89stroker

whoa, mine says 78.......i guess 7700 feet will do that.

colorado sucks when it comes to making engines run right.....

kevm14

But you have reduced pumping losses through the exhaust, which helps.

89stroker

the main thing is that on a good day i have 15% less oxygen to burn than the sea level guys, so performance is hindered quite a bit.

DM91RS

Bob..........could you elaborate on how this change to enable async would help to be able to run smaller injectors.

Also if you don't mind I am confused about setting the N/V tables.

DM

RBob

iTrader: (1)

The high RPM/load async mode has a set injection repetition rate. The injectors are fired every 12.5 msec. Sync mode fires the injectors relative to engine RPM. And at 6,000 RPM it is every 5 msec.

In the normal sync mode as the RPM increases the injectors fire more often. This reduces the available open time. Usually duty cycle is used, but it isn't the full picture. Instead of duty cycle it should really be time available to close. If we use 6,000 RPM and fire the injector every 5 msec: at 85% duty cycle that leaves 0.75 msec for the injector to close.

Now switch to async mode at high RPM/load. To retain the 0.75 msec closing time with the injector firing every 12.5 msec. We can run a duty cycle of 94%. Now there is less time spent opening and closing the injector, and more time with it open delivering fuel.

Not only is there a gain via duty cycle. But also a gain during the time the injector is now not having to open and not delivering fuel.


N/V tables. . .

These are only used for a stick transmission. If an auto is selected via the TCC option bit, they are not used. The value that is entered into the N/V tables is the ratio of the engine RPM vs. MPH in each gear. N being RPM, V being MPH. I hate doing this, but all I can do (at the moment) is to toss equations out.

N/V = (gr * 336) / td

gr is gear ratio (transmission gear * rear gear)
td is tire diameter

Lets do an example: a T5, 3.23 rear gears, and a 25.5" tire diameter.

This T5 has the ratios of: 2.95 1st, 1.94 2nd, 1.34 3rd, 1:1 4th, and a 0.73 5th (OD).

First get the overall ratio for each gear. Multiply each trans gear by the rear gear:

1st: 9.52 (2.95 * 3.23)
2nd: 6.27 (1.94 * 3.23)
3rd: 4.33
4th: 3.23
5th: 2.36

Now plug those values into the above equation (I'll bet Excel looks good right about now ):

1st: (9.52 * 336) / 25.5 = 125

To make it easier we can divide 336 by 25.5 and use that as the multplier: 336 / 25.5 = 13.18

1st: 9.52 * 13.18 = 125
2nd: 6.27 * 13.18 = 83
3rd: 4.33 * 13.18 = 57
4th: 3.23 * 13.18 = 43
5th: 2.36 * 13.18 = 31

To plug these into the N/V ratio table reduce each value by about 5%:

1st Lo: use 119
2nd Lo: use 79
3rd Lo: use 54
4th Lo: use 41
5th Lo: use 29

Then for the 1st Hi entry, take half the difference of 255 and 1st Lo and add it back to 1st Lo:

(255 - 119) / 2 = 68

119 + 68 = 187

Use 187 for 1st Hi.

I just had a thought, I've been working on a BIN ripper program that includes this and a couple of other calculations. Maybe I should to a quick utility program just for equations/tables such as this. The user would still need to edit the values into the BIN, but I could have it available more quickly.

RBob.

DM91RS

Rbob..........thank you for both answers.

Don't apologize for giving equations.

We (at least me) are grateful for being able to learn whenever possible.

Although nobody could complain about having a program to plug in gears and tire diameters and have it spit out the values. LOL

Now having said that what effect does using the N/V table have?



DM

RBob

iTrader: (1)

The end result of the N/V ratio stuff is that the ECM knows what gear the transmission is in. For the EBL setup this is used to select the PE SA. First gear can use more SA then second gear, second gear can use more SA then third gear, and so on. In the upper gears need little PE SA.

A bit more PE SA in 1st & 2nd can really get a car to move out.

RBob.

Fast355

iTrader: (2)

I know exactly what you are talking about, I extended my Launch mode SA, reworked the tables, etc. Really helps with the looser converter in how the engine just snaps to life when you roll onto the gas.

DM91RS

Thanks again Rbob.

I was pretty sure the PE SA table was getting values from somewhere.

I have noticed different WB afr's in different gears. IIRC that more spark leans the mixture out. Correct?

Dominic Sorresso

Guys,

Took my Xfire for a 130mile run to Bloomington IL today. First time I was able to scan after installing IAT sensor. Managed 23mpg(observed) running 75-80mph in addition to getting stuck in a traffic jam around Joliet for 30 minutes.
DGD showed 26mpg, so I am adjusting scalar to compensate.

Downzero

My EBL won't VE learn and my motor runs like crap, presumably because it's running pretty damn lean.

Any suggestions? I'd like to try to improve the way it runs by tomorrow.

If anyone has a link to vacuum hose routing for TBI, I'd appreciate that as well.

DM91RS

Are you trying to learn with the WB or NB sensor? There are certain settings that have to be met for either to work starting with the engine up to the starting temp for VEL in the preference window.

What items do you have that need vacuum ran to them? Mine is down to a minimum.

If I had a 383 I would want to have it running too. It would have to be a fun torque monster.

DM

kevm14

Would the WUD show the same inaccuracy?

RBob

iTrader: (1)

For the VE Learn to work via the BLMs the ECM needs to enter closed loop. Then it is a matter of setup.

1). Select: File -> Preferences menu.

a) select the temperature scale in C or F
b) select Learn From: BLM.
c) set the Learn Minimum and Maximum CTS values within the engine normal operating range. This will be for the selected temperature scale (C or F)
d) click OK

2). Select: File -> Learn VE menu.

a) enter/select the BIN file that is to be learned from.
b) enter/select the BIN file to create/write the new VE table to.

(learn is now enabled)

Once the ECM goes closed loop and the engine coolant is within the min and max CTS range, the VE will start to learn in. I also recommend data logging at the same time. This way you can also do a playback and do a VE Learn. Burn the newly created BIN and run another VE Learn. Each time the engine will run better.

If you are not sure of the min/max CTS set the min to 0 and the max to 220. Once the VE is close set the min/max CTS to the range of normal operating temperature.

RBob.

RBob

iTrader: (1)

The DGD and WUD MPG displays are based on an injector fuel flow constant. They are set in the BIN calibration tables. There is a separate one for each of the 2 displays.

The ECU/XDF takes care of the conversion from #/hr to the scalar value. But the issue is, what is the real #/hr the injectors flow, and at what fuel pressure. I tell folks to enter the #/hr that you believe the injectors are, then tweak it from there.

RBob.

Dominic Sorresso

RBob,

The WUD showed a 31.7 mpg while my DGD calc'd 26.7. I had the DGD setting in the bin at 129. Observed mpg was 23, so I have adjusted the DGD scalar to now be 150#/hr. Should be pretty close now.

Downzero

I have some data logs from yesterday. I'm going to give it a shot. Maybe it's the CTS thing that kept mine from VE learning. I did turn it on, but it just didn't make any corrections.

It was the CTS settings, I got it to work now!!

Grr....now the EBL software wants to crash on me...what gives? It keeps shutting down!

DM91RS

Glad you got it to work. As far as the crashing some people have been reporting problems when using usb/serial converters. Are you having to use one?

RBob

iTrader: (1)

Dominic, be sure to also adjust the WUD injector fuel flow scalar. There is a separate one for each display.

RBob.

kevm14

Uhh...ok so WUD was off by nearly 9mpg, before calibrating it.

I'll ask the tough question - have the people who are observing "unreal" fuel economy calibrated their setup yet?

In other words, I was planning on justifying EBL based on my expecting to get another 4mpg average out of my car. If that's not the case, I have to say I'd be less interested...

Fast355

iTrader: (2)

I am getting an observed 17.67 MPG over the last 3,500 miles with the EBL. I can't say that my WUD is 100% accurate for all situations, but it is close. I have run 712 miles and used 33.7 gallons. I ran the EBL WUD for the first 70 miles of this tank (the first stop). It was showing 20.5 MPG. I got 21.12 MPG observed. That is about as close as it is going to get with a VAFPR & the WUD. It doesn't give provisions for fuel flow changing with pressure. I went with a flow rate that got me close to observed.

Downzero

Unfortunately, yes.

It stopped crashing now, I'm glad it's not anymore.

EBL rocks. I've been using my ECM in two different trucks, and I really like it.

Seems I still have a lot of bugs to work out in my offroad truck before it's going to run well. I have a lifter ticking, and I suspect that I have a vacuum leak because it really runs like hell thus far, but I'm sure I'll get there.

Dominic Sorresso

Done. Thanks.

DM91RS

Glad you got it going.

I agree about the EBL. I would not want to have to go back and not have a WUD or the Data analysis screens. Not to mention all the other items like the better code and VE Learn and performance graphing.

Only problem with the performance graphing is that I have no traction in trying to get a 0 to anything.

liquidh8

I second that, did a WOT log, and got a 13.8 with a 2.1 60 ft time. That's without the n2o, now to bolt on the slicks and take it to the track. BTW, does anyone know where I can get a stiffer spring for the FPR?? I have it cranked up, with a shim, and can only get 26 psi. It is a VAFPR BTW. I was getting close to 85 % DC in syn mode, now in the asyn I am higher, haven't gotten a good log though. I figured I'd get it up before getting a 4bbl TB and RBob's mod to drive 4 injectors. I need to fuel the upcoming turbos

Fast355

iTrader: (2)

Have you looked into the factory BB spring from 1994-1995. The factory pressure was around 32-36 PSI in thos applications.

I have a VAFPR from Xtremefi with the extra high pressure spring (no cost option when I bought it) I have run as high as 45 PSI.

Downzero

I'm at 26 psi now and I ended up at 100% with some VE learn. Looks like it's time for more fuel pressure.

Dominic Sorresso

Down,

I am using n Aeromotive 13301 that comes with 2 springs. One will take you from 20 up to 65psi FP.

liquidh8

I bought the VAFPR from GM last year. Though I don't remember what year it was from. I also have that spring in it and have tried a few others. no luck though. I'll have to put up a post to see if someone has a spare one laying around.