SUPRA ULTIMATE JB4 GUIDE AND LOG REVIEW (V1)

[ColonelAdama]

Great example where having total control of ignition timing and fueling would be very helpful. Anyway, I'm not here in this thread to keeping shouting the merits of actual ECU control.

No worries, I think it is a valid discussion point for 2020s.

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[Bug2th]

Meth gains are huge lol, like 50whp+. It would need a new tune since boost requests would be much higher when fueling or octane are no longer the bottleneck.

and this wouldnt require anything else like fuel pump upgrades, etc. to get there?

 

[Phantomx]

MHD BEF and JB4 is a great combo. It was about 60rwhp more and a bunch of tq as well using the two vs an OTS map for MHD. I’m sure you can get there on a custom MHD map but I love the flexibility of tweaking with the Jb4 and not having to keep reflashing or getting tune updates and then reflashing. I could tweak in the car on demand.

 

[ColonelAdama]

and this wouldnt require anything else like fuel pump upgrades, etc. to get there?

Nah, Meth is the additional fuel. Will reduce the DME fuel demand substantially. Trims drop a lot, which should allow you to run more boost and ethanol.

I have reviewed some meth logs, but I've not custom tuned someone on it yet.


Here is a 99% meth log on an M340 for example:
https://datazap.me/u/coloneladama/log-1714512217?log=0&data=1-2-4-14

It is running 7-8psi over stock and trims are in the single digits and teens. DME is actively removing fuel to keep AFR at lambda 1 (14.7).

A ton more pulls of the same car - Trims bottoming out. In theory, you should be able to add a ton more ethanol and boost and it'd take it fine.
https://datazap.me/u/coloneladama/log-1714512399?log=0&data=1-14-18&zoom=1183-1403

Presumably you'd just reach the limit of the stock turbo at ~25psi, good bit over 500whp.

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