Ok I am realy starting to get conflicting information and no longer know what to think. I have some serios doubts about the tuner I use what is the correct way to tune and what information is correct and what is just plain bull. First let me say I am trying to get the A/F correct for driving not WOT at the moment.

I am geting ready to install new injectors in a few days so I decided to get some good data logs to form a base line and didn't like what I was seeing. I am lean across the board in other then WOT driving.
Here is how I made my logs.
I ran the car at consistant RPMs 1500 for several miles then 2000, then 2500, them 3000, then 3500, and finaly 4000.

Now once I collected the data I noticed that I am consistantly in the 135-145 range for my LT counts (BLM) and I want to be around 123-125. I thought the proper way to correct the problem. Well I read an article that said to set the injector constant then change the MAP tables I thought this seemed wrong sisnce the MAP constants should be correct as I have a factory MAF sensor. I then called TTS datamaster to see if there was any way to relate the data collected to the MAF Hz offsets and they stated I shouldn't touch the MAF tables anless I have other then a GM MAF sensor. He then talked with me a great leanth about tuning and gave me a lot of information I have never heard of before.
Here is the basic run down on how he told me to tune the car (Start with a bone stock bin file)
1. Disconnect the MAF sensor and disable the code
2. Set the injector constant as close a posible for proper BLM's then set VE tables ( Iw ould use VEmaster for this part)
3. Once the BLM's where consistant across the board (if they where off by 10% for instance that would be fine) reconnect the MAF and see whats what.
4. Change the MAF tables if nessasary to get back near my base BLM's from the MAP only readings.

After getting compleatly conflicting information from several sources I gave my tuner a call and told him about my high BLMs and that I thought the car was running lean. He said that the ECM was correcting and it was fine, I think this is a load of $^%$ but someone please correct me if he is right. I now feel that most tuners only tune for WOT and wideband A/F on a dyno and do little or nothing for the other then WOT driving ( 90% of the time the car spends its driving life is other then WOT). So now I am at a compleate loss of how to get the proper A/F ratio.
Here is what I am curently thinking set the injector constant untill I am close 120-130 then start tweeking the VE tables (Mabey the way TTS described) then after I get the BLM's to 123-125 send the car back to the dyno and take a look at the timing and A/F for PE and WOT.

Thanks for any help in advance

Here is the link I refered to in the post about basic tuning of an LT1
http://members.nuvox.net/~on.roz/cars/z28/tuning.html

 

Usually what I do is load up a base file that has been done before and proven then load it up on the dyno and check everything out.

Just kinda review where the BLM's are going to be.. I typically shoot for say a 114-134 blm while driving and any thing maxed at 160-108 or consistant lingering at a particular BLM (say 114) needs to be addressed before getting on the dyno.

 

Ok I changed the injector constant and all of my BLM's came right in. Next I am going to run VE master, probably the way described by TTS then it will be back to the dyno for the wide band stuff. I really think that tuners need to start getting the BLM's where they need to be long before a car ever sees a dyno JMHO. I rely need to pull a little fuel from the WOT and PE because it was a tad rich to begin with due to an upstream exhaust leak the day it was dynoed and the wide band was in the tail pipe. I love the way the thing runs but I want the tune the way it’s supposed to be and not "close enough" that’s just not how I do things. After talking to TTS data master there is a full 2 seconds between when an event occurs and when you see it on the data logger. The ECM sends 8 data words at 250 ms per word. I am considering pulling the fuel in a linear scale to the fuel I added. So f I changed the injector constant by 1.06 percent I should be able to subtract 1.06 from the fuel tables and be ballpark I hope. I know it’s not perfect but it will have to do until I can get to a dyno with a wide band.

 

Re Datalogging-

1. On-board WB units have become fairly inexpensive lately (~$200+).
2. DATAQ makes a fine little 4-channel data aquisition unit that collects 240 samples/sec
(on 1 channel) for about $30.

Thus there is no real need to wait on dyno time to record relevant data, if you are willing
to do some of the work yourself. An example application is described here:
http://www.corvetteforum.net/c4/doctorj/carwb.htm

The on-board system is also good for looking at throttle transients (tip-in) in real time.


Re tuning a PCM with both MAF and MAP control, there is some analogous insight available
on the LS1 tuning boards. For example, discussion threads like this:
http://www.hptuners.com/forum/YaBB.p...num=1101917527

HTH

 

Dr J,
Thanks for the feed back. I have data logging software both TTs and Freescan just not the wideband stuff. I looked into the innovative but it was over $500 and I gave up. The information in the HP tuners section on ve tables is great info to have and seems to fall in line with the tuning method TTS recommended. I am going to disable the MAF sensor this weekend and get the ve tables correct then hook up the MAF sensor and see where I am at. BTW as I have thought all along without changing the MAF tables it seems there are two basic ways to add fuel across the board change the displacement information about the motor or the injector constant. The reason I mention this is this was where I was at several days ago when I was told to change the ve tables and then PE tables. I was asking about other then WOT at the time so I decided the PE tables where no part of the equation and started messing around with the ve tables but my results where mixed. After I decided I needed a new game plan I decided to give TTS a call and he confirmed much of what I was thinking and gave me a lot of good advice, at least I think so. Any how today I followed my gut and changed the injector constant and all of my BLMs fell right into place. They are now between 120 and 130 across the board and I have a feeling after I get the ve tables done it will be spot on at 123-128. Now the only problem is my WOT tables are off and I am sure I am adding to much fuel and need to pull some and that is where a wideband comes into play. I can either drop a couple hundred on a WB and hope it's accurate or take a 5hr drive back to my tuner and let him correct the WOT settings or rent a local dyno for $175 an hour with the wideband (This guy is a flat out crook). I think I am leaning on a trip the NC since my dyno graph looked great after he tuned it and I think he did a good job tuning the WOT portion of the ECM it was everything else that was average at best. BTW I understand that most tuners spend three to four hours just getting the WOT tuning correct and that they are not ripping anyone off I just wish I knew a lot of this information before I went to tune the first time, live and learn I guess.

 

There are only a couple of choices on WB sensors. The NTK I have was the same one
used in the multi-$K Horriba laboratory-grade analyzers (and I believe was also the
standard used by Dynojet in the past). The newer Bosch sensors are apparently now
standard issue on other dyno machines and FAST(?) installations.

There is some background on this board, among others:
http://www.turbobuick.com/forums/sho...d.php?t=157179


Re accuracy of the sensors, I don't understand your point. Most people go to tuning to
optimize Engine Performance - rather than to achieve some specific AFR. The WB reading
is just a way to see in which direction the fuel is going (and by roughtly how much) while
looking for the best engine output.

As such, the absolute accuracy of the WB reading (within reason) is entirely irrelevant.

If lab-grade accuracy is what you want, you will need to have your dyno-person do a
calibration of his WB with reference gases before he runs your car. If you are going to
that much trouble, have him run your (new) portable WB on the same gases - then you
will know exactly how accurate it is.

 

How do you meausre engine performance with out a Dyno?
I can either rent the dyno (It has a wide band) or get a wide band and shoot for a spacific A/F ratio.
I am not saying that the wideband has to be perfect but it needs to be fairly close. I would rather have a proper A/F ratio then a few more HP to be quite honest. I realy don't likethe idea of my car looking like a turbo desiel and fogging the world just for s few extra HP, now I want HP I just think that an A/F around 12-13 to 1 can be had and still be near max HP.

BTWd anything about the Zeitronix WBs? I was looking at them a while back and they where around $250 with the o2 and the software

 

F = MA is a pretty good equation to start with.

From the previous reference (http://www.corvetteforum.net/c4/doctorj/carwb.htm) :
"The slope of the RPM curve gives the power output of the test. Absolute power output
can be estimated by calculating delta Kinetic Energy (1/2 mV*V) for each RPM band."

There is some further discussion here:
http://www.corvetteforum.net/c4/doctorj/cartest.htm

Re WBs, try the Search function here or on TGO - Zeitronix has been covered before.

 

THanks, That realy does help and I may look into a wide band but with 12K in doctors bill it may have to wait a while.