[XC3LLR8]

Originally Posted by Hendo741

K&N drop in filter, Active Autoworkes catted DP, JB4 Map 4 w/ 2 gal E85.

245 Conti DWS 06+ all season tires on a damp overcast day. Car is still learning the map and IATs were over 110. I think getting down into the 3.2s, maybe even 3.1s is attainable under the right conditions.

I've seen where you've posted runs with Map 4 and Map 2. Do you have a preference of one over the other when using E30?

[dasistato]

So for map5 you need to fill 3-4gal of e85 gas and rest 93?

[XC3LLR8]

Originally Posted by dasistato

So for map5 you need to fill 3-4gal of e85 gas and rest 93?

That's the general recommendation.

[danallxt]

Originally Posted by XC3LLR8

That's the general recommendation.

In other words you are shooting for an E30 mix, assuming the 13.7 (US) gallon capacity of the M240
Now since E85 ranges from 100-105 octane, that calculates out to 94.9 octane with 3.6 gallons of E85 of 100 octane, or 96.2 octane if the E85 is 105 octane.

So roughly speaking, to summarize, with 3.5-3.6 gallons of E85 (in a full tank with the remainder of 93 octane) your range of running octane will be between 95 and 96.
If someone wants me to run the numbers with a 91 or 92 octane base (instead of 93) let me know.

Oh yes, i believe (but not verified) that an E30 mix is about the limit of what this BMW system can handle.

[danallxt]

Just a followup of the above with 91 octane base fuel (this assumes also a 10 percent ethanol content of the 91 octane.
I am using a 3.65 gallon of E85 mix (as i did above and that is to hit the E30 mix mark)
So to assume a low octane of 100 for E85, the 91 octane base will result in 93.4 octane and 94.7 with the 105 octane E85. (mix as described above).

No way of knowing (just from the pump) what octane the E85 is but will usually be between 100 and 105. Why the difference?? E85 can be a mix of 3 different classes of fuels. "Pure" E85 is (Class 1) is 80-85 percent ethanol, there are classes 2 and 3 that have lower amounts of ethanol 70-79 percent, however all 3 classes and mixes of those can all be "marketed" and sold as E85.

Why ??? Ethanol does not burn as readily as gasoline at low temps. Since straight ethanol has a relatively low Reid vapor pressure (meaning it doesn't like to light off at low temperatures), greater percentages of gasoline are added to the blend for colder weather. So while E85 is often described as 105 pump octane, its actual rating can vary depending upon the seasonal blend.

So a "winter" blend of ethanol is likely to be at the lower end of the 100-105 scale. Retailers are not required to post the actual Octane rating of the E85 , I do believe they are required to post the potential minumum ethanol content of the E85 which is 70, (it will be an orange and black sticker). So ya never really know what you are getting.

[XC3LLR8]

Originally Posted by danallxt

In other words you are shooting for an E30 mix, assuming the 13.7 (US) gallon capacity of the M240
Now since E85 ranges from 100-105 octane, that calculates out to 94.9 octane with 3.6 gallons of E85 of 100 octane, or 96.2 octane if the E85 is 105 octane.

So roughly speaking, to summarize, with 3.5-3.6 gallons of E85 (in a full tank with the remainder of 93 octane) your range of running octane will be between 95 and 96.
If someone wants me to run the numbers with a 91 or 92 octane base (instead of 93) let me know.

Oh yes, i believe (but not verified) that an E30 mix is about the limit of what this BMW system can handle.

I use E75 because you'll never likely encounter E85. Heck, even the government defines E85 as 51-83% E, so E85 is likely never E85.

(and this takes into account the 91/93 having 10% E)

[danallxt]

I use E75 because you'll never likely encounter E85. Heck, even the government defines E85 as 51-83% E, so E85 is likely never E85.

that is a very safe and sensible way to approach this when running a tune or JB4 or JB+. good suggestion.

[XC3LLR8]

Originally Posted by danallxt

that is a very safe and sensible way to approach this when running a tune or JB4 or JB+. good suggestion.

I've been running E30 for nearly a month now and the car's running great on JB4 Map 4; just need to get off my ass and install the AA DP.

Using the Fuel-It app calculator I missed the 93 volume by 1/10th of a gallon on my last fill-up, so I was happy with the measurements.

[danallxt]

your "e75" is right about 100 octane.
actual "pure" e85 105 octane.

In case folks are wondering the rough E30 limit is based on injector size and trying not to exceed a really high duty cycle of the injectors, thereby forcing a lean condition. Higher ethanol mix requires higher volume of fuel, thus potentially exceeding injector limits. Thus modified cars will often need to upgrade/upsize injectors to accommodate higher fuel demands based on engine mods.

[PNTDG42]

Makes me wonder how much the car would pickup with just a fill-up of E30 but otherwise entirely stock. Probably not much to gain at stock boost mapping, but maybe a little something.

[danallxt]

Originally Posted by PNTDG42

Makes me wonder how much the car would pickup with just a fill-up of E30 but otherwise entirely stock. Probably not much to gain at stock boost mapping, but maybe a little something.

It will pick up poorer gas mileage. Performance, just guessing but likely negligible.

[XC3LLR8]

Originally Posted by PNTDG42

Makes me wonder how much the car would pickup with just a fill-up of E30 but otherwise entirely stock. Probably not much to gain at stock boost mapping, but maybe a little something.

Without a tune to account for the ethanol I do not believe it's really adding any power but rather providing a safety blanket from knock.

In a thread on a Supra forum from Jesse DaBears I read where he stated there's a substantial performance increase between a custom JB4 E30 tune vs. a 93 tune, and of course in that scenario the tune is accounting for the E.

[XC3LLR8]

Originally Posted by danallxt

It will pick up poorer gas mileage. Performance, just guessing but likely negligible.

Yes, I've noticed my MPG have dropped some with E30. No surprise as I had an E85 tuned STi a few years back and knew what to expect.

[PNTDG42]

Originally Posted by XC3LLR8

Without a tune to account for the ethanol I do not believe it's really adding any power but rather providing a safety blanket from knock.

In a thread on a Supra forum from Jesse DaBears I read where he stated there's a substantial performance increase between a custom JB4 E30 tune vs. a 93 tune, and of course in that scenario the tune is accounting for the E.

Ya it basically depends on if the ECU is going to try and push ignition advance further based on knock feedback or not. Only one way to really know for sure if nobody tried it.

JB4 tuning isn’t genuinely accounting for E content since it’s not able to do any fuel injection or ignition tuning for the B58.. but knowing that you will run E he probably brings in more boost and has a boost curve he found works well. But to be clear; JB4 is not tuning anything but your boost curve. (Boost controller).

[beshsefen21]

Does JB4 leave a trace in the DME even after it is removed?

[XC3LLR8]

Originally Posted by beshsefen21

Does JB4 leave a trace in the DME even after it is removed?

Yes, indirectly. The DME will show boost levels higher than OEM.

[PNTDG42]

Originally Posted by XC3LLR8

Yes, indirectly. The DME will show boost levels higher than OEM.

I think you'll find the actual boost is concealed from the DME by JB4, otherwise you would have some overboost protection kicking in and the EWG duty cycle would be in some feedback loop trying to lower boost to hit the OEM target. I put my ECUTEK Connect dongle into the car and checked out the parameters the DME is logging. Its absolutely insane. There is no shortage of ways you could determine the car is making more power than intended with access to so many parameters. I was trying to figure out a way to show you guys what all is in there. I started to take screen shots but it was going to take 30+ photos. Maybe I can take a quick log and export it to excel and then get them all listed in a row.

The fuel injection duty will be operating well beyond typical with the power cranked up, that would be an easy giveaway. The accelerometers are logged by the DME so they might analyze that one too, to just say wow look how fast its accelerating (it is also logging temps and inclination, so they can work it out in consideration of hills etc). The fuel trims will be super wonky looking, probably reaching levels a whole magnitude beyond what they would ever expect to see in a stock car because they are now being used for entirely tuning the car rather than the little quirks they were intended for.

[Brett_C_F30_G42]

Originally Posted by Hendo741

I did some map 0 logs to get a baseline, and the car is usually around 14.5-15.5. Engine nerds are going to say the B58 doesn't have a boost table and that it works by using volumetric algorithms with cylinder fill and target load to calculate boost from requested torque and so on. Usual boost is around 15 stock

Edit: Upon further review of logs (some from the M240 some from my Supra but still a B58TU) it appears the ECU will sometimes request boost up to 20 PSI. It looks like it requests higher boost with higher IATs. Sub 100 F IATs result in 14-16 psi requests. Once the IATs start going up, so does requested boost. Makes sense from a stand point of hotter air is less dense and contains less O2 particles, so jam more air in the engine for similar burn. It also retards ignition advance in these scenarios.

My boost pressures are at 20psi+ on my sports displays with a MST Intake, catless downpipe, and muffler delete. That’s it.