[M340i Pride]

Hello guys. Its been a while since I posted. Some of you may remember that I wrote a few posts about how JB+ worked for me. I've been doing the 4'O clock position (80% ish) and enjoying it ever since I got the car about a year ago. I should have immediately boosted my octane with some E85, but I did not know about it until about a month ago lol... And now I am smacking my self on the head, how could I miss this easiest and actually a cheaper way to add octane to our boosted B58 engine, and even more so for the added boost from the wonderful JB+? I felt like an idiot. Now, I am pretty sure that I'll never drive without some ethanol mix in my gas tank!

Well, for anyone who is either looking into getting or is just interested in JB+, hopefully this little write up would help. I tried various mixes of E85 with our lovely Socal 91 octane and would like to share how it felt for me.

So first, disclaimer: No draggy / dyno / lap time info available. This is just me driving my everyday drive, mostly the same route, and feeling the butt dyno difference (ha) as best as I could. But trust me, I felt a definite discernable difference!

Second disclaimer: The octane mix is an general APPROXIMATE, ASSUMING that E85 is around 100 octane and giving the benefit of the doubt that it will stay that way at the gas station that I go to. I do not have the ethanol / octane reader and therefore please take the info as such: An educated guess and a easy baseline info to give some reviews on. I do think that I am pretty close to the actual numbers. But feel free to let me know if you have any more info regarding the possible fluctuations.

I started with the E30 mix (93 octane) and immediately felt more power. It felt like there was more power all around the power band, from 2k rpm to 5k. Even when cruising around town, I felt like the throttle response was more immediate. I went to my favorite fwy on a saturday morning when it was mostly empty and pushed the car little bit. I could say with confidence that the pulls were definitely harder. I also drove the car for a week and tried to drive the same way I do in my daily commute in order to compare. More pull. I enjoy the 50-70 5th gear pulls on a fwy on my commute everyday (I commute pretty early in the morning so I am able to) they were even better than usual. With the regular 91 octane, there is a point in the acceleration where the power pans out and torque gets limited. But it felt like the E30 allowed the car to add more fuel to the engine and actually MATCH THE ADDITIONAL AIR THAT JB+ is putting into the engine. The car kept pulling more evenly.

I then tried the E40 mix (94.5 octane) and I want to say that the easy power was even more available than E30. Easy power is meant as where car feels more powerful on lower RPM around town. 5th gear pull seemed even more powerful. No problems, no engine lights.

Then I took things up a notch and got a little dicey. I went up to E 50 (96 octane) and took the car up to a mountain switchback for around an hour. The car felt as good as the E40 mix, but I could not in any way tell that there was a discernable difference from E40 to E50 mix.

HOWEVER, the engine light came on as I was driving down from the mountain switchbacks. I am thinking too much octane... Nothing wrong with the car whatsoever. So I am currently driving it around with a check engine light, and I'll wait a bit until the fuel gets all the way down to empty and go back to E40.

So... There you have it. Looks like the JB+ really benefits from some added corn in it. Since we who live in so cal do not have option to get the 93 octane, I'd say try a little bit and see how it it feels if you have any kind of piggy back on it. Made me a happy camper.

I'll update this post or post a new one If i discover anything else. Hope this helps!

[GD1981]

Nice to hear that youre enjoying some of that corn juice - it most certainly makes a difference. That being said, with your setup, I would advise you not to go pass E30, as you reach a point of diminished returns and can actually hurt performance and tax the B58. Additionally, to be even more safe, I’d upgrade to the JB4 w/ewg harness and start logging to make sure the car is running healthy and that your fully optimizing the JB4.

I’m currently running the JB4 with a customized Map 6 provided by Terry (on E30 with AA DP and MST intake). The car absolutely rips and according to Dragy, I’m running similar times as that of the G80C.

Lot of misguided people hate on the JB4, but when fully optimized + used with proper octane, the unit is a worthwhile upgrade, especially for us 2021+ owners.

Here is my 100-200 run of 7.9 seconds and the second attachment includes dragy run of an F80 (stock and modified) and a stock G80.

[mike@x-ph.com]

Thank you for the review, glad you are happy with the tune

[M340i Pride]

Originally Posted by GD1981

Nice to hear that youre enjoying some of that corn juice - it most certainly makes a difference. That being said, with your setup, I would advise you not to go pass E30, as you reach a point of diminished returns and can actually hurt performance and tax the B58. Additionally, to be even more safe, I’d upgrade to the JB4 w/ewg harness and start logging to make sure the car is running healthy and that your fully optimizing the JB4.

I’m currently running the JB4 with a customized Map 6 provided by Terry (on E30 with AA DP and MST intake). The car absolutely rips and according to Dragy, I’m running similar times as that of the G80C.

Lot of misguided people hate on the JB4, but when fully optimized + used with proper octane, the unit is a worthwhile upgrade, especially for us 2021+ owners.

Here is my 100-200 run of 7.9 seconds and the second attachment includes dragy run of an F80 (stock and modified) and a stock G80.

HOLY COW you are out running a M3 competition. That's some serious times. I did not consider JB4 before, but I think like you said, a good e30 mix can bring out a lot out of the JB4, much more than the JB+ ever could. What would the 1/4 with your car be now? may be low 11's? Anyhow, with minimum money that you spent you have made a sub-super car out of the M340i. very nice! Oh and like you said, I am beginning to think more and more that I should stick to 93 octane, no higher. E40 did feel like it gave more power but it could just be a "feeling".

Update: I burned through a half of my current E50 tank and the check light went away. I am doing to go down to E30-E35 for the next fill up and see how it goes. Thank you.

[VipinLJ]

Like the previous poster said, don't go past E30. ~E25 is perfect for timing correction. More than that and it won't help unless you have a proper tune (not a piggyback). Post E30 (true E30 and not going by assumed values like we usually do), your car will more often than not throw up a drivetrain malfunction error (car can still be driven like you said). Because enough fuel isn't being delivered because of the excess ethanol.

[M340i Pride]

Originally Posted by mike@x-ph.com

Thank you for the review, glad you are happy with the tune

Yes! I am literally slapping myself for not knowing this before. and I am actually saving money lol.... In Socal 91 goes for high 4's, while the e85 was like, 3.35 ha. i am loving it.

[M340i Pride]

Originally Posted by VipinLJ

Like the previous poster said, don't go past E30. ~E25 is perfect for timing correction. More than that and it won't help unless you have a proper tune (not a piggyback). Post E30 (true E30 and not going by assumed values like we usually do), your car will more often than not throw up a drivetrain malfunction error (car can still be driven like you said). Because enough fuel isn't being delivered because of the excess ethanol.

I see. Thank you for the information! Yes, I am planning to bring it down to E30 as soon as I use up this E50 I have lol. The check engine light disappeared so I won't mess with the E40-50 anymore

[xnick101]

Good info in here for you >06/20 owners

[GD1981]

Yes, when I first started messing with E85, I started slowly with E20-E25 and worked my way up to E40, but then my car would throw a drive malfunction error. I then started researching more and more, plus speaking with Terry - I then figured out more E is not necessarily better, actually quite the contrary.

That said, with a proper flash tune, yes, running E40-E50 is certainly possible and would yield substantial power gains over a JB4 + E30. But right now, as a 2021 owner, I’m just happy there is an alternative to quench my thirst for more power

To the OP, I highly recommend you go with the JB4 + EWG + bluetooth to maximize the experience.

[GD1981]

Originally Posted by M340i Pride

HOLY COW you are out running a M3 competition. That's some serious times. I did not consider JB4 before, but I think like you said, a good e30 mix can bring out a lot out of the JB4, much more than the JB+ ever could. What would the 1/4 with your car be now? may be low 11's? Anyhow, with minimum money that you spent you have made a sub-super car out of the M340i. very nice! Oh and like you said, I am beginning to think more and more that I should stick to 93 octane, no higher. E40 did feel like it gave more power but it could just be a "feeling".

Update: I burned through a half of my current E50 tank and the check light went away. I am doing to go down to E30-E35 for the next fill up and see how it goes. Thank you.

I’m RWD, so don’t really bother with dig runs like 1/4 miles. That said, on a prepped track, assuming I can cut a 1.9 60’ foot I’m easily in the mid 11’s @ 122-123mph.

My mods are JB4 E30 + MST intake + AA DP + MPE

[M340i Pride]

Originally Posted by GD1981

I'm RWD, so don't really bother with dig runs like 1/4 miles. That said, on a prepped track, assuming I can cut a 1.9 60' foot I'm easily in the mid 11's @ 122-123mph.

My mods are JB4 E30 + MST intake + AA DP + MPE

Do you think that jb4 alone with e30 could bring a good amount of gains? Not ready for a dp on my leased car.

122-123 is a beastly numbers!!

[GD1981]

Originally Posted by M340i Pride

Do you think that jb4 alone with e30 could bring a good amount of gains? Not ready for a dp on my leased car.

122-123 is a beastly numbers!!

Absolutely. I’d start with Map 3, log, and if that looks good, then try Map 5.

[Mstocker1]

so are we supposed to run 91 0r 93 octane in a new m340I?

[TupperBMW]

I run 93 always

[jpowers36]

93 Shell always.

[GD1981]

if you have 93 available, then 93 it is. Some states get the 91 unfortunately. As far as brand, Shell is recommended by BMW, but any of the other premiums will do, ie Chevron, Exxon, Mobil/Lukoil etc

[M340i Pride]

Originally Posted by Mstocker1

so are we supposed to run 91 0r 93 octane in a new m340I?

I believe in the manual it is recommended that we run 91 octane. But with the JB+, we'll need the additional octane to support the higher boost that will come with it. so E85 is the way to go to get some additional boost. And of course 93 wouldn't hurt in any rate.

[Bootsy]

What all does the JB+ actually add in its tune device? Just a PSI increase or some timing etc. With the JB+ only hooking into the MAF I am curious.

[Antec800]

Just psi increase, jb4 cannot do timing changes either, it can try to spoof some numbers with timing but doesn’t really work

[M340i Pride]

Originally Posted by Bootsy

What all does the JB+ actually add in its tune device? Just a PSI increase or some timing etc. With the JB+ only hooking into the MAF I am curious.

My understanding is PSI increase only. I think it lets to engine DME to do the rest and let it cope with the increased pressure.

I do feel the power increase from having it on and then off. Car is ultimately smoother with it off but the added boost is unmistakable for me. A nice plug and play device for a lease

[Bootsy]

Can our cars run E30 as is or will they need something changed out?

[M340i Pride]

Originally Posted by Bootsy

Can our cars run E30 as is or will they need something changed out?

Im running e30 and am totally stock. Well except jb+. Not a single problem so far.