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I'm adding a Flex Fuel sensor to my junk and pulling my trunk mount Alcholinjection kit. My car is a mostly street car so one less thing to worry about.
I'm sold on E70, I love it. E70 is such a nice ratio 1 gallon of 93 octane E10 to 4 gallons of e85. It does also yield a considerable reduction in pump workload, and injector duty cycle. If you one of those guys like me, that likes the Siemens DEKA 80s, for many reasons, that makes a difference when your right about my HP level because I'm just about out of injector. I only run 15 lbs of boost at the back of the manifold, data logged through HP tuners on MAP in the OEM locations. I actually measure about 16.5lbs at the turbo outlet, where I get the feed to control the wastegate. That 1.5 lb difference would be the intercooler, and the intake piping, throttle body, etc.
Here is my timing map. It is aggressive, but there in no knock data logged on it on the Dyno. I'm running the BR7EF at 0.028. I'll continue to check #7 plug regularly, but for now it is looking good. I actually never thought I'd get that much timing in it.
This it the dyno graph on the 5.7 LS1, A4 with the converter unlocked, through the muffler, using that timing map, and E70. It makes about 60 more HP with the converter locked, but I only have a single disk, so I don't normally lock it while tuning just to get a number. It would be in the 775 range locked. It was still making more power when I let out of it at a little over 6600. This is setup like my signature says.
Not to change the subject or hijack, but can someone explain "cylinder air mass " and how it compares to boost psi?
Originally Posted by ScottyBG
I'm sold on E70, I love it. E70 is such a nice ratio 1 gallon of 93 octane E10 to 4 gallons of e85. It does also yield a considerable reduction in pump workload, and injector duty cycle. If you one of those guys like me, that likes the Siemens DEKA 80s, for many reasons, that makes a difference when your right about my HP level because I'm just about out of injector. I only run 15 lbs of boost at the back of the manifold, data logged through HP tuners on MAP in the OEM locations. I actually measure about 16.5lbs at the turbo outlet, where I get the feed to control the wastegate. That 1.5 lb difference would be the intercooler, and the intake piping, throttle body, etc.
Here is my timing map. It is aggressive, but there in no knock data logged on it on the Dyno. I'm running the BR7EF at 0.028. I'll continue to check #7 plug regularly, but for now it is looking good. I actually never thought I'd get that much timing in it.
This it the dyno graph on the 5.7 LS1, A4 with the converter unlocked, through the muffler, using that timing map, and E70. It makes about 60 more HP with the converter locked, but I only have a single disk, so I don't normally lock it while tuning just to get a number. It would be in the 775 range locked. It was still making more power when I let out of it at a little over 6600. This is setup like my signature says.
Cylinder air mass is the weight of air in the cylinder before the spark is set off. This is per cylinder per every firing of the cylinder. So if we were at say 1 gram cylinder air mass at 5000 RPM we would be 20,000 grams per minute. Only half of our cylinders fire each revolution since we are 4 stroke engines, so 1 gram times 4 cylinders times 5000 RPM is 20,000 grams or 44lbs per minute. This would be producing about 500 hp at that point. So the more boost, the more air is in there. There are other things that effect that too, like the cam, how long or wide the intake valve is open, temperature of the air, efficiency of the intake manifold and the intake runner in the head etc. The cylinder air mass is calculated by the ECU in speed density mode using 3 inputs, the IAT, the MAP and the engine RPM, then this number is multiplied by the VE it looks up in your VE table. This cylinder air mass is used to determine both fueling and timing. For example of it calculated there was 1 gram of air and you were commanding a stoic of 9.8 like in the case of E85 it would inject 0.102 grams of fuel. More boost, will be more air in the cylinder just like having the throttle open more. It doesn't matter to the engine or the computer how the air gets there, the fueling and spark requirements are the same for a given amount of air. Hopefully this helps you understand the math the computer is using. Typically only the last line of the spark table is used when in any reasonable amount of boost, my engine maxes out about 0.95 grams cyl air naturally asperated so almost any boost pushes me to the timing on the last line. If the cylinder air mass is greater than the last line in your table the ECU uses those values for timing. Let me know if this helps, or you have any more questions.
Thanks Scott. After reading it a couple times, it made sense. Intersting though that the last line is the "end all be all" should you up the boost past that last Cylinder air mass value. Based on that ideology, am I correct in assuming you're running 19 degrees at 15 psi?
Well the newer ECUs do go higher. And you will hit the bottom of your table much sooner on a 7.4L than you would on a 4.8. It really isn't a big problem though, you just set the last line of the table to be what you want at mac boost. You are maybe giving up 1 degree that you could maybe use at partial boost, but it isn't a big handicap. If you look at my table it wouldn't matter because the last few lines are the same. I don't really need anymore table.
Heres what I run for timing and boost with 87% ethanol out of the pump. Plugs show it will still take a couple more degrees. I also verify timing on all builds.
I didn't use any sealant doesn't leak either. I used a 1/4" npt tab and screwed the nozzle in. Nothing special.
If you can put the nozzle down lower towards the outlet of the intercooler that'll work to, heat also rises so the fluid stays cooler also if you get a fire having it down low keeps it out of the flames longer. It also hides it from view and looks cleaner.
For the record 26lbs on a small cam 5.3 long block. S476 and 14* was fine for many many passes. Bumped it to 17* without reading plugs and torched the head/deck the third pass. Intercooled E85 setup. With water/meth. IAT in the 160's. Again what someone else runs makes little to no difference.
Also seen base timing off as much as 2*... so a commanded 18* might be 20* on your setup and 16* on someone else's. Plugs won't lie start low and work your way up...
This is an overall great thread!
As far as reading plugs for timing, I am guessing you're reading the strap. Have you found that you can read the straps of the plugs you drive around with on the street (after a pull or two and drive home), or do they need to be fresh plugs with a sharp cut after a pull like reading mixture?
02-13-2017, 11:37 PM
