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Starting this thread to post results, starting this morning my car will be on E85. With premium here creeping to ~$4 a gallon while E85 is ~$2.50, it seems like a good idea to save some money while maybe making more power. There is a gas station almost right in the middle of my drive to work that advertises its E85 at 70% ethanol (I have tested and verified) so I don't have to worry about going out of my way for gas. I am not expecting much for improvements but I figured this is something cheap to play with and others may be interested in the results. I currently have my car idling the last of the premium out of tank so I can pour in a couple gallons of E85 to test my tune with. I don't have the most confidence in myself for the tune as I am not sure what all I should change, so I imagine if today goes well I will play with the tune for a month or two. I am starting by just changing the fueling so the AFR will be right with the timing being untouched and see what happens.
For before and after comparison, my last ~900miles of city driving (mostly just work and back) averaged 19.2mpg according to the dash, with the last oil change averaging 18.7mpg. I have a draggy but don't have a satisfactory sample size of 0-60/1/4 mile times to compare against however I have a good handful of 30-60 and 40-60 times which I have from attempts to find the best time to shift into second gear. A typical good 30-60 for my car is ~2.75s, with 40-60 being ~1.9s. My 40-60 times are probably going to be the best measurement for power improvements that I can use as that is just a pull through a good section of the powerband.
Over on the ISF side of the house at least, folks been running E85 mix gas forever now especially alot of us guys on the west coast with trash 91 oct. But that's like 3-4 gal to bump up the octane rating, I don't think I've heard of anyone running straight E85, do you have any fueling mods? Cause all i can see is an extremely lean situation incoming if you are still on stock fueling and trying to run 100% E85
Over on the ISF side of the house at least, folks been running E85 mix gas forever now especially alot of us guys on the west coast with trash 91 oct. But that's like 3-4 gal to bump up the octane rating, I don't think I've heard of anyone running straight E85, do you have any fueling mods? Cause all i can see is an extremely lean situation incoming if you are still on stock fueling and trying to run 100% E85
Looking forward to seeing how your acceleration times change when you get your IS350 tuned to run e85. RR Racing had recently posted some dyno results from a variety of setup configurations on the newer generation IS350 and it looks like there's a potential ~12rwhp gain from pump gas to full e85.
Car is currently has ~an hour of driving on E85. It was a bit frustrating at first trying to get rid of the old gas, I let my car idle for 30-45 minutes after driving 10ish miles after the dash said I had 0 miles left in the tank. I put another ~30-40 miles on the car driving around trying to run it out before giving up and just adding the 2 gallons of E85 I had in a can. I then drove around a little until I saw my short term fuel trims go weird and pulled over and flashed the new tune for E85. Car seemed to run ok so after a few minutes i went back to the gas station and threw in a few more gallons of E85 so what was in the tank should have been close to representing a tank of E85.
The software I have for editing tunes has a value labeled, "AFR value as stoichiometry" and I thought changing that is what I needed to do to as a starting point. I set that to 10.7 as that is what 70% ethanol calls for and the car currently drives around fine but something isn't right. Driving around my car is reading ~an AFR in the 19-20:1 range, but it sounds and drives fine. I don't know why but the ECU is requesting an AFR in the ~20:1 range and that is what it is getting. I did a few WOT pulls thinking it might read differently in open loop but it shows the same AFR, I have no idea where that number is coming from. Speaking of the WOT pulls, car felt slightly slower but pulled fine. I only had draggy on for one of the pulls and my 30-60 was at 2.9S and the 40-60 was at 1.98s, well within what I might see any other day.
Thinking I needed to add fuel without changing the stoich value in the software I went and found a table for changing fueling based on load and modified all tables to match the fueling difference I was hoping to see. Car ran, but wasn't right. I am about to cheat and return the fueling changes back to how they were originally and try to cheat the difference through maf scaling. Worst case scenario... my first version worked well enough to run out this tank and I can just revert back to pump gas.
I think I have the fueling thing figured out and have ran through a 1/4 tank of gas without any issues with the lambda values hanging out in the .9-1 range throughout the rpm range at different loads. It seems like I have some low load timing to adjust in the 1200-2500rpm range however that just appears to be an area for improvement, the car still drives fine and I can't really notice any difference compared to when I was on 91. I've done a few wot and higher load pulls to see how the car behaves, for some reason it feels like it really picks up power at around 6k. I don't think it's making substantially more than before, I am probably just down some and need to log it to see what the timing and AFR is doing.
Many times when a car is Tuned well through the rpm range people often say they don't feel a difference. Lots of times it's because it's performing better, and lacking any illregular dips in the power band it's pulling smooth. Thus there is no dip, and the curve is smooth. You would need a Dyno run to see what's really going on.
Finally have an update worth posting. I tried messing with the fueling a couple ways Ithe tune and I had it so the car would drive fine most of the time. Problem is that I would still have oddball hiccups where the car would run lean and although the ecu did a good job adapting quickly, my long term fuel trims were higher than I'd like. When I initially went to adjust the maf scaling, I ran into a problem where I couldn't change the values by enough as there was a maximum value that I ran into within a range I could see while driving.
What I ended up noticing is the fueling difference I needed was really close to the cross section difference between a stock sized maf housing and my 3.5". I reverted back to my stock sized 3d printed maf housing and flashed back to my previous tune before getting into e85. This has shown the best results so far with the fuel trims being almost spot on driving in light to medium load. I haven't put too many miles on this setup, but the two pulls I tried have my lambda values being within .1 of what I am requesting in the tune which is tighter than what I was getting previously with a stock air box and original maf scaling. I think I'm going to leave it alone for a while now and monitor a few things.
Minor update with some results to share. I've made one revision to fueling since my last post in hopes of making a little more power at wot, I'll probably make one more revision to fueling then work on my timing. The car feels faster, and the few cleaner draggy pulls seem to suggest I'm definitely making more power. Previously if I were to cherry pick my best 0-30, and 30-60 times I'd end up with a 0-60 at ~4.6s. This morning I had a 0-60 of 4.65s, and that's with launching a little more conservatively to avoid spinning and I had a less than ideal 1-2 shift. I wasn't really expecting that much of an improvement.
Gas mileage isn't looking like it will be as bad, but it's too soon to say for sure. It looks like my daily drives to work and back are averaging between 15-16mpg, from 19.2mpg. Highway driving has a small sample size, but not disappointing getting 26.2mpg in a stretch where I'd previously expect 31-32mpg. It looks like it's safe to say it's only a 20% hit in gas mileage, which is worth it when I'm paying a third less per tank. I'm willing to bet with optimized timing it will look even better, but I'm not sure I'll be able to dial it in perfectly.
Minor update with some results to share. I've made one revision to fueling since my last post in hopes of making a little more power at wot, I'll probably make one more revision to fueling then work on my timing. The car feels faster, and the few cleaner draggy pulls seem to suggest I'm definitely making more power. Previously if I were to cherry pick my best 0-30, and 30-60 times I'd end up with a 0-60 at ~4.6s. This morning I had a 0-60 of 4.65s, and that's with launching a little more conservatively to avoid spinning and I had a less than ideal 1-2 shift. I wasn't really expecting that much of an improvement.
Gas mileage isn't looking like it will be as bad, but it's too soon to say for sure. It looks like my daily drives to work and back are averaging between 15-16mpg, from 19.2mpg. Highway driving has a small sample size, but not disappointing getting 26.2mpg in a stretch where I'd previously expect 31-32mpg. It looks like it's safe to say it's only a 20% hit in gas mileage, which is worth it when I'm paying a third less per tank. I'm willing to bet with optimized timing it will look even better, but I'm not sure I'll be able to dial it in perfectly.
Great progress on the 0-6-, it's very impressive. Just for reference, what mods do you have? I think I remembered you have Intake, exhaust and ported lower Mani? What Mods exactly do you have?
I currently have my homemade 3.5" intake, 74mm throttle body, headers, 2.5" dual exhaust with cats and now an e85 tune. I had a lower intake that I ruined, it never made it on my car.
Another minor update. I haven't changed the tune since the last update, but I have been keeping an eye on a few things. The last tank of gas I went through ended up at 15.9mpg, which is quite acceptable for me. My sub 2500rpm KCLV pegged at 28 within a trip to work and back, with the knock feedback value suggesting that it would go higher if it could. KCLV over 2500rpm at the time I refilled my tank was ~23.5ish, I cant recall the exact value. I didn't want to ruin my average mpg, but my >2500rpm KCLV is now at 26.4 within a dozen or so WOT pulls since refilling my tank. So far the car drives just fine with the only difference that I have noticed is that on occasion the first second of a cold start sounds different. I think my next "project" for my car is to make an airbox with a swappable maf housing or insert that is sized for e85 or normal gasoline so that I don't have to worry about flashing the ECU if I want to switch between the fuels.
Forgot to update this earlier. I can confirm that my is350 doesn't like to start as easily on e85 when it gets cold out. I don't know how cold I can go until it won't reliably start, but it will start as cold as 26/27F after several seconds.
I'm now back on e85 after winter without issues. I think I'm going to work on the tune more to see if I can get it running smoother and to maybe improve mpg. I specifically to fix the calculated load as that is based on MAF values which is now wrong due to fixing afr by playing with the MAF scaling.
E85 Tune
