[vrships]

I have read I suppose all the threads in the forum about choosing between flash and piggybacks. I understand their pros and cons but still cannot really make decision because I've not tried either one before so the risk could be different from what I perceive.

But I guess the JB4 is a little more favored now because of the BMW's more hostile policy on any flashed car. Their ISTA system now scans the tuning status anytime the car's hooked and made sure it throws the warning if there is a flash tune, regardless of what service you take it in for.

I know eventually BMW's gonna find out whatever tune is on the car, flashed or piggyback when they want to. But this just feels different that they now flag you as a dishonest customer and they'll start treating you bad however they want for a justifiable reason.

I mean with JB4 one can still hide it most of the time and there may be some kind technicians to pretend they do not see it if the system doesn't report.

And correct me if I am wrong:

1. Both are gonna bring up the performance similarly for the lightest-mid level maps?
2. BM3 can be flashed back to stock and JB4 can be removed for dealer service. But the former is gonna leave a permanent record in the DME, while for the latter the dealer really has to look through all the traces in the log to suspect it has gone thru some tuning?

And I didn't keep up yet with the DME locking situation on 2020 m40i. Is the trouble still there for BM3 with cars with older than 11-19 update?


Anyway, which one would you choose for a stock car? I'll say I am gonna do anything too abusive with the tune so I don't think either one will really do damage the the car.

[Alias1431]

The chance that a) your powertrain dies on this B58/ZF8 platform (within the warranty period), and b) the dealer would NOT find out you were using JB4- is very, very low. Just get BM3. Better/smoother power. Probably better for your engine, too. Not that JB4 is bad, a tune is just better.

[suby01]

BM3 power gains are higher than anything from JB4 even without a custom BM3 tune.

Dealer will always find out if car was flashed/tuned no matter what option you use. If they decided to dig deep enough. They will find your JB4 and any stickers you had on the car previously.

I cannot confirm if JB4 is less "visible" But I can confirm BM3 is very visible based on my last dealer visit. lol. Again they will still find JB4 if they want to look.

This was said countlessly. 1. get into a good relationship with your service advisor. 2. dont mod your car. 3. say f warranty and enjoy the hrspwrs.

You will definitely enjoy either option you choose extra HP is always fun.

[ramparts]

If you tune or piggy back, you need to go into it knowing that you're potentially voiding the warranty.

If you want to tune and keep a warranty intact:

Option 3 is you buy an AC schnitzer ECU.

410HP, 600Nm torque, and a 3/5 engine warranty
https://www.ac-schnitzer.de/en/bmw/x...ive-19293.html

[vrships]

Originally Posted by Alias1431

The chance that a) your powertrain dies on this B58/ZF8 platform (within the warranty period), and b) the dealer would NOT find out you were using JB4- is very, very low. Just get BM3. Better/smoother power. Probably better for your engine, too. Not that JB4 is bad, a tune is just better.

I know. If anything about powertrain brakes with a tune on the car, BMW will investigate and dig out anything you modded about the car.

But with BM3 what I am afraid is, if I have a faulty headlight, an alternator or battery issue, when the dealer hook up their ISTA, they will be immediately notified that the DME is tuned and blame everything on it.

With piggybacks, as long as it's not for an engine or tranny warranty claim, they probably won't bother looking into all the fine details about performance logs just for repairs on electronicsl or any other accessories unrelated to engines.

[vrships]

Originally Posted by suby01

BM3 power gains are higher than anything from JB4 even without a custom BM3 tune.

Dealer will always find out if car was flashed/tuned no matter what option you use. If they decided to dig deep enough. They will find your JB4 and any stickers you had on the car previously.

I cannot confirm if JB4 is less "visible" But I can confirm BM3 is very visible based on my last dealer visit. lol. Again they will still find JB4 if they want to look.

This was said countlessly. 1. get into a good relationship with your service advisor. 2. dont mod your car. 3. say f warranty and enjoy the hrspwrs.

You will definitely enjoy either option you choose extra HP is always fun.

I am not gonna really mess with the car to the extent that a piston rod breaks. And in fact most of the time I am very gentle with it.

But I am just so inconfident in the quality of a lot of peripheral parts on modern BMW. I am afraid it's very likely at some time there's a gonna be an oil or coolant leak on some gaskets. (And BMW certainly have 4-5 times more junctions with gaskets than NA cars with similar power). And maybe an oil filter housing crack. And many other unrelated issues on suspension bushings, window rubber seals...

So if the car is sent in for any of these issues, an upfront FLAG saying your car is "hideously" modified simply makes everybody think you are guilty for all of them.

[Alias1431]

Originally Posted by vrships

But with BM3 what I am afraid is, if I have a faulty headlight, an alternator or battery issue, when the dealer hook up their ISTA, they will be immediately notified that the DME is tuned and blame everything on it.

They can't do that, it has to be related to what failed.

[Alias1431]

Originally Posted by davidoff86

Option 3 is you buy an AC schnitzer ECU.

410HP, 600Nm torque, and a 3/5 engine warranty
https://www.ac-schnitzer.de/en/bmw/x...ive-19293.html

What does that run?

[vrships]

Originally Posted by Alias1431

They can't do that, it has to be related to what failed.

Yeah I am aware of that. But I saw a case here on the forum that (probably in UK) they literally voided all electrical and electronics warranty on a car that simply has been Bimmercoded.

They tend to extend the range of the "related" the furthest they can. Of course we can always argue but it'll become a huge pain.

[Alias1431]

Originally Posted by vrships

Yeah I am aware of that. But I saw a case here on the forum that (probably in UK) they literally voided all electrical and electronics warranty on a car that simply has been Bimmercoded.

They tend to extend the range of the "related" the furthest they can. Of course we can always argue but it'll become a huge pain.

I don't know what they have or don't have in the UK, but in the US there's the Magnuson–Moss Warranty Act. But yes, the arguing could be very unpleasant.