Tuning/Piggyback Questions
 

I have several questions I want to try to get sorted out. If the answers already exist, which I'm sure some do, please feel free to redirect me as I know how aggravating it can be to constantly repeat the same answer over and over. (But please don't think I'm just asking to keep from having to find them on my own, I have looked, I've just gotten mixed results. I thought if I asked here I might could get a definite answer.)

First of all, my current setup: I've got a 1989 Turbo R-154 with a full 3" exhaust from the turbo back, stock ct26, 2.5" ic pipes, and open air filter. Eventually I would like to upgrade my turbo, probably to the 57 trim, but I'm still considering options so opinions and advice are welcome on this topic too.

1. My first question is regarding the ever so famous lex+550 injector upgrade. I know in order to use the lexus AFM, the injectors have to be upgraded, pretty sure that dead horse has definitely been beaten. But if I upgrade to the 550 injectors and get a fuel controller, is the lexus AFM still necessary? Would a fuel controller be able to adjust the AFR enough to keep it from running too rich all the time?

2. Also, if I do upgrade my injectors, do I also have to upgrade my fuel pump and get a FPR? I've heard that the stock fuel pump is sufficient for the 550's, but I'd like to be sure.

3. I want to get a good piggyback to make sure everything is tuned properly. So far from what I've researched, I like the safc neo. However, I also want an electronic boost controller. I know the Maft Pro is capable of doing both, but I don't really want to convert to S/D. Furthermore, I'm not very experienced with tuning and I don't want to bite off more than I can chew and therefore I'm definitely not ready for a standalone. Is there another piggyback that I can use to tune my car that also has a built in boost controller? Like I said, I'd like to keep the KVAFM. Or, if there isn't a good option for a unit that can do both, can anybody recommend a good electronic boost controller that I can use in addition to the safc neo? I've read about scramble boost and turbo time out features and they both interest me, but aren't necessarily deal breakers either way.

4. With a fuel controller (or a boost controller) will I still hit fuel cut?

5. With a fuel controller (or a boost controller) will I be able to use an actual BOV instead of the stock BPV without the stalling issue between shifts? I'm not really after this upgrade in particular, but if my stock BPV ever craps out in the future I want to know what other BOV options I could consider.

6. While we're on the topic, are there any advantages a BOV has over a BPV besides the cute little whistle? What about vice versa?

1) If you upgrade the injectors and add a good fuel controller then no, you don't need the Lexus AFM. If the fuel controller is limited then it may make things easier to add the Lexus AFM as the fuel controller is only responsible for 1/2 of the adjustments then... I hope that makes sense.

2) A HEALTHY fuel pump and a HEALTHY FPR can support 550s with no problem. If they're original I wouldn't trust them.

3) Speed/Density is a great and very flexible system but getting it all dialed in can be tough even for a seasoned tuner. The MAFT Pro in general is a tough system to learn on and if you're a complete novice I'd recommend starting with something else unless your Supra is a project/weekend car. I love the MAFT Pro for it's flexibility and expansive feature set and you don't have to convert to S/D if you don't want to. Installed and configured as a basic fuel controller the system becomes much easier to handle... but alas, you can't use the boost control functionality without S/D.

With all of that covered... I have no problem with the Apex'i Neo. It's a strong and stable piece of hardware and has a lot of support in almost every car community.

4) You'll still hit fuel cut unless you supply more fuel per cycle (see: larger injectors or higher fuel pressure). Installing 550's will raise the level at which you see fuel cut.

5) You can't use a BOV with the stock air flow metering system. You'll need to convert to S/D (or a very creative use of another type of airflow meter system) to do this.... Well, that's not entirely true... With a good fuel controller which allows for tuning tip in and out you can tweak things to compensate, I still think there's a performance hit though and for me performance is more important than a toot from the engine bay.

6) There is no benefit to a BOV. I've heard it argued that BPVs may provide a slight increase in performance coming out of a shift and right back in on the throttle. An adjustable BOV or BPV could both be setup to provide that extra response though