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E85 Cold Start Issues addressed.

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30K views 30 replies 9 participants last post by  salvi 
#1 · (Edited)
Disclaimer: I make no claims that this will work for you or that this is even the right way to do this. All I can say is it worked very well for me on more than one case.

This subject is really an addendum to the tuning section listed in the E85 Sticky but it is a topic of much debate in the E85 community that I thought it should warrant its own thread. First let me say that my findings here are in no way conclusive and are still in the experimental stage. I am posting this now in the hopes of getting some of you to try these methods and report your findings to help further refine these steps.

I am finding the information regarding cold start issues with E85 in the Subaru community scattered and inconsistent. The RomRaider and E85 forums were of some help but the best and most reliable information came from our friends at EvoM forums. I was able to piece much of the information gained and form a solution for the Subaru community.

This experiment will be specific for RomRaider. All of this info comes from personal observations over the course of two years. Any input or insight to the subject would be Greatly Appreciated and no question is to dumb to ask.

***EDIT*** Cobb has updated the AP Firmware and AccessTuner Race. The procedure for this is the same as it is for OpenSource.

Explanations...

The reason E85 has trouble starting in cold weather is very simple. It does not evaporate at the same rate as gasoline in temperatures below 56*f and evaporates less and less as the temperatures fall from there. As a result you require more fuel during crank to compensate. However, too much fuel and you run the risk of saturating the cylinders to the point were fuel can no longer atomize properly and the droplets simply condense instead of vaporize. You need to find just the right amount because if the fuel does not atomize into a mist you will simply snuff out the spark and flood the cylinder.

To combat cold start issues thus far, methods have been employed that are no more than band aids. Things like block warmers and starter fluid and feathering the gas while cranking have all been employed but the best solution is to compensate for cold starts from with in your tune. With the following methods I have completely eliminated the need for block warmers and fuel heaters and any other hokey s**t.

Tuning concept...

RomRaider

In RomRaider there are tables for adjusting the Injector Pulse Width during crank as it related to temperature. This is fantastic because this is exactly the adjustment we have to make.

It is as simple as increasing the IPW for a given temperature, however the amount to adjust is still of debate. I will publish what I found to work for me but you really have to experiment with this on your own. You can probably use my numbers to get you started.

So to do this you want to open up your ROM in RomRaider and the tables for "Cranking Fuel Injector Pulse Width A,B,C,D" under the "Fuel - Cranking menu" Before you have access to modify these tables you need to change your user level to 5.

Once open, you want to increase the IPW in each cell from 68* and below. What I have found to work for me is begin to apply a 3% increase @ 68* and continue to increase the percentage from that point all the way to 30% @ -40*. See the below picture.



Now that gets us started but what about keeping us running. For that, you will find several tables under the menu for "Fueling - Warm-up Enrichment" called "Min Primary Base Enrichment" and "Min Primary Base Enrichment - Initial Start 2, 1A,B and 2A,B" You apply the same multipliers here as you did in the previous step.



That's it and it is that simple though the values must be discovered on your own. These may or may not work for you. It would be good if anyone has any personal findings regarding this experiment to please comment.

George.
 
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#4 ·
I am going to make an attempt perhaps this weekend to solve my issues with this annoyance. 40 degrees out and I am cranking for at least a minute to get started. I have an accessport and Tim Bailey gave me all my tunes in racetuner (?) format so I could modify them if needs be. I think the time is now.
 
#5 ·
That worked awesome!! I used the same multipliers you did on all 8 categories. 40 degrees outside and she fired right up no problems like before!

Thanks a ton for sharing this info! Now my starting headaches are gone. :D
 
#7 ·
I used your numbers to a tee. The problem was figuring out celcius versus fahrenheit.

So far it works great. It does need a bit of tweaking. Perhaps less fuel in my case around the 50 degrees fahrenheit mark.

If I tap on the pedal repeatedly while cranking she fires right up. Much happier with that versus the engine not popping off for over 30 seconds of cranking.

Thanks for posting this.
 
#9 ·
You are in Texas, this issue won't affect you. :D

Seriously though, I matched my tables to the ones posted and it made a huge difference. Although not perfect it is about 300% better than it was.
 
#12 ·
I understand about the 30% increase of injector scaler due to e85 vs 100% gas. In my last post, I was only refering to scaling the stock cranking tables based on increase in injector scaler and e85 use. I was assuming these tables were dependent on injector size, but you are saying they are not. That would explain why my adjustments weren't working and seemed like I wasn't getting enough fuel. I tried your table values but reduced them by 20%(I believe you have 1000cc injectors and I have 1200cc injectors) and it was much closer to where I need to be. I think I will try your exact numbers tonight and see if it improves my starting. That will prove that these cranking tables are in fact not dependent on injector size.

This has been the biggest help I have found on this topic so far. Thanks!
 
#13 · (Edited)
It was 28 degrees the morning and my battery went dead trying to get her started. I need to adjust the maps a bit. Will post results after some experimenting.

For my first trial I am changing everything to a 30% increase except for 50 and 68 which I will change to a 20% increase.

Will reflash today and post results tomorrow morning when I try to start her in 25 degree weather.
 
#14 · (Edited)
Outside temperature was 30 degrees. The temp inside the garage was 36.

Check out this video I made this morning.

E85 cold start map rev2 - YouTube

Thoughts? More fuel or less? Definitely helped by adding more fuel on the revised map. Should I bump everything from 32 and below up to 40%.
 
#15 ·
What happened! you had it working didn't you?

I would first try it with leaner mixtures first... say something like 15% over stock values and see if it improves or worsens. Then if it worsens I would go with increasing over current levels but I would do it in only 5% increments. Your getting close to saturation if you go much beyond 40% over stock.
 
#16 · (Edited)
I thought I had it working until I tried to start it after it was sitting all week in my garage. I suppose it did not help that it was 28 degrees out.

I am going back to square one. The revision 3 map I made @ 40% is even worse than yesterday. I will start @ 15% like you suggested.

What's the deal with the car not staying running if I let off the pedal after it starts?? Also the constant dips in the rpms until it gets warm??

Todays attempt to start. E85 cold start map rev3 - YouTube
 
#19 ·
I found out today that here in Oregon we do not get a winter blend of e70 which is the majority of my problem. I am done messing with this. I ordered a block heater which is highly recommended by cobb for Oregon winters and e85. 50 bucks shipped on ebay. Will report back with success or failure.
 
#20 · (Edited)
#21 ·
bumping an old thread, but wanted to share my experience tuning these tables on E85. You will need to come up with your own numbers, OP's guide is a good start but every car is different. Since these settings are in straight pulsewidth values, they are not affected by injector scalar value changes. 1ms of pulsewidth one a 1000cc injector is nearly twice the fuel as a 550cc injector.

Also be very careful about adding too much fuel. Knew a guy who had ID2000s and ended up washing down his cylinders and had poor ring seal and ended up losing compression. Even if you spend a lot of time tuning these tables, E85 cold starts are pretty tough when it gets down below 40-45F. REALLY tough below freezing.
 
#22 ·
If you really want to know how to get your cold startups successful using E85 visit this thread I made. It has a bunch of seasoned tuners (most from Norway, where it gets really cold) giving you the simple solution to all of this.

I did not realize how simple it is to fix and have been fighting with it for 3 years.

This method outlined in this thread here on IWSTI DOES NOT WORK properly.

Read here, READ THE ENTIRE THREAD!! RomRaider • View topic - E85 (not e70) Cold startup @ 16 degrees FIXED!! LOOK!!!
 
#23 ·
anyone happen to have an E85 tune for the hawk eye 2.5 WRX on the stock TD04? hell even an E85 tune for the hawk eye STi on stock turbo that i could compare to a stock hawk STi rom to get an idea of the sort of changes id be looking to make.

really wanting to jump on the E85 bandwagon even if only for a sneaky boost in power for drag racing, etc and then reverting back to my current tune.
 
#25 · (Edited)
yea im not too worried about that aspect of an E85 tune. its the ignition timing, AVCS and boost/WGDC im somewhat lost on. dont know if id want to leave AVCS as is and just up the boost or up the boost and up the ignition timing or up all 3, etc, etc.

only been tuning my WRX for maybe 2 weeks collectively. before that my only experience in opensource tuning was with 20+ year old BMW's so im on a monumental learning curve.. also i cant tune in real time on the WRX like i can on the old BMW's with the aid of an eprom emulator. hoping someone has something i could ideally load up and tweak.

im already managing to run about 1.3 bar peak and about 0.9bar after boost drops off on UK 95 octane with a tune i sort of mashed together from a stage 1 and stage 2 i pillaged from the WRX base maps section on romraider. so far so good with that and i am tweaking/learning but E85 would be a massive jump without a base to work from.

would the stock injectors + a walbro 255 suffice for fuelling on E85? the hawk eye WRX has the same injectors as the hawk eye STi. also would i need to replace my fuel filter before running E85 or anything else along those lines? lastly could i switch back and forth between E85 and my current tune or would the fuel system/filter/lines potentially give me problems?
 
#26 ·
Stock injectors? Nope. I think you need to reread this ENTIRE thread or start lurking romraider more. I learned how to tune on my own with very few questions since the information is out there you just have to search for it. No one here will spoon feed you. :D
 
#27 · (Edited)
not looking spoon fed but tbh someone is bound to have done E85 on the hawk eye WRX already..

also every newcomer to OS tuning on these subarus is being spoon fed in all reality because theres guides and stuff galore. on the old BMW's i have been tuning for years there is far, far less and those who know dont share much. here you simply download romraider or ecuflash and download the defs which are all done for you already and maps all correctly labelled and explained, etc. you try reading an ECU and then having to use some half figured out def with wrong map axis values when your a newbie because people dont know the conversion, tuning fuel maps in raw values because people dont know the conversion and then eventually getting up to a stage where you can read the code and identify and then figure out maps that were previously unknown and then get to a point where you know enough to make your own defs correctly with what conversions are out there or that you have managed to figure out.. thats not being spoon fed..

i dont need to read about E85. i looked into it years ago for my old BMW just because i could have tuned for it but there was no point as it was N/A at the time.

im asking about the stock injectors because they are the same as whats in the STi and people have run them to over 300bhp (250whp ish or more). considering 280bhp or so is possible on the TD04 and E85 can yield 30-40hp the numbers fit right in where people have gone on normal fuel on the stock injectors im not 100% sure but i swear i remember reading up on a couple things where people have seen 350-400 on the stock injectors (and larger turbo) on normal fuel. i know E85 requires about 30% more fuel but what im wanting to know is can the stock injectors manage that or not. obviously fuel pump ill need to be upgraded but i dont know if stock injectors could possibly stretch that far? what makes me wonder is that i knot know how much more normal fuel you would need to be injecting for say 400bhp but lets say its 25% for fun and giggles (probably not but i dont know) then by rights 310bhp or there abouts should be do-able on the same injectors with E85.. get where im coming from? obviously they wouldnt be ideal but im wondering if they would suffice atleast enough to get running on E85 and make more power than i can on normal fuel.
 
#28 ·
You can do 300+whp on stock injectors... on gas and a DynoJet. Below is the first Subaru tune I did years ago. It is on stock injectors and a VF39 hitting ~17.5 PSI on the dyno. We later ran it at 19 PSI before swapping out to ID1000's and E85 and then stripping 3rd gear.



I've done quite a few Hawkeye WRX's and STi's. Here is one of my favorites (a good friend of mine) that is currently undergoing a turbo swap to a Dom 2.5XT-R.

22.5 PSI and moderate timing.


20-21 PSI with what I consider low timing for E85.


Same car against my old SHO.



Can you run the stock injectors on a TD04, sure... But you'll probably find yourself injector limited fairly quickly. On my STi, I have ID1000's, Walbro 450, and my base pressure set at 50 PSI on a 20G @ 23PSI and my road dyno showed 430 whp. My IDC's are in the mid 80's, however, Subaru does not count 100% as static, so in those terms, I am much lower than the mid 80's.

I do have stock STi injector on my S2000 running E85. I think I am in the 60's for IDC, IIRC.
 
#29 ·
You will be lucky if you can run 17 psi on E85 with the stock injectors. You are going to lean them out at WOT. If you use unleaded fuel you may be able to run upwards of 20 psi on the stock injectors but I do not recommend it.

All of the maps you are looking for are on romraider.
 
#30 ·
well at the minute im running UK 95 octane and my boost gauge reckons im just a hair under 1.4 bar at peak boost. in my logs though it looks lower (peaking at 18psi according to logs, unless im not logging the right boost parameter).

i did a virtual dyno off of one log on the flattest road i could find and according to that with smoothing at 1 and using the "virtual dyno" dyno setting which gives numbers between dynojet and mustang dyno its saying 300lbft and 250whp.

mind taking a peek at some of the logs to see if you think i can add more boost/WGDC or ignition timing anywhere as going drag racing on sunday.. its the logs and last rom i posted towards the bottom.

RomRaider • View topic - MY06 EDM WRX - Stage 2(ish) - TD04, SRI, CBE - Help?
 
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