[bellguy]

Probably a stupid question, but not knowing the answer i will ask anyway lol

My 440i has almost 3 years warranty on it so i do not want to flash tune it like i did my 440i as i know BMW can tell the DME has been unlocked, my question IS, can they tell if a piggyback tune used and if NOT what would you recommend for a simple stage 1 tune.

[baldeagleman]

JB4 is detectable, all tunes are detectable. They will see you were running higher boost than you should be able to. Bottom line is if you are concerned with warranty do not install a tune.

[NISFAN]

The ECU logs peak parameters. So even with a piggy back, the ECU will be full of 'implausible' value markers, and peak values for reference.
In other words, there is no warranty safety to any method of power increase.

[bellguy]

Thanks all for your input, as it's only 12 weeks old i will leave it stock for at least 18 months i think re tune.

[BMW in NE]

Provided your warranty is BMW, you could always go with Dinan. They match the factory warranty so if there's issues you're covered.

[IMS-340C]

MPPSK

[Supr3me]

Originally Posted by IMS-340MP

MPPSK

2019 440i in UK likely has the gasoline particulate filter and therefore not eligible for MPPSK

[Fuel-It!]

JB4 isn't detectable as has been well proven over the years, the vehicle is never aware it's making more power than stock, never aware it's making more boost than stock, and never aware it's using more fuel than stock.

That said as they always say pay for any damage you cause operating your vehicle outside of its factory specifications.

[chenry]

Originally Posted by BMW in NE

Provided your warranty is BMW, you could always go with Dinan. They match the factory warranty so if there's issues you're covered.

agreed but so many restrictions with that warranty. I love it but it is certainly not black and white - after decades of hearing about "the dinan warranty" i read it and there are many restrictions

ps-love me some Dinan first modified a BMW via Dinan in 1987 on our 1985 528

[chenry]

Originally Posted by Fuel-It!

JB4 isn't detectable as has been well proven over the years, the vehicle is never aware it's making more power than stock, never aware it's making more boost than stock, and never aware it's using more fuel than stock.

That said as they always say pay for any damage you cause operating your vehicle outside of its factory specifications.

+1 totally agree with you:

Sure the JB4 or JBXX or any other piggyback (or flash for that matter) is not physically detectable if you remove it - however the results of what it does (higher boost outside of oem parameters etc) are certainly detectable if someone (er uh the dealer - BMW etc..) digs deep enough

TLDR: any mod is "detectable" if the oem wants to dig deep enough - we need to move beyond this piggyback vs flash making detectable an issue

[Fuel-It!]

Originally Posted by chenry

Sure the JB4 or JBXX or any other piggyback (or flash for that matter) is not physically detectable if you remove it - however the results of what it does (higher boost outside of oem parameters etc) are certainly detectable if someone (er uh the dealer - BMW etc..) digs deep enough

That claim is often made by those pushing flash maps but it's simply not true. For the JB4 to function the vehicle can never be aware it's making more than the factory boost or power levels. Otherwise it just wouldn't work and you'd get a CEL every time you tried to build boost.

The flash on the other hand by design results in the ECU and many other modules storing higher than factory boost, torque, and load levels, in the trans module, stability control module, and others, and can never be fully removed even if "flashed to stock" after.

There are a lot of things you can do on the flash side that are just not possible with a JB4 but it's also important to understand there are things not possible with a flash tune that are possible with a JB4. Removal without a trace is one of those things.

[chenry]

Originally Posted by Fuel-It!

That claim is often made by those pushing flash maps but it's simply not true. For the JB4 to function the vehicle can never be aware it's making more than the factory boost or power levels. Otherwise it just wouldn't work and you'd get a CEL every time you tried to build boost.

The flash on the other hand by design results in the ECU and many other modules storing higher than factory boost, torque, and load levels, in the trans module, stability control module, and others, and can never be fully removed even if "flashed to stock" after.

There are a lot of things you can do on the flash side that are just not possible with a JB4 but it's also important to understand there are things not possible with a flash tune that are possible with a JB4. Removal without a trace is one of those things.

+1 we agree
okay most any engine modification can be detected by BMW if they dig deep enough

[Fuel-It!]

Originally Posted by chenry

+1 we agree
okay most any engine modification can be detected by BMW if they dig deep enough

BMW guys often check social media and will even subpoena your credit card statements if it gets that far. I've heard of them showing customers forum posts or FB group posts they had made to people who make warranty claims. Sometimes they go around tracks and take photos of the VIN of cars there too.

[NISFAN]

Originally Posted by Fuel-It!

JB4 isn't detectable as has been well proven over the years, the vehicle is never aware it's making more power than stock, never aware it's making more boost than stock, and never aware it's using more fuel than stock.

That said as they always say pay for any damage you cause operating your vehicle outside of its factory specifications.

Sorry, but this is incorrect. Maybe you are talking about dealer level interrogation alone, but the engine has a web of sensors that will show implausible readings, detectable by a deep scan. JB4 has no influence on MAF, fuel duty, EGT, waste gate PWM, etc which will show out of range (but not out of bounds to bring on CEL) readings.
Next up, the car registers speeds and acceleration data, which again will raise flags. Put these together and the picture is clear that the car was making more than stock power.

Probably won't go for a deep scan if your turbo fails, but if you blow the engine that's when Germany will want to find out if there is some issue with their product. There are cases where the ECU has been sent away for evaluation.

[Fuel-It!]

Originally Posted by NISFAN

Sorry, but this is incorrect. Maybe you are talking about dealer level interrogation alone, but the engine has a web of sensors that will show implausible readings, detectable by a deep scan. JB4 has no influence on MAF, fuel duty, EGT, waste gate PWM, etc which will show out of range (but not out of bounds to bring on CEL) readings.
Next up, the car registers speeds and acceleration data, which again will raise flags. Put these together and the picture is clear that the car was making more than stock power.

With a JB4 wastegate duty and fuel are both managed and appear like factory as does MAF flow. There is no EGT sensor it's modeled and reflects factory values with JB4. There is a reason some JB4 more aggressive maps require additional connections like the EWG connector.

The JB4 does not remove the factory speed limiter and you can't infer tuning from the sorts of acceleration measurements the vehicle records. Also that system has no way of knowing whether you're going up or down an incline. It has no way of knowing whether you're running E0 89 octane or E15 93 octane. All of the data recorded has plausible ranges and the JB4 keeps those values within the plausible ranges for factory tuning.

Most people who are flagged are because they failed to remove it or the dealer sees other modifications and voids based on those like a downpipe. With a flash map on the other hand anyone attaching in to the OBDII for diagnostics can easily spot the vehicle has been tuned and flashed back to factory.

[NISFAN]

Originally Posted by Fuel-It!

With a JB4 wastegate duty and fuel are both managed and appear like factory as does MAF flow. There is no EGT sensor it's modeled and reflects factory values with JB4. There is a reason some JB4 more aggressive maps require additional connections like the EWG connector.

The JB4 does not remove the factory speed limiter and you can't infer tuning from the sorts of acceleration measurements the vehicle records. Also that system has no way of knowing whether you're going up or down an incline. It has no way of knowing whether you're running E0 89 octane or E15 93 octane. All of the data recorded has plausible ranges and the JB4 keeps those values within the plausible ranges for factory tuning.

Most people who are flagged are because they failed to remove it or the dealer sees other modifications and voids based on those like a downpipe. With a flash map on the other hand anyone attaching in to the OBDII for diagnostics can easily spot the vehicle has been tuned and flashed back to factory.

JB4 has no connections to MAF, no connections to wastegate, etc. It is unable to 'bend' signals it isn't connected to. Please tell us how it keeps a plausible MAF reading.

[Fuel-It!]

Originally Posted by NISFAN

JB4 has no connections to MAF, no connections to wastegate, etc. It is unable to 'bend' signals it isn't connected to. Please tell us how it keeps a plausible MAF reading.

The JB4 attaches to the wastegate signal for higher boost maps that would throw plausibility out of range, using CANbus which connects it to every sensor and computer on the car, and it's other connections, it's able to manipulate airmass recordings. If it didn't manipulate them the vehicle would throw a limp mode every time you floored it from "airmass too high".

It's funny that every few months this is a "new" topic. The JB4 has been out since 2008 and every time I've heard of someone claiming they were "detected" after removal there always turns up additional details to blame. Meanwhile, there are 100s of posts of no detection when removed. Compared to flash tune where the only people not flagged are those whose dealership didn't bother to document them (due to friendship) or tech who was too lazy to check. Any major warranty claim almost always denied even after flashed to factory and I get regular accounts of lease trade in denied, CPO denied, etc, due to flash.

[NISFAN]

Originally Posted by Fuel-It!

The JB4 attaches to the wastegate signal for higher boost maps that would throw plausibility out of range, using CANbus which connects it to every sensor and computer on the car, and it's other connections, it's able to manipulate airmass recordings. If it didn't manipulate them the vehicle would throw a limp mode every time you floored it from "airmass too high".

It's funny that every few months this is a "new" topic. The JB4 has been out since 2008 and every time I've heard of someone claiming they were "detected" after removal there always turns up additional details to blame. Meanwhile, there are 100s of posts of no detection when removed. Compared to flash tune where the only people not flagged are those whose dealership didn't bother to document them (due to friendship) or tech who was too lazy to check. Any major warranty claim almost always denied even after flashed to factory and I get regular accounts of lease trade in denied, CPO denied, etc, due to flash.

Ah, so the optional OBD connection and the optional wastegate connection resolves all plausibility issues? Even when not connected or even optioned by the buyer? Or is +50hp undetectable by the state of art Bosch DME? :

By the way, OBD is a diagnostic portal. It does not have the ability to become the master in the signals you say it has power over (MAF, O2, manifold temp,etc). Those signals run on a different network. PT-CAN is what DME uses to talk to engine modules, OBD is not connected to PT-CAN.

[Fuel-It!]

Originally Posted by NISFAN

Ah, so the optional OBD connection and the optional wastegate connection resolves all plausibility issues? Even when not connected or even optioned by the buyer? Or is +50hp undetectable by the state of art Bosch DME?

The optional connections allow for higher power gains without detection.

PT-CAN is what DME uses to talk to engine modules, OBD is not connected to PT-CAN.

Of course this is also false, otherwise how would you flash your DME via the OBDII port? It's a gateway connected to each bus on the vehicle.

It's fine to be skeptical but keep in mind the JB4 is not some brand new device. It's a well established tuning platform that has been out almost 15 years. In addition to its reliability the diagnostic invisibility has also been well established over that period. Meanwhile, the record for flash tuning detection even if flashed to stock has also become painfully clear.

[Supr3me]

Me watching this thread

[BMWILUVU]

Originally Posted by baldeagleman

JB4 is detectable, all tunes are detectable. They will see you were running higher boost than you should be able to. Bottom line is if you are concerned with warranty do not install a tune.

My Active8 was not detected. I have seen posts where JB4 was. I thought flash tunes definitely would be but I have seen one guy's engine replaced and all he did was flash back to stock. This being said, the safest path is to get a stage 1 flash after warranty expires and do not get greedy with power. 390hp is more than enough for the street.

[mike@x-ph.com]

Originally Posted by bellguy

Probably a stupid question, but not knowing the answer i will ask anyway lol

My 440i has almost 3 years warranty on it so i do not want to flash tune it like i did my 440i as i know BMW can tell the DME has been unlocked, my question IS, can they tell if a piggyback tune used and if NOT what would you recommend for a simple stage 1 tune.

No one knows for sure whether they can detect it or now. What we know is that if you remove the jb4 before your visit, you are safe.

Tens of thousands of users have been doing it for years