I know we have just been here but I am still cornfused, please bear with me.

I spent quite a bit of time today searching the GMECM archives about this & did not come up with anything remotely solid (hence question #1 about archives).

It appears that John Gwynne (sorry if I killed your name), tried the 747 into 730 switch for a blown V8. however, he had problems with it that involved the TCC & the Boost regulator (cant recall the name of it).

in one of his posts he said that he had modified the anht code to accept the 2 bar map but the only purpose that it served was to be another bit in the ALDL data stream & that it did not do anything to control timing or IOT. I don't understand this @ all. why would he go through the pain & hassle if it did not do that? there has to be another reason, or I missed something.

it appears from Grumpys posts on the topic that he does not think that this is the best way to skin this cat. if not what do you think is a better way? I have looked through Ludis site & the diy site & on the www.diy-efi/gmecm/faq/ecm_selection.html page it lists the different ECM's & which ones have hac's & so on. it appears that there is

the 749 for the 4 cyl turbo MAP,(sunbird I think)
the 749 for the 6 cyl turbo MAF & MAP (GN/TType & Sy/Ty respectively)
The 749 for the 8 cyl turbo MAP (what the heck is this, this is what I want!!!!)

is the last one a boo boo?


I guess the question that no one has really answered is, has anyone stuck the Sy/Ty code into the 730? does it work, or are there obstacles to big to overcome? if that is the case is there a clean way to do this or are the two alternatives, buy a FelPro setup or use a FMU?

I would REALLY like to hear from Bruce & John if only a short note. thank you guys!!


Bob Wooten
r71chevy@earthlink.net
www.r71camaro.homestead.com


------------------
Bob Wooten
r71chevy@earthlink.net
www.r71camaro.homestead.com

 

Hi. You might want to check out DIY_EFI-1999.txt, page 621 (in word). It´s in incoming. -CGL

 

thank you. I am checking it out right now.

BW

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Bob Wooten
r71chevy@earthlink.net
www.r71camaro.homestead.com

 

Bob, I don't want to sound critical, but why not just get a 1227749 and skip all the hassle of running the 7730 w/$58 code? IIRC you can change the cylinder select to support an 8cyl.

If you go to http://car-part.com/ and search for SY/TY ECM's there are a bunch listed all over the USA for $35-150. Try searching 1991 Syclone.

 

this is actually a very good question. In short I made an asumption. It was that this was probably the best/easiest way to go to a turbo setup from a NA 350 TPI. there have been a couple of them done & I assumed that this is the way to go. I checked into the ECM & the prom & the applications & this seemed to be rather simple.

the question that really needs to be answered is how do the pin outs compare. I just got a copy of the Turbo sunbird harness (hoping that it is the same as the sy/ty) & am going to compare it to my 91 Camaro harness & see if they are pinned out the same w/the few noted exceptions (wastegate etc). if they are the same then it seems to be obvious that it would better/simpler to get a 749 if not then we come back to the original question, what is the best/simplest way to go from NA 350 to Blown 350.

BW


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Bob Wooten
71 Camaro, 91 EFI, 01 HP
r71chevy@earthlink.net
www.r71camaro.homestead.com

 

two things, what is IIRC? also i went & searched for the ECM & did not find one. i found a bunch for the 2.8 but not the sy/ty/turbo sunbird. the apps for this ECM are:
1987-90 2.0 OHC L4 PFI turbo “M” LT3
1987-88 2.3 DOHC L4 PFI “D” LD2
1991-93 truck 4.3 V6 PFI turbo “Z” LB4at

no biggie, i will go there later if need be.

thanks
BW

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Bob Wooten
71 Camaro, 91 EFI, 01 HP
r71chevy@earthlink.net
www.r71camaro.homestead.com

 

If I Remember Correctly

I found 749's at the site mentioned using:

1991
Chevy Syclone
Engine Computer
All States

Perhaps I'm wrong about the ease of running a blown V8 with the 749. I don't know how to set the hardware cylinder select and I'm sure it has to equal the software setting.

Anyhow, good luck with your project.

 

Went to the local pick a part today....and woohoo!!! Scored a 749 Turbo Sunbird ECM, wastegatem, map sensor, and spare ECM connectors. This should take care of the TCC and Wastegate problems the 730 has. Now to order the SyTy memcal..Stay tuned! Bob Ward

------------------
79 Chevy Malibu Cpe
305 TPI/700-R4,
Custom Turbocharged,
ported upper and lower intake,
214,224 duration .450I .465E lift
730ECM,SyTy software,custom eprom,
Website:
www.turbotpi.homestead.com/SATURN5.html

[This message has been edited by SATURN5 (edited March 31, 2001).]

 

Bob,

I dont think that all that is needed (if you dont want). I just downloaded the prints for the Sy/Ty ecm & compared them to the one for my 730. the TCC in the Sy/Ty is the Converter Divert solenoid output (Pin F4) & the Waste gate is the Port Solenoid (Pin F2). I am not using either of them on my car, but the wires are haning there @ the front of the motor. there are a few other pin outs that change but they appear to be small differences.

have you fired it up yet? if so have you tried to talk with the ECM on the ALDL yet? i think that you are going to find that it does not work (unless the Memcal changes it somehow, but i dont think that it does).

You did totaly score on the parts .

BW



------------------
Bob Wooten
71 Camaro, 91 EFI, 01 HP
r71chevy@earthlink.net
www.r71camaro.homestead.com