# going for mpg's



## rocklizzard91 (Dec 18, 2007)

finally got my 16v running well on MS-2 thanks to valvecovergasket (thanks again man!)

now i'd like to get it to have good gas mileage.

my setup is:
complete 9a w/ 9a trans
stock other than 2.25" exhuast
autotech sport cams
lw flywheel
lw cam and int shaft gears
bbm fuel rail
stock aba injectors
fuel lab adj fpr

all in my mk3
so i do realize it weighs more than most of the megasquirted cars on here since they seem to be mostly mk1-2 and it seems like you all get 30+ i dont really expect that (would be nice though!)
but i think i should be getting more than 20-22 mpg seeing how im mostly on the highway 

so my questions, what should i do to get max mpg?
what should i set the adjustable fuel pressure regulator to? i think i have it at 40-45 right now.
and how lean should i go?
i have it around 15-16 right now. its even gotten to the mid 17's before for a couple seconds. and all seemed well. the plugs do look lean when i cruise with it lean, cut the engine and stop to do a plug reading. a nice tanish whitish color. and they are dry.

the thing is i got bad mileage even when i had the stock aba in it 
ive never once gotten above 26mpg in the car :sly:

lastly, is it better to drive with the rpms lower with the WB saying its rich, or rev higher before shifting, allowing it to lean out and then shift?


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## ValveCoverGasket (Mar 20, 2002)

leave the fuel pressure stuff alone... changing it will require redoing more or less the entire map. 

should have no problems running up to around 17:1 if the load is low enough... id shoot for 15-16 


not sure i understand that last part... 
ideally youll want to run around at lower rpms with the lowest load possible, around 16 or so. 

im sure paul will have some things to add here as well  :beer:


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## rocklizzard91 (Dec 18, 2007)

ValveCoverGasket said:


> leave the fuel pressure stuff alone... changing it will require redoing more or less the entire map.
> 
> should have no problems running up to around 17:1 if the load is low enough... id shoot for 15-16
> 
> ...


 ok cool. i left it at 42psi on the fuel pressure reg. 

ive had it at 17 a few times tonight and it seemed fine. 
what happens if its too lean? it just doesnt run? or it starts bucking (like you mentioned?) 
i know under load itll detonate. but im unsure of what itll do under low load. 

the last part im asking, is it better to shift early even though the afrs will be more rich. so like shift at 2200rpm even though the whole way there ill be like 13afr 
or should i keep going and shift at 3k-3.5k where it iwll begin to lean out like its cruising. 

basically do i use less fuel in lower rpm even though the afr gauge says its rich 
or do i use more gas in higher rpm even though the afr says lean


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## Prof315 (Jan 5, 2009)

rocklizzard91 said:


> ok cool. i left it at 42psi on the fuel pressure reg.
> 
> ive had it at 17 a few times tonight and it seemed fine.
> what happens if its too lean? it just doesnt run? or it starts bucking (like you mentioned?)
> ...


 You'll surge and or buck a little if you go too lean at light throttle cruise. However to a point that can be cured with a little more timing at the load point where the problem is. 

My best friend is currently tuning on his 94 Civic DD with a DIYPnP and that motor can deal with 18 to 1 while cruising. However ~17 to 1 will likely be your max lean point. 

I'd go ahead and shift normally but the only place on your AFR table that needs to be 13 to 1 is at the very top of your load bins. In fact on N/A VW motors I rarely set AFR targets below 13.2 to 1. 13.2 to 13.5 seems to make the best power on all of the VWs I have dynoed. 

Another thing you can do to improve fuel economy is turn on and tune EAE. It's kind of a pain and definately time consuming but it will help your around town mileage a bunch and help on the highway as well.


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## rocklizzard91 (Dec 18, 2007)

Prof315 said:


> You'll surge and or buck a little if you go too lean at light throttle cruise. However to a point that can be cured with a little more timing at the load point where the problem is.
> 
> My best friend is currently tuning on his 94 Civic DD with a DIYPnP and that motor can deal with 18 to 1 while cruising. However ~17 to 1 will likely be your max lean point.
> 
> ...


 ive been up at 18 for a few seconds with no harm it SEEMS. before when i had ms-1 i had it up at 18 a few times too and all was fine. but im not sure if its safe so ill leave it at the 17:1 as suggested. 

oh really? so i shouldnt dip into the 12's? im pretty sure i do whenever i get on it. i can check tonight when i drive home. i just took a look at that EAE. looks a little complex, but i can play with it some after i read through a few more times. :thumbup:


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## need_a_VR6 (May 19, 1999)

NA motors I tune between 12.8-13.2:1 at WOT no richer. AE spikes I might let go a little richer, but try and tune that out if you can. I agree EAE can help here but is a lot of work. 

As you lean it out, as Jeff said, add timing. Don't be afraid of it, there's very little load. Into the 40s at mid rpm and low map is where you will likely end up. 

I've never been able to go leaner then about 17.5:1 on VW motors without getting surge that just can't be tuned out. 

I can squeak out 30mpg out of my Mk3 with a 4.24 final .755 5th and a 3.2L ... I'm sure you can get there with a 16v!


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## rocklizzard91 (Dec 18, 2007)

need_a_VR6 said:


> NA motors I tune between 12.8-13.2:1 at WOT no richer. AE spikes I might let go a little richer, but try and tune that out if you can. I agree EAE can help here but is a lot of work.
> 
> As you lean it out, as Jeff said, add timing. Don't be afraid of it, there's very little load. Into the 40s at mid rpm and low map is where you will likely end up.
> 
> ...


 alright, ill hook up the afr table and turn on the autotune on the drive home and try to work out the ve table so its not so rich at WOT 

ill see about leaning it out at cruise too. if you can get 30 with a vr6 i better be able to with a 4-cyl! 
i do have the 9a trans with the original gearing though. so that does set me back some i hear. 
i need a long 5th


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## ValveCoverGasket (Mar 20, 2002)

rocklizzard91 said:


> oh really? so i shouldnt dip into the 12's? im pretty sure i do whenever i get on it.


 i had the AE turned up pretty fat on that, theres probably some more tweaking you can do there but i would touch on the map first. like i mentioned the whole thing is probably a bit richer than it needs to be, but you shouldnt have to touch the full or 3/4s load stuff much to improve your highway mpg. 
another thing you can try to play with is the trigger threshold for the AE so that it doesnt trigger as often, but it really shouldnt be (and i doubt that it is) affecting your highway mileage.


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## rocklizzard91 (Dec 18, 2007)

ValveCoverGasket said:


> i had the AE turned up pretty fat on that, theres probably some more tweaking you can do there but i would touch on the map first. like i mentioned the whole thing is probably a bit richer than it needs to be, but you shouldnt have to touch the full or 3/4s load stuff much to improve your highway mpg.
> another thing you can try to play with is the trigger threshold for the AE so that it doesnt trigger as often, but it really shouldnt be (and i doubt that it is) affecting your highway mileage.


 oh ok i hadnt looked at all 
and like you said im going to play with the map first. 

AE as in accel enrichment correct? that actually might be it. i do have a lot of hills and if its map based (i think thats how you have it set) each time it gets to the hill load increaces and may trigger the accel enrichment. 
good call. ill check that out today too


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## ValveCoverGasket (Mar 20, 2002)

yeah AE = accel enrichment 
and im pretty sure its set to tps based


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## need_a_VR6 (May 19, 1999)

rocklizzard91 said:


> i do have the 9a trans with the original gearing though. so that does set me back some i hear.
> i need a long 5th


 My trans is WAY worse! I've even gotten up to 32 when I had the 3.94 and stock 5th. Your 020 should have a 3.67 and the same or close 5th ratio.


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## rocklizzard91 (Dec 18, 2007)

need_a_VR6 said:


> My trans is WAY worse! I've even gotten up to 32 when I had the 3.94 and stock 5th. Your 020 should have a 3.67 and the same or close 5th ratio.


 oh wow 
hopefully i can squeeze that out! i'd love 32! it'd be like when i had my old civic hatch! i was getting like 32-36  it was awesome!


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## wantacad (Apr 4, 2003)

Going to be putting together a trans with a 3.67 and .71 5th for my setup.


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## psychobandito (Sep 10, 2009)

the lightweight flywheel is a big part of it. when i installed the 8lber on my VR6, i dropped almost 50 miles to a tank. sport cams will also drop it, as you're moving your optimal powerband higher away from your cruising RPM.


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## rocklizzard91 (Dec 18, 2007)

psychobandito said:


> the lightweight flywheel is a big part of it. when i installed the 8lber on my VR6, i dropped almost 50 miles to a tank. sport cams will also drop it, as you're moving your optimal powerband higher away from your cruising RPM.


 really? interesting.


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## psychobandito (Sep 10, 2009)

flywheels store energy. they're a rotational mass, so they keep the engine spinning, when you lighten it, you remove a bunch of it's ability to store energy.


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## B4S (Apr 16, 2003)

wantacad said:


> Going to be putting together a trans with a 3.67 and .71 5th for my setup.


 I'm converting my new daily 94 Jetta ABA to a 4spd with a .71 4th, just for this, lol.


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## need_a_VR6 (May 19, 1999)

All my miles were with a 10lb flywheel and at least 262 cams... really big cams might help cruise mileage due to large overlap causing 'unintended egr.'


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## rocklizzard91 (Dec 18, 2007)

well on the way home yesterday i put in the afr tables to set crusing to 17 and then tapered down from there and hit autotune. im running around 16-17ish now for most of my cruising. i can already see an improvement! im at 1/4 tank left and im at 220miles 
ususally im at 1/8 tank left and 220 miles. 1/8 tank is 10gallons used. 
so 22mpg :/ 

i didnt start leaning out til late in this tank. but it LOOKS like it has helped out! 
i also lowered my idle down to 900-1000ish


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## ValveCoverGasket (Mar 20, 2002)

rocklizzard91 said:


> i also lowered my idle down to 900-1000ish


 an idle valve and a lower idle should improve your overall economy also :thumbup:


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## rocklizzard91 (Dec 18, 2007)

ValveCoverGasket said:


> an idle valve and a lower idle should improve your overall economy also :thumbup:


 yeah i found a plug for the idle valve you gave me (thanks a lot!) 
just gotta figure out how to wire it up and how to route hoses. the idle valve has big ass hoses...none on my manifold are very big  

i do have the mk3 aba purge valve. its currently just an on off valve via PWM settings. 
100% duty cycle (open) 
to give a high idle (1100ish) until 160* then it shuts off and im back down to 900-1000 

seems to be working decently 
i had to give it more timing to not dip at idle though. it was at 10* and now its at 15* 
that ok? 
vacuum is unchanged so i THINK its ok


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## Prof315 (Jan 5, 2009)

yeah 15* at idle will be ok and you could always use the idle advance feature so as not to mess with your main advance table.


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## rocklizzard91 (Dec 18, 2007)

Prof315 said:


> yeah 15* at idle will be ok and you could always use the idle advance feature so as not to mess with your main advance table.


 sweet 
ill look into the idle advance. does it just switch over to its set idle adnaces when it thinks its idling? 
how will it mess with my map otherwise? doesnt it only sit there while its idling anyway


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## Prof315 (Jan 5, 2009)

rocklizzard91 said:


> sweet
> ill look into the idle advance. does it just switch over to its set idle adnaces when it thinks its idling?
> how will it mess with my map otherwise? doesnt it only sit there while its idling anyway


 Basically yes the idle advance activates only during preset conditions (usually no tps and below a specific rpm... you set the parameters) 

Well the car might idle best at 15* for example but off idle it might like only 10 or 12 as the car starts rolling. By using idle avance you can retain a smooth advance curve for driving but use whatever is best for your idle. 

I've monitored factory stuff on the scan tool and a lot of Fords and Toyotas idle with 20*+ advance but only run 5 or 6* immediately off idle.


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## rocklizzard91 (Dec 18, 2007)

ah! i see! makes sense. so i can add as much advance as i need at idle to run well? 
even if its more than 15? 

and if thats the case ill have to datalog and see how it likes going from 15* back to 10 right off idle and then back up.


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## Prof315 (Jan 5, 2009)

rocklizzard91 said:


> ah! i see! makes sense. so i can add as much advance as i need at idle to run well?
> even if its more than 15?
> 
> and if thats the case ill have to datalog and see how it likes going from 15* back to 10 right off idle and then back up.


 Exactly!


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## rocklizzard91 (Dec 18, 2007)

awesome! 
thanks! 

this whole megasquirt experience gets better and better! 

i may send out the old ms-1 ecu i spoke of before to get looked at/fixed. then possibly upgrade it to ms-2 and see about making it run my second car after i learn some more with this one :thumbup:


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## ValveCoverGasket (Mar 20, 2002)

rocklizzard91 said:


> this whole megasquirt experience gets better and better!


 its easy to get hooked


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## rocklizzard91 (Dec 18, 2007)

ValveCoverGasket said:


> its easy to get hooked


 haha i can tell! 
i feel so cool doing it even though im just playing with the simple stull like the ve table. 
my frineds all think its cool my laptop controls the car  

i have a really cool idea im hoping to put into action here in the next couple weeks. im building the first prototype this weekend. we'll see how it goes from there  
i think you guys will appreciate it


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## need_a_VR6 (May 19, 1999)

Interesting that you're running the purge valve... you can always hook up an egr valve as well if you want to shoot for even more mpg... that'll make more difference then the purge. I usually just delete those and let everything vent through the canister.


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## Prof315 (Jan 5, 2009)

need_a_VR6 said:


> Interesting that you're running the purge valve... you can always hook up an egr valve as well if you want to shoot for even more mpg... that'll make more difference then the purge. I usually just delete those and let everything vent through the canister.


 I actually plan on reinstalling my evap system. I probably lose over 1/2 a gallon of fuel per tank because I'm venting to the atmosphere. Just need to find an OBD2 MK3 canister....(its the one that mounts to the right inner fender) as I have turbo plumbing going through the hole that the stock one mounts in.


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## Prof315 (Jan 5, 2009)

rocklizzard91 said:


> awesome!
> thanks!
> 
> this whole megasquirt experience gets better and better!
> ...


 It does get addicting!


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## rocklizzard91 (Dec 18, 2007)

need_a_VR6 said:


> Interesting that you're running the purge valve... you can always hook up an egr valve as well if you want to shoot for even more mpg... that'll make more difference then the purge. I usually just delete those and let everything vent through the canister.


 im running the purge as an idle valve. just on the end of a vac line and the other side it open to suck in atmosphere air. i guess i could run it to the old lines (which are just venting right now) 
i dont even have the canister anymore. i think i threw it away  

my car never had an egr. on the car so idk how they work or what they do. 



Prof315 said:


> I actually plan on reinstalling my evap system. I probably lose over 1/2 a gallon of fuel per tank because I'm venting to the atmosphere. Just need to find an OBD2 MK3 canister....(its the one that mounts to the right inner fender) as I have turbo plumbing going through the hole that the stock one mounts in.


 really? how come deleting the evap makes you lose gas?  
i HAD an obd2 canister. like i said i think i threw it away


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## need_a_VR6 (May 19, 1999)

Prof315 said:


> I actually plan on reinstalling my evap system. I probably lose over 1/2 a gallon of fuel per tank because I'm venting to the atmosphere.


 You need to move somewhere colder  If you just run the canister and plug the vent hole that normally runs to the valve, it's nowhere near that much.


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## rocklizzard91 (Dec 18, 2007)

need_a_VR6 said:


> You need to move somewhere colder  If you just run the canister and plug the vent hole that normally runs to the valve, it's nowhere near that much.


 ineed to do that then  

it has one line in and one out right? 
run the line in and then plug the line out?


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## Prof315 (Jan 5, 2009)

need_a_VR6 said:


> You need to move somewhere colder  If you just run the canister and plug the vent hole that normally runs to the valve, it's nowhere near that much.


 Yeah and what was your high temp for the day? 81*F here!  

I'd rather recycle the vapors. Might get me another mpg or so.


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## rocklizzard91 (Dec 18, 2007)

im starting to get weird connectivity issues. 
ever since i added the tach/launch control 

itll connect and then randomly lose the connection to the laptop. i have to unplug it, wait, plug it in and cycle online and offline in TS 

sometimes i even have to restart TS 

anyway to figure out if its a TS or ECU issue?


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## ValveCoverGasket (Mar 20, 2002)

does it show up in logs as a reset or a crash?


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## rocklizzard91 (Dec 18, 2007)

ValveCoverGasket said:


> does it show up in logs as a reset or a crash?


 ill have to check. how will i know? 
ill do a log in the morning to see


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## ValveCoverGasket (Mar 20, 2002)

if you take a log, logviewer will tag each reset event... thatll probably help narrow it down


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## rocklizzard91 (Dec 18, 2007)

ValveCoverGasket said:


> if you take a log, logviewer will tag each reset event... thatll probably help narrow it down


 sweet, thanks! ill let ya know after i drive to work and see what it says


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## need_a_VR6 (May 19, 1999)

Prof315 said:


> Yeah and what was your high temp for the day? 81*F here!
> 
> I'd rather recycle the vapors. Might get me another mpg or so.


 55 maybe felt pretty nice to me! My people come from a small, cool, rainy island so I'm partial to mild weather.  

I just run the tank hose into the canister, plug the hole that would go to the motor and then leave the bottom vent open as per normal. That'll let it vent through the carbon canister (like when the car is sitting) and help it keep from evaporating quite as quickly.


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## rocklizzard91 (Dec 18, 2007)

ValveCoverGasket said:


> if you take a log, logviewer will tag each reset event... thatll probably help narrow it down


 got a log 
when i looked at it, the log just ends. 
i can email it to you if you want. 
idk what im looking at really. i can see all the variables and everything. but im nto sure what to look for in the signal for dropped connection or restarts


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## rocklizzard91 (Dec 18, 2007)

rocklizzard91 said:


> got a log
> when i looked at it, the log just ends.
> i can email it to you if you want.
> idk what im looking at really. i can see all the variables and everything. but im nto sure what to look for in the signal for dropped connection or restarts


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## ValveCoverGasket (Mar 20, 2002)

email it over :thumbup:


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## rocklizzard91 (Dec 18, 2007)

sent! thanks man


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## ValveCoverGasket (Mar 20, 2002)

replied 
i have a hunch its something local to your laptop, as you were using a usb adapter if i remember right


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## rocklizzard91 (Dec 18, 2007)

ValveCoverGasket said:


> replied
> i have a hunch its something local to your laptop, as you were using a usb adapter if i remember right


 yes its a usb adapter 
i cant play with settings on it at all. the rate is set at 9600 which may be it. 
but the fact it DID work for extended periods before and now doesnt is weird  
ill try another one if i can find the driver disc for it


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