Directscan files collection!

[BM Computer Src]

Due to popular demand, we have created a Directscan file collection at:

www.bmcomputersource.com/dscollection.html

Users may upload or download files, and the files are categorized by level of modification. Please check it out, and contribute or learn if you like!

Bob

 

[325DR]

EXCELLENT idea!

 

[bruce]

Originally posted by BM Computer Src

www.bmcomputersource.com/dscollection.html
Please check it out, and contribute or learn if you like!

I hope this is what you mean,
I spent some time looking at the runs posted and have a few notes.

Cat1-1
The FAPE is perfect the O2 voltages stay right up there thru out the run. Very conservative WG DC 65% and drops to 48.9 in 3rd gear.

Cat1-2
THE PERFECT EXAMPLE OF WHY NOT TO TRUST O2 VOLTAGES.
You'll see a commanded AFR of 11.6, at 765 millivolts at 391
Then 10.3 commanded at 1208 and it's 780 millivolts!!!
This is why tuning to a given O2 voltage is so darned bad. You changed an AFR of 1.3 in 15 one thousandths of a volt.....
Also is running 21d timing, and triggering the K/S. Would be better with less timing.

Cat 3-1
WG is 100% all the time.
Again, at 364 the commanded AFR is 11:1, and an O2 of 788
Then at 804 is 8.0 commanded, and O2 voltage of 804
Bad thing at 305 the MAF drops out the engine goes lean, and look at the knock.

Cat4-1
Looks like a shuttle launch.
Darned thing is a rocket
With on and off the gas things never really go stable for a real good look see at what's going on.
Again, 9.9 AFR at 671 is 671
then 11.5 at 775 is 729, O2
So richer in this case dropped the O2 voltage.

Bottom line,
Using info supplied by others,
O2 voltages are about meaningless.
A MAF drop out, is bad news Knock wise.

Just my 2 cents worth.
Not meaning to bash anyone, just items that I see. Any other comments if they are within the realm of this thread, I'd like to compare notes on what ya'll see.
HTH

 

[BoostKillsStres]

Wideband info

I haven't yet donated to the file collection but plan to. I now have my wideband O2 logging with directscan being reported as MAT so once I get finished with the new timing gear and rear main seal it will be interesting to look at the stk o2 voltages compared to the trend of the mat(true A/F) in the graphical display. I still have to make a lookup table of MAT to voltage to A/F but it should be fun.

Hopefully I'll get some data up this weekend but they'll only be some street blasts as I want to tune w/ the WB and get a nice fuel curve and then hit the track and make FP adjustments w/ my BLM lock patch in the chip and see which way makes it quicker mph better.
FYI.

 

[bruce]

Re: Wideband info

Originally posted by BoostKillsStres
Hopefully I'll get some data up this weekend but they'll only be some street blasts as I want to tune w/ the WB and get a nice fuel curve and then hit the track and make FP adjustments w/ my BLM lock patch in the chip and see which way makes it quicker mph better.
FYI.

Once you get familiar with the WB and tuning you can forget the stock O2 all together, and just do Open Loop.

BUT,
without going to a translator, or translator Plus you'll still have MAF drop out problems. I should say most likely, there are some MAFs that don't report well enough to peg, and hence don't drop out.
Please look at Cat3-1, and at distance 305 look at the MAF, and at the KR.
HTH

 

[BoostKillsStres]

Bruce, I've got the std xlator per my sig so the dropouts have been cured. Not sure if I'm brave enough to go open loop and start tuning all over again.

 

[bruce]

Originally posted by BoostKillsStres
Bruce, I've got the std xlator per my sig so the dropouts have been cured. Not sure if I'm brave enough to go open loop and start tuning all over again.

Per what sig line?.
I keep seeing people say that, and no sig line.....

If your mostly at 128s your close enough to just set teh C/L enable temp to FF and be there.

 

[BoostKillsStres]

Are you saying you cannot see the 3" translator as the first item in my upgraded parts list under my post?? I wasn't aware it wasn't showing up... My blm's are decent in the table in a range from 110 to 135 but when driving hills and such I've seen a 14-18 point swing so I think I'll stick with C/L and let it handle those load changes and temp changes from winter and summer.

If you set the C/L to FF would it then totally ignore the blm table? Or once you reset the ecm would the values just stay at 128 and never store any correction? Could you then pull the o2 out but leave it plugged in just sensing free air and be able to run race gas until you ran the gas all out and were ready to put the o2 back in??

 

[bruce]

Originally posted by BoostKillsStres
Are you saying you cannot see the 3" translator as the first item in my upgraded parts list under my post?? If you set the C/L to FF would it then totally ignore the blm table? Or once you reset the ecm would the values just stay at 128 and never store any correction? Could you then pull the o2 out but leave it plugged in just sensing free air and be able to run race gas until you ran the gas all out and were ready to put the o2 back in??

I see not parts list.

For the BLs to wander 10 points is immaterial.
Targetting 14.7:1 is just for the converter, and has nothing to do with how well the engine is running. I run right at 14:1

In running O/L the Bls just stay at 128.
You just then use the MAF tables and scalers to dial in what AFR you want. At one time or another I've run 15 to 12.5 at idle and 13.5 to 16.8 AFR in cruise.

You can use the chip you are now, and let the ecm remember those BL corrections, and then use an Open loop chip. ie the same chip but with the C/L enable to FF.

OR, clear the computer and then start with an Open loop chip, and then dial it in to not need to know the BL corrections.

The only trouble with the first option is that you have to carry two chips, and if you have to disconnect the battery, you have to relearn the engine with the open loop chip. If you have race gas init you'll still lose a sensor.

 

[BoostKillsStres]

Sounds interesting. As far as sigs you might want to check your usercp:edit options and check your setting for -->Thread View Options : Show user's signatures in their posts?

In your last statement did you mean to say relearn w/ the C/L chip?
HTH

 

[bruce]

Originally posted by BoostKillsStres
Sounds interesting. As far as sigs you might want to check your usercp:edit options and check your setting for -->Thread View Options : Show user's signatures in their posts?

In your last statement did you mean to say relearn w/ the C/L chip?
HTH

OK,

and yes, massive brain fade on that one, your correct.

 

[lazaris]

Bruce

In looking at cat 4 where do you see the on and off the gas? Not that I trust O2's but it looks pretty stable after the launch.

 

[BM Computer Src]

Im glad the collection is providing for excellent discussion. I hope we can all benefit and learn from this exchange of information.

I do want to comment on the O2 Voltage vs A/F ratio's, however. I have never had an experience when the O2 ranged much from my EGT meter, so I have grown to trust the O2.

I have to say I do ignore the ecm's commanded A/F ratio (in WOT)as reported by Directscan, because that is a commanded function, and the O2's are an actual result. I dont believe the relationship between one and the other to be of major concern. I am not an expert, however and this is just my findings. I could be wrong

Great discussion guys.

 

[Iceman]

TTT

 

[bruce]

Originally posted by BM Computer Src

I do want to comment on the O2 Voltage vs A/F ratio's, however. I have never had an experience when the O2 ranged much from my EGT meter, so I have grown to trust the O2.

I have to say I do ignore the ecm's commanded A/F ratio (in WOT)as reported by Directscan, because that is a commanded function, and the O2's are an actual result. I dont believe the relationship between one and the other to be of major concern. I am not an expert, however and this is just my findings. I could be wrong

EGT is a function of timing and fuel, there is no way to accurately seperate one from the other other then to make a change and note the result.

If you use a WB, the commanded AFRs and actual should line up. If your ignoring the stock O2 that's understandable.
Once you get to WB terriotory then you can get accurate, and really seeing whats going on.

Using the correct injector size is one thing I harp on. That way you can compare notes on what the actual numbers are. Star lieing to the ecm about injector size and you start digging a hole for trying to see what's actually going on. The down side is if forces you into reworking the MAF tables and scalers and you really need a WB to get them right.

BUT, the pay off is you can run a SCREENLESS MAF Translator as a blow thru!. Virtually no restriction that way.

 

[ijames]

Don't forget that the commanded afr that ds is showing is calculated by ds (and isn't anything used by the ecm) based on the measured maf, and once that pegs at 255 gm/sec the commanded afr will be further and further from what the engine is actually running at as the airflow continues to increase. For example, if the engine is actually running at 12:1 afr and the maf is actually 510 gm/sec ds should report a commanded afr of 6:1.

 

[bruce]

Originally posted by ijames
Don't forget that the commanded afr that ds is showing is calculated by ds (and isn't anything used by the ecm) based on the measured maf, and once that pegs at 255 gm/sec the commanded afr will be further and further from what the engine is actually running at as the airflow continues to increase. For example, if the engine is actually running at 12:1 afr and the maf is actually 510 gm/sec ds should report a commanded afr of 6:1.

I would have though that it was obvious that when you peg the MAF that at that stage things quite reading right.
So once you get the numbers to jive at the lower values, and if you know the AFR at the higher flows (using a WB) then you can approximate the actual airflow. Then as a sanity check you can figure the airflow using the pulse width, knowing the actual AFR.

Considering FAVAL is the Total Fuel Air Value, that while DS might figure the commanded AFR, the data is in RAM to access and read thru the edge card connector.
Since Lockers reads the same value, while it might be the same correct formula, I know Lockers just reads values.

 

[bruce]

Originally posted by lazaris
Bruce
In looking at cat 4 where do you see the on and off the gas? Not that I trust O2's but it looks pretty stable after the launch.

Was lookiing at the burn out, the actual run was off the screen.
Yes, they are pretty stable, you can see the commanded AFR go richer, but they still drop a little. Yes not enough to be anything near critical, thoou.

I still say it's a rocket.

 

[KEVINS]

This is a great idea.. I submitted mine although I use a ME 16 so I don't know how much the tables/O2's will help anybody..

ks

 

[ijames]

Originally posted by bruce
I would have though that it was obvious that when you peg the MAF that at that stage things quite reading right.
So once you get the numbers to jive at the lower values, and if you know the AFR at the higher flows (using a WB) then you can approximate the actual airflow. Then as a sanity check you can figure the airflow using the pulse width, knowing the actual AFR.

Considering FAVAL is the Total Fuel Air Value, that while DS might figure the commanded AFR, the data is in RAM to access and read thru the edge card connector.
Since Lockers reads the same value, while it might be the same correct formula, I know Lockers just reads values.

I may be wrong about ds calculating the afr, but I am pretty sure the ecm doesn't use a total fuel air value for anything in the fueling - it just starts with the maf value and multiplies by things until it gets an injector pw and uses that. I always thought that that was a little bit of a waste since calculating lv8 duplicates about half that math so they should just start with lv8 (which is intended to be a measure of how much air is in the cylinder as a measure of load). I've never used Lockers so don't have any idea how it does things. However, you were commenting on the commanded afr vs. O2 volts in cat3-1 above where the maf is clearly off scale, so it looked like you were expecting it to still be valid.