ECU Hardware Differences

[zin]

I'm just wondering if anyone out there can shed some light on this question: Are the turbo SBECs basically the same, as in just a calibration change allowing a T1, to work on a TII or TIII car? I seem to recall that the turbo computers had an extra driver to work the waste gate sol, and the V6 cars had extra drivers for the extra 2 injectors, but were otherwise the same. I'm hoping that a more common ECU can be configured to work with the TIII. This is both to facilitate tweaking of the Spirit, and allow an easier hybrid conversion (no dizzy). Any info would be helpful.

Mike

[Frank]

Read these three articles that Russ helped us out with....

http://www.turbo-mopar.com/forums/vb...e&articleid=24
http://www.turbo-mopar.com/forums/vb...e&articleid=25
http://www.turbo-mopar.com/forums/vb...e&articleid=26

[ShelGame]

If you're speaking just about SBEC's, then there was no TII, only TI, III, and IV (VNT). "Real" TII was only '87 LM and '88/89 SMEC.

The main hardware on each SBEC is essentially the same. But, there are detail differences that make them non-interchangeable.

The TI and IV use the same codebase. The code has provisions for both T1 and VNT boost control. A single bit switches the boost control. But, the TIV computers had an extra driver for the 2nd VNT solenoid. Apparently, some T1 comuters also got this driver making some of the T1 computers interchangeable. But, with the drivers all covered by large heatsinks, it would be hard to tell at a glance if the driver was present or not. All TIV computers can be converted to T1 with just a chip (the extra VNT driver simply doesn't get used).

The TIII had other differences. Again, because the main hardware is the same, much of the hardware-related code is the same or very similar to the T1/IV. But, the TIII has an extra coil driver that the T1/IV never got. Making the TIII computer unique.

[zin]

Thanks for the detailed explanation, though its not what I wanted to hear! Any ideas as to how to make a non-TIII computer work? If it's an extra driver, as in something to shoulder a load, maybe an external addition could do the trick? If it's a separate channel, maybe not... Not too many people have a good knowledge of the inner workings of these things (certainly not me), so the info is much appreciated.

[Turbodave]

Would a 3.3 computer have the extra coil and injector drivers needed to run a TIII? They are distributorless. I'm guessing they have no driver for boost control, but what if a manual boost control was used?

[ShelGame]

Thanks for the detailed explanation, though its not what I wanted to hear! Any ideas as to how to make a non-TIII computer work? If it's an extra driver, as in something to shoulder a load, maybe an external addition could do the trick? If it's a separate channel, maybe not... Not too many people have a good knowledge of the inner workings of these things (certainly not me), so the info is much appreciated.

Probably, since (I think) the boards are the same. But, it would really be too much work to be worth it; unless you figure out a solvent that removes the potting without destroying everything else. I've tried to get at the drivers, it's really tough.

[ShelGame]

Would a 3.3 computer have the extra coil and injector drivers needed to run a TIII? They are distributorless. I'm guessing they have no driver for boost control, but what if a manual boost control was used?

I don't know about the 3.3 computers. But, if it's like the 3.0, then it doesn't have enough fuel drivers (the 3.0 only has 3, they run in pairs just like the 4cylinder SMEC's).

[zin]

I don't know about the 3.3 computers. But, if it's like the 3.0, then it doesn't have enough fuel drivers (the 3.0 only has 3, they run in pairs just like the 4cylinder SMEC's).

Curious as to why the "extra" driver would be a problem? Would the code be able to just ignore the superfluous components? If they are driven in pairs, it begs the question as to how the SBECs are supposed to be sequential if they fire injectors in pairs? Isn't that batch fire?

[ShelGame]

The 4 cylinder SBEC cars are sequential (there are 4 injector drivers in the 4-cylinder SBEC's). The 3.0 SBEC only has 3 drivers and therefore must fire them batch-style.

The SMEC (88-89) only had 2 injector drivers for the 4-cyl cars and did fire them batch-style.

[gvare001]

But, the TIII has an extra coil driver that the T1/IV never got. Making the TIII computer unique.

Doesn't the 1991 TI computer have that coil driver that the 1990 TIV doesn't have?

[zin]

The 4 cylinder SBEC cars are sequential (there are 4 injector drivers in the 4-cylinder SBEC's). The 3.0 SBEC only has 3 drivers and therefore must fire them batch-style.

The SMEC (88-89) only had 2 injector drivers for the 4-cyl cars and did fire them batch-style.

Ah Ha! Batch for the 6, sequential for the 4s! I'm guessing since the TIII code is so much different than the TI code, we couldn't really mix and match the code to allow a batch fire SBEC, could we? If you can't tell, I'm really worried about not having computers to play with! As an aside, if something like this were possible, building a hybrid 16V wouldn't be as difficult.

[TopDollar69]

I wonder how many drivers the 88-89 3.0L van SMECs have?

[ShelGame]

I wonder how many drivers the 88-89 3.0L van SMECs have?

3, they added one (there's space on the board). They also had to add 2 control wires from the logic board to the power board internally because there weren't enough pins on the 14-way. Other than that, the V6 SMEC is the same as a turbo SMEC...

[johnl]

Great thread.