ECU Mod List & Feedback
12-15-2018, 04:08 AM
#31
Not to be pedantic, but if you want to run E50, it would seem to require about a 60/40 blend of E85 and gasoline (85% ethanol x 60% = 51%).
No argument about the cooling and octane benefits of ethanol, but since ethanol requires a richer mixture for the same output than gasoline, and the increased output requires even more fuel, can the stock injectors keep up? How much headroom do they have?
No argument about the cooling and octane benefits of ethanol, but since ethanol requires a richer mixture for the same output than gasoline, and the increased output requires even more fuel, can the stock injectors keep up? How much headroom do they have?
We will be monitoring fuel trims closely. But at 20% E85 in a full tank of 93, there are no issues. Test and measure, each stage. The real issue is to get the throttle to stay open, as Boost target is being so easily exceeded, the throttle closes. Waste gate duty is only 55%. So plenty of head room. YMMV.
12-15-2018, 09:11 AM
#32
Rennlist Member
I'd second Cobb, and a custom pro-tune. Wasn't aware that the pro-tune capability was delayed but I'm sure it'll be released eventually.
If you'd like to tune your car all you really need is a Cobb Accessport and a competent tuner with a dyno, local to you. Don't get too caught up in tuners trying to brand their tunes, most competent tuners will/should do a good job, this is not rocket science. A custom tune for your car is almost always a better option than something OTS, and you need the guy local since in my experience it does take a few revisions to really perfect things.
I know guys just tune remotely these days, looking at logs etc, and if they're very meticulous it could work, but I do like the local access. Some of the street tuning is tough to do remotely via logs and verbal description.
If you'd like to tune your car all you really need is a Cobb Accessport and a competent tuner with a dyno, local to you. Don't get too caught up in tuners trying to brand their tunes, most competent tuners will/should do a good job, this is not rocket science. A custom tune for your car is almost always a better option than something OTS, and you need the guy local since in my experience it does take a few revisions to really perfect things.
I know guys just tune remotely these days, looking at logs etc, and if they're very meticulous it could work, but I do like the local access. Some of the street tuning is tough to do remotely via logs and verbal description.
12-15-2018, 11:44 AM
#33
Burning Brakes
Terminology. When we say E50 tune, we do not mean it contains 50% ethanol. What we mean is its a 50/50 mix of E85/93. The Same as E20 tune, we mean 20% / 80% meaning 20% E85 and 80% 93. (We aren't chemists, so we keep it simple. ) Just percentage of E85 in the tank. The concern of the end user is how to mix the fuel, not what the true percentage of Ethanol is. So when you get an E50 tune, you know half and half. Half E85 and half 93.
We will be monitoring fuel trims closely. But at 20% E85 in a full tank of 93, there are no issues. Test and measure, each stage. The real issue is to get the throttle to stay open, as Boost target is being so easily exceeded, the throttle closes. Waste gate duty is only 55%. So plenty of head room. YMMV.
We will be monitoring fuel trims closely. But at 20% E85 in a full tank of 93, there are no issues. Test and measure, each stage. The real issue is to get the throttle to stay open, as Boost target is being so easily exceeded, the throttle closes. Waste gate duty is only 55%. So plenty of head room. YMMV.
As to the throttle closing, could it be that the engine knows that the injectors are about to hit their fueling limit and that allowing any more mass air flow would cause the engine to go lean?
12-15-2018, 07:10 PM
#34
Understood, though it is confusing when E85 at the pump means one thing and E50 in the tank means something else. And if someone can calculate the fuel proportions to produce an E20 tuning fule mixture, they could surely calculate the 60/40 proportions needed to produce a true E50.
As to the throttle closing, could it be that the engine knows that the injectors are about to hit their fueling limit and that allowing any more mass air flow would cause the engine to go lean?
As to the throttle closing, could it be that the engine knows that the injectors are about to hit their fueling limit and that allowing any more mass air flow would cause the engine to go lean?
So its easier to talk about what percentage of E85 you are running in the tank, rather than what amount of ethanol you have. Its more correct to say you have an "E50 Tune", not running E50. E50 tune being a 50/50 mix of E85 and 93. There are Flex fuel sensors to calculate amount of ethanol in the tank. Hopefully COBB will release one for our car.
The issue is Boost Target is exceeded. Meaning the Headers have made the tubo's more efficient, and they are hitting the target with ease.
It's the torque table that needs revising. Once they are done, we can increase boost, and the throttle will need to remain open to hit that target. : )
Air/fuels are fine at present. Not lean at all.
12-15-2018, 08:02 PM
#35
Burning Brakes
The issue is, that apparently some fuel station don't tell the truth. Their E85 is sometimes E70.
So its easier to talk about what percentage of E85 you are running in the tank, rather than what amount of ethanol you have. Its more correct to say you have an "E50 Tune", not running E50. E50 tune being a 50/50 mix of E85 and 93. There are Flex fuel sensors to calculate amount of ethanol in the tank. Hopefully COBB will release one for our car.
The issue is Boost Target is exceeded. Meaning the Headers have made the tubo's more efficient, and they are hitting the target with ease.
It's the torque table that needs revising. Once they are done, we can increase boost, and the throttle will need to remain open to hit that target. : )
Air/fuels are fine at present. Not lean at all.
So its easier to talk about what percentage of E85 you are running in the tank, rather than what amount of ethanol you have. Its more correct to say you have an "E50 Tune", not running E50. E50 tune being a 50/50 mix of E85 and 93. There are Flex fuel sensors to calculate amount of ethanol in the tank. Hopefully COBB will release one for our car.
The issue is Boost Target is exceeded. Meaning the Headers have made the tubo's more efficient, and they are hitting the target with ease.
It's the torque table that needs revising. Once they are done, we can increase boost, and the throttle will need to remain open to hit that target. : )
Air/fuels are fine at present. Not lean at all.
12-15-2018, 08:05 PM
#36
12-16-2018, 02:04 AM
#37
Rennlist Member
I'll second the injector comment as a definite thing to monitor. I think an extra 20% flow is needed for E85 and my son installed high flow injectors for his E85 project, with supercharger thrown in (not Porsche). It will be good to hear your progress, 4 Point 0.