Using multiple maps?
 

Hey all... I'm getting a supra soon and i just have a question concerning the ecu as I am trying to plan ahead. I had an sti but I didn't get far enough into it before I gave it up to get familiar with this stuff. I remember talking to people about standalone ecu's, piggyback chips, and plug n play programmers. Basically when I get a supra I want to be able to use multiple maps so that I can have a range of hp that I can use either towards fuel economy or with the flip of a switch I can take down vettes ect. Of course I plan on doing this after I've modded the engine, how what I go about doing this and what piece of electronic equipment would I need. Thx

Most of all the standalones out there will allow u to save multiple maps on the laptop used for tuning. But then need hooked up to the ECM to be reflashed with tune of your choice. I am not familiar with any that u can change tunes with a push of a button all though they might be out there.

Gosh...where to start. Here goes:
1) A fuel efficient vehicle can also be a high horsepower vehicle. There are several reasons for this, not the least of which is that your cruising rpm range and load is a very different part of your fuel/timing map than the high load, high rpm (and subsequently high boost) part of your fuel/timing map.
2) The Mkiv's ecu can't be 'chipped' or reprogrammed. There is an expensive procedure to add a 'daughter board' to allow the oem maps to be replaced, but most folks go straight from piggybacks to standalone ecu replacement.
2) A standalone ecu replacement is very pricey. It's at least $2500 for everything you need (including sensors), and then that much again for a *proper* tuning job. The oem Mkiv TT ecu (with piggybacks) will take you to 700rwhp (6spd) and beyond. To me, spending the coin for a standalone is only necessary above 800rwhp...
3) Piggyback ecu's (eg. an A'PEXi AFC Neo) can allow you to create a quickly-changed fuel map for a lot less $$$ than a standalone ecu.
4) The use of race fuel together with high boost is a legitimate reason to keep a secondary map handy. A secondary map is not necessary for fuel economy vs. horsepower if both would be on pump gas.

Above all (relative to your situation):
- Be sure to get an Mkiv TT (not an n/a)
- Read through the basic BPU modifications. These will get you significantly more horsepower than stock, with a minimal expense.
http://www.mkiv.com/faq/faqtt.html#bpu1
Consider mastering this level before moving on to anything fancy like multiple maps.

Please read through these points, and post any followup questions you might have.

It would be great if I actually knew how a piggyback or a stand alone ecu works... I understand what they do but I don't understand how they do. Does a stand alone completely replace the stock ecu and does a piggyback plug into the stock ecu? Also is a piggyback programmable or does it just come with a base map?

They're not popular among the MKIV crowd for some reason, but the MAFT Pro is compatible and has two maps for fuel, boost and ignition... and yes, you can wire in a switch to change it on the fly.

Yes, standalone EMS = An all in one engine management system.... technically the stock system is a standalone as no functions are passed on to external devices for processing. A piggyback is a device which attaches to your EMS and serves to alter or reinterpret data.

oh man that is way cool... thanks for the clarification. What you described as not popular for MKIV owners I would agree except now days you have fuel economy to worry about as fuel cost almost $4 a gallon. Also this might seem extreme but my idea is to put an extra fuel tank in... like a 5 gallon or so to keep down on weight and be able to pull up to a stop light next to oh say a new Z06... purge the fuel line switch maps and burn rubber!

That sounds like a way-cool system. Please keep us informed with your build.