Got the 2 bar GM maf in and rescaled a bunch of tables in the pcm. Installed it in the car (had to dremel out a keyway, otherwise plug and play) - everything seems to work fine. Occasionally it sets a low map code but that doesn't seem to present any real problems (I just need to get that code deleted) - other than that everything was fine.

Put about 100 miles on it - city, highway, etc. Car is in closed loop and l-trims didn't change appreciably, drivability was fine despite the reduction in resolution, WOT (still NA) feels the same, and gas mileage is right in the range in normally is.

The barometric reading is ~50kPa as expected, but as long as I am in MAF mode it doesn't seem to be a problem (since no density measurements are needed there). Were I running in SD or were this a 93 then something would have to be done for that.

All in all it looks good - so no reason one can't handle all boost related timing in the pcm. I wouldn't want to do a 3 bar as I think the timing resolution would be to small then - but with a 2 bar I am comfortable with it.

Supercharger is just waiting on the intercooler from Jordon, so when that gets in I will test it out under boost - but it's 0-5v just like the stocker, so no reason at all for it not to work.

Chris

 

Wow, sounds promising. What all tables did you have to go and redo?

Let us know how it works once the blower is on...should be interesting

 

I rescaled the:

Open Loop Temp vs. Load
BLM Control
DFCO
Load Vs. Advance - 400-4000 and over 4000
Max Retard - MAP.

Still need to do 2 of the VE tables - as long as the MAF is working they don't matter, but if it dies I would like to be able to limp home. No boost tuning in those though since it won't take values over 100 I believe (another reason why this wouldn't work for a SD setup without other trickery like rescaling the ve and injector by .5 or something like that so 50% VE actually = 100, etc.)



Chris

 

I've got a 2 bar sensor working in my car too


Its a speed density 93, It did take some trickery cause you need values like 120% in VE

I've also got a wideband inputted in my computer so i can datalog it.

that improves the quality of life when tuning it DRASTICLY !

 

Yeah, is definitely a bigger pain on a SD car - did you end up doing anything specific to account for the new air density measurements also? I would imaging you could scale the injector constant to compensate for that, as well as tweaking it to give you more headroom in the VE table (e.g. if you /2 the inj constant then you can rescale the VE table so 50% = 100% VE, 100%=200%, etc.) - sounds like it requires a bunch of trial and error though!

What input did you use for the wideband output? I tried the AC pressure input but the sampling rate wasn't very fast on that - could use the stock o2's, but since i run closed loop didn't want to mess with that.


Chris

 

How would you use the stock O2's for an input? I would love to use one of my rear O2's as an input on my OBD2 car, but I think the computer outputs some voltage...like 500mv. And then the sensor modifies it in some way and the computer reads it from 0-1000mv. Dunno how you would go about hooking up the 0-5v output of a DIY wideband.

 

I have an innovative wideband and it has a user programmable output - you can define the voltage range and the a/f range that corresponds to that - so I just need to find a voltage input that samples fast enough.

Rear o2's would work great, but I am obd-I(converted) - so I don't think it samples rear o2's (been so long since it was anywhere near stock I don't remember though ).

Chris