tuning for E85

[n0dih]

The higher the compression the better with E85.

Start off with running it as low on fuel as you can, and then fill up with E85.

Monitor the BLM/LTFT, and scale the injector flow value to approx the same % as how much the BLM/LTFT is off.

IF you have a table for Fuel Flow, you are golden. I took my datalog, toss into Excel and then sort by MAP. Taking 0-9, 10-19, 20-29, etc and find the MODE of the LTFT, and use that as your scalar. My LTFT's on my SC 3800 are within 2% max across the board, most of the time 0%. I only scaled it 2x, initially to get it to where I was at 100% E85, and then to fine tune and I haven't NEEDED to mess with it at all.

You can run MAF or SD. I would leave it in MAF personally, but once you get it dialed in on the MAF and you want to fine tune the VE tables, that isn't a bad idea, especially if you are heavily modded, if fairly stock, nothing is really gained.

[MonkeyGod]

I converted my 04 GTO to E85, and I love it. Running 10lbs of boost with a mp122 and can use 36deg of timing at WOT. Using 60# mototrons, at 90%IDC.

Not much really involved with tuning it, other than setting the stoich AFR to 10 or so (10.5 for me) and playing with timing and cold start enrichment tables.

[n0dih]

If you stay at 14.7 for stoich, you don't have to touch any other tables, just set the injector flow rate to lower (slightly more % than the LTFT's that will be off. Scale it appropriately and you will find all the other tables will be perfectly in line. And it works pretty well if you are in a crunch and have to go back to gas to get to an E85 station (93 octane only due to the timing changes).

I found my LT1 when I got to the 80-85% DC range started to see some slight changes in the engine's acceleration, it did pick back up, but still something is going on when you get to 85%. It all depends on the cam, but you don't wanna be spraying fuel at a closed valve.

Not sure on HPT, but on TunerCat you can set the injector closing crankshaft degrees. It is important to set properly.

[tahoe]

I feel it is much easier to set the soich to deliver close to zero LTFT running
E85.
It is benificial to spray on a closed valve, by doing so, you get better fuel vaporization and at the same time cool the valve.
E85 use a lot more heat to evaporize than gas.
You also dont want the hard to vaporize E85 going in past the valve as liquid,
washing you cyl walls of off oil film.

//

[n0dih]

I was looking at the stock L59 tune and it REALLY cranks up timing in the high airflow lower rpm range. +16 degrees over all other timing add/subtracts. I am running my 454 L29 on E85 and patterning some of this in (timing table in the L29 is rpm vs map) and it really perked up drivability. Not enough to know mpg, but I found it interesting that in the low cyl air, regardless of rpm, timing is actually pulled out vs high cyl air and lower rpm.

[Runn WS7]

Much easier to just change the stoich (GM does this on their own flex).

[n0dih]

I tried it both ways, changing stoich and all the other tables that deal with AFR it just never ran right or as smooth sa just changing injector flow rate. And my LT1 doing it that way was able to start and run @ 25F (-4c) just fine. I tried stoich and cold drivability wasn't right. I don't have a wideband to mess with it.

I tried it on a couple different cars and never got it running as smooth or as easy as injector flow change.

What all did you change for cold? You run E85 down sub 0C there? What settings do you use?

Much easier to just change the stoich (GM does this on their own flex).

[Runn WS7]

I added a lot of fuel (copied from gm flextunes) and it starts almost rightaway, i almost never uses my car under 10 celcius. It´s my summercar :-)

[n0dih]

I use E85 on Vortec 7400/454, my L67 3800 (rarely, mpg isn't worth it, it is that bad) and my 94 LT1.

So none of these got Flex so I didn't get to copy anything. I'll look over them and see if I can get something closer.

The nice thing on changing stoich is the fuel economy gauge reads properly, but changing injector flow it reads thinking it has gas in the tank.

I added a lot of fuel (copied from gm flextunes) and it starts almost rightaway, i almost never uses my car under 10 celcius. It´s my summercar :-)

[Runn WS7]

Try and increase the cranking fuel tables a little if you having trouble starting.

[n0dih]

Once it get going in open loop it is pretty lousy too, once in closed loop it settles down.

How much different did GM do on the L59?

[tthrasher]

I converted mine last week. I added 2 degrees of timing across the board and it idles better and runs smooth. The only other change I made was to my stoich value.

[Runn WS7]

I converted mine last week. I added 2 degrees of timing across the board and it idles better and runs smooth. The only other change I made was to my schoich value.

Easy isn´t it