Ive seen both tunercat. 7747 seems to have more features to change. however i have a harness that came with the 8746. which should i use for best results on a modified 350+ engine in that sort of car. if you were starting from scratch which ecm would you prefer to program chips for?

thanks.

 

Its kinda personal preference since there are editors and hac's for both.

The 7747 has been hac'ed for longer so any errors that may have been made are probably uncovered by now.

I personally would use the 7747 since there is a larger support base for it.

The 8746 does have Canister Purge, IAT and maybe some other things the 7747 doesn't so.......

 

canister purge is good for what.

i do like it having the iat. i think it helps the computer with the map sensor in figureing how much fuel to add.

 

I ran a 747 for years on a hot rodded 355, and the IAT made about 0 difference, in the winter I just set the distributor back a couple degrees.
When the 747 does the intial Baro Comp., it takes care of that. Only problem with a 747 is if it's in a heated garage, and you drive out into snowy weather it takes a brisk accleration to take a second baro calc and then it's OK.
On a Turbo or S/C engine the situation is completely different.
BTW, on the GNs they had an IAT and the IAT timing correction is 0'd out, where in the N/A 148 ecms they used it.

It would be neat if some one did an IAT patch for the 747, as I recall they both use the same printed circuit board, but the on board ROM messes things up.

 

The 8746 has everything you need. It's like the 7747 but with a few extra goodies. It's all up in the air, worth it, not, etc. If I had the choice I think I would keep the 8746 just because it's a lot of fun to edit your own definition file. With the hack (70+pages of it) you find things that you might want to have as a switch etc, it's like finding a secret.
If you need the hack file, let me know. Pablo dumped it all on me when he went to the 7747 ecm. I think I'm the only guy on thirdgen that's going through the hack and changing the tdf file! If somebody else is doing this please let me know. I think Lars92rs was but I haven't talked to him in a few months.

------------------
, Jon (350 TBI!)
91 Red My website

 

jon, i'll work with you. give me a few months and ill be right with you. i burnt 4 chips today. and i think i could do that every weekend or more. but then again. ive got the 92 down. messed with the spark curve mostly. did a litte bit of ve. and tc lockup. shut myself off at 65mph. um, thats not going to work for long. especially since ill get run over doin 70 in omaha on our interstate. and thats in the middle lane. we dont worry much about speedlimits on i80 cuz its like 6 lanes and there arent enough cars to fill em up

i just fiddled with stuff like idle etc. went from the hypertech i had and modified. they dont do jack, i cant beleive i spent so much $, then again it was like 4 years ago. who knew anything about doing it yourself that long ago.

anyway, car idles better now, and runs smoother. i think my timing was off a little before know its corrected. truth will come when i set it up at the dealership and check everything out. i want a realtime lcd blm reader on the dash. but that will have to wait, i still gotta get in touch with some people to see how much$.

anyway.. ill talk to you tomorow. i think im stickin with the 8746, just to be a pioneer, and because its what harness i have. the iat cant be there only for emissions sake, it must have some drivabilty advatage too.

incase i didnt say so. ya, i would like the hack. all 70 pages of it.

 

Send it to me too. Even tough I dont have any prom burning stuff I plan on getting it sometime.