I've been reading as much as I can find on each ECM, the accompanying system it uses, and the pros and cons of each.

I'm buying a 85 IROC w/ the 870 MAF system. The engine is a 350 with some mods. I plan on making sure everything is tuned before I jump in to the PROM game. I've read all the FAQ's and I think I have a pretty good grip on what's goin' on... just want to make sure I'm on the right page.

I understand the SBC, and for the most part the TPI systems. My questions directly involve individual experience and ACTUAL data.

I plan on acquiring Tunercat, the ZIF adapter from Craig Motes, the UV eraser and the Pocket Programmer. I also plan on using on of the adapted cables to read the ALDL output on my laptop.

But before I do that, I haven't decided which system I want to convert to. I know the '870 has to go. Everything I've researched tells me trying to burn PROMS on the '870 is NOT the hard part. It's actually being able to get ENOUGH usable data to tune from, since the baud output of the older ECM is so much slower than the '165 or the '730.


I understand that the MAF system is alot more forgiving when it comes to engine mods than the MAP driven Speed Density system, but common sense tells me that like anything else, when something is made to work OK with alot of different variables, performance suffers over a system DESIGNED and compensated to each change in the engine itself. I understand the '730 may be more time-consuming when it comes to tuning and each mod makes a difference in the end result.

I don't mind doing research, I don't mind tuning the car to get it JUST right. That's what this all about right? But I'm thinking that I should be able to get the best overall performance out of the EXISTING engine and components, BEFORE I start making more modifications. The SD system seems to me alot more like a Q-Jet setup... it's very sensitive to vacuum , and estimating the resulting airflow from that.....am I off here?

That being said........ since I've chucking the '870 regardless, it seems to make more since to go ahead and convert to the '730 SD system. Frying one MAF sensor would make a '165 conversion the worse economical choice in either case.

MY main concerns regard keeping the existing '870 harness in use. Would it be more time consuming to change to a SD harness? Is it worth the extra effort? I would like to keep the '870 harness intact, but if it's driving 20 miles to save a $1, i'd rather just bite the bullet and swap the harness.

I know that the MAF sensor is eliminated, as well as the MAF style knock sensor and the ESC module. A MAP sensor is added, as well as a MAP style knock sensor ( NO ESC used ) the knock sensor communicated directly to the ECM......correct?

Can I realistically get the car running DECENT after a MAP conversion, decent enough to drive while I start tweaking that PROM myself?

Is that where VEmaster comes into play?


If these are stupid questions, I apologize. Just trying to get my homework done before I start pulling things apart.......



Thanks
Chris

 

here's what I have said on the subject.

https://www.thirdgen.org/techbb2/sho...hreadid=124659


With the '870 harness the cleanest install would be with the '730. You would bassically move the all the wires from their current connector to the right spot on the 730 connectors. And you would use 3 of 5 MAF wires for the MAP sensor. The other two wires you could use as firewall pass-thru wires for extra gages or other things- kinda convenient. that is if for the wiring. I would definately keep the 870 harness because the connectors on the harness are different than the SD ones.

Getting it running really good is easy with VEmaster, so I would use that at first to get it going ncely and then fine tune targeted areas manually.

I have found that tuning on the 730 is nicer because you can target specific conditions. I drove my car for a week on a stock AXXD 305 chip with just injector constant, fan temp, and cylinder volume changes. There were some flat spots under certain accelerating conditions (I scanned it to verify that it wasn't dangerously bad) but it was definately driveable, and no worse than when my '870 computer would act up or when my old 305 would burn oil.