2 bar tune for Turbo LT1 F-body possible with '93 ECM? DA3

[Skinny Pedal]

Not hard. Just remember to scale everything.

[hotrodf1]

Cool I think I’ll get a 2 bar map and try to set everything up NA to prove to myself I can do it!

[Skinny Pedal]

Awesome!!! If you need any help just ask.

[hotrodf1]

I do have one question to start with. Since the VE tables only go to 100, I need to rescale by some factor, correct? The motor wanted more fuel even in NA trim, so I recall that I bumped the cylinder volume up about 10% or so, and then scaled all the VE tables down by 10%, thus gaining headroom for more fuel.

Is this the right way to go on a turbo motor as well? So then I'd bump the cylinder volume up by say 40% or so, then decrease the VE tables by 40%? Or is there a better way? I know you could use injector flow too. ??

I'm running Open loop, so I use the % change fuel vs. MAP sensor table which has worked out well in NA trim - I could use that to dial up the fuel too I guess, since the kPa range will affect that table. Any thoughts there?

[hotrodf1]

I have another question too, I read that I need to disable the barometric refresh / sensing or something of that nature when I go to the 2 bar sensor. I have noticed the ECU has a separate reading for barometric pressure and MAP, but perhaps it's coming from the same sensor?

i'm not sure I've got that capability to turn off in TunerPro RT. I don't see anything like that in the variables that I have to play with. So if I can't do something with that, am I screwed trying to get to a 2 bar tune with the stock ECU on $DA3?

[Skinny Pedal]

Map and baro come from the MAP.

Is your fuel pressure reg boost referenced? This will have a huge effect on VE table in boost. Scaling the VE for a 2 bar is not hard to start. Copy your 100 kpa to 50 kpa..... and so on. Leave 55 and up flat from the 100 column and bump it if you like, that depends on regulator.

[hotrodf1]

1 bar vs 2 bar MAP.jpg

Map and baro come from the MAP.

Is your fuel pressure reg boost referenced? This will have a huge effect on VE table in boost. Scaling the VE for a 2 bar is not hard to start. Copy your 100 kpa to 50 kpa..... and so on. Leave 55 and up flat from the 100 column and bump it if you like, that depends on regulator.

Yes, the FPR is the stock unit, and will be boost referenced, I believe, 1:1. I run in open loop, so I can use the open loop % fuel adder vs. MAP signal to add fuel "across the board" in addition to the VE tables. I have a wideband so tuning in boost area should be OK, just gotta sneak up on it.

I think I have the scaling figured out for the most part. Made a chart that tells the old vs . new MAP reading. It isn't actually 1:2 ratio which is interesting. But like you said 55 (2 bar) ends up being 100 (1 bar). 40 (1 bar) is 70 (2 bar). Attached a pic that shows my conversion table.

The thing that's the biggest question for me: what does the ECM do with the baro reading when you turn the key on? If it used to be 100 or so with the 1 bar sensor, now it's going to be 55 ish kPa with the 2 bar sensor. What's that going to do to the tune? Do I just need to find another table to scale somehow so that the computer still calculates the same results for fueling or what?

I don't have $EE so I don't have quite the same parameters list as that. The $DA3 isn't as well researched and pulled apart I think.