Did a search, and could not come up with anything. Just curious on how you guys learned how to tune your FAST systems. Trial and error can be deadly.

 

go get it tuned the first time and ask a bunch of questons and pay close atention. load the program on your computer and go thru everything a million times so you know what it is before you get to the dyno. read as much as you can. then be smart and cafefully make minor adjustments and check them against the wide band, the egt's, what th plugs look like etc etc. if it looks good, continue.

the hardest part is probably not tuning for wot, but the part throttle drivability and the decel tables etc.

best of luck to you!
Lee

 

To a degree it's trial and error, but you need to look at it as getting it close and tweaking it to perfection. While I havn't tuned with FAST I have tuned with Megasquirt-II and the ideas carry over. In fact I strongly reccomend looking at the tuning guide for their systems.
The first thing you do is configure the ECM for your engine hardware. On the MS-II units this constitutes setting up the triggers, injector size/impedance, pulse width etc. etc. Based on the hardware in the system, or educated guesses on it. After this one sets the fuel tables and spark tables up. The fuel table can be figured *roughly* based on the peak hp/tq numbers and RPMs (MS-II has a built in ap to generate this table) however timing is another issue. Due to the variance in heads out there, it would probably be best to find someone with a similar configuration and ask what their max total advance is, and when they have it in by then average your table out based on this. After this you put in numbers for cold enrichment, and idle air controller numbers. Should be fairly ready to crank now. After it starts, let the afterstart enrichment (usually a few hundred ignition cycles after the engine starts) kick off, and adjust the IAC counts until you're at the desired idle speed. When there, you can start tweaking the temperature based enrichment, but provided it's not crazy rich I'd just leave it until the next step is done.
Be aware that pre-ignition is a bad thing, and can easily grenade a motor. Going too lean can cause pre-ignition, as can running excessive timing. Tuning an N/A motor should leave more room for error then if you've got the boost cranked, just something to keep in mind. When N/A you want to keep an AFR of around 16:1 when at idle or cruise, ~14.7:1 when in the mid range, and under heavy acceleration you want to have ~13.5:1. Besides an O2 sensor, a Dyno or G-tech should be helpful at this point. Keep in mind you're not trying to stab the throttle but hold it at a steady state and get the AFRs at a certain RPM/load squared away. Past this, the next thing is acceleration enrichment. Once again, this is a spot where a dyno or G-tech can help you out. The enrichment can be added one of two ways on the MS-II units, by the MAP reading's change or the TPS changing. I'd start out rich and lean out until you stop increasing in power and then richen it back up a bit. The last part of the fueling is the cold start enrichment. Your engine has to be dead cold for this, so leave it over night and go out on a frosty morning. Crank the engine over, and then adjust for optimal idle at the temperature range, then as it warms up adjust each proceeding temperature range. I would just like to say that this is my very limited experience tuning with my ECM, and that there's a lot to it. I still have a lot to learn, but I'm getting there slowly. Do your home work, start off with something that's not crazy and you should be able to do it. Hell, I put my MS-II on my daily driver.

 

I thought that I would have to start off with a base tune, and the good thing is, the car already has a good tune in it. I know the basic areas you want the car operating in, and every car is different on where it likes to be. There are just so many adjustments that can be made, its just going to take some time. Thanks for the advice for tuning the fuel.