Hi. New to the forums. Please feel free to flame me or redirect me if i've posted this in the wrong area but since i'm trying to understand the tC for a turbo application i thought this would be appropriate. I used the search button but didn't find much that was helpful. Anyways i'm trying to understand the ECU on the tC. I used to build Mustangs and understand tuning very well. This is my first tC and was intended to be my grocery getter and run around town car but it's too much fun and true to being a tuner i couldn't leave well enough alone. I'm going for a turbo kit soon and need to know how much boost can i run before i need to 'tune' the ecu. How far can the stock ecu compensate? In a lot of other cars tuning is a must for forced induction. There arent any hand held units to my knowledge for do you just take it to a shop that tunes tCs? Thanks for the help

 

Well if your a tuner, Get out your logging device, log timing.

You will notice what kind of timing our cars run oem.

Then you should look into the stock injector size, and relise what HP you can make on them.

Unless you ment tune like.

 

FWIW, the 07+ ECU can trim fuel +/- 25%. The oe injectors are 320cc and only good for ~200BHP at stock FP. The ECU uses a sensitive knock sensor to detect detonation and retard timing.

I'm running the stock ECU, 440cc injectors, Split Second Enricher (closed loop fuel enrichment), a T3/T04E 50 trim pushing 6 psi thru a small SMIC and the car runs great. My max LTFT is -18.8%, CL AFR is 14.7:1 in vacuum, 12.3:1 in boost (w. enricher) and 11.5:1 in open loop. I've been running like this for over 10,000 miles (w/o the enricher) and 2000 miles (w. enricher). No CELs and IMO this setup works very well. It also worked well at 7psi but I was seeing 95% IDC on the 440s so I backed it down to 6psi. I believe I am very close to the limits of the stock ECU without having a permanent CEL or worse. YMMV.

If you want more power than this, you'll need bigger injectors and additional management. The AEM FIC works well for many, the Greddy E-Manage Ultimate is also popular and arguably better and there are several other options from Unichip, et al.

Hope this helps.

 

I just learned alot from that and Ive been on the site for a while lol - Thanks - What do you put down on the dyno with that setup? I ran that exact same setup for a while with a front mount on my tC - Ran the stock injectors for a while at 5psi then to 7psi with the 440's

 

I'm hoping to get it on a dyno very soon but until I do I can only guess 200-225whp (AT). How did yours run w/o a piggy? I'm surprised the oe injectors could handle even 5psi.

BTW, I should have clarified that the ECU can actually trim up to 45% fuel between LT and ST but it doesn't work very well outside the +/- 25% LTFT range. I've also learned how sensitive MAF sensors are to the slightest changes in pipe diameter, mounting depth, turbulence, etc. and how important it is to maintain the oem MAS signal slope. I used to think that a 10% smaller tube would result in a fairly linear ~10% higher MAF signal but it doesn't appear to work that way. I had numerous tune issues with a 66 mm MAF tube that disappeared with a better designed 72 mm tube (oe XB2 is 72 mm).

 

with the mustang pcm you can run from stock 260hp to almost watever, run huge injectors, have a built motor, forced induction, nitrous feed it on the factory computer just keep tuning and adding files. the scion ecu isnt as tunable as the mustang pcm, learned that from my friends turbo tC. he has an aem piggy back which i also suggest. i dont know if its cuz of memory, processor or just capability. i dont think theres a hand held programmer for the tC so you'll have to hit up the dyno

 

The tC ECU has not been cracked and so you cant reflash it. The only way to tune then is either with a piggyback, like the AEM FIC or Greddy Emanage, or with a standalone ECU.

You can try and trick the stock computer to deal with boost but it is not recommended.

 

Mike where did you find that picture hes my idol!!! I want my supra to have a 350small block too!

 

Thanks for all your help guys. Yeah with the Mustangs every little part i put on or took off i could just pull out my tuner, hop on the dyno, and write a new code. So for a straight forward turbo setup i could just get a piggyback unit? Sounds like thats the easiest way to go. I just know a lot of piggyback units aren't as 'intelligent' as you might like.

 

The car ran amazing - Just like OEM - I dont know how well it ran in terms of AFR with the OEM injectors but it pulled hard. I beat my buddy in his 311whp Cobalt with a Hahn turbo kit time after time and I know I wasnt making NEARLY that amout of power. I beat him by car lengths. GTO 6.0L I pulled close but couldnt beat it...but only lost by maybe a single car length at most. My car is gutted and has some smaller upgrades...But I loved it would do it again for sure. I just bought some 700cc injectors from "TRD07" but havent received them yet after almost 3 weeks (giving him the benefit of the doubt he has been nice to me so far) and am converting to return system, 12 psi and e85. I cant imagine 12 psi i had so much fun with 6

 

It's great to hear some objective feedback from someone else who has actually ran boost on the stock ECU instead of the usual subjective speculation. I have a dyno appt tomorrow and I'll post the results so all can see how good or bad this setup works.

I haven't done any street racing but I do have a lot of fun zipping past left-lane squatting morons on the highway 5 days a week. They tend to make it even more fun when they try in vain to close the door on me. Why do they do that? Anyway, I hope to get some 1/4 mile passes in soon and post the slips.

I hope you get those injectors soon and wish you luck with the new build. Hopefully you won't be visited by piggyhack electronic gremlins like I was.

 

i did 4.5-5 psi on stock injectors with a ebay to4e.. afr was ......drum roll...............16+ at wot(scary)

so no stock injectors aint good enough lol

 

BTW I do use a blow-thru setup.

 

My setup is also blow thru! Im at 8 psi with a small 16g TRD tune and 410cc. I also have a Fuel return with FPR and a walbro 255. The car feels just like stock except when you hit boost it really pulls. Gonna get it tuned in 2 weeks for 12 psi!

 

FWIW, I was seeing 95% IDC with 440cc at 11.5:1 AFR and 7 psi on a T3/T04E. You might run out of fuel before 12 psi so be careful.

 

Thanks but I think I will be ok I have a FPR and a return system. Or do you think I should still get bigger injectors?

 

You might be okay by raising the FP but I don't know for sure. Hopefully someone else here knows better.

 

raising fuel pressure is fine up to a point. optimum is 85% duty cycle on injectors, 40-45psi and around 9 on air-fuel ratio.

i think you guys are fine with a returnless fuel system til you start touching 450hp but doing a return shouldnt be too difficult.

but to complete the turbo system upgrade the fuel pump 255lph should be more than enough, 550cc injectors heard some people running a lil lean with 440cc, adjustable fuel pressure regulator,