Which is the better choice?

[Bigfwd69]

Been looking into all the efi tuneing crap out there and seems to me that they all claim to do the same things, but the differences in pricing is boggeling my mind. With the F.A.S.T. systems, AFM PMS unit, and the tweecer. Basically wondering, if anyone has experiences with these, and what they thought of them. Then theres the old school DFI systems from 5 years ago floating around that can be pickd up pretty cheap too. Wondering what the pro's and cons over each system was. Looking at getting one very soon, as I need to take controll of my ghetto stock a9l.

[White90GT]

Talk to Ben about the Tweecer. He's a tuner and sales rep for Tweecer. He's running it on his high 9 sec convertible and tunes another 9 second convertible as well. Sounds like it has almost as much if not as much tunability as any of the more expensive systems out there for about 1/2 the cost.
www.saleenv8.com
Saleen91 on here.

[Chad82GT]

I had a TwEECer in my 94 and it worked fine. It is just as capable as a custom “chip” if you know how to use it… and that is where the TwEECer’s main fault comes up. Support is sketchy at best with a "blind leading the blind" approach from a mailing list and message forum. The designer tries to answer questions as best he can, but even he doesn’t have the knowledge of a professional tuner who has been at it for years. For someone who is new to tuning it’s not the best route unless you have a local resource that has lots of time to teach you what each parameter controls, or can program it for you... but then you might as well but a chip and save several hundred bucks. TwEECers are also limited by the stock computer’s performance. Maybe Ben or Fred can speak more towards what those limits are, but my understanding a stock ECM has a hard time controlling the more radical the combinations where precise injector pulse-widths become crucial.

Currently I’m leaning towards a BigStuff3 (www.bigstuff3.com) setup if/when I decide to upgrade from the antiquated system currently on my car. It was created by the same guy(s) who originally came up with DFI and FAST, and can do everything those systems can and a bit more. A new BS3 is priced less than what you see used FAST systems selling for online, so that’s a bonus too.

[Saleen91]

Here's my $.02 ( and Carl, my biz site is www.v8mustang.com, personal site is saleen.v8mustang.com ;) ). This list goes from the cheapest to the most expensive. About $300 - $2500 (retail & new).

Custom Chips: Great for cars running probably low 10's. You pay somebody else for their knowledge to tune your car. Set it and forget it. The problem is when you change your combo. I.e. want to run more boost, or a dual power adder, or race gas, or new/better components (heads, cam, intake, power adder)...basically anything that can drastically change your combo. When that happens your tune becomes outdated and should be/could be improved up with your new components. This applies to ALL custom chips. I don't care whose hardware/software you go with (Diablo, SCT, old Autologic, etc).

TwEECer - The custom chip for the DIY'er. Great for cars running 83# injectors and lower. Anything past that and you've reached the limit as far as what the stock EEC can do. After all, it was only originally designed for a car running 19# injectors that has to pass emissions and get decent gas mileage with 200RWHP and less. Of course this applies to a custom chip and a PMS as well since they're all using the same EEC. The learning curve is steep, but if you aren't afraid to experiment, and READ, you have all of the capabilites that ANY custom chip tuner can offer with optional datalogging. Datalogging is the big bonus here, but just remember you can only datalog things that the factory EEC can read. There are a few tricks for optional things like datalogging a wideband o2 or boost, but for the most part if the factory EEC doesn't know about it you can't datalog it.

PMS - A custom chip with a dumbed down interface. I'd say these are good to low to mid 9 second cars. Great support, it's been around a long time. But the granularity of the custom chip/TwEECer aren't there. I.e. things like cranking fuel pulsewidth for large injectors, electronic fan parameters, base spark vs borderline spark, dashpot decrements, etc just aren't in it. The pluses are that for WOT performance it's got everything you need, plus add ons for datalogging, using low impedance injectors, logging boost, etc.

Stand alone EFI...I.E. BS3, FAST, DFI, AEM, etc.. You have to have these if you're going to run 150/160# injectors! Don't even bother trying to do this with a stock EEC and ANY tuner attached to it (chip, tweecer, pms, etc) These are great products... no doubt about it. You pay high dollars for them and you get what you pay for. Feedback loops that can use a wideband o2 to dynamically control your fuel trims based upon a pre-programmed A/F ratio at specific RPM's/Load's is a GOD send for race cars! They can save your motor from a fuel pump that is on it's way out and tell you about it afterwards! The draw backs are cost, and the fact that you have to write your tune from SCRATCH! All of the previous methods rely on using your stock EEC's tune as a starting point. If you can afford it, and can get a baseline tune that will atleast let your car start, you can use ANY of these standalone systems.

IMO, there's a niche for each one of these products. There's no point installing FAST/BS3/DFI on a 13 second car and there's no chance of getting an low 8 second ride to have great street manners with a chip. It's all of matter of getting the right match for your combination...just like everything else in this hobby. A mis-matched intake for a motor can make the rest of the combo be slow and lazy, where a matched intake can make it scream.