fuel efficiency tuning

[snooopy365]

Hey,
I`m using my DSM as a dailydriver with E85 fuel, so I want to improve my milage while not using much power.

first step was some more Timing while idling and cruising and lambda 1.15 do get more miles out of it.

Is there any good adivce how to tune for milage? can i give it as much timing as I wish until it knocks, like I would do it while tuning WOT?

If anybody tried that yet: how much timing do you have while crusing? is it a good idea to get more than 50°?

engine: 8.3:1 compression, stock NT cams

Any info would be nice

 

[Joesmoke]

What do use for engine management / logging?

One of the things I like about the talon is that it can be a high MPG car if setup and driven correctly.

Cruise timing on fuel could be in the mid 40's on gasoline, so 50 may work for ethanol.

 

[snooopy365]

What do use for engine management / logging?

One of the things I like about the talon is that it can be a high MPG car if setup and driven correctly.

Cruise timing on fuel could be in the mid 40's on gasoline, so 50 may work for ethanol.

MMCD for logging, Aem WBO2, tuning: chip burning for big differents, S-AFC for fine adjustments (fuel only)

 

[turboglenn]

well, the way i tune for highway cruising or MPG is to get on the road and drive the car in those areas (best to have some one else drive honestly) and slightly lean it out until it start to just make that little lean burbbling sound, then add timing until it stop, then lean out some more and add timing again, do this until you've gone as far as you can get away with (within reason of couse.. you don't want to be at 19:1 with 48* of timing). I usually end yup with about 30-36* in the cruising areas with afr's in the 15.2 - 16.2:1 area for a good comprimise of drivability and fuel economy.

Then depending on your programming capabilities/skills you can add timing and lean out some other areas in the first few PSI of boost (where you'd be under light acceleration) just don't go as lean as your cruise areas.

 

[snooopy365]

I know that gasoline have the most milage at 16.2:1 (~lambda 1.15) so I`m tuning for the same lambda with E85

cruising here in germany is different... most of the time I`m driving 30-50mph ... sometimes 60mph.
so my main rpm for fuel ecconomy is 1-2.5k!
30-36° cruising sounds like stock to me?
I`m cruising in the very light load range... so ~35-40+° with stock maps is what I see!

but glenn, you don`t recommand to tune for zero knock? or do you just do it like this because 2Gs knock sensor is not really accecable?

 

[turboglenn]

I don't run a 2g knock sensor, i have an aftermarket independant knock setup, but i only pay attention to it during WOT and i dont' really tune for no knock, but more of a minimal knock. But none of that applies in the cruising tuning since I have the knock system ignoring the engine during cruise. I really won't pay attention to any knock sensor at anything less than a few psi of boost on a turbo engine. Knock sensors no matter how great they are will still pick up stuff that isn't really knock, so tuning to please one isnt' usually the best way to go. I strictly use it as a reference... YOU can see my knock sensor display light up everyday, everytime i drive and a lot of time it's not really knock... sometimes it's light piston slap, sometimes it's my AC compressor, sometimes it's the springs in my cheap-o coil overs making the suspension clank at just the right time that the sensor is sampling (gated monitoring on my car) so i only watch them under WOT and then i'm only watching how they behave, not if they just go off or not.

I just add timing and lean it out until i reach the best mix of timing and AFR while keeping it driveable without being annoying. YOur low cruising RPM makes it a bit more difficult since the engines timing and fuel requirements are different at those RPM's as it is compared to my cruising RPM os 3 - 4K RPM

I don't really recall what a stock map looks like or how fast it gives the engine timing, i'm just saying what i come up with when tuning. If you're getting 35-40* timing under 2500 RPM though that sounds kind of odd, the factory tables that i do remember usually don't give the motor is peak timing until almost 3k RPM and only see timing in the mid to high 20's between 2 and 2.5K RPM (unless it's under full decell ).

MOst of the time the cars i'm tuning have parts that are a lot different than stock so if my maps are coming out with near stock numbers while cruising it's solely because that's what the motor was happy with and is purely by coincedence. Sure you can push the tune leaner and leaner and get better mileage, and you can keep adding timing through what ever theory you want to use to decide when to stop adding timing. IIRC, there was a post on here recently where a guy said he regularly ran an AFR of like 19:1 while cruising. However, when i try going that lean and keeping the AFR stable in that range, the large injectors coupled with the fuel percentage changes made by the closed loop control swinging, will often put the car so lean at some points that it will stumble and buck and get on my nerves to drive.

Everyone's tune will be best suited to their motor with no two being exatly the same, so my best advice is to monitor your engine (datalog if that's your only way) and just come up with a tune you're happy with, trying to chase a tune some one else has is only going to drive you nuts and give you marginal performance at best.

A very prime example is that a few years ago i had a friend who got the same exact car (2gb talon..i have the eclipse) and almost the exact turbo/fuel/intercooler setup as me (we had the same turbos, fuel injectors, pump and IC along wtih me doing most of his other mods and them being damn close to mine). Finally when we put the same brand stand alone in it (getting rid of his SAFC ), i put in the map from my car which ran great, and it would barely get his car running at idle and cruise (WOT wasn't too far off) but the differences in the little stuff that changes air delivery and even little stuff down to dirty filters can cause enough of a change that the car still needed completely tuned in order to feel like an OEM daily driver. And more of what i shoot for is an OEM feeling tune, i want the car to run nicely, not stumble, idle great and that way anyone can get in the car and drive it without having to do anything special or keep an eye on anything, they can just get in and drive.

 

[snooopy365]

oh sorry the 35-40°+ I wrote was at 3-4k like you cruise!

I`ll try your methode, sounds good to me.

btw. does anybody know a good reson to use a "performance" and a "fuelsave" timing map? many new cars hav settings like that and I can`t get the reson? isn`t a good tuned map, good at cruising and good at making power while flooring it at the same time??

 

[1bad92awd]

Well really that depends on your personal preferences. Most drivers use their cars as daily drivers or weekend cars. So for someone who wants to drive their car most of the time, fuel economy will be more important to them where as a strictly track driven car owner wont care about fuel economy. Another good way to sum that up is that the more you emphasize performance on your car (aggressive tune), the lower your fuel economy will be. However depending on the modifications, sometimes it wont matter. My old 99 GST which made 332fwhp on pump gas got approximatly the same fuel economy as my 96 TSI with the stock turbo. The key is to find the right tune for your driving.

 

[pneumo]

oh sorry the 35-40°+ I wrote was at 3-4k like you cruise!

I`ll try your methode, sounds good to me.

btw. does anybody know a good reson to use a "performance" and a "fuelsave" timing map? many new cars hav settings like that and I can`t get the reson? isn`t a good tuned map, good at cruising and good at making power while flooring it at the same time??

The only reason to use different maps is if you use different fuels, such as 91 octane vs E85 vs 116 octane etc. If you use the same fuel all the time, just tune the light load/ low rpm areas of the fuel and timing map for best fuel efficiency. Tune the max load/ high rpm maps for best power.

 

[snooopy365]

The only reason to use different maps is if you use different fuels, such as 91 octane vs E85 vs 116 octane etc. If you use the same fuel all the time, just tune the light load/ low rpm areas of the fuel and timing map for best fuel efficiency. Tune the max load/ high rpm maps for best power.

thanks, thats exactly what I wanted to know

 

[mikelv]

If you want better gas mileage, put your stock injectors in, and change your driving habits.
I drove my FWD which is over 400hp to the wheels....put in the stockers and drove easy.
Got 41 HW MPG.

I drove on 1 tank of gas from Columbia, SC to Hagerstown, MD which is on the Pennslyvaina border.

Other than that, stop reading into it. If you run bigger injectors, mess with timing, and all that jazz, it's like having a giant oxymoron. You can do it that way, but all the extra time spent to squeeze an extra drop out of her isn't worth it.

Gas prices are down, so don't bother wasting your money on that corn fuel junk. I've heard different about it, but my experiences with it sucked.

 

[dsm-onster]

My 1000cc injectors did not change my fuel economy. 14.7:1 a/f ratio is 14.7:1 a/f ratio no matter the injector size.

Don't mess with e85 if you don't want MUCH higher octane fuel and a MUCH cooler combustion chamber.

 

[mikelv]

My 1000cc injectors did not change my fuel economy. 14.7:1 a/f ratio is 14.7:1 a/f ratio no matter the injector size.

Don't mess with e85 if you don't want MUCH higher octane fuel and a MUCH cooler combustion chamber.

Yeah you would think so huh?

 

[dsm-onster]

Smaller turbo than yours (flows about 10lb/min less) with a heavier car than yours: e-85 30psi 11.1sec@131mph. One of hundreds of results. Not what you've 'heard different'

Something could have been wrong. But I doubt it was the fuel.

 

[turboglenn]

oh sorry the 35-40°+ I wrote was at 3-4k like you cruise!

I`ll try your methode, sounds good to me.

btw. does anybody know a good reson to use a "performance" and a "fuelsave" timing map? many new cars hav settings like that and I can`t get the reson? isn`t a good tuned map, good at cruising and good at making power while flooring it at the same time??

There's definitely a good reason as far as i'm concerned. I can do a tune on the highway that's so spot on as far as AFR's that the closed loop barely has to do anything and i get great MPG, but the mapping is fairly lean and not good for a motor to make good torque which is what you need for the daily light to light driving. When you floor it on the "highway map" in lower gears (1st and 2nd) and want it to kick out of closed loop and go, the car will be so lean that it won't have any power until you can properly load the car enough to get the ECU into the right cells to become rich enough to accelerate nicely.

BY having an economy map you could just get on the highway, flip the switch and get a really good MPG rating and then flip back as you get off the exit so that the car's not a slug in the city. This could probably be offset more in a smaller turbo scenario, and there's also ways to tune enough to get nearly the same results without 2 actual maps, but you need an ECU with a lot of programmable load points per RPM point. But there's lot of ECU's with nice resolution.

The way i get around this is to have the areas where i'm steady state cruising mapped out about perfectly on the stoich AFR, then near 0 vacum and under the first few psi i have the closed loop make up the difference between the target 14.7:1 and ~12.5:1 that i have mapped in the cells that the ECU resorts to when there's no closed loop active.

This works well when you gun it in a low gear and can't get enough load to spool the turbo you can at least be rich enough to have the most torque you can produce at the lower RPM's (1 - 3K rpm's)

But then when i'm cruising and hit these same spots at less than 27% TPS the ECU uses the closed loop to make it inject at 14.7:1 and save me gas.

 

[grantman10]

Smaller turbo than yours (flows about 10lb/min less) with a heavier car than yours: e-85 30psi 11.1sec@131mph. One of hundreds of results. Not what you've 'heard different'

Something could have been wrong. But I doubt it was the fuel.

Nice Own3d!

 

[Loewen21]

If you want better gas mileage, put your stock injectors in, and change your driving habits.
I drove my FWD which is over 400hp to the wheels....put in the stockers and drove easy.
Got 41 HW MPG.

I drove on 1 tank of gas from Columbia, SC to Hagerstown, MD which is on the Pennslyvaina border.

Other than that, stop reading into it. If you run bigger injectors, mess with timing, and all that jazz, it's like having a giant oxymoron. You can't have it both ways....power or enconmy.

Gas prices are down, so don't bother wasting your money on that corn fuel junk. I've heard different about it, but my experiences with it sucked.

This is probably the most common misconception about larger injectors, that they will decrease your fuel millage drastically no matter what. Truth is, its just like dsm-onster said. If you tune for a good fuel ratio and timing, you will achieve the same gas millage no matter the size of injectors. This myth most likely comes from SAFC systems and other basic tuning devices where you are not fully able to dial in the cruising fuel maps. With something link Link or AEM for example you should be able to achieve the same gas millage as with stockers.

 

[dsm-onster]

I am NOT trying to own or pwn or whatever any person here. I was trying to give some good evidence that may help everyone involed in the thread. If mikelv can get e-85 relatively easily, then this may help him get the most out of it.

 

[mikelv]

I am NOT trying to own or pwn or whatever any person here. I was trying to give some good evidence that may help everyone involed in the thread. If mikelv can get e-85 relatively easily, then this may help him get the most out of it.

Yeah, I hate to change the subject to me, or E-85 experiences.

I made a mistake of not reading much into this thread before posting, so I'm sorry to all for that.

After looking at this guy's profile, and some of the posts, it's pretty hard to understand why he wouldn't be getting great MPG anyway. He's not even running anything larger than a stock.

So I guess with that, if you're getting poor MPG, then check into some other options before racking your brain on some tuning. What sparked your concern for this? Were you not getting decent mileage in the first place?
Try looking into a new air filter, fuel filter, spark plugs, wire, ect... That might be some of the problem. Like I had mentioned earlier, I was getting over 40 MPG highway, and you're not going to get much better than that out of this motor.

As for me and the E-85, I had this conversation on the Link forums, and we were all contemplating that the tank I was getting E-85 from was filled with diesel fuel prior to. I had a great tune for cruising, but the fuel just smelt something awful when burned. Plus, I don't like the idea of adding nearly 25%more fuel under load.
I had pulled the head, and you couldn't imagine how much carbon build- up was on the pistons.
For me 110 is all I burn in the car (AWD) and it's easy to get around here. 4.35 a gallon is well worth it, plus I don't DD the car.

 

[snooopy365]

sorry, updated my profile today, it was WAY off...
running 850 Inj., Evo3 16G Turbo, Evo3 mainfold, custom downpipe, Rebuilded NT head, 255lph walbro...


I never said that my mpg ratio is sooo bad, just want to make it better!

Stock inj. and stock fuel im getting: 23-24mpg (everyday driving...on highway upto 30mph)

with just the inj. and some fuel adjustment in the ECU im getting 18 mpg (everyday driving! not cruising only.... have not tested highway)
with some adujstments (more timing, lambda 1.15) im getting 20mpg (everyday... have not tried highway yet)

E85 used 20-30% more fuel, so according to the mpg im doing good!

And yes. the car is maintance well, new plugs, oil, cables...
So why is my mpg rate so lousy? I`m not living in the US! That sounds stupid but traffic is way different here! Roads are windy and your doing way more braking and acc than you do on US Streets.

Why I`m using E85? because its clean, cheap, high octan and car is runnig great with it.

What I want to reach is a near to stock (as it is while using regular fuel) mpg while using E85.

 

[pneumo]

You said that you're using an eprom to tune. Which code base are you using? There has been a lot of work done to the e931 code. If this is what you're using I have some ideas for you.

 

[snooopy365]

Yes I`m using E931 code

 

[pneumo]

e931 is the code I use, too. Are you on the DSM-ecu list? Jeff O. posted some code called 'lean burn code' and I added some extra map lookups to alter the A/F ratio depending on airflow level. It's extensive and powerful if you're willing to put in the time to tune it. autos.groups.yahoo.com/group/dsm-ec...s.groups.yahoo.com/group/dsm-ecu/message/5497
and
Lean Burn Oversight
Yahoo! Groups

 

[turboglenn]

so you're trying to get near stock MPG on E85? Well, if you pull that off i'd love to see your fuel and timing tables, or hear about anything else you might have done to get it. I LOVE E85 and run it all summer, but on long trips the best i got out of a good tune on the highway was just under 20mpg, and i can get almost 30mpg on highway cruising with pump gas, so i keep a map programmed for pump when i'm on trips or can't get corn juice.

It sounds like you're doing ok to me...

 

[snooopy365]

I thought this code is kinda useless when you have set the A/F ratio to 1.15 controlled with a wideband o2?
and yes, I know the group, great stuff