MPG- give me some input please
 

Hey,

I would like to know if my fuel consumption is normal.
Lately I run on low boost 7-8psi in order to see if that will help my mpg.
It almost made no change, I run 12-17mpg (5-7km/liter)

Normal ?

This is my AFR auto generated table:
https://www.miataturbo.net/attachmen...1&d=1400844469

What do you think ?

:party:

Thats very low MPG. Seams rich in the middle. Could be closer to 15-16.

first off, you mean mpg right? cause even a semi truck doesn't use 17 gallons per mile

second, your target afr table means nothing to us, you'll need to post logs or tell us what its actually achieving.

third, what fuel are you using.

lastly, if you're not getting the same mileage driving it normal as you did when it was unmodified, then you either have a problem or your tune sucks. at worst it should be within 10% difference. that's assuming you're not constantly WOT and in boost

Please stop posting lazy uninformative threads, or we'll stop helping you. I realize you're foreign, so there's a language barrier, but you'll still have to try harder and provide more info.

I got 23mpg on my last highway cruise and it was very spirited... (cruising 4-5k)
Run ~15.5-16 at cruise on HWY.

Car is still very untuned so these numbers should get better

MPG fixed.

I will post logs asap, but this table was used by the autotune so it represent quite good the actual AFR - I see my AFR live when I drive and it is the same as the table.

I use 95 (RON?) fuel.

I use a small turbo TD04-13C when I'm at 100-120kph I'm in boost (or very close to) so I can not compere it to the unmodified MPG.
When I disconnect the actuator I get close to normal MPG.

I'm sorry to understand that you think this is a lazy uninformative post, I disagree.

If some info is missing I would be happy to give it.

This is my first turbo project, I have no previous background in turbo charging or mechanics (I'm an IT guy) I do my best...

:party:

logs asap.

If disconnecting the wg nets close to OEM gas mileage, then your tune might not be that bad actually. Looks like you're just dipping into boost WAY often with that tiny turbo. Also post your timing map to make sure you're not retarded too much and giving up efficiency.

I meant no disrespect with my "lazy" comment, just frustrating because I'm genuinely trying to help you out here.

My ignition map:

https://www.miataturbo.net/attachmen...1&d=1400864003

Thank you for your help.

That ignition map looks pretty average to me. Is your turbo really that small that you are just constantly sitting in or near boost even while cruising? I am getting around 26mpg combined with mine and I am using the tiny stock IHI turbo.

Yeah, not a bad spark map. You can bump up the 35-80kpa rows to 40 or closer to it if you want, but otherwise not bad. So far I see nothing bad with your maps. If you're in boost when at steady state cruise like you say, then yeah that's gonna eat gas like crazy

I beat the crap out of mine and usually rev it in the driveway until it's warm. I still get 19mpg regularly. This is with cruise cells tuned, as others have said, to 15.5-16 afrs.

Here's what you do:

Go out for a drive on the freeway. Get in the slow lane and go 50mph. Put the car in 5th, or 6th if you've got it. Drive for 10 miles, paying attention to your RPM and map readings, remember them. Then go to your fastest cruising speed. In Oregon we don't have speed limits over 65, so I'd probably do this at 70mph, but your results may vary. Again, drive 10 miles at this speed, paying close attention to your rpm in top gear and map reading when CRUISING (aka: not the readings when you're letting off if you accidentally go too fast, or boosting back up).

Find the 50mph numbers on your afr target table, and draw a line straight up at the rpm, and horizontally right at the map. With the 70mph (or whatever) numbers, draw a line straight down at the rpm and horizontally left at the map.

Make all cells that fall in the box created by these lines equal to 15.5-16.0. Tune for these. If you have an hesitation or you're worried about the transition into the box, or out of the box (and/or if you have a giant MSII or better target table), you can reduce the boarder to a smaller number.

Come back with results.

P.S. Your signature is a lot better than most newbs, but make sure to ad your car's year and engine type. 17mpg with a 1.6t is much worse than a 17mpg 1.9t.

he's got a 1.8 nb iirc.

another reason I asked for logs is cause I want to see if he really is in boost at low throttle accelaration

Is that the highest octane available in your area? I would put 97 or 99 RON in your car if it is available. Depending on the blend, 95 RON is somewhere around 90 AKI octane. 97 RON around 92 AKI and 99 RON is around 94 AKI.

Keith

Way too rich. As said a target afr map means nothing however i'm assuming your real map is fairly close. That said...

1600-3800 up to 64kpa tune for 15.2. Your location is unknown however in the winter i go up to 15.5

Between 1600-3800 change 78kpa to 14.3 , 92kpa to 13.5

Also a small turbo wont make it so you're always it boost. Doesnt work that way. That depends on your throttle / rpms. Yes it spools faster than a large turbo however if u find ur self at 120kpa all the time in low rpm then you need to ease on the throttle and keep it in a higher rpm. An engine at 3-4k rpm at 70kpa will give u a better mpg than lugging it at 120kpa at 1500 rpm on every green.

Like that ?

https://www.miataturbo.net/attachmen...1&d=1400911430

I drive a 1.8 1997 NA.

Winter here is 15-25C and summer is 30-35C.

I will get some cruising logs today hopefully.

Its probably worth a shot, but honestly .3-.5 of a point of afr wont' make much difference, especially in cells that get swept through real quick and usually are bouncing around to find the target.
Your normal hwy cruising should be out of boost, and it should be in the 30-40* range, and it should be in the 14.7-15.5 range. Your idle should be in the 14.5-15.0 or so, and your startup/wue should not be pig rich.

just some general pointers

I can tell from older logs that my cruising is @ 60-70kpa.... @ 3000-3200rpm

I enriched my cruise map last gas tank was at 15.8ish, went down to 15.2. Went down from almost 25 to 23.3

Yes, that should help. Keep it less than 75kpa while accelerating and shift at 3500rpm.

Got my logs, this is after the AFR table change and autotune that, I can see that the AFR is very close to the table.

btw... my 3rd gear started knocking this drive.... very calm drive.... :\

3rd gear started knocking? Pinging?