Directscan files collection!

Originally posted by Mr URL
Doesn't make sense to me. Top speed was 109. :confused:
Click to expand...

Can't explain it either. My DS file's mph readings have NEVER agreed with what was actually going on. I don't know how DS extrapolates MPH. It doesn't read the VSS. I've always had the tire size set to either 26" or 26.1", just never bothered to try and fix it.
 
Got DS hooked up last night with my new GN, this site should be of great valve to DS users!
 
Has anyone heard from Bob lately?.
as in who is hosting the file depositatory.
 
Im back

Sorry guys,

I was away for the week. I'll get those posted shortly, this includes you Bruce, sorry I didnt get yours posted before I left for the week.

Thanks!
Bob
 
Originally posted by BM Computer Src
Bruce's file has been uploaded. It's under the category 5. I dont have anyone else's files waiting to go, so if anyone else has one they would like uploaded, please send it to me at webmaster@bmcomputersource.com
Click to expand...

Thanks Bob,

I figured I'd record a pass just to point out a few things. What you see, as I've stipulated to is how things are, and yes, some things are masked so as to not fully give away what I'm doing. This is a ROMless GN 148 ecm, part GM, part mine code wise.

First, you'll notice this is an Open Loop chip so there is no O2 voltage displayed. I was playing with different injector strategies so ignore the injector PW. I data log my WB stuff with another system, and used DS to just make an easy to view file for folks to see.

The items I was trying to point out were.

How the AFR changes as a matter of time. ie this is the FAPE correction working.

Notice how that battery voltage changes as the TPS changes, that is a volt blaster at work. High loads and this allows the fuel pump to pump just a little harder, and gives the ignition system, a much hgiher reserve voltage.

Notice no hints of K/R or counts.

While the MAF is limited to reading 160 on this particular prom, this is at the same freq as the Normal 255. With using a Translator Plus, and even with the MAF pegged, notice not a blip of Drop Out.

Comparing the MAF readings from this file to all the other MAF readings on all the other files and they all are interesting, at least to me in how the all peg at about the same point. I will point out my Wastegate gets applied at different thresholds then stock, and also my LV8 scaler is much different then stock.

The MAT has been relocated into the upper plenum, and this shows how the intercooler gets saturated, and then the temps climb. In this example the starting temp was 140dF, it was a very hot day, and I had heat soaked the car before the run, and again with the MAT temp at 190, not a hint of K/R. Ask why they use the FAPE. The FAPE correction runs for quite a while, and while critical for a 1/4 mile car, is even more important for a top end car, where instead of 11 secs of WOT it might be a minute, Or sustained PE mode like for several minutes.

K/R wise you can imagine that if the timing/ boost/ fuel control can work this well in these bad of conditions, how good the tune really is, and what the performance is like on a cool day.

I also, left from idle so you could see that little WOT spark map.

Hope this sheds some light on how things work, and can be made to work.
 
I found a bug in DS (time slips don't work with 9 fps and may not work with anything but 18 fps) and while I was corresponding with Kent Chu I asked about the vss/tire height thing. He says that he takes the tire height from preferences and uses that to modify the vss reading at the time the data is recorded. After the data is recorded, changing the tire height does not change the displayed vehicle speed. I opined that storing raw data was best but he countered that he didn't want people to have to send along all of their preferences with a data file. Personally I think that there are few enough preferences like tire height and vehicle weight that they could be stored in the data file with very little size penalty, and the displayed data updated when they are changed, that that would be a nice upgrade. That's where we left it but if you users feel strongly about this send him an email :).
 
Funny you should mention that, because I was doing some fooling around with tire size changes just the other day on the way home from work. Trying to punch in the actual tire size as measured yielded a large error between what my speedo was displaying (digital speedo that I have checked and know to be dead on balls accurate) and what DS was displaying.

So, I decreased the tire size (in whole one inch incraments) Down to 25, and for some strange reason the error that DS displayed indicated I was going a lot slower than what the speedo said. Then went up to 28" and DS showed I was going just a little faster than speedo. I think I finally ended up at 27.5", so at least DS corresponds with the speedo. It's probably only off ¼ of a mph, because just as the speedo flips over to the next digit, just a couple seconds later DS flips over (on a very very slow speed change).

Anyway, I think my tires actually measure something closer to 26.5" or so :confused:
 
Originally posted by TurboDave

Anyway, I think my tires actually measure something closer to 26.5" or so :confused:
Click to expand...


And at 100 MPH what diameter?.
Depending on the tire construction, there can be a signifigant amount of growth. Especially bias to radial.

I wonder if this isn't also part of the GTech MPH difference, other then just being an instananeous measurement.
 
DS & tire size

I am just beginning to use directscan and recorded my first runs at the track yesterday. I'm running a 9 x 28 et drag which mt says is 27.3 dia. Well, i typed this value in and its way off. my et mph was shown as 98 vs 104 from the actual timeslip. it also shows i let off 43 feet before the end of the 1/4 mile WRONG! The actual circumfernence is 88" which is 28" Now do you have to take into account the amount the tire squishes down from the car weight? to get ACTUAL tire dia? If so this makes things tougher. You would have to calibrate DS by going against a known good speedometer. Im not trying to beat this to death its just that my MPH was 104 and DS shows i went through the lights at 4950 TC unlocked and this seems too high. Is there somone who could take a look at my file and see what you think? I'm running a MAX-E so the BLM cells will look different. Thanks and sorry for the length of this post.:D
 
squeeze87
Send the file to me.I will look at it.

When I look at my files in scope mode,us the arrow keys and move the line over until where you start you run and hit the 0 number key (at the top of the keyboard)and it will zero the run and start where you have the line.
:cool:
 
Originally posted by TurboDave
Funny you should mention that, because I was doing some fooling around with tire size changes just the other day on the way home from work. Trying to punch in the actual tire size as measured yielded a large error between what my speedo was displaying (digital speedo that I have checked and know to be dead on balls accurate) and what DS was displaying.

So, I decreased the tire size (in whole one inch incraments) Down to 25, and for some strange reason the error that DS displayed indicated I was going a lot slower than what the speedo said. Then went up to 28" and DS showed I was going just a little faster than speedo. I think I finally ended up at 27.5", so at least DS corresponds with the speedo. It's probably only off ¼ of a mph, because just as the speedo flips over to the next digit, just a couple seconds later DS flips over (on a very very slow speed change).

Anyway, I think my tires actually measure something closer to 26.5" or so :confused:
Click to expand...

That kind of thing is why I think the raw vss should be stored, and then the raw and corrected speeds displayed. You could record one run at the track, and then tweak the tire size (or heck, he could even put in a back-calculate funcion) up and down until the corrected ds mph agrees with the time slip, and now you're calibrated. I also like to compare ds speed with speedometer speed on the highway just to make sure the speedo is still correct, but now that I know the ds reading depends on the tire size I have to dig out turbo link to check the speedo. This doesn't guarantee the speedo is right relative to true vehicle speed, but does guarantee that it's right relative to how fast the speedo cable is turning. I can then check the tire size (at 65 or 75 mph, yes, not at 110) vs. speedo by comparing odometer to mile markers on the interstate for 10 miles or farther (10 miles traveled and 0.1 mile resolution gives 1% accuracy).

I think the two biggest sources of difference between an accelerometer-based measuremnt like the GTech or Tazzo, and ds, are wheelspin and tire size, but I can't say which is worse :).
 
Originally posted by ijames
That kind of thing is why I think the raw vss should be stored, and then the raw and corrected speeds displayed. You could record one run at the track, and then tweak the tire size (or heck, he could even put in a back-calculate funcion) up and down until the corrected ds mph agrees with the time slip, and now you're calibrated. I also like to compare ds speed with speedometer speed on the highway just to make sure the speedo is still correct, but now that I know the ds reading depends on the tire size I have to dig out turbo link to check the speedo. This doesn't guarantee the speedo is right relative to true vehicle speed, but does guarantee that it's right relative to how fast the speedo cable is turning. I can then check the tire size (at 65 or 75 mph, yes, not at 110) vs. speedo by comparing odometer to mile markers on the interstate for 10 miles or farther (10 miles traveled and 0.1 mile resolution gives 1% accuracy).

I think the two biggest sources of difference between an accelerometer-based measuremnt like the GTech or Tazzo, and ds, are wheelspin and tire size, but I can't say which is worse :).
Click to expand...

Quite a dilema indeed ;)

The only reason I feel confident about my speedo accuracy is being able to turn the GPS receiver on and do a comparo every few days. Works great, so I just calibrate DS to agree with that.
 
Re: DS & tire size

Originally posted by squeeze87
Is there somone who could take a look at my file and see what you think? I'm running a MAX-E so the BLM cells will look different. Thanks and sorry for the length of this post.:D
Click to expand...

Yes, we all can! Thats the idea behind this :)

Send it to webmaster@bmcomputersource.com and I'll post it on the Directscan files collection so we can all look at it.

www.bmcomputersource.com/dscollection.html

Thanks,
Bob
 
2 new additions!

Please check out Category 5, the newest one. I put it up for a customer who blew a head gasket, but there is reallly no show of it in the recording.

Any suggestions appreciated. The customer is pulling it apart and will tell us what he found. I suspect a failure of something physical, but not detonation induced.

Also uploaded is Julio Don's first blast into the 11's CHECK OUT HIS 13 PSI LAUNCH!!

Thanks,
Bob
 
Re: 2 new additions!

Originally posted by BM Computer Src
Also uploaded is Julio Don's first blast into the 11's CHECK OUT HIS 13 PSI LAUNCH!!
Click to expand...
I'm guessing he has a stock TC? It looks a lot like my 15psi launches with the stock TC. We both stall to around 3000 rpm then the TC flashes to around 4000 rpm before the car even moves.. Pretty KOOL!

ks;)
 
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