JB4 install on Cupra ST 300 4drive

Zer0

Active Member
Jun 22, 2019
522
242
I was wondering if anyone has installed a JB4 on their Cupra. I took a test drive in the Cupra ST 300 4drive recently and loved it, what a car. So I will order one in a couple of weeks. :)

However although not slow by any means, my GTI motor with JB4 felt about as quick so I'm looking to improve it a little. Install on the GTI was fairly simple but I've heard one of the plugs is hard to reach on the Golf R, is the the same true for the Cupra, meaning you have to install it from below on a ramp?
 

Zer0

Active Member
Jun 22, 2019
522
242
Don't have to do it on a ramp, if you have skinny arms you can reach it, if not park it in a kerb and you can access it that way

Alright thanks. Yeah my arms are a bit bigger than average but not that big, I could just about reach from above on the GTI with scratches all over hehe.

BTW I would be very happy if someone with a new 300 "Copra" could post a picture of their engine bay, trying to find out which AFR harness I need to get, I would like to avoid tapping into the wire directly.
 

Nivster

Active Member
Sep 3, 2019
53
43
What was the verdict with this AFR JB4 situ...? Did you tap in directly or what was the alternative?

I'm looking at the JB4. Do you need an OBD connection also?

Cheers
 

Zer0

Active Member
Jun 22, 2019
522
242
What was the verdict with this AFR JB4 situ...? Did you tap in directly or what was the alternative?

I'm looking at the JB4. Do you need an OBD connection also?

Cheers

Yes it ls tapped into the AFR wire directly, skipped the harness. OBD wire is required else the JB4 is running in passthrough mode on later firmwares and I'm using the latest. I've routed the OBD cable and USB cable through the firewall into the cabin. Had to remove the splash guard below the car to install the last plug.

Proper quick now, big difference. Currently running map 3 which has a peak boost of 6 psi over stock. Will do some logging once I have time and work with George at Burger Tuning to fine tune it but very happy about how it runs already.
 
  • Like
Reactions: Nivster

Nivster

Active Member
Sep 3, 2019
53
43
Yes it ls tapped into the AFR wire directly, skipped the harness. OBD wire is required else the JB4 is running in passthrough mode on later firmwares and I'm using the latest. I've routed the OBD cable and USB cable through the firewall into the cabin. Had to remove the splash guard below the car to install the last plug.

Proper quick now, big difference. Currently running map 3 which has a peak boost of 6 psi over stock. Will do some logging once I have time and work with George at Burger Tuning to fine tune it but very happy about how it runs already.

Cheers, how do you find economy if not pushing it? Has there been any improvement over stock?
 

Zer0

Active Member
Jun 22, 2019
522
242
Cheers, how do you find economy if not pushing it? Has there been any improvement over stock?

It drives just the same as standard when you're trying to save fuel so the economy is the same. Doubt there is an improvement but not worse either.

Managed 38 mpg on christmas day with the car fully loaded. Me, wife and two kids and the boot full of gifts, very impressed with that. I really feathered the throttle and it was an hour+ drive mostly non-urban though. From what I've read it's easier to save fuel on a tuned diesel compared to stock than a petrol.
 

Kirky

Copper Cupra Advocate
Apr 10, 2019
1,042
497
It drives just the same as standard when you're trying to save fuel so the economy is the same. Doubt there is an improvement but not worse either.

Managed 38 mpg on christmas day with the car fully loaded. Me, wife and two kids and the boot full of gifts, very impressed with that. I really feathered the throttle and it was an hour+ drive mostly non-urban though. From what I've read it's easier to save fuel on a tuned diesel compared to stock than a petrol.
Zero, what are the different map options on the JB4 for the Cupra? I'm about to fit one later this month and want to run a default map before dabbling with Map 6.
 

Zer0

Active Member
Jun 22, 2019
522
242
Zero, what are the different map options on the JB4 for the Cupra? I'm about to fit one later this month and want to run a default map before dabbling with Map 6.

Default is map 1 which is shipped with from factory. It's fine for all cars and fuel but leaves a lot of power on the table. To switch from map 1 you need the optional USB cable and a laptop and you can change maps and settings with the free JB4 software. There are also apps for Android and IOS.

Map 2 and above requires that you tap the AFR wire but the included positap makes it very easy.

If you have the 7 speed DSG map 4 is a good start. It tapers off boost past 6k so launch control works as intended. If you don't use LC you can go with map 3 instead, it holds boost up top. The IS38 turbo isn't very efficient above 6k anyway so either one will be fine. If you plan on running a E85 mix you can setup a map 6 and log some runs until happy. In my opinion unless you go with E85 mix, map 3 or 4 are set and forget, given that the fuel is good enough that is. Otherwise you can drop down to map 2 which will probably give you 350-360 hp and 350-360 ft lbs or so if you have no other mods. I'd guess map 3 and 4 are around 360-370 hp.

Be sure to change the Fuel Open Loop setting from the default (60 I believe) to 45. It's also a good idea to up the Boost Safety setting a little bit (mine is set to 28 but I run a high boost map), otherwise it will automatically set the unit to map 8 if you hit the limit. I recommend going with the stable 60/86/5 firmware, I think all units ship with it.

Here is a list of the different maps:

Map 0: This is a stock map with JB4 logging ability. It is also the starter map for cars that are running flash tunes and are stacking the JB4.
Map 1: Tuned map with a average of 4.0psi over stock. This is the shipped map and is compatible for both 91 and 93 and can be used with cars on hardware.
Map 2: Tuned map with 5.0psi peak boost over stock. 93AKI/98Ron recommended
Map 3 Peak boost 6psi 93AKI/98Ron recommended
Map 4 Peak boost 6psi (Golf R and Audi S3 7speed DSG specific), it has a taper at higher rpm so will also work well for all on 93 in hot climates
Map 5 Absolute map peaking 25 tapers to 20psi. E30 with bolt ons needed. (not to be used on 1.8T or 2.0T Jetta)
Map 6: User adjustable boost map. The map comes preset with a 5.0psi over stock peak and is ready to use on any car running 93 octane. The preset map is also suitable for manual cars with clutch longevity in mind.
The mapping can be done in two manners. If the value at 1500 is kept below 10 it will work as a boost adder map. If the value at 1500 is higher than 10 it will work as a absolute map. This means actual total boost targets will need to be entered.
Map 7: Meth integration map using our FSB Meth controller
Map 8: This is a valet map/safety map where 50% of the boost is cut. It is also the starter map for cars that are running flash tunes and are stacking the JB4. It will give the ability to log the car via the JB4. This is also the safety map, so in any circumstance the JB4 detects a unsafe condition regardless of map it will default to this map. This includes knock detection, lean AFR or the boost safety value being triggered due to lack of boost control.

 
  • Like
Reactions: sir_ace and Kirky

Kirky

Copper Cupra Advocate
Apr 10, 2019
1,042
497
Default is map 1 which is shipped with from factory. It's fine for all cars and fuel but leaves a lot of power on the table. To switch from map 1 you need the optional USB cable and a laptop and you can change maps and settings with the free JB4 software. There are also apps for Android and IOS.

Map 2 and above requires that you tap the AFR wire but the included positap makes it very easy.

If you have the 7 speed DSG map 4 is a good start. It tapers off boost past 6k so launch control works as intended. If you don't use LC you can go with map 3 instead, it holds boost up top. The IS38 turbo isn't very efficient above 6k anyway so either one will be fine. If you plan on running a E85 mix you can setup a map 6 and log some runs until happy. In my opinion unless you go with E85 mix, map 3 or 4 are set and forget, given that the fuel is good enough that is. Otherwise you can drop down to map 2 which will probably give you 350-360 hp and 350-360 ft lbs or so if you have no other mods. I'd guess map 3 and 4 are around 360-370 hp.

Be sure to change the Fuel Open Loop setting from the default (60 I believe) to 45. It's also a good idea to up the Boost Safety setting a little bit (mine is set to 28 but I run a high boost map), otherwise it will automatically set the unit to map 8 if you hit the limit. I recommend going with the stable 60/86/5 firmware, I think all units ship with it.

Here is a list of the different maps:

Map 0: This is a stock map with JB4 logging ability. It is also the starter map for cars that are running flash tunes and are stacking the JB4.
Map 1: Tuned map with a average of 4.0psi over stock. This is the shipped map and is compatible for both 91 and 93 and can be used with cars on hardware.
Map 2: Tuned map with 5.0psi peak boost over stock. 93AKI/98Ron recommended
Map 3 Peak boost 6psi 93AKI/98Ron recommended
Map 4 Peak boost 6psi (Golf R and Audi S3 7speed DSG specific), it has a taper at higher rpm so will also work well for all on 93 in hot climates
Map 5 Absolute map peaking 25 tapers to 20psi. E30 with bolt ons needed. (not to be used on 1.8T or 2.0T Jetta)
Map 6: User adjustable boost map. The map comes preset with a 5.0psi over stock peak and is ready to use on any car running 93 octane. The preset map is also suitable for manual cars with clutch longevity in mind.
The mapping can be done in two manners. If the value at 1500 is kept below 10 it will work as a boost adder map. If the value at 1500 is higher than 10 it will work as a absolute map. This means actual total boost targets will need to be entered.
Map 7: Meth integration map using our FSB Meth controller
Map 8: This is a valet map/safety map where 50% of the boost is cut. It is also the starter map for cars that are running flash tunes and are stacking the JB4. It will give the ability to log the car via the JB4. This is also the safety map, so in any circumstance the JB4 detects a unsafe condition regardless of map it will default to this map. This includes knock detection, lean AFR or the boost safety value being triggered due to lack of boost control.

Thanks very much for that awesome response. That's helped loads as I didn't even know about most of those maps. I have a laptop and the usb cable and also have the breakout harness for the AFR connection. I'll start with Map 4 as I have the 7 speed DSG. Not looking forward to that connector at the bottom of the engine bay......
 
  • Like
Reactions: Zer0

Zer0

Active Member
Jun 22, 2019
522
242
Thanks very much for that awesome response. That's helped loads as I didn't even know about most of those maps. I have a laptop and the usb cable and also have the breakout harness for the AFR connection. I'll start with Map 4 as I have the 7 speed DSG. Not looking forward to that connector at the bottom of the engine bay......

Hehe yeah I had to get it from below the car, couldn't get it from the top.
 

Zer0

Active Member
Jun 22, 2019
522
242
Hey @Kirky I just spotted this JB4 review that was posted on the n54 forums yesterday, I think you'll find it quite useful. Talks a bit about the different maps and what they do, basically what I wrote but a little more details. Also some 0-60 dragy runs with video.

 
  • Like
Reactions: Kirky

Kirky

Copper Cupra Advocate
Apr 10, 2019
1,042
497
Hey @Kirky I just spotted this JB4 review that was posted on the n54 forums yesterday, I think you'll find it quite useful. Talks a bit about the different maps and what they do, basically what I wrote but a little more details. Also some 0-60 dragy runs with video.

Thank you.
 
  • Like
Reactions: Zer0

zzakzz17

Active Member
Feb 8, 2017
35
6
Which color wire would the o2 sensor be on the newer (2019) cupra? Theres no red wire. In place of it, theres a white wire. Would it be that one?
 

Zer0

Active Member
Jun 22, 2019
522
242
Which color wire would the o2 sensor be on the newer (2019) cupra? Theres no red wire. In place of it, theres a white wire. Would it be that one?

Yes it is the white wire as pictured here.

IMG_3715.jpg
 

johnmcclane

Active Member
Jun 29, 2021
16
6
Hi @Zer0
Still using jb4 & hows it treating you?
st300 with 7dsg here.

Anyway, got jb4 & racingline intake elbow + pipe installed yesterday.
Got a harness from ebay for the afr & did not mess with the positap.

Tried MAP4 (I rarely do launches actually for launch control)
I understand it cuts off boost/throttle a bit from around 6k rpm? At least thats whats visible on logs & can be slightly felt while going full throttle (at every gear in high rpm, differs a bit from gear to gear).
MAP3 doesnt have this cut off and should be keeping higher boost also at higher rpm?
Default boost failsafe is 25. I see rarely it keeps hitting a bit over 25 (something like 25.4 on chart) & thus reducing throttle based on the limiter a tiny bit. Should I lift the limiter or keep it like this for now?

Contacted George yesterday, to see whats he reads out of the logs & if anything needs to be finetuned :)
 

Zer0

Active Member
Jun 22, 2019
522
242
Yes map 4 is great for most cars and fuel, set and forget. :)

My warranty is up so I'm waiting for a flash tune + dsg tune in a few weeks.

I've just recently uninstalled my JB4 and it's for sale, asking £275 plus shipping if someone wants it. USB cable included.
 

johnmcclane

Active Member
Jun 29, 2021
16
6
We have 98 octane fuel here, so I guess ill try map3 three and see how its translating to logs.
In the log you can see on MAP4 the boost/throttle cutting at high rpm between gears.

Screenshot 2021-06-29 152515.png
 

Zer0

Active Member
Jun 22, 2019
522
242
Map 4 has a boost taper up top. It's for DSG7 cars, launch control will not be great with map 3. If you don't use LC you can use map 3 for a wee bit more power up top.

It is still a good idea to use auto shift boost redux to limit boost between shifts to save the clutch. A value of 60 or 70 is sound.
 

johnmcclane

Active Member
Jun 29, 2021
16
6
Great tip! Will check what the boost redux default value is.
I guess as the dsg soft is uncahnged, then its going to stay a bit slower (closer to original output) between changes anyway due to those circumstances stacking up.

Ive launched this car probably twice since buying it, so not often. Just feels too brutal for the drive drain, even if it comes from factory.

---

One more question, how many miles/km you did in your 2 year jb4 usage?
Mostly on custom map6 (based from map3)?
 
Genuine SEAT Parts and Accessories.