td04 = horrible MPG's?

[DougFresh]

i thought i was getting HORRIBLE fuel mileage before the TD04 swap. after a month of having the TD04 on, my fuel mileage in town has averaged from 10-12mpg.

i have the fuel purge solenoid that i have to replace.. but i didnt think my lego would get this poor of fuel mileage.. Maybe my Catalytic converter is slightly plugged?

[macipusy]

Something is up. My fuel mileage increased every time I upped the size of the turbo....usually spent less time in boost and more in the 14.7:1 AFR range.

The vf11 is so small it would spool in reverse...always eating gas.

You need a way to tune the car, or at least monitor the AFR's. Could be running super rich all over, binge drinking octane.

[DougFresh]

I knew it! ugh. i knew that if i were to up the turbo that my efficiency would be better. like you said less time in boost.

time to check my spark plugs and see what is happening on the inside of the engine.

it sucks only getting 120~ miles per tank.

ill have to see if a friend has an AFR set up i could borrow.

[kimokalihi]

Lowest I've seen was 19 with tdo5 and I average 23. Highest was 26 or 27. You've got a big problem. My lowest in my toyota pickup 4x4 was probably 15.

[mike-tracy]

Yeah I'll echo what the others said. I am tuned for a td04 (stock JDM ecu) and putting in a td05 had the gas mileage dip from 25 down to 20, but I'm hoping to regain some of that with a robtune. For you to get half the mileage of mine doesn't make sense.

[DougFresh]

i am pretty sure its a few things; stock 19 year old cat, and a bad purge solenoid with a possible bad 02. but the 02 sensor doesn't pop up as faulty... just the purge solenoid. i posted on the good old facebook and my friends came through. I have about 3 different friends that all said i can use their LC1 or AEM uego. so that's pretty neat.

after a few weeks i might have it figured out. i have a downpipe to replace.

[kimokalihi]

Probably intake leak, bad o2 sensor, coolant sensor and knock sensor.

[cj91legss]

I lost a couple MPGs switching from a vf39 to a td04

[keithmoilanen]

Yeah i really need to have someone look at mine this summer i am only getting 14 mpg and i can tell its running supper rich from all the black smug on the back bumper. Sucks going to school during the year and summers traveling for work i really dont have much time to work on my car

[DougFresh]

ok, update time; I found 2 problem areas with my fuel problem. I installed a recirc bpv froma wrx and ran it atmospher style. Due to the WRX BPV being designed to run recirc it was meant to be partially open to run back to the intake to avoid compressor surge. I installed my friends Turbo XS RFL on and that cured my idle issue and gave me 4 mpg more in fuel economy.

the second issue was a coupler for my fmic was leaking, sinched that up and all is good. in town i now get 16mpg while hitting full boost (10psi) on the daily several times. if i keep it out of boost i think i can get 18-20 mpg.

i want to upgrade to a STi VF48 with larger injectors, walbro pump and fuel cut defender. then i would like to order a RRFPR to help with fueling. possibly get a piggy back unit to control the fuel map.

The one thing that scares me with going to a larger turbo now is my automatic, i think the auto clutch packs will not like the upgrade in power.

does anyone have experience with what the auto can handle for power? I have heard rumors that it can hold up to 300hp, not sure if thats crank or whp.

i have a 3" DP to install one of these days and i would like to install a new a/f sensor at the DP (or O2 sensor). I won a Electronic boost controller so i will install the electronic and my manual to run a hybrid boost controller set up.

well..... thats my update.. thanks everyone!

[James614]

Ive been running my auto for about 2 years now on a TD04 at 13psi on the stock tune, and have done many power brake launches, multiple drag passes, and monthly auto-x events spring through fall. Its definitely gotten 'tired', and the 2-3 shift is pretty sluggish to the point where I'm loosing at around .2 - .5 secs on the 1/4 mile waiting for it to shift. No slipping in gear, yet. But I'm sure it'll happen eventually. I'm sure the transgo shift kit would help a lot if you put it in before your clutches turn to pudding (increases line pressure/shift pressure, reducing slipping and clutches last longer).

[Alphius]

...fuel cut defender. then i would like to order a RRFPR to help with fueling. possibly get a piggy back unit to control the fuel map.

I know this isn't relevant to your question, but...
Don't do this! Your car will run poorly! It might be faster than it is now, but it will be nowhere near its capability and it will be poor to drive anywhere but full throttle and it will be at much more risk of catastrophic failure.

Best setup for cheap, reliable power on one of these cars (I post this whenever someone asks about power upgrades):
RobTuned EJ20G ECU
550cc STI injectors
JECS (green label plastic) MAF
VF39 or TD05-16g turbo
06-07 WRX intercooler w/recirc BPV
Boost Controller at 17psi
Free-flowing exhaust
Stock intake with de-snorkel and coffee cup mod

Done. This will make about 220-230 AWHP on a bone stock EJ22T safely. Any more than that and you are looking at standalone ECU and tossing the MAF.

As far as the transmission goes, if you get the TransGo shiftkit it should last a little longer, and if it is already in good shape it should last pretty well with that power level. Just don't abuse it. Same advice I would give for someone with a 5MT.

[cj91legss]

As far as the transmission goes, if you get the TransGo shiftkit it should last a little longer, and if it is already in good shape it should last pretty well with that power level. Just don't abuse it. Same advice I would give for someone with a 5MT.

Unless you're like me and like breaking 5mt SS transmissions

[Legacy777]

I know this isn't relevant to your question, but...
Don't do this! Your car will run poorly! It might be faster than it is now, but it will be nowhere near its capability and it will be poor to drive anywhere but full throttle and it will be at much more risk of catastrophic failure.

Best setup for cheap, reliable power on one of these cars (I post this whenever someone asks about power upgrades):
RobTuned EJ20G ECU
550cc STI injectors
JECS (green label plastic) MAF
VF39 or TD05-16g turbo
06-07 WRX intercooler w/recirc BPV
Boost Controller at 17psi
Free-flowing exhaust
Stock intake with de-snorkel and coffee cup mod

Done. This will make about 220-230 AWHP on a bone stock EJ22T safely. Any more than that and you are looking at standalone ECU and tossing the MAF.

As far as the transmission goes, if you get the TransGo shiftkit it should last a little longer, and if it is already in good shape it should last pretty well with that power level. Just don't abuse it. Same advice I would give for someone with a 5MT.

This is very good advice and really probably the best bang for your buck and easiest upgrade path.

[DougFresh]

ok, i am used to dealing with OBD2 on all of my other Subarus. This OBD1 game sucks. for longetivity isnt it better to purchase a standalone for the future? unless a RobTune can compensate for larger (then oem) turbo's and injectors?

[DougFresh]

As far as the transmission goes, if you get the TransGo shiftkit it should last a little longer, and if it is already in good shape it should last pretty well with that power level. Just don't abuse it. Same advice I would give for someone with a 5MT.

Unless you're like me and like breaking 5mt SS transmissions

I have shattered multiple 5 speeds. lmao. i feel your pain.

[Legacy777]

ok, i am used to dealing with OBD2 on all of my other Subarus. This OBD1 game sucks. for longetivity isnt it better to purchase a standalone for the future? unless a RobTune can compensate for larger (then oem) turbo's and injectors?

Going with a stand alone is a far LARGER investment in parts and continued tuning, not to mention time. I think Rob has some flexibility to "tune" for larger injectors and other MAF sensors, so if that's the case, you get the setup listed above, and if you decide to upgrade, send the ECU back to Rob and have it setup for the larger injectors and MAF sensor. Email Rob and see what he says and whether he can do that.

If you've got the money, time, and patience a stand alone can provide good results, but it's just A LOT more involved. Trust me, I know.

[Alphius]

A piggyback like you originally said is different than a standalone.

As far as I know, Rob hasn't been able to change the MAF scaling values so you are limited to the max air that the plastic MAF can flow, which you will exceed by going for more power than the setup that I listed above. That setup is pretty much as good as it gets while using a stock non-OBDII Subaru engine computer.

If you wanted maximum futureproofing, get a standalone ECU and have it tuned for your current setup, but that is a way more expensive proposition in both time and money as Josh said.

[DougFresh]

i understand a piggy back is different then a standalone.

I know that the standalone is very time consuming.

What sucks about this ECU is all the limitations, at times i want to install DOHC from a wrx or STi and then do a wiring harness merge to run opensource tuning on the newer ECU.

There is really no wrong way to do it.

I also would love to put the car in the garage, put it on jack stands and drop the drivetrain (minus the engine) and start buiding it the way i want. 6 speed would be the start. then pull my engine and this time rather then do just a overhaul do a complete build on the block. but. financially with my new child it just doesnt seem to be an option. ........yet.

[Alphius]

Wiring merge with newer turbo car wiring is a decent tuneable option. There's some engine hardware changes needed on that path as well.

I apologize for mistaking your level of understanding, usually when we get people in here asking about FCDs and piggybacks and stuff they are not as knowledgeable as you seem to be, so I take a bit of a hard line and explain things that some people already understand well.

[DougFresh]

No hard feelings. I completely understand where you are coming from buddy. Most people just ask due to not knowing what to search for.

maybe i didnt add enough information or didnt describe well enough.. i tend to do that

I just think a rob tune is a bandaid for temporary fix for power. because face it. with boost when you raise the boost level 4 psi you get them "feelings" of ...i want more. with the standalone you can cure that by retarding the timing and upping the boost while adjusting the injector latency. my comprehension on how everything works is great. my means of explaining what i know and how to do.. thats where i dont do to well.

from what i remember in the past/ a general rule of thumb is for every lb of boost you add you want to retard 1* of timing. but then you have CFM and injector #'s to match up. along with compression ratio. and with switching to DOHC vs SOHC you have a whole different ball park for compression. due to the combustion chamber size difference on the heads.

I have a set opf ACL bearting that i want to install on my 22t but they are not jet coated so i am unsure if i want to waste the time on installing the bearings.

last quick question. the rods and the pistons on the 22t are forged correct? MY(model year) = 94 legacy. if the rods and pistons are forged, i will upgrade piston rings and bearings with a quick cylinder hone, ARP head bolts and then i want to run a GT40 or larger, rotate my manifold and run dual walbro pumps. probably ID1000 injectors. That is where i am stuck between running a standalone or flipping the coin for STi valve train and wiring harness to mate with the stock legacy wiring harness to run speed density. but before i can do ANY of that i need a reputable transmission...

I know for the transmission i can run an STi 6 speed with an 05 RS auto drive shaft and also use my stock legacy rear diff. the stock legacy runs 3.90FD correct? until i can afford an R180 rear end.

[James614]

I wouldnt say the rob tune is a band-aid, its the equivelent of an Access Port or open source tune on the 02+ cars. The big difference being rob is the only one who has the resources and drive to do the old ecus, so there's no customization for individual setups.

If you're looking for ever-oncreasing gains, then everything short of the Max the engine will handle will seem like a bandaid until you get there :-p

[Legacy777]

Agreed, the Robtune, just doesn't allow you the infinite amount of flexibility a stand alone offers you. If that's what you want....then yes, definitely go with a stand alone. As I have found....sometimes that infinite amount of flexibility and tunability isn't all it's cracked up to be.

The rods are forged, the pistons are not. However I wouldn't suggest upgrading to forged pistons and keeping the stock rods. They work fine, but are far from what the aftermarket forged rods will be.

Yes, the stock turbo Legacy final drive ratio is 3.9.

[Alphius]

I agree fully with Josh.

[DougFresh]

I wouldnt say the rob tune is a band-aid, its the equivelent of an Access Port or open source tune on the 02+ cars. The big difference being rob is the only one who has the resources and drive to do the old ecus, so there's no customization for individual setups.

If you're looking for ever-oncreasing gains, then everything short of the Max the engine will handle will seem like a bandaid until you get there :-p

Touche sir. (i should have said band aid. i am not trying to say rob tunes are not good by any means. from what i have researched, he is the man for doing what he does.

i know i cant do what he does so i will give him a high five all day long.