The Silver Buick's well Silver Buick!

[milner351]

Re: The Silver Buick's well Silver Buick!

Ah the life of a gearhead bachelor.

Randal - superbuickman - able to swap cams and reprogram his EFI in a single bound!

[dieselgeek]

Re: The Silver Buick's well Silver Buick!

If you are having challenges with the baro settings, you should consider asking the developers about it. I'm not familiar with MS2 or MS3 baro/altitude correction "stuff" yet, but I know when I ran into troubles with t on MS1-Extra, the developers got me straightened out in a matter of 1 or 2 forum posts.

Are you running the Extra firmware on the Buick? using a mapdaddy upgrade from DIY?

[TheSilverBuick]

Re: The Silver Buick's well Silver Buick!

If you are having challenges with the baro settings, you should consider asking the developers about it. I'm not familiar with MS2 or MS3 baro/altitude correction "stuff" yet, but I know when I ran into troubles with t on MS1-Extra, the developers got me straightened out in a matter of 1 or 2 forum posts.

Are you running the Extra firmware on the Buick? using a mapdaddy upgrade from DIY?

Nah, no trouble in anything but spending the time at the Vegas elevation. I'm either at 6500' or at 900'. It's real simple to adjust, there is a graph table with a point showing where you are barometrically, then move the line up or down to richen or lean it out. Just have to adjust across the elevation. The last time I played with it I went from 100kpa atmospheric in CA to 76kpa at a summit just outside Ely in the same trip! It worked pretty good, I just tweaked it at some point for some unknown reason (put a bend in the correction that wasn't needed).

I'm currently just running the standard BG MSII 2.89xx firmware, but am looking at going to a MSII/extra firmware after thanksgiving.

[Tazracing]

Re: The Silver Buick's well Silver Buick!

why isn't the ecu making the corrections on it's own?
or do you have to write maps for every 500' change?

[dieselgeek]

Re: The Silver Buick's well Silver Buick!

why isn't the ecu making the corrections on it's own?

It is.

or do you have to write maps for every 500' change?

You don't. www.megamanual.com


Randal's using an upgraded setup that allows "more tune-able" baro corrections on-the-fly. Every engine responds differently, most EFI systems cheap out and make you use closed loop O2 corrections. The better systems can run without the O2 sensor feedback, and correct on their own. To do it this way, you have to tune for your combo. All it is, is a sliding scale. You tune your one VE map at one altitude, then you adjust the scale to bring the AFRs back in check when you are at different altitudes. Randal can probably post pics of the screens that make this clear.

The reason every engine is different, is because when you change the pressure altitude an engine is breathing in, not only do you change the oxygen content per volume of charge air: you are also changing the backpressure of the exhaust, which is a significant change in volumetric efficiency.

Randal is doing it the more challenging, but better, way IMO.

[TheSilverBuick]

Re: The Silver Buick's well Silver Buick!

Milner351 can pipe in as I showed him the screens in the tuning software.

But typically there are two ways to make corrections. One is using the O2 sensor corrections, so as it senses it's leaning out or richening up it'll make the corrections. When I first started tuning I had the O2 corrections turned off, which meant my tune HAD to be good because it wasn't going to correct it. Well that led to problems when I drove off the mountain I live on, as soon as I dropped 1000ft it'd be dead lean and start missing. That's when I figured out the barometric correction table (still leaving the O2 correction turned off), so as I came off the mountain and it leaned out, I'd adjust the graph for that elevation until it richened back up. Had to do that about every 1000ft drop or so in elevation. And guess what? It was a linear correction (which I later put a bend in....). After I had done that, I then turned the O2 correction on to further smooth out the tune, which by then was pretty close on it's own.

Now the recent issue with the tune was going from 3.70 gears to 3.08 gears was the load on the engine was greater across the rpm range so it put my fuel (and spark) curve into places I hadn't really tuned for. It wasn't a huge deal, but as I showed Milner351, I was now hitting the area of influence I had tuned into my fuel map for the MSD's 2-step rev limiter. Basically at 2500rpm and WOT I took a bunch of fuel out so I could lay the gas pedal to the floor at the start line and the engine sounded good (not flooded). Well now with the 3.08's it doesn't instantly shoot past 3,000rpm in all gears, so was hitting that spot on the map and created a flat spot in the power curve. Little stuff like that.

It's easy to just tell the O2 sensor to do all the work and keep a sloppy tune that runs pretty good, but it was a saving grace that I did it right when my LC-1 died back in August and didn't replace it until mid-October, and putting well over 2500 miles on the car in that time it was out.

Basically as long as I make one good tune for the local elevation here, a properly set barometric correction table will make sure it's correct at all elevations. As Scott says though, if I make changes to the exhaust system I may have to change my baro correction table.

[Tazracing]

Re: The Silver Buick's well Silver Buick!

is there a way to see the sofeware interface.. without having a ms to hook to..
like a tutorial interface to see how all the tools work

[dieselgeek]

Re: The Silver Buick's well Silver Buick!

is there a way to see the sofeware interface.. without having a ms to hook to..
like a tutorial interface to see how all the tools work

yes., but it's not a tutorial. just load the PC software and create a tune without burning it to an ECU.

http://www.diyautotune.com/softwarelinks.htm

[Tazracing]

Re: The Silver Buick's well Silver Buick!

thanks
I suck at search

[TheSilverBuick]

Re: The Silver Buick's well Silver Buick!

Go do DIYautotune.com and on their software page you can download MS TunerStudio (which I use). From there you can start various "made up" projects if you will picking different firmware versions that can be loaded into MegaSquirt. So you can see what the interface is like with the different firmware in the Megasquirt and options available in each (aside from reading the cheat sheet of options on the megamanual link). The software is free. There are a couple video's on the DIYautotune site that they have put together EFI'ing a Nova that show some of the hardware and software steps taken.

[milner351]

Re: The Silver Buick's well Silver Buick!

After seeing what the interface was like and riding around in Randal's car in Vegas - even with the tune off a bit, DIY EFI went from a some day thing for me, to a someday thing much sooner. I'm thinking the '54 after I get it running on the carb for a while. Don't want to start with that many unknowns at once - especially with a flat tappet cam.

It seems like the barometric correction is the best part of this deal for Randal - with his long drives and huge changes in elevation - tuning a carb for those transitions would be a royal pita.

However - even with the rough start ups cold (easily correctible) the 455 ran, well, "crisp" is the best word I can think to describe it - there was some excess fuel smell at idle if the wind was just right - but for the most part - it idled and ran without drama - no three footing it - no loading up at stop lights - and only one lean misfire when he tromped on it due to the correction mentioned above being non linear (another easy fix).

I'm not sure how the MAF vs Speed Density systems compare - I would think doing MAF would be easier, but I'm not sure,
either way - if Randal's car is any indication of a typical DIY EFI set up - after spending time in the car and seeing the software interface - I'm MORE tempted to do it than ever.

[Tazracing]

Re: The Silver Buick's well Silver Buick!

Go do DIYautotune.com and on their software page you can download MS TunerStudio (which I use). From there you can start various "made up" projects if you will picking different firmware versions that can be loaded into MegaSquirt. So you can see what the interface is like with the different firmware in the Megasquirt and options available in each (aside from reading the cheat sheet of options on the megamanual link). The software is free. There are a couple video's on the DIYautotune site that they have put together EFI'ing a Nova that show some of the hardware and software steps taken.

it list that "tuner studio as a beta.. is that the right one?

[TheSilverBuick]

Re: The Silver Buick's well Silver Buick!

That's the one. Been using it for a long time now. It updates from time to time.

[TheSilverBuick]

Re: The Silver Buick's well Silver Buick!

why isn't the ecu making the corrections on it's own?
or do you have to write maps for every 500' change?

Here is a snap shot of my baro correction table. Milner351 will notice I removed the bend :P Basically when the engine is on there is a yellow dot and a line going down to the x-axis showing the current barometric pressure. So when I turn it on, the yellow dot is typically around the 85kPa point, then as I drive off the mountain the dot starts sliding up the line, if it needs more fuel I raise one of the blue dots (or change the numbers on the right, but I prefer drag and drop), needs less, lower it, iirc. You can tell I was watching for the 5kPa intervals driving off the hill, and when I got to those atmospheric pressures I would cruise at a steady rpm with a steady known load (point on the VE table), and move the blue dot until the AFR's moved back to what I considered normal for that speed/load. Or you can do it safely by pulling over and adjusting the table so your idle AFR's are back to normal :P


Interestingly enough, the set limits of the software wouldn't let me set points below 80kPa, but since I was writing this and thinking about it, I openned up the mainController.ini and and found the baro correction limits and changed it to 60kPa so I can set a point at 75kPa or lower (since I have actually seen it). I had to do the same modification to run the MSD box on the dwell settings.

Simple right?

[milner351]

Re: The Silver Buick's well Silver Buick!

Looks familiar ;).

Interesting that the "non linear" correction - is actually linear!


How's it run after the cam swap? happy with the change? I'll be expecting a full MPG report after Thanksgiving weekend!
;D