Tuning for better fuel economy

s300 and SManager software questions & answers
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Joined: Wed Sep 12, 2018 6:20 am

Tuning for better fuel economy

Post by johnlawress »

I recently purchased a 97 civic with a fully tuned lsvtec motor. The motor setup isn't really anything too crazy, 81.5 b16 style pistons and ctr cams with a minor valve job on a b16 head with a S2 pro mani and 66mm TB. Motor is NA.

I was told that the car was tuned for 6 hours on a dyno dialing in the tune very well. It runs great, with no issues really, but the fuel economy is way worse then I would expect for the setup. I've seen similar engines with bigger cams get better fuel economy then this thing. I don't currently have a wide band, because when I bought it I was told the wideband o2 had gone bad (reads 14.8 consistently),I just got the car a few days ago and haven't replaced it, so I don't know if the car is running really rich or not, but it smells pretty rich. I tried to upload the calibration but for some reason when I click browse in the attachments section I can't find my calibration, even though it is saved on my computer in the calibrations section and I can open it perfectly fine with Smanager. I tried to type in the file name manually, but when I click open it tells me the file name cannot be found. All of the pre saved calibrations can be attached, but I cannot attache my saved calibration. If someone knows of a better way to attach a calibration or knows what I'm doing wrong that would be great.

I guess I'm just looking for a bit of advice on how to possibly tune for better fuel economy. I'm not looking for amazing gas mileage, but it would be nice to save a few gallons in the cruising RPM's. How lean is too lean? Should I just shoot for slightly higher then stoich and add a degree or two of timing to aid the combustion? Comparing my fuel tables to the stock ITR tables in row six, the ITR fuel values are actually a bit higher than mine from about about 2000 to 3000 RPM's, then after that my tune jumps ahead quite a bit from 3000 through about 4500. I was thinking that I could pull a tad bit of fuel in the 2000-4200 cruising range, monitor the wideband, and aim for a slightly leaner then stoich mixture and be fine if I add a tad of timing. Is this a practical and safe method for street tuning for better MPG's? Would it be too dangerous to run in say the 15.2 AFR range? I'm pretty new at this hands on ECU tuning and would hate to ruin a perfectly running engine. If when I get the wide band it does in fact appear to be running quite rich it would be safe to say that I could get away with making it run more stoich and probably save some gas without having to go lean but I figured I would look for some insight on the best way to go about doing this without being on a dyno and paying someone else to do it for me. Thanks for any help.
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Joined: Mon Jan 01, 2018 7:31 pm

Re: Tuning for better fuel economy

Post by skaterguy1986 »

Pretty sure by default the SManager software creates a folder under /USER/Documents/S300 Calibrations/ and doesn't save to the location of the premade calibrations.

As far as tuning and trying to make the engine more efficient, need to replace that wideband, it's the only way but it can't be tuned all that great if the fuel mileage is terrible since a rich mixture at low-med load does nothing for power and MPG.
Posts: 65
Joined: Thu Nov 03, 2016 12:23 pm

Re: Tuning for better fuel economy

Post by creizlein »

the calibration is a file archive as any other archive in your machine, you have to be able to find the actual archive using your explorer, make sure the archive has .skl extension as well (do not confuse your archive with a link to your actual archive, that might give you issues). But if you need help with that check with any friend that has basic OS knowledge that is able to find the file for you and move it to the proper folder.

about the rest, as skaterguy1986 mentioned, go ahead and replace that wideband and see exactly what AFR you are getting while cruising and move from there.
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