Jb4 custom tuning: an honest discussion.

[saik]

As a former JB4 user and Jesse customer. I was pretty satisfied with it. OTS was totally fine, but Jesse really smoothed it out and made it feel more natural. Don't worry too much about peak numbers.

I ended up doing the finland unlock route and bm3. It's a little bit more smoother and feels like it has higher torque in the lower RPM range. But damn, I wouldn't say it's night and day difference and I'd probably wouldn't mind going back to JB4.

Sponsored

 

[i3igpete]

Side question. Whats the best way to update my firmware of my JB4?

you can connect to the jb4 as soon as you open the door and the interior lights turn on. But it's probably a good idea to sit down and buckle the seat belt just in case.

 

[ColonelAdama]

As a former JB4 user and Jesse customer. I was pretty satisfied with it. OTS was totally fine, but Jesse really smoothed it out and made it feel more natural. Don't worry too much about peak numbers.

I ended up doing the finland unlock route and bm3. It's a little bit more smoother and feels like it has higher torque in the lower RPM range. But damn, I wouldn't say it's night and day difference and I'd probably wouldn't mind going back to JB4.

First person I've heard say that, but I'm not terribly surprised.

JB4 is very fuel limited <4k rpm. Factory fuel tables are not generous enough and STFTs aren't enough to compensate for high boost targets, hence lower torque.

5k+ rpm - doesn't seem to be fuel limited, I can have the JB4 push as much boost as I want (as long as timing looks good) Peak hp gains shouldn't be much different unless flash tune runs more timing than stock.

 

[saik]

First person I've heard say that, but I'm not terribly surprised.

JB4 is very fuel limited <4k rpm. Factory fuel tables are not generous enough and STFTs aren't enough to compensate for high boost targets, hence lower torque.

5k+ rpm - doesn't seem to be fuel limited, I can have the JB4 push as much boost as I want (as long as timing looks good) Peak hp gains shouldn't be much different unless flash tune runs more timing than stock.

Oh yeah, I'll disclaim I'm not an expert and this is all purely butt dyno feelings lol. But overall driving it feels pretty similar to me. And I should mention this is all on CA 91 Octane, and I told the tuner my goal is drivability, not necessarily all out mo' powah.

 

[DHarkKnight10]

In my personal experience; on 93 octane a custom JB4 tune made a noticeable change and made the power delivery feel much smoother over OTS maps. There was likely a 10-20 whp gain but tbh I didn't dyno anything so I'm merely spitballing. On E30 is when I noticed the most "gains" with a custom JB4 tune. Definite increase in whp but a crap ton of wtq gains all while having a very smooth power delivery and much less jerky/laggy feelings I was getting on the OTS maps

 

[NitroYellowMKV]

There is an ass for every seat, same way there is an application for JB4 and custom tuning and unlocks, Ive said this before, from a purely financial standpoint if you are buying everything new, the difference is sub $500 to go from a Jb4 with custom tune to a real flash on a bm3 OTS, but again there are drawbacks to both, and positives to both. as a manual owner myself I am still waiting to see how everything gets smoothed out with the tuning as its been a bit problematic, but for a locked ecu car looking to gain between 50-70 whp, buying a used Jb4 for 450 or so is going to be your easiest and best bet for power gain.

 

[wilorichie]

I picked up a used JB4 that was about 3 months old, from a dude that was using it in his bmw.

BMS confirmed go ahead, grab it for the supra. It cost me about $400AUD (300usd-ish) with bluetooth and wgc.

The guys in the jb4tech forum got me to grab logs from map 1. Confirmed all good. Then confirmed map 2 was all good and then finally map 4 was the limit of my car.

I run map 4 and it feels smooth and powerful. Car feels sluggish when the jb4 is switched off. So I leave it on map 4 99% of the time.

They offered to look at a map 6 tune, free of charge, but in the end I decided not to bother with it. They said it wouldn't be much different to my map 4, and that has plenty enough go for what I want.

Overall, super happy with the JB4, what they (BMS) offer and their willingness to help others.

I'll now always give them a thumbs up and spread the word

 

[ColonelAdama]

I picked up a used JB4 that was about 3 months old, from a dude that was using it in his bmw.

BMS confirmed go ahead, grab it for the supra. It cost me about $400AUD (300usd-ish) with bluetooth and wgc.

The guys in the jb4tech forum got me to grab logs from map 1. Confirmed all good. Then confirmed map 2 was all good and then finally map 4 was the limit of my car.

I run map 4 and it feels smooth and powerful. Car feels sluggish when the jb4 is switched off. So I leave it on map 4 99% of the time.

They offered to look at a map 6 tune, free of charge, but in the end I decided not to bother with it. They said it wouldn't be much different to my map 4, and that has plenty enough go for what I want.

Overall, super happy with the JB4, what they (BMS) offer and their willingness to help others.

I'll now always give them a thumbs up and spread the word

Glad to hear it! Map 4 is usually my recommendation for most cars too! Very similar to most "custom map 6 tunes" on 93.

 

[GoldenEye]

I'm happy with the JB4 and the custom tunes from Jesse. If I decide to go big turbo I'll look into ecu unlock but until then this is plenty fun enough...

 

[totalone]

I still see Jesse's price at 575, but honestly you can just get a secondhand JB4 here for $400 and run an OTS map...

Or post the logs in my thread, or on the JB4 forum for review to see if custom tuning is needed. Its not required to get a Jesse tune... He can charge what he does because everyone thinks its mandatory lol.

Expect ~440whp for dp, intake on 93 if you've got clean logs.

Femto + BM3 would be easily over $2k before even getting into custom tuning. You could make 40whp+ gain easily for under $500 on JB4.

Is it possible you can take a loom at my logs and see if I would need custom tune?
Very new to this forum, if there is a thread for this please point me to it.


Please l

 

[ColonelAdama]

Is it possible you can take a loom at my logs and see if I would need custom tune?
Very new to this forum, if there is a thread for this please point me to it.


Please l

You can upload your CSV log to datazap to my Map 6 thread:
https://www.supramkv.com/threads/seeking-more-info-on-jb4-map-6-tuning.16759/

Map 1: 3rd gear 2500-redline. 4th if traction limited.

Sponsored