Correcting an E85 Tune
 

I've been running E85 for almost two years now and enjoying every single minute. I originally had my EVO professionally tuned when the larger injectors were installed. However, I was not as knowledgeable then as I am now so I did not know the questions that I should have asked. As I have become more knowledgeable, I have also become more dissatisfied with the tune.

I am not writing this as a tuner bashing missive. I’m simply stating the facts and pointing out the necessity of fully understanding what is involved in a tune and knowing exactly what to insist upon, rather than to blindly accept what the tuner says and does. Especially true when you have traveled 100s of miles to get your car tuned, as opposed to local.

I just recently had a wideband installed. (Yes, I know, W/B should have been a first mod. My bad.) Now I feel ready to make the remaining corrections to my tune. I’m hoping I can count on some input from those of you who are far more knowledgeable and experienced.

My original tune had the following deficiencies (in my opinion):
1. Fuel trims: low -12.25%; mid 0.3%; high 0.1%
2. Fuel and timing maps were not re-scaled for higher load cells
3. Knocksum required for slow CEL set to 10
4. Knocksum required for fast CEL set to 20
5. Too much knock & too high knock (10+) at high RPM
6. Lean spool on

I am attempting to make the rest of these corrections:
1. Get the fuel trims within + or – 5%
2. Re-scale fuel and timing maps
3. Set knocksum required for slow CEL to 3
4. Set knocksum required for fast CEL to 6
5. Minimal knock, 1-2 random counts
6. Lean spool off


1. The whole injector latency thing for me is like a being in a really thick fog in the Smokey Mountains about daybreak. I quickly gave up and simply searched until I found some different E85 scaling and latency settings. Now the fuel trims are: low -5.78%; mid 4.6%; high 0.1%. Do I really have anything to gain by adjusting these any further? If so, please help me out.

RC 1,000cc
E85 scaling 609
3.312
2.184
1.560
.936
.624
.384
.288

2. I re-scaled the timing and fuel maps, and then did it again when I moved from the 94170014 ROM to the 96530706 Tephra V7 ROM.

3 & 4. Resetting the CEL knock light was obvious.

5. The timing map was too mild in the off-boost area and way too aggressive under boost. Rather than simply pull out timing, I opted to use MRFred’s posted IX E85 timing map. I consider it to be a conservative map for an VIII, and I’ve been running it unchanged for almost two years.

6. Wow! Turning off lean spool really does enrich the mix considerably. A lot of threads on lean spool, but not many on disabling it and retuning the fuel map. I’ve been working on this for the past several days now. It finally occurred to me that fuel should be pulled out across the entire boosted area of the map, not just in the individual cells within the map trace. I tried that at first, but ended up running richer at part-throttle than at WOT. DUH!

However, as I’m pulling out fuel across the boosted portion of the map, I am severely flattening the fuel map as well, is this normal? Is there a standard approach to disabling lean spool and correcting the fuel map?

Thanks for any/all help,
Jim

:mitsu:

1. Decrease latencies and decrease scaling. This will lean up your idle and richen up your cruise. Go in that direction, you are pretty close though...don't give up. That will change depending on E blend, etc., so don't get to fanatical about a % or 2.

2. The fuel map will become pretty flat with LS disabled...here's mine. This map has very nice tip in, spool up, and a 12.0-12.3 WOT. It's pretty crazy how lean this stuff likes to be compared to pump. Took a bit of getting used to after messing with pump for a few years.

good thread hope to learn a lot out of this.

Will do. In increments of what? 1%? 5%? Or is it best to increment numerically?

EDIT: Decreased scaling from 609 to 597, and decreased latencies by 1%. Is that enough to notice any difference?


Your map looks nice and neat and very mathematically progressive. Mine looks like a Charlie Manson Helter Skelter toon. I think I have some work to do in this department. Is your A/F curve fairly flat? I'm shooting for a nice flat 12:1 A/F, but I feel like I'm chasing my tail. Adding fuel here. Pulling fuel there. Here a little. There a little...

:mitsu:

there's so much to be gained from smooth maps so do your best to get the maps smooth. more so on timing the car will real feel that much smoother
good thread jim and its deffo great when you understand what your doing and get it all working much better
the mods you made from the pro tune you got are deffo the way to go.

I think I drove enough today...not sure. Trims are now -0.1% and 3.8%. Should I leave this alone? Or can I get mid any closer to 0?

:mitsu:

Leave a good thing alone :)

Those trims look great. I know you can check trims after a 30min drive or so, but I feel to get a great picture, check your trims in a day or two. I usually do that anyway, just to make sure everything is as it should be.

I'm sure you noticed that it doesn't take much adjustment to get the trims to swing one way or the other. Baby steps, unless its really off. I always adjust my trims numerically an increment at a time...I find that the % method is a little broad for a perfectionist ;)

Oh yeah, Do you have the big map or any other autosmoothing excel sheet? It's a definite help.

Jim you were one of the early adapters with E85. I'm sure a lot has been learned over the past few years.... Oh, BTW i sold my E85 Evo and got a X MR instead :P

How did you capture the photo of your BIGMAP? I wanted to post mine, just for the embarrassment and humiliation. :eek:

With smallmaps I simply use print screen, but the BIGMAP is wider than the screen on my tuning computer. :confused:

:mitsu:

Agreed. Please understand, I was NOT complaining.

I am envious; the new MR is my dream car. I just turned 58 last week, and the older I get the more the automagic tranny appeals to me. Man it hurts to admit that. :o


:mitsu:

Nice post, I'm kinda in the same boat as you as I just started tuning for e85.

My tuning computer is a 17" laptop...kinda bulky but effective. I use the print screen function also.

Wow! that is big.

http://www.cnet.co.uk/i/c/blg/cat/laptops/rory9800.jpg


:mitsu:

Ya i'm getting old too :P Tranny shifts like a dream. Only problem is you can forget running E85 on the X MR as the tranny can only handle 320 lbs/torque... which can be achieved on pump gas and just a tune with no bolt on parts... :thumbdown

Until very recently, that's what I was using too: 17" widescreen, 1920x1200 (Inspiron 1721). Awesome desktop replacement, not very comfortable in the car. ;) I actually had to upgrade my DC inverter to be able to power the damn thing (I could now comfortably power a refrigerator if I needed to :D).