jdbaugh1

iTrader: (1)

I'm trying to optimize my cold starts with my 80% ethanol blend. By cold starts lets assume it's 28 degrees or below. I don't have any experience with ethanol and haven't been around other ethanol cars other than factory flex fuel vehicles. I'm wondering if I can get some real world feedback from people who run E in the freezing temperatures. I tried to ask the question on Facebook and all the mouth-breathers could tell me was to get a good tuner and no matter how cold the car will start perfectly just like theirs. I'm the tuner so getting a good tuner is out the window. So a few questions:

• With high ethanol content can I realistically expect the car to fire up instantly in subfreezing temperatures?
• Do you bump the ignition timing up and if so how much at 32F and then do you increase and how much for each 5-10 degrees cooler temperatures?
• I'm experimenting with bumping up the fuel I dump in but don't want to flood it. It seems to take a lot. Mainly wondering if I should keep dumping fuel or mess around with ignition timing for faster starts.

BlackielawlessSS

iTrader: (1)

Not in a balt, but I had a 5.0 fox body that I ran 75/25 ethanol in. The coldest I ever started it was 35 degrees I believe. I had to add some timing. I did back my air fuel off. It was already running semi rich as it was. There wasn't much tuning that could be done to the computers on them. I had a idle air adapter that allowed me to increase the fuel and air. I had to back it off from my summer settings. I did go from 14 degrees on that car to 16 degrees. It still struggled to idle, but it started right up. It was also a fully built heads, cam, intake car. Not sure that helps, but my cam was a .498 lift and a 282 duration. Not a real radical cam, but still enough to cause issues with idling. I had better luck with the .512/288 cam that I ran in another car. E can be tricky to tune as I found out.

steelmesh

An idea is to find a few flex fuel platforms (GM truck?) where you can download a stock tune via HPT repository, then see what they do with ethanol tables and multipliers related to cold start.

Looking at some engine calibration resources here are some general cold start tips:
- Winter blend of E85 is more like E70 to aid in starting
- Timing needs to be added to offset increased friction and pumping losses in cold weather
- Going rich is usually good to give more power and compensate for port wall film thickness and slower evaporation, if warm AFR is good and it reads lean when cold, you need more fuel (warm up WBO2 before the cold start to see what it is)
- The expect result of increase power during cold start is higher idle speed, rule of thump is +400 rpm
- Some VVT cars increase overlap to reduce pumping losses in extreme cold

5-Speed

My Evo takes 2 tries to get it started when below 50°. The Infinity isnt the best when it comes to cold start tables (not sure what additional tables you have being DBW). I have tried a lot of different things and could only get it so good. If I can remember tonight, I will post up my cold start ethanol tables. Might help point you in the right direction. Main thing is its going to take a lot more fuel than you think.

63 Nova SS

iTrader: (3)

High e content fuel when it's cold is not your friend when trying to start the car. Doesn't light off very fast,like regular gas does.

jdbaugh1

iTrader: (1)

So far I've just been incrementally increasing the fueling and experimenting each cold morning. I've also bumped the ignition timing significantly for colder weather. The additional fueling table is driven off of coolant temperature and ethanol content. The ignition table is only driven off of coolant temp and engine speed. The recipe of dumping more fuel and adding ignition timing has worked very well. I almost have it dialed in to crank up with a normal single duration down to 35 degrees ambient. I'll have to wait for colder mornings to get the lower end of the tables dialed in but it seems as it gets colder and colder it requires a surprisingly significant more amount of fuel before it will light off.

After getting the engine to fire after cranking I am using another table driven off of coolant temp and a duration in seconds after start for fuel trim. I've found it requires a significant amount of extra fueling for about the first 5 seconds after cranking and almost all of the fuel trim can be dialed down to zero by 30 seconds after cranking to maintain proper AFR.

It's been interesting but the main challenge is having the right cold enough ambient conditions to experiment combined with the fact that the engine must also obviously be cold.

tomss

JD - couldn't you run 93 in the winter? You are not daily driving it it in the snow.

steelmesh

Gingerman raceway in the early morning could see freezing temps in April

jdbaugh1

iTrader: (1)

Reality is I don't even have to drive my car in the cold at all. More just doing this as a learning and sort of just because reason I want to get the tune dialed for startups throughout the temperature range. I've got it pretty dialed down to around 30F currently.

63 Nova SS

iTrader: (3)

E85 sure makes it hard to start when it's really cold. I noticed a big difference even on E47. I always went back to 93 over the winter because I didn't drive it much and didn't want the ethanol drawing moisture as it mostly sat.

dcrep06

E85 here tuned by zzp and when its around freezing, its a pain in the dick unless i had it running the day before. I switch between this and my sierra so dont care to go to a 93 tune, thats lame.

jdbaugh1

iTrader: (1)

I've never tuned with the stock ECUS so I have no idea the limitations but I am guessing the AEM Infinity I am running allows for more cold start E85 adjustment than standard equipment. I've fount that a combination of dumping excessive fuel at crank, combined with a significant increase in ignition timing, can allow it to fire off without much hesitation. To keep it running after it fires I also require a significant "lambda" offset towards the rich side from the VE table for especially the first 5 seconds but less for up to 20 seconds after cranking. I think the cold head/engine doesn't allow the fuel to atomize very well so it just requires a lot of fuel until some heat is accumulated.

I'm glad you guys are honest about cold starts with E85. When I posted on facebook the only people to respond claimed they had perfect E85 starts in the middle of Antarctica in the dead of the night because they had a "good tuner".