Timing Ramp Eaton E-85

[Black02GT]

So now that I have my E85 tune A/F dialed in, I want ti add some timing to take advantage of it. I've seen a lot of guys saying they run upwards 23° +-1° (maniac I got my Posi blower from was running 26° on a 2.93/6#, pretty crazy). Everyone only talks about peak timing though.

I'm wondering to you guys just adding the difference though the whole curve or adjusting the slope. Additionally how steep is the slope you normally run E85 or 93, for instance 3000, 4000, 5000+, etc. I don't max out load till about 4500 so, should I look for a linear increase or let it use the timing from the lower row in the table?

Don said when I switch to E85 to just use the Race Fuel SCT file but that maxes out at 21°, it seems others usually run a couple degree more on E85. On 93 I just ran the SCT 93 Spark table to be safe, with the corn now I feel it's worth asking about this.

Relevant Specs: 8.8:1 CR, Posi Eaton, 2.93/4# seeing about 15.5 +-.5psi, ait2~120.

 

[Mach828]

You can just follow the trend from the values in the race fuel file. If you want to add a little more than I'd just add a degree across the board. I would do it after peak torque so you aren't getting too greedy, peak torque detonation pops engines easily. If you have access to getting it on a dyno it really helps determine how its responding to the timing.

 

[Mach828]

Its important to remember that timing is just when you are lighting the air fuel mixture. Different fuels have different ignition characteristics. Low octane regular gasoline fuel doesn't need much timing because it ignites fast and violently. With e85 you have a lot more fuel to burn and it doesn't burn the same way. It needs the extra timing because of its burn characteristics. Its not just add timing make more power, you need to match it to your combo so the piston and flame work together. 23* degrees with one combo isn't the same as 23* with another.

 

[Black02GT]

Yeah, I was thinking about the different burn rate. Thanks for answering that's kind of what I figured.

All on the back burner for a week or two as my transmission gave out, time for a Magnum I guess.

 

[decipha]

you should NEVER use the timing value files in SCT, just dial your spark table in youself you'll be much happier

is this is a 2 valve or 4 valve? which heads? stock 2 valve goes ahead and shoot 23 degrees to it, I would

 

[Black02GT]

04 Cobra heads stock size valves, stock cams, Posi Eaton blower 15.5#, 8.8:1 CR. Out of curiousity, what's wrong with the SCT files?

I've seen people say they're running a flat timing curve but feel like when you take engine speed and burn rate into account that doesn't seem to be the best idea

I'm road tuning so it's harder to judge the results of small changes and trying to figure how fast to bring the timing in. Hopefully have the new Magnum in next weekend and be back at messing with the tune.

 

[decipha]

their timing recommendations are not efficient, not to mention that when you dial your timing in chances are your going to change every single one of those cells anyway to give the engine what she wants, and if your maf is scaled you'd need to set it up manually anyway

when you say you max out load at 4500 are you referring to hitting 200 load?

If I were tuning it I wouldn't hesitate to take her on up to MBT and shoot 27 degrees to her at 3k+

I always scale my tables 750,1k,1250,1.5,1750,2250,3,4,5,6,7, doing so i'd shoot it as follows

11 14 16 19 21 24 27 27 27 27 27

you'd have to interpolate your WOT load to setup your table accordingly to reach those targets

 

[Black02GT]

Yeah I ment 2.0 by "max" I ment the top row of the borderline spark table. Are those numbers for an 03 Cobra? Seems like a lot even on E85. Gives me a good idea how soon your going to max spark though.

Edit: I originally had it all scaled the SCT way (approximately halfing displacement, intake volume, injectors). Now I'm using the BP method, load both ways agree within 10%.

 

[cj428mach]

Yeah I ment 2.0 by "max" I ment the top row of the borderline spark table. Are those numbers for an 03 Cobra? Seems like a lot even on E85. Gives me a good idea how soon your going to max spark though.

Edit: I originally had it all scaled the SCT way (approximately halfing displacement, intake volume, injectors). Now I'm using the BP method, load both ways agree within 10%.

I've been told that you'll go past MBT and begin to loose power before you ever detonate so feel free to play with it. I wouldn't hesitate to follow what Decipha suggests.

 

[decipha]

yes that is how I would setup your tune and adjust from there

you do know the top of the spark table should never be reached correct? If you are hitting 2.0=200 load then you need to kick up the engine size scalar to get load down

Heres everything you need to know about timing in the ecu

http://info.efidynotuning.com/saftot.htm

 

[Black02GT]

There's a lot of back and forth on here about that. I believe Don's tuning guide specifically states "Never change engine displacement to get datalogged load to where you think it should be". Not sure if that counts maxing load. It wouldn't take much to stop it from pegging, just curious what else that make effect, like higher timing at part throttle/lower loads.

Thanks for the link I'll have to read through that and see.

CJ428Mach, I was curious about that because the SCT MBT table is much lower the Decipha's suggestions. Even at 1.7 load it's 21-22 degrees at the upper RPMs, I'm curious where that table came from vs the 27° for 3K up on his site.

I know this is mostly an academic discussion at this point since you guys gave me an area to work in. I'm just trying to understand as much as I can about how it's working.

 

[cj428mach]

CJ428Mach, I was curious about that because the SCT MBT table is much lower the Decipha's suggestions. Even at 1.7 load it's 21-22 degrees at the upper RPMs, I'm curious where that table came from vs the 27° for 3K up on his site.

I know this is mostly an academic discussion at this point since you guys gave me an area to work in. I'm just trying to understand as much as I can about how it's working.

I assume Decipha's information comes from real world dyno experience so it would be hard to argue the data if thats where it came from. I've used about every write he has on his website and with out it the tune on my street rod wouldn't be half of what it is.

Michael can you explain why its bad to max load out on the newer ECUs? I believe on the older ECU's they can't handle a load of 200/2.0, but the new ones seem to do fine once you peg it.

 

[Mach828]

His chart is 27* at 0 boost and is a blanket 4.6 4v amount. I've taken my e85 4v up to 27 degrees on e85 NA and it hit MBT at 23 degrees verified by the dyno output. I continued to add timing and it made no change in power.

It doesn't matter what you change the top of the spark table to be. If you leave it at 120% it doesn't matter if it reaches 200% actual load, its still going to use the top row.

Go run 27 degrees and have fun rebuilding your engine.

Once again, go look at the trend from the stock MBT table, compare it to the SCT value files, and develop your own table. You don't have a dyno and you don't have knock sensors, so don't get too greedy.

 

[decipha]

I post my own results from hands on tuning and experiences, if your mileage varies thats great too, I always like to hear what others have found as well, it seems as though most dont like to share because this happens and they get called out on it, I dont mind sharing and if you've found any of my info to be incorrect please let me know, in this case though I have found most of the 4 valves Ive tuned to like 27 degrees or there abouts, of course there will always be exceptions but thats what I start from and go from there

200 load isnt good because you cant have efficient spark control in that transitional range where it hits 200, nor can you dial in the failed maf PCT_Load table and most importantly you cant put any overboost protection in there in case you loose the reference line off the wastegate or decide to turn the boost up after the fact, its just not safe, I have no problem kicking up sarchg (engine size) to get load down when I hit 200 I usually multiply sarchg by 1.5 and cut back my spark scaling by the same 1.5 and fn035 by 1.5, it usually works out fairly close

also keep in mind the mbt table is modified by the other tables, just like the borderline knock table the value in the cell is not what you will actually get if you dont cross calculate the modifiers, not saying the mbt modifiers are in effect at a normal operating temp but just for reference, also keep in mind youll see identical engine setups with different mbt values, that can be a good starting point but shouldnt be regarded as an absolute mbt chart

 

[itzl0l]

Have you ever tuned a terminator with 27 degrees of timing?

 

[XCSEDAN]

easiest way would be to throw it on a dyno.
as someone else has said e85 will stop making power before it detonates, so if that happens you know you have gone too far.
all a learning process, boost seems low, so does the comp, id throw more boost in it if the bottom end is safe, it'll respond really well with the e85

 

[Black02GT]

Hey lots of great info on here since I last visited, thanks. Finally got the T56 Magnum in today, shifting is amazing I love it. Put 60 miles on it. Then a block from my house my battery light came on and my dash brightened checked with the handheld quick, making 14.3V at idle 15+ at 1500. Guess the regulator in the alternator gave out, nice timing.

Anyway, I know boost and comp are "low" for e85, but it's just a DD/fun run car, hasn't ever and probably won't ever see a track. Engine was built a couple years ago not for e85 and just ran a 3.0 upper stock Eaton for a while. Bottom end can handle way more but can only add maybe a pound or two with the Eaton, might stick the 6# lower on (2.93/4# now) but that's about the limit on the blower. E85 wasnt around at the time but when I added pumps and injectors figured I'd take advantage since it's $1.20 cheaper than 93 here. Don't have the cash for a vmp/whipple/kb right now and still having fun with the Posi and learning to tune.

Just trying to get the most out of my setup right now for the season. I figure there's a few more ponies available optimizing the timing and have fun with it. Looks like for E85 I'm running a pretty conservative setup and can add a bit more and probably lose power before I cause damage. Without a dyno probably settle in around 23+-1 or 2 and not be too crazy, yet not leave too much on the table. Now I know I don't have to worry as much about bringing the timing in quick. I will have to experiment once I get a new alternator in, if it's not one things it's another. :nonono:

 

[decipha]

yes all the termi's on e85 i shoot 27 to and see where shes at, i then yank 3 degrees and make another pull to see if it likes it, usually I find the lower boosted ones < 20psi to be happy up near the mid 20s and most of the higher boosted ones > 20 psi to be happy in the lower 20s

Keep in mind the OP is using e85 this doesnt apply to pump gas

 

[XCSEDAN]

few questions for you, are you using pump e85? if so,
do you know what kind of quality e85 you're getting?
any idea what they are mixing the other 15% with out of the pump? and do you have an ethanol meter?
there is some major discrepancies down here (i dont know about stateside) with pump e85, it can legally vary from 70-85% ethanol content and be labeled E85 not e-flex.
the other thing is station to station can change a lot & brand to brand. again it may be different in the states, but here its riot. and it is a pain in the absolute ass.

also didn't realise you were running the stock eaton still, TVS would be a major upgrade, or you can go all out on a KB or 3.3 whipple, but as you say its all money right?
least you got the base right to start with, most people **** that up.

 

[Black02GT]

I always use the same station, there's a bunch around here but I stick to this one. I use this station since it's only a couple years old, built on a new plot (not reusing tanks) and has always had E85 since it opened. I like the piece of mind that the underground tank only even held E85, I've heard issues with gunk at station switching over diesel, kero, etc tanks.

I had borrowed a tester from a buddy and it's right around 85% +-, that was in the beginning of the summer. In a month or two when it chills off ill retest to see if they use winter blend. Not sure what the other 15% is in terms of octane, it's a Gulf station not a small private one if that matters.

I'd love to get a TVS, whipple 2.3 or even go all out with a 2.9 just not in the cards at the moment. Had the money for it but thankfully didn't get it. Right before I pulled the trigger my transmission shit the bed and the money went to a T56 Magnum instead (Had a TKO 600 never liked it).