For all you with the SMT6

[ryan_george]

I've been doing a bit of research into the smt6 unit, and have a few questions.

1) The smt6 basically just changes the incoming afm/maf and crank position sensor signals, to make the ecu think that it is operating under different conditions, right? So if I want it to run richer, I would tell the ecu (via the smt6) that we are putting more load (more air) on the engine. But, the ecu can check the 02 sensor, and realize that we are now running too rich, and reduce fuel flow.... right? So do we force the 02 to run in open-loop, so that the ecu doesn't know we are fooling it?
Please clarify if you can. If any of the above info is wrong, let me know so I can try to have a better understanding.

2) Can the home mechanic succesfully program this unit? Or would I need access to a chassis dyno?

3) Is it worth my money? Time isn't a real issue, as I'll be doing this mostly for the experience and the fun of it.


I've already read "Bosch Fuel Injection & Engine Management", and some other threads here about it.

Thanks for any input, but don't tell me to .

[Screaming_bmwe30]

man....get megasquirt....much more tunable...i think cheaper, even with the extra sensors....and it's STANDALONE. You can't beat standalone with a piggy back....usually. Megasquirt install writeup below

http://www.jdturbocharging.com/14801.html

[ryan_george]

man....get megasquirt....much more tunable...i think cheaper, even with the extra sensors....and it's STANDALONE. You can't beat standalone with a piggy back....usually. Megasquirt install writeup below

http://www.jdturbocharging.com/14801.html

That shit looks like a lot of work. I think I should just start off with a piggy-back.

[turboe30]

I have an SMT6 for sale. PM an offer.

[ryan_george]

C'mon. There should be some more of you out there with some valuable input. :idea:

[turboe30]

The ECU ignores the O2 at wide open throttle anyways.

It is worth it to have any kind of engine management system because the stock motronic really sucks for getting the most out of your mods.

Tuning the timing is a huge advantage... especially if you live in Canada and have access to 94 octane fuel at the pump.

A dyno would be best for tuning... unless you have a wideband. MegaSquirt is easier to tune I find, but then again I have a wide band for it.

The SMT6 will let you swap to a MAF sensor and remove the AFM as well. I would say that the MegaSquirt is a better system, but the SMT6 works too without much work into setting it up.

As I said, I have one for sale... make me an offer.

[mspiegle]

if you haven't messed with engine management stuff too much, the SMT6 is a great starter unit. You'll learn a bunch and get a chance to play around and not screw things up too much (since the motronic still provides you with a base for tuning. Just reset your SMT6 maps if you mess things up too much).

With that in mind, turboe30 is right in that the O2 gets ignored for WOT which is where your SMT6 mods will matter. Aside from that, the O2 circuit is only allowed to compensate for so much, the primary data comes from the MAF.

If you're ever planning to go forced induction or anything that would require bigger injectors, you can always use the SMT6 to lower the MAF voltage across the range to allow the use of larger injectors without the setbacks (like rich idle).

If you're expecting to get a certain amount of power from this unit because it costs $250-300, don't get it. It won't give you more power than a JC chip unless you go nuts with ignition mods because you have access to high-octane. If you're gonna spend the money... do it because you want to learn, you want to be different, you want to do a MAF conversion, or you want the ability to tune.