6G Celicas Forums

315cc injectors ( assuming ) that they are balenced and in good order. Are good for about 252hp. I like to side on caution and say that with age of
most fuel systems, pumps, thus you probably can support only about 214hp. You don't want to be operating at maximum injector cycle duties and
should have a buffer zone.

350cc is good for about 280hp. However, I ponder if the injector drivers are capable of supporting such large injectors. I expect very poor control.

With that said you need to understand how other aspects work, the factory 7AFE injectors aren't big by any means, they are something like 180cc.

Beyond that, The Apex-i SAFC or NEO etc, such systems are really only good for fuel corrections, not comparable to standalone management.

What these systems do is alter / modife the signal that is being sent to the ( factory engine-management. ) Where as something like a true piggy back like a e-manage or e-manage ultimate actually acts as a standalone.

It keeps the factory original ECU in a closed loop state, basically the ECU thinks everything is operating as normal. And the E-management and corrisponding sensors and so on are communicating. However, you still have to work within the factory limitations of the factory architecture.

I don't know how extensive you have built your 7AFE or 7AFTE as you call it. But, 10 psi is a tad ambitious with a Apex SAFC II. Sounds like you are using the old ( dump a lot of fuel and pray method. = ) You are better off with a smaller high response turbo and well balenced induction system using maybe 4.5~6psi tops. A well sorted low pressure, high response
system is superior to lots of lag and huge amounts of power.

One of the aspects of my job is that I not only design the hardware but the software as well for engine-management systems and ancilary devices.
Beyond this and amongest other terribly borning stuff, I have pretty much used every major competitive engine-management system on the market.

Good luck,
Mick

PS, It all depends on how extensive you want to get and how well refined.
Remember the fuel is only one aspect, induction systems are a multitude of parameters and beyond that
we haven't discussed the ignition system. ^_^

No need for bigger injectors when using a fmu. The fmu is meant to be used with stock injectors and it simply bumps the fuel pressure by a preset ratio for every psi of boost . So for example if you buy a 5:1 fmu and you have a base fuel pressure of about 40 psi, for every lb of boost your fuel pressure will go up by 5 psi .

0 psi boost = 40 + (0 x 5)= 40 psi fuel pressure
1 psi boost = 40 + (1 x 5)= 45 psi fuel pressure
5 psi boost = 40 + (5 x 5)= 65 psi fuel pressure
7 psi boost = 40 + (7 x 5)= 75 psi fuel pressure

Safc is a good cheap device if you on a budget but it has a really bad disadvantage. When you use bigger injectors and a safc to trim , everytime you take off fuel through the safc the ignition timing actually advances which is very bad. The more trimming you fuel injectors need the more you timing is advanced.

My suggestions if you cannot afford a proper standalone or proper piggyback (AEM FIC).

Option 1 : Fmu and better fuel pump on stock injectors.

Option 2 : 2 bar Toyota map sensor + fuel injectors approx 2x the size of your stock injectors and a good fuel pump.

you dont need an FMU with 350 injectors. the SAFC will do the job. i do suggest something a little more powerful though.

I think the SAFC will be just fine... I would recommend you do the "gray wire" / "boosted safc" modification if anything. It's much better overall than tuning by throttle position.

http://www.alltrac.net/mods/boostedSAFC.html

On mine I got a safc-II and a fmu 12:1. I'm still building it at the moment so no boost yet. But I've heard people say fmu is good for low boost but having ability to tune can help more