JB4 vs Femto unlock

[SupraMike40]

Curious, why are so many choosing to do the JB4 tune instead of sending it to Femto and unlocking it the correct way? I've heard a lot of negative things about JB4 and given that this is a $60-65k sports car, why are people opting for the quicker, cheaper tune?

The cost savings on the JB4 can't outweigh the risk / depreciation resale value of going this route versus a full unlock right?

Seems like 90% of the 2021+ Supras I've seen for sale have the JB4 tune.

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[R1Outcast]

What negatives are you hearing? I've only seen positive reviews.

To answer your question though: For me it's mainly about convenience. I daily my Supra. I don't like the idea of not being able to drive it for weeks/months while someone across the ocean unlocks the ecu.

 

[Myeil]

why are people opting for the quicker, cheaper tune?

Because it's quicker and cheaper. Not everyone is out to make big power and many prospective buyers wouldn't touch a used modded car even if the ECU was unlocked.

 

[oreobbq]

A piggy is cheaper, easily removed, adds a nice bit of power, and can be resold. And no risk of a dealer accidentally updating the software, requiring you to unlock again.

I’d go femto and tune, just haven’t got around to it. With my luck sometimes, watch it be the first ecu we know of to be lost in shipping lol. Or a stateside unlock revealed the next day.

 

[Rocksandblues]

love to hear how it affects depreciation?

 

[ColonelAdama]

Curious, why are so many choosing to do the JB4 tune instead of sending it to Femto and unlocking it the correct way? I've heard a lot of negative things about JB4 and given that this is a $60-65k sports car, why are people opting for the quicker, cheaper tune?

The cost savings on the JB4 can't outweigh the risk / depreciation resale value of going this route versus a full unlock right?

Seems like 90% of the 2021+ Supras I've seen for sale have the JB4 tune.

• Its around $400 used
• Not detectable by dealer when removed (to sell, for warranty work, etc)
• Retains factory safeties and has built in safeties of its own that revert to stock map if it sees anything dangerous
• up to 75-80whp gains on E30, and 100+ whp on methanol
• Depreciation as in JB4 depreciation? your car will not lose value for it.
• Its enough to maximize power on 91/93 and E30 fuel on stock turbo. You won't see much gains going unlock unless you go E40+ or bigger turbo.

Femto is at least $1k, but most people do a delivery service, so expect 1500+. Then Bm3/mhd license for what, 500? So you are looking at at least 1500-2000 just to use those OTS maps and likely $1k+ more for custom tuning.

All that to just scare off the next clueless owner who would prefer the car is stock with warranty ? Which, of course, it would be after removing a JB4 (which you can sell and get back most of what you paid for it).

Its not like a JB4 is some cheap untested thing. They've been making them since the N54 16+ years ago.

 

[SupraMike40]

• Its around $400 used
• Not detectable by dealer when removed (to sell, for warranty work, etc)
• Retains factory safeties and has built in safeties of its own that revert to stock map if it sees anything dangerous
• up to 75-80whp gains on E30, and 100+ whp on methanol
• Depreciation as in JB4 depreciation? your car will not lose value for it.
• Its enough to maximize power on 91/93 and E30 fuel on stock turbo. You won't see much gains going unlock unless you go E40+ or bigger turbo.

Femto is at least $1k, but most people do a delivery service, so expect 1500+. Then Bm3/mhd license for what, 500? So you are looking at at least 1500-2000 just to use those OTS maps and likely $1k+ more for custom tuning.

All that to just scare off the next clueless owner who would prefer the car is stock with warranty ? Which, of course, it would be after removing a JB4.

Its not like a JB4 is some cheap untested thing. They've been making them since the N54 16+ years ago.

How is it not detectable by the dealer if you decide to remove the tune? I thought any alteration to the ECU can be detected, even if brought back to stock.

Thought I read a thread about the JB4 removing the safety parameters of the engine which was a disadvantage from a custom tune?

 

[ColonelAdama]

How is it not detectable by the dealer if you decide to remove the tune? I thought any alteration to the ECU can be detected, even if brought back to stock.

Thought I read a thread about the JB4 removing the safety parameters of the engine which was a disadvantage from a custom tune?

The whole point of the JB4 is that it intercepts the pressure sensors to trick the car into thinking there's less boost than there actually is. The car's ECU never sees anything outside of factory parameters, so no, its not detectable when removed.

It retains factory safety parameters and adds several safety mechanisms of its own.

To your point, yes it is worse than an unlock + custom tune. But not everyone wants to fork out $2500+ and lose their warranty for a bit more power than a JB4 could do. I recommend unlock for people who want to run E30+, a bigger turbo, or go PI. ?‍

 

[SupraMike40]

The whole point of the JB4 is that it intercepts the pressure sensors to trick the car into thinking there's less boost than there actually is. The car's ECU never sees anything outside of factory parameters, so no, its not detectable when removed.

It retains factory safety parameters and adds several safety mechanisms of its own.

Thanks for the clarification!

 

[Dven11]

I was undecided if I wanted to pay for the JB4 or just use that towards the Femto unlock. Ultimately, I decided against the downtime to send out my ECU and I am not aiming for big power gains anytime soon. I'm also a bit paranoid of something happening to my ECU or ultimately voiding my warranty.

As others have mentioned, the JB4 with the proper adjustments has worked perfectly fine. The fact that you can remove it in 15min as if it was never there, is a plus. You can take a look at this thread for help with the JB4 tuning:

SUPRA ULTIMATE JB4 GUIDE AND LOG REVIEW (V1) | SupraMKV - 2020+ Toyota Supra Forum (A90 MKV Generation)

 

[JoshuaQ]

Convenience. Send ecu across the planet and risk bricking it or losing it or get a boost bump.

Supra fast. It doesn't need a jb4 or tune. So either is fine.
Cheap. IDC how much money I have, I am too stingy to be paying $2000ish for a tune...that can be ruined by dealerships.

Preference. Haven't heard many bad things about the jb4 outside of the "I r by $2000 tune cuz r jb4 bad" ppl.

To each their own. The car is fast AF with or without those options.

 

[Extreme Power House]

I've tried both on my car. If you're looking for quick power with minimal investment, the JB4 is an excellent choice. It takes just 45 minutes to install, and the difference is night and day.

If you're after the best tune and aiming for even more power than the JB4 can provide the Femto + Bootmod3 combo is the way to go.

For my BMW M4 rear wheel drive, I chose the JB4 because I wanted to limit the power increase to avoid traction issues.

On my BMW M4 X-Drive, where I want maximum power, I got Femto + Bootmod3.

 

[scarletspider]

I would also like to add that since the JB4 isn't a full-fledged tune, some customizations will be completely unavailable. You will never be able to adjust the 'burble' on JB4, tuning with BM3 gives access to higher ethanol content (more fueling control) and in-dash ethanol readout compatibility.

I would love to save some money and go with JB4, there's a ton of support for it and it has great results but I REALLY dislike the burble (sometimes lol) and that's one of the main reasons that convinced me to go the BM3 route. JB4 is a great option if the limitations are not important to you.

 

[Alljdmralf85]

What negatives are you hearing? I've only seen positive reviews.

To answer your question though: For me it's mainly about convenience. I daily my Supra. I don't like the idea of not being able to drive it for weeks/months while someone across the ocean unlocks the ecu.

I got it done in 5 days from the east coast sent out on a Monday had it back by Friday at noon ??‍

 

[R1Outcast]

I got it done in 5 days from the east coast sent out on a Monday had it back by Friday at noon ??‍

Based on what I've heard from a lot of other people, your experience isn't the norm.

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