going to only use Map 1...you might as well get a Neuspeed Power Module and save yourself some money. I ran Map 1 and there wasn't a noticeable difference between the NPM and JB4. The NPM in the 7psi setting feels like it makes more torque than the JB4 in Map 2. The issue I had with the NPM is that as you move into the upper part of the RPM range...the NPM dies down big time. The JB4 in Map 2 feels like its more consistent all the way to redline. I'm in So Cal and run 91. The octane for Map 2 and 3 say "93 recommended" not absolutely needed.

When its really hot out...just don't romp on the car. Don't rev the engine out at high RPMs.
 
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Yungaxel3

New member
Location
SF Bay Area
Car(s)
'19 GTI DSG Autobahn
@shovelhd I think I'll do that eventually. How do I get help on setting up a map 6? I bought my jb4 secondhand.

@Chogokin I'm planning on using map 1 for now, but I want the option to use map 6 in the future. Do you need any bolt ons to run map 2 or 3 with 91 octane?
 

Andrewbens

Go Kart Newbie
Location
Modesto
Car(s)
2019 GTi S 6 Speed

shovelhd

Go Kart Newbie
Location
Western MA
@shovelhd I think I'll do that eventually. How do I get help on setting up a map 6? I bought my jb4 secondhand.
So did I. The first thing you should do is clear all the values from the previous owner. I got lucky and was able to participate in a JB4 beta release test which gave me access to George. He helped me build my first Map 6. After that, some great people in this thread like Diggs, shortyb, ChrisMK77 helped me understand what each change meant to the log. I would ask someone running California 91 octane to provide starter settings, then post logs and ask for feedback.
 
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