I recently bought an '85 Z51 corvette with the 4+3 and a blown engine. I own an engine shop so of course I can't put a stock TPI 350 back in it. But I'm also on a budget, so some things like an LT1 intake are old news now, but I can't afford a completely new intake and runners.

I've been reading this DIY prom stuff on this forum for a week now trying to figure out where to begin with the tuning etc.

One thing for sure is that the 870 ECM in my car has got to go, so the 165 ECM seems to be the logical choice. I assume keep a MAF setup is best.

My question is what .BIN file and what mask is best suited for my application and my mods.

So here's a list of what I have and what I plan on doing:

383 ~ 9.5:1 CR mild cam daily driver / track day / road race.
Aluminum aftermarket heads, bigger valves etc. etc.
switch to LT1 intake, and in turn, lose the cold start injector.
Keep my 4+3 trans, what .BINs can control the O/D?
Remove AIR system and any other emissions stuff. (no emissions test for this car, since it is past 25 years old)
Add a WB02.
Would like to get decent mileage, A/C and drive-ability.

From what I see the $6e mask is the popular and has the most features for the 165 ECM, but there were never and 4+3 vettes with this mask. Can it be made to work? $32 and $32b have 4+3 .BINs, but what is the difference in the masks? which is better if any?

thanks in advance,
George

 

check this out: dynamicefi.com

read the datalogging capabilities, VE Learn as well as flash based. Note port mod option. You will need a donor GM ECM. It is speed density. MAF has a limitation in air flow I recall.

 

Idk anything about the 4+3's but its really preference with 32b vs 6e. I liked 6e and it works well. Use arap bin or aujl bin depending on type of heads. Timing table in arap is too aggressive for some heads like new afr's and vortec type heads. Aujl is stock 89 fbody L98 bin and i used that with good success on my 383 with afr heads. Old afr heads may like the arap. I know the 190 heads do.

32b has pulsewidth tables as well as maf tables to tune. 6e just has maf. Really no big deal just have to tune the pulsewidth tables with 32b. Just a slighty different way to tune it. Both will work.

 

Thanks for the info. I'm glad to hear that the differences between $32b and $6e are minimal. The more I read the more it looks like $32b will be what I have to use to get the overdrive to work without turning it complete manual control.

DynamicEFi has a bunch of neat stuff, but no mention of 4+3 stuff, plus the price puts a bid dent in my budget.

Is MAF really that restricted on airflow? I've seen other posts where people claim big HP numbers on MAF cars. I'm building a quick daily driver, nothing drastic.

 

The TCC logic can be dumbed down to control the 4+3 unit. I have been using a 7730 ecm for the better part of 4 years in my car and think its a lot better than the convoluted logic gm used in the 165 ecm. You could also use the TCC logic in the 165 ecm for controlling the 4+3. The TCC logic will allow you to force the od off for passing and you can use the console or shifter switch to shut the 4+3 down. I even eliminated the 1st gear switch to allow the 4+3 to go into overdrive in 1st.

 

Maf is limited in what fueling it can provide based on airflow its capable of reading. Its only able to read 255 grams/sec airflow which most mild heads cam intake motors are easily capable of seeing. Most will max out the maf fairly early. My 383 pegged the maf at 4000-4500 rpm when shift point rpm was 6600-6800. Lol the meter cant read the air to compensate fueling so you use Power Enrichment mode tables. PE vs rpm used to bring in fuel versus rpm to make up the difference. Real easy to use and works so you can run some decent power thru a maf, just descreen it for flow if your motor really needs it. Mine made 400 whp and worked well with descreened maf

 

Just about when I thought I understood something.... haha

So 255g/sec comes out to 413 CFM from a calculation done on another site. Does that sound right? Basically after that point the additional fuel needed is not calculated by airflow and just based off the enrichment table. Am I understanding that right?

884+3, would you mind sharing how you set-up the O/D in the 730 ECM? I'm not opposed to going to MAP, just haven't seen any success cases with the 4+3 O/D until now.

 

Yeah thats right. Reads and can somewhat control fuel to 255. Everything after that is thru enrichment vs rpm table. Just a percentage adder

 

I run EBL(dynamicefi) and I have a 4+3. The bin for a manual vs auto trans are always different. All .bins with EBL are EBL specific and address all those issues. Support from RBob is extremely good. EBL has a solid resale value IMO.