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BMS VW GTI JB4 info thread

Drincc

Go Kart Newbie
Location
Vancouver, Canada
Car(s)
2019 GTI
Now that I'm debating between switching off JB1 or just adding light support mods and keeping it (broken connector is the debating point), what's the theoretical limit that the JB1 can take before JB4 is required? I was considering an aFe or VWR R600 intake.
 

Clem604

Autocross Champion
Location
Vancouver BC, Canada
Car(s)
2018 VW GTI
Now that I'm debating between switching off JB1 or just adding light support mods and keeping it (broken connector is the debating point), what's the theoretical limit that the JB1 can take before JB4 is required? I was considering an aFe or VWR R600 intake.
Intercooler>intake. If you have the funds do both!
 

shovelhd

Autocross Newbie
Location
Western MA
Here is the combined log of a few pulls

datazap.me | panpolanski | 08/25/21 Log

Now that I see my IAT's at WOT of 132F in an ambient temperature of 85, makes me wonder what they were when it was 98 yesterday...Could that cause the pinging/knocking? However, the time my GF took the car out it had been sitting in a garage (albeit on a super hot day and after I had driven it so it likely was heatsoaked) so not sure if that was contributing... Could I have fouled my spark plugs with the CRC valve clean? Plus, if that was the issue (the plugs), wouldn't I have misfires on a more regular basis, not just intermittently and only at high engine load @ low RPM? I don't know... also, AFR of under 10... that don't seem right...

Those short pulls give some info but a single pull in third from 2000 to redline then shift to 4th is a lot more revealing. It's possible that your valve treatment has fouled the plugs, but did you follow the directions on the can? Treat it at operating temp at idle with a bunch of doses, then dose it until it stalls. wait 30 minutes, then drive for 30 minutes between 3000-4000 rpm steady. I also wail on it full throttle for a few runs after that.

When was the last time you changed the plugs? Are you adding ethanol?
 

Panpolanski

Passed Driver's Ed
Location
Kansas City
Car(s)
2019 Jetta GLI
Those short pulls give some info but a single pull in third from 2000 to redline then shift to 4th is a lot more revealing. It's possible that your valve treatment has fouled the plugs, but did you follow the directions on the can? Treat it at operating temp at idle with a bunch of doses, then dose it until it stalls. wait 30 minutes, then drive for 30 minutes between 3000-4000 rpm steady. I also wail on it full throttle for a few runs after that.

When was the last time you changed the plugs? Are you adding ethanol?
That log I posted has such a run in it (4th one in the log), I started in 3rd @ ~2000 RPMS and floored it until it shifted into 4th and kept it going for a second after, the pull subsequent to that one is a WOT 2-3-4th gear pull as well (I shifted manually into third a bit early on that one though). I did follow the directions on the can. The car has under 14k miles on it, the plugs have never been changed. Been running a JB4 for 3-4k miles maybe? I do not add ethanol (I do add octane booster frequently) other than what is already in the gas that I buy, which I suspect is ~10%. Thanks for the input!
 
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jimlloyd40

Autocross Champion
Location
Phoenix
Car(s)
2018 SE DSG
Now that I'm debating between switching off JB1 or just adding light support mods and keeping it (broken connector is the debating point), what's the theoretical limit that the JB1 can take before JB4 is required? I was considering an aFe or VWR R600 intake.
Save your money and just get a drop in filter.
 

Panpolanski

Passed Driver's Ed
Location
Kansas City
Car(s)
2019 Jetta GLI
Set FOL to 60

put it on map6

1500 0
2000 1
2500 2
3000 2.5
3500 3
4000 4
4500 5
5000 5
5500 5
6000 5
6500 5
7000 5
So I want to add more boost up top and less down low…? With having episodes that sound like engine knock and an AFR of 10 is that a good idea? Why my AFRs running so rich?
 
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