Getting Best MPG during Cruise

[GST Motorsports]

Originally Posted by tephra

you are really dying for better fuel consumption hey

generally:
1) make more power from the fuel you put in - ie MIVEC or IgnitionAdv changes
2) put less fuel in (ie lean cruise) - but this will require MORE IgntionAdv again otherwise you will loose power from the slower burning mix

I have yet to see any empirical proof that #2 works, feel free to do some tests for us

1. has shown to produce better MPG to me.

I tested both closed/open loop cruise and ignition changes for over a year on my personal Evo 8. Keeping it in closed loop and tweaking ignition produced better MPG on my Evo 8.

On the 10's and 9's, I've seen better mpg with ignition and mivec cruise changes.

- Bryan

[Clipse3GT]

Originally Posted by tephra

you are really dying for better fuel consumption hey

generally:
1) make more power from the fuel you put in - ie MIVEC or IgnitionAdv changes
2) put less fuel in (ie lean cruise) - but this will require MORE IgntionAdv again otherwise you will loose power from the slower burning mix

I have yet to see any empirical proof that #2 works, feel free to do some tests for us

I am beginning to think that scaling and latency has a affects fuel consumption. I know when I was running 696 scaling and 14v @ ~1.400 for my DW800cc I would get 24-25mpg on the highway with a setting my injectors to 770 and about ~1.200 latency @ 14V I get about 18-19.5mpg. No changes to MAF or Ignition or any changes to my High Octane map in the cruise range.

I figured out the that the stock 600cc injectors are about 11% scaled down to about 532. If you scale the DW 800cc injectors by 11% you should get about 713 in ECUFLASH. I will try to rescale my car for 713 and see if I net any better gas mileage.

I am thinking that 770 is too high and you need to lower the latency about .25 @ 14v to get your car into +/-5% cruise and idle.

If it dosent work, well then I can go back to my now working scaling and latency. I will do some testing today.

[GST Motorsports]

Originally Posted by Clipse3GT

I am beginning to think that scaling and latency has a affects fuel consumption. I know when I was running 696 scaling and 14v @ ~1.400 for my DW800cc I would get 24-25mpg on the highway with a setting my injectors to 770 and about ~1.200 latency @ 14V I get about 18-19.5mpg. No changes to MAF or Ignition or any changes to my High Octane map in the cruise range.

I figured out the that the stock 600cc injectors are about 11% scaled down to about 532. If you scale the DW 800cc injectors by 11% you should get about 713 in ECUFLASH. I will try to rescale my car for 713 and see if I net any better gas mileage.

I am thinking that 770 is too high and you need to lower the latency about .25 @ 14v to get your car into +/-5% cruise and idle.

If it dosent work, well then I can go back to my now working scaling and latency. I will do some testing today.

Of course it has an effect if the car has to keep adding fuel to get the trims inline. It will always overshoot with too much fuel, then take fuel out, it's a downward spiral.

The 10's can be a pita in this way compared to the 8/9's since the LTFT is so sensitive and effects open loop fueling as well and is way too sensitive about it.

[Clipse3GT]

Originally Posted by GST Motorsports

Of course it has an effect if the car has to keep adding fuel to get the trims inline. It will always overshoot with too much fuel, then take fuel out, it's a downward spiral.

The 10's can be a pita in this way compared to the 8/9's since the LTFT is so sensitive and effects open loop fueling as well and is way too sensitive about it.

Yeah I just did a run with much lower scaling at 680 and much high latency, now getting 28 mpg cruising.

Here comes the fun of rescaling everything again.

[GST Motorsports]

Originally Posted by Clipse3GT

Yeah I just did a run with much lower scaling at 680 and much high latency, now getting 28 mpg cruising.

28mpg for now until the fuel trims come back in line. What are your STFT's doing?

[Clipse3GT]

Looks fuel trims look terrible.

STFT is within +/- 5%
LTFT IDLE is -1%
LTFT CRUISE is -12.5%

LOL , I need to adjust them.

Before I had it at 770 and latency lower and I was within these values:
STFT +/-6%
LTFT IDLE + between 1-5%
LTFT CRUISE +/- 2-3%

[GST Motorsports]

Originally Posted by Clipse3GT

Looks fuel trims look terrible.

STFT is within +/- 5%
LTFT IDLE is -1%
LTFT CRUISE is -12.5%

LOL , I need to adjust them.

Before I had it at 770 and latency lower and I was within these values:
STFT +/-6%
LTFT IDLE + between 1-5%
LTFT CRUISE +/- 2-3%

hehe cruise maxed out negative.

Looks like your 770 scaling is much more inline

Go back to 770 and add a little bit more latency

[Methodical4u]

which turbo would be the one that might save a bit of fuel instead of the oem mitsu turbo? One that doesn't start into boost so fast?

[Methodical4u]

Originally Posted by Methodical4u

which turbo would be the one that might save a bit of fuel instead of the oem mitsu turbo? One that doesn't start into boost so fast?

bump... still wondering about this question... any insight?

[tephra]

you got a right foot yeh?

[Methodical4u]

Originally Posted by tephra

you got a right foot yeh?

no I don't... I actually lost it in a freak bear hunting accident.

[tephra]

mmm - should have gone the SST then

[Methodical4u]

ANYWAY... I guess what I am asking is which turbo's spool up more slowly than the OEM ones... and wouldn't that save fuel by doing so?

[tephra]

lol

almost ANY aftermarket turbo will spool slower.

red/dom2/30r/35r

I don't think the fuel saving will be much

[Methodical4u]

Originally Posted by tephra

lol

almost ANY aftermarket turbo will spool slower.

red/dom2/30r/35r

I don't think the fuel saving will be much

hmmm, well I had considered getting another turbo once money got a little better so I am just doing research now. Would I just be better off getting a TBE UICP IC drop in filter, etc and get better mileage that way? Less restriction, so I would think it would help maybe a few mpg.