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]

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]

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.

[BM Computer Src]

Ok,

Now that we have discussed O2's, lets talk about spark advance. How accurate is the commanded Advance (as shown on DS) compared to the actual? Has anyone really compared the two?

[bruce]

Originally posted by BM Computer Src
Ok,

Now that we have discussed O2's, lets talk about spark advance. How accurate is the commanded Advance (as shown on DS) compared to the actual? Has anyone really compared the two?

There have been several threads on this, and when you get all done, they match within the error of the time for the switching delays within the transistors. And were talking usec., here. And DC only reports to the nearest tenth.

Direct Scan is reading the actual RAM location values in the ecm, other then the HP and Torque numbers, I don't think it's actually doing ANY math, other then simple conversions.

If the airflow entry is FF, the ecm is thinking it's passing 255 grams/sec of air. And DS reports 255.

There is a thread about timing in the Trasher chips, and I posted the actual timing code with all the adders and factors.

What you see in DS is what the ecm is doing.
If the numbers aren't what you think then you need to look at the code and see what your missing.

And it's all relative anyway. When tuning your looking for best performance if your at 16 or 18 it really doesn't matter so long as you know that at 16 or 18 gives you best performance.

[ijames]

Originally posted by BM Computer Src
Ok,

Now that we have discussed O2's, lets talk about spark advance. How accurate is the commanded Advance (as shown on DS) compared to the actual? Has anyone really compared the two?

There was a thread on Thrasher timing in the Chips forum where a guy posted that he had made measurements on his ecm bench that were in severe disagreement with the chip tables. I started a thread called bench vs on-the-car timing where I posted measurements I made with a timing light that agreed within 1 deg with what the chip was commanding and what ds was reporting, at all rpms and lv8's that I could access with the car sitting still and the tires on the ground. The difference was constant to less than .25 deg so I think most of it was tolerance stackup in my timing chain, crank sensor placement, and keyways. After this he found a math error in his bench software and then his measurements aligned with mine. This is one case where ds must be doing some math because the Thrasher chips change the base offset for the main table (and others) and ds doesn't correctly handle that so I think it is assuming the stock offset instead of reading it.

[BM Computer Src]

I have to agree, but it always seems so odd that some cars you cant put more than 20 degrees timing on, even w/alky or race gas, and others can tolerate 30 degrees. I think those intolerant cars are the variants which may have anomalies, like higher compression or some other unknown changes / problems. It's just hard to look for problems in cars running fast on low timing. My TTA is a prime example. It can only take 20 degrees and 21-22 psi on alky, yet it's fast. I had the same results on race gas. The car is a screamer, and should break into 119-120 mph next time out. I have never run this low of timing and run so fast, it's always been 24+ degrees of timing and same boost.

Conclusion / Bottom line: The actual numbers dont matter, if it's making power.

[bruce]

I think it might be alot less confusing to actually talk in the way the ecm does things rather then confuse things with how folks expect things to read.

In the 1227148 the basic timing stuff is

There is Spark Advance.
There is the Spark Reference angle.
There is spark retard, in PE
There is spark retard, not in PE.
timing correction for Coolant Temp.
timing correction for Manifold Air Temp..
Highway Spark
TCC lockup retard

DS reports SA.
Again, I already snipped the code and posted in the Trasher Thread about what it is really there. ie what makes up SA.


Spark retard, in PE or not, is spark retard, ie not to be confused with SA.

If you change the spark reference angle, and displace the SA table accordingly, then those numbers are still the SA. But, they would be applied to the different reference angle.

There is a difference from SA to actually timing in use. Or I should say they can a difference from SA to what you would see with a timing light.

[Iceman]

Would someone send in a file(To Bob at BM Computer Src) with lean popping so we can see what it looks like.I am chasing a popping at 21# of boost or higher.At 20#it is ok no popping.
Or you can send me the file at vrice@arn.net

[bruce]

Originally posted by Iceman
Would someone send in a file(To Bob at BM Computer Src) with lean popping so we can see what it looks like.I am chasing a popping at 21# of boost or higher.At 20#it is ok no popping.
Or you can send me the file at vrice@arn.net

Why not post one of your's?.
There no guarantee that it's gong to manifest itself the same way from car to car. Might be something else going on that your missing.

[striker_29]

Hey Bruce I'm cat2-1, could you look at that one and give me any thoughts? I have been chasing several different problems, some of which started about that time. Also would just like to see what you think, as I'm still a tuning newbie. Thanks...Mark

[bruce]

Originally posted by striker_29
Hey Bruce I'm cat2-1, could you look at that one and give me any thoughts? I have been chasing several different problems, some of which started about that time. Also would just like to see what you think, as I'm still a tuning newbie. Thanks...Mark

Commanded AFR is as low as 6.9.
Injector DC is 124%
O2 voltages drop thru out the run.
It would tell alot more, with a WB, but looks like it's going lean as it goes down the track which may or maynot be EGT going up, or intercooler heat saturating, but with the alky inject that shouldn't be as much as of a problem.

Looks like the Alky might be slow as you get alot of K/R then it pretty much goes away, might be false, but I'd try readjusting the alky trigger and see what happens.

Without knowing the mechanical shape of things, from what you've supplied, looks like better alky injection methology, and or more injector.

BUT, you can hit several walls at once, and curing one doesn't mean you'll instantly go faster. Gets to better intercooler may help, larger injectors, refashioning the alky, might take one or all to get over the hurdle. Again assuming the mechanical stuff is OK, ie O2 sensor is accurately reporting things, good enough fuel pump, fuel filter etc.

[striker_29]

Hey Bruce thanks a lot for your help man, I really appreciate it On that particular run though, I had unhooked the alky and my intercooler shroud was missing. I was running c16 and 25 psi. Does that change your outlook on that at all?? Thanks again ...Mark

[bruce]

Originally posted by striker_29
Hey Bruce thanks a lot for your help man, I really appreciate it On that particular run though, I had unhooked the alky and my intercooler shroud was missing. I was running c16 and 25 psi. Does that change your outlook on that at all?? Thanks again ...Mark

Anything else to want to tell me?.

I'm glad you said that in a way. I just so happened to notice.
In scope mode, put the Inj PW, right on top of the Knock Retard.

See anything?.

At the first sudden demand of fuel the DC goes over 100%, the injectors are out of fuel and the motor detonates.

AND, this might be an indication of the injectors chattering as they go static, so far I haven't really been able to tell if an injector goes static, is it's chatering longet closed then open, or if it varies. Some have said that the injector just hangs 1/2 way open, that would be lean.

Then as you go further down track the DC disparety increases even more and you get into more detonation.

Adding F/P might help,
But your still trying to run static.

Again, assuming no mechanical ills causing a false knock, or leaving other details out.

[striker_29]

Thanks Bruce. The first instance of detonation occured with o2 mv's in the 840 range. I was actually thinking this may be an indication of rich knock. This was an RA106 chip with only 25 lbs of boost, and fp@48 line off if I remember correctly. I was thinking I needed more boost, but I guess thats not the case. There should not have been any reason for any false knock there. Thanks again...Mark

[bruce]

Originally posted by striker_29
Thanks Bruce. The first instance of detonation occured with o2 mv's in the 840 range. I was actually thinking this may be an indication of rich knock. This was an RA106 chip with only 25 lbs of boost, and fp@48 line off if I remember correctly. I was thinking I needed more boost, but I guess thats not the case. There should not have been any reason for any false knock there. Thanks again...Mark

I doubt it's false knock.
It might be a injector chattering as it goes to static.
DS just reports what the ecm wants to happen or things is happening. An injector chattering ain't going to show up unless your running an Oscilliscope on the injector. All it takes is one injector chattering, and one cylinder going lean for the Knock sensor to be triggered.

[TurboDave]

OK, I submitted my quickest and fastest run ever. It went to BM just moments ago, and was submitted for category 3. Don't know when it'll show up.

[BM Computer Src]

It's been updated!

The is great, exactly the type of response and help I was hoping would happen!

I see lots of buick's getting faster because they will learn how to interpret and tune better. Thanks to everyone who participates!!



Bob