Running map 7 with jb4 and e85 mix

[nyc f82]

Is this safe to do for this map? I am currently running about 4 gallons of e85 (tested at e71) and the rest 93 octane with 10% ethanol. The car seems to be running fine with the occasional drivetrain malfunction once in a while but that doesn't happen often. I have many logs but not sure how to post them up.

[CaryTheLabelGuy]

Originally Posted by nyc f82

Is this safe to do for this map? I am currently running about 4 gallons of e85 (tested at e71) and the rest 93 octane with 10% ethanol. The car seems to be running fine with the occasional drivetrain malfunction once in a while but that doesn't happen often. I have many logs but not sure how to post them up.

Those drivetrain malfunctions are probably from maxing out your fuel trims. Map 7 might be a little too aggressive for your fuel trims. Raise your FOL to 75 and see how it runs.

Edit: fixed shitty iOS autocorrections.

[Fast4d]

based on what bugertuning told me you are on the edge.

you need some 100 octane (race fuel) mixed in to run map 7.

I experienced knock with 4 gallon e85 and 91 octane.

[CaryTheLabelGuy]

Originally Posted by Fast4d

based on what bugertuning told me you are on the edge.

you need some 100 octane (race fuel) mixed in to run map 7.

I experienced knock with 4 gallon e85 and 91 octane.

4gals of E85 mixed with 91 octane and 4 gals of E85 mixed with a proper 93 octane are two totally different things, honestly. They should not be compared. You've still got to pay attention to overall octane rating and 91 piss is notoriously terrible.

[CaryTheLabelGuy]

Furthermore, 4gals of E85 (testing a true 85%) mixed with 91 oct (E10) is about 94 octane (E29) (R+M/2) and that's if you have access to decent 91.

Contrast that to E85/93 octane mixes, 4gals of 93 octane (E10) mixed with true E85 is also E29, but overall octane is raised to right at 96 octane (R+M/2).

It's not until you get into the E30+ range before you really start to significantly increase the detonation threshold, especially mixed with a quality 93 octane.

By E60 or so (especially with a quality 93 blend), you have most of the benefits of running a full-tank of E85......key word here being 'most'. "The more ethanol the better", will always be true. Obviously your car is incapable of running much more ethanol content than E32 (unless you have a ZCP, then you can get to about E40 or so), but it's better than 91 by itself for sure. I wouldn't venture past Map 2 or maybe a map 6 targeting no more than 21 psi or so.

Like stated above, you need increase your FOL to at least 70 or even try 75.

[CaryTheLabelGuy]

You piss-91-octane guys with non-ZCPs would really benefit from a flash that raised the fuel scalars enough to run as much ethanol as possible on the stock fuel system. The ZCP cars will be luckier from the piggyback perspective, simply because the ZCP tune is a much better base to stack a JB4 on.

[nyc f82]

Originally Posted by CaryTheLabelGuy

Furthermore, 4gals of E85 (testing a true 85%) mixed with 91 oct (E10) is about 94 octane (E29) (R+M/2) and that's if you have access to decent 91.

Contrast that to E85/93 octane mixes, 4gals of 93 octane (E10) mixed with true E85 is also E29, but overall octane is raised to right at 96 octane (R+M/2).

It's not until you get into the E30+ range before you really start to significantly increase the detonation threshold, especially mixed with a quality 93 octane.

By E60 or so (especially with a quality 93 blend), you have most of the benefits of running a full-tank of E85......key word here being 'most'. "The more ethanol the better", will always be true. Obviously your car is incapable of running much more ethanol content than E32 (unless you have a ZCP, then you can get to about E40 or so), but it's better than 91 by itself for sure. I wouldn't venture past Map 2 or maybe a map 6 targeting no more than 21 psi or so.

Like stated above, you need increase your FOL to at least 70 or even try 75.

Thanks that was very helpful. I read one of your older post that increasing the FOL passed 70 became a issue with your car and you had to back it down. This is safe to increase this high?

Thanks

[CaryTheLabelGuy]

Originally Posted by nyc f82

Thanks that was very helpful. I read one of your older post that increasing the FOL passed 70 became a issue with your car and you had to back it down. This is safe to increase this high?

Thanks

Good question.

On my non-ZCP, anything over 72 caused a Fuel Pressure Too Low DTC, however on my ZCP I have gone beyond 80 without issue, with max boost pressures of 23psi and I never actually found the FOL limit on the ZCP. I used 75 to 80 depending on how much ethanol I was running at the time. E42 required an FOL of 80 and boost pressure to not exceed 23psi on my ZCP. The ZCP can handle ethanol much better than the non-ZCP before trims go too lean and the ZCP also seems to be more forgiving of higher FOLs on the JB4, further allowing more ethanol content.

To answer your question about being safe, increasing the FOL is safe. Even if you get a Fuel Pressure Too Low DTC, it's not hurting anything really. The DME will just throw the CEL and if allowed to persist, will likely lead to limp mode. Whenever I got it, I knew I was at my limit for those specific boost pressures and that specific amount of ethanol. You either lower boost pressures or lower ethanol content, or both.

Tuning is always a balancing act.

[mike@x-ph.com]

Originally Posted by nyc f82

Is this safe to do for this map? I am currently running about 4 gallons of e85 (tested at e71) and the rest 93 octane with 10% ethanol. The car seems to be running fine with the occasional drivetrain malfunction once in a while but that doesn't happen often. I have many logs but not sure how to post them up.

I would not run map 7 since the car is giving you a clear signal that something is wrong with the drivertrain malfunction.
Start by posting a datalog to see what is going on

[M2_MEDUSA]

I hate to do this but what is FOL and how do I increase or lower FOL.