Tuning for E85

Discussion in 'Modifications & DIY how-to' started by crashtke, Jun 17, 2008.

  1. crashtke

    crashtke Member Supporting Member

    Well, one other side note that I have noticed with the 30% ethanol...seems my WGDC are too high now...I was not overshooting boost, but now (probably since there is more post combustion exhaust gases) it will overshoot boost a little. With the current outside temps, it should be rock solid at 90 degrees ambient, but it is overshooting a little...might have to tune down the WGDC today when I switch to 100% E85.
     
  2. crashtke

    crashtke Member Supporting Member

    All I have to say is DAMN!! 100% E85 and things are good, lol. The only negative is I have to totally retune boost....all my WGDC tables are now obsolete. This stuff spools the turbo soooooooooo much better. I'll go into more detail later.
     
  3. crashtke

    crashtke Member Supporting Member

    Ok some more detail about the whole install and tuning aspects. The modded injectors were kind of difficult to tune for. They did not seem to want to scale right...on the low end they acted kind of like 625cc injectors, but then if you scaled them for that, they just DUMPED fuel in at the top end. So they took a little bit of work. In the end I scaled them as best I could for what they were...I think the scaling ended up being around 725cc if I remember right. Then I worked a bit with the injector latency just a tad. I barely had to move that any. From there I just adjusted the intake calibration map in order to make sure all my AFRs were what they were supposed to be. The idle is still a bit lumpy. I think it needs a little more work in the latency tables. I am not exactly sure, but I have heard of others having similar issues with these modded injectors.

    Next I moved into the E85 and filled up at the local E85 station. I added in about 20% more fuel through injector scaling. When I started up the car it ran almost exactly like it did on E30. No problem. The switch was almost flawless. I ended up taking a bit of the 20% back out as it was running a little rich, but in the end there was not much to it.

    The only part that I had a minor issue on was one spot in the map that just consistently ran rich. Right where the boost drops down at around 5200 rpm it wanted to drop down into the mid 10's. I was shooting for 11.25 (displayed 11.25 but actually it is 7.49 or lambda of .765). While it is still within the max power range of E85, it is in the lower end of the scale. The cool part is that with E85 you can run it a bit leaner in the lamda range and still be ok due to the fact that it burns cooler and is 105 octane :)

    So those are my initial findings. Once I get this thing ironed out, I'll take it to a dyno and see what I have yielded thus far. How much does a could dyno pulls cost at battleground? I would really like to go back to their dyno so that I can compare any gains on the same dyno...bad part is that my last pulls were in like 45 degree weather and I don't want to wait that long, lol.
     
  4. slowwrx

    slowwrx Supporting Member

    Thats awesome, Glad to see you are having good results.

    I guess I'm going to install the fuel system later this week and start tuning, I was going to do it last week but I wasn't in the mood.

    Matt
     
  5. Cool_____

    Cool_____ Banned

    Sweet. Too bad it isn't widely available. I travel a lot so I need the availablity. Don't want to simply switch maps all the time.
     
  6. UpSideDownDesi

    UpSideDownDesi Active Member

    awesome write up Mike, i am saving up for the goodies :D.
     
  7. crashtke

    crashtke Member Supporting Member

    Now the bad part is I want a new turbo badly...I bet with the excess exhaust gas, it could spool a 20g without too much trouble...maybe even a T3/t4oE...but gotta save more money up for all that. I could only imagine what a 2.5 and a GT35R would be like with E85. Lots of fuel, but it would be worth it! Only limitation would be what the engine could take.

    Matt let me know how it goes, I am curious to see the outcome and what it ends up making in comparison to 93.
     
  8. crashtke

    crashtke Member Supporting Member

    Any news yet matt?
     
  9. Batlground

    Batlground Active Member

    No I haven't had time I've been working like crazy. I haven't totally finished the pump gas map yet, it still has some smoothing out to do.

    Matt
     
  10. crashtke

    crashtke Member Supporting Member

    Matt what are dyno runs costing these days, once I get done here I would really like to take a couple pulls on your dyno again just to compare apples to apples (minus the +40 degree ambient temp difference).
     
  11. crashtke

    crashtke Member Supporting Member

    Well, things are on hold...my old rear o2 sensor gave up the ghost after 125k miles. So this is messing with things a bit on the tuning side...can't seem to just eliminate it. I suppose I could just do a mechanical fix, but would rather let the ECU see what is happening and have heard that the rear o2 sensor DOES have some things to do with LT fuel trims. So till I get this p0037 cel taken care of, the tuning has stopped for now.
     
  12. Batlground

    Batlground Active Member

    We just finished an e85 sti and an e85 evo at the shop. The are both running the full e85 pump gas. Remember that e85 can be as low as 70% ethanol. Make sure you tune on the 70% ethanol mix if you are trying to get the most power out of it and you want to be safe. If you don't account for the fluctuation in ethanol content at the pump then your ecu will pull timing and add fuel if it knocks. Get a good hydrometer or electric meter to test for ethanol content.

    The results were what we expected. You can run 30 psi on the e85 which gives you about 10 more pounds of pressure than 93 pump gas. 80 more horsepower is easy to get as long as you can hold the boost up.

    Sidenote: You can run the 30 psi on 93 pump gas but you have to run it so rich and run so little timing that you end up overheating the exhaust valves and the turbine wheel of the turbo. In conclusion, running 30 psi on pump is not a good idea for long term use. You don't really get the benefit of more boost because you cant run the timing to go with it. Thats why we don't tune customer cars to 30 psi on pump gas.

    Back to the ethanol. At 20 psi we ran between 6 and 9 degrees more timing. The fuel consumption was a little less than double that of 93 octane. You can run a little different air fuel ratio but I am not going to get into that right now. So at 20 psi we got an increase of about 40 horsepower due to the change in fuel, the cooling effects of the ethanol in the combustion chamber and the addition of ignition timing. Then we turned up the boost. We saw another 40 horsepower. This was all on an sti and an evo that were both making around 320 hp on 93 octane gas. They both left with around 400 hp to the wheels.

    As we do more testing we may have dyno charts available for public viewing.
     
  13. crashtke

    crashtke Member Supporting Member

    What turbo on the Sti? Was this just an otherwise stock sti with bigger injectors and fuel pump? Pretty amazing results!
     
  14. crashtke

    crashtke Member Supporting Member

    Well, trouble cleared with a new o2 sensor. 125k miles is not to bad for an o2 sensor, hopefully the front is not about to go as well, lol. So back to tuning. Hopefully I can produce some similar results. I dynoed last time at around 210 whp/220 wtq. Since I am still on a stock turbo, I doubt seriously that it will be able to boost much higher than what I am currently running...time to find that old compressor chart and see. I am hoping for around 250/250 or in that range.
     
  15. Cool_____

    Cool_____ Banned

    I don't see why you won't get 250/250.
     
  16. crashtke

    crashtke Member Supporting Member

    Well, hitting around 20 psi of boost in 3rd and 4th gear and have added a little more timing. Seems to be liking it so far. There has been a corresponding increase in MAF with each change. It is still not optimal, and trying to get the fuel leaned out a bit more. But the car just goes!
     
  17. crashtke

    crashtke Member Supporting Member

    Worked on the intake calibration to get the fuel where I wanted it today. Basically I am shooting for 11.27 afr which is a lambda of .77 It is a little on the rich side, but it is right in the middle of the power range for E85 summer blend :) I will probably end up tuning up to around 11.70 but taking things a little at a time.
     
  18. crashtke

    crashtke Member Supporting Member

    Well, tuned up to around 11.54 and so far everything is going very well. I need more work in the part throttle areas of the map, but other than that, things appear good. The only thing I have noticed is that upon startup it can be a little odd. Sometimes idles rough till it gets up and running. I have heard that a block warmer or intake warmer works wonders with E85. Seems it likes things warmed up, lol. I am going to be swapping out the plugs here shortly and I am trying to determine what plugs to put in the car. I have about decided on NGK iridium plugs...just not sure if I want to go stock or one heat range cooler.
     
  19. crashtke

    crashtke Member Supporting Member

    Well, some more observations. I have had to zero out several of the initial boost targets and wastgate duty sections. With E85 this thing wants to spool that tiny little turbo with almost ANY input to the throttle. So that I was not running minor boost while cruising on the highway I have lowered or zeroed out up through 38% throttle. So at this point it just runs spring pressure and that is it for those areas of the map.

    Since doing this fuel economy has returned. I am still not exactly sure what it is as I am still regularly doing pulls to try to get the entire MAF table dialed in, so I am doing a lot more WOT pulls than it would normally see. When I first started it was around 16 city (with a bad rear o2 sensor)...then 17 as I started getting the intake dialed in...now around 20 combined with about 25% highway. I averaged around 23-24 before combined on 93 octane gas. Again, this is sitting in heavy traffic and such too, so hard to tell exact mpg. Also any time I have taken it on the highway I was doing some WOT pulls and datalogging, so again, hard to tell, but it is getting close to being what it was before.
     
  20. crashtke

    crashtke Member Supporting Member

    Well, just to give an update since it has been a bit since I have been working on the tuning with the whole appendectomy and deaths in the family. I started back the past couple weeks and I am seeing some GREAT results. At the advice of Christian from Cobb, I leaned it out to around lambda of .82 or the gasoline equivalent of 12.09. Since doing that, the car just screams! Still no dyno, but seat of the pants, the car has never been faster.

    I still have a ton of injector left...maybe enough for a 16g, lol. I just hate buying another turbo when I plan on doing the 2.5 and going rotated. I have even thought about going rotated now (since the E85 spools the turbo sooooo much faster...read 19 psi by 2900-3000 rpm in 4th), but worry that the tranny would get upset and quit on me.

    So leaning things out seems to be the way to go with E85. The car seems much smoother, the exhaust note had changed a bit for some reason. And the engine has not knocked once since the switch!! All in all I am very pleased with running the car on E85.

    Big thanks though to Christian at Cobb. He was quite helpful and forthcoming with his knowledge.
     

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