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05-21-2011, 11:05 PM #1
Ultimate Guide To Starting LT1 Tuning. 94/95 and 96/97 Obd2-1 Conversion version.
Feel free to ask questions and post your information or additions for me to edit in. This will be a huge work in progress. I'm drinking so don't expect much right now... Im also working on an iPad so it won't be that great until I can do some better copy/paste work on my desktop. Mostly a framework for now.
This is a guide, use at your own risk. I assume no liability in writing this. Again, use at your own risk. These are suggestions.
This is intended for 94/95 cars or 96/97 converted cars.
Equipment:
Tuning cable;
Pick the one that applies to your car and computer.
YOU NEED TO DOUBLE CHECK YOUR OBD style connector.
94 cars:
aldl cable USB or serial connector, 12 pin obd1 connector.
Where to buy: http://aldlcables.com/ $59 or http://www.Moates.net $80
95/96/97 cars:
Aldl cable USB or serial cable, OBD1 - 16 pin obd2 STYLE!! connector (NOT AN OBD2 CABLE!!!).
Where to buy: S.A.A.
Laptop/Netbook;
Pretty much any windows based pc from the last 10 years will work. Make sure the battery is good! You don't want it dying in the middle of reading/writing your tune. I use an acer netbook with the 3 cell battery and it lasts me 4 solid datalogs and editing in between at the track.
Software:
To read and write from PCM;
Winflash. This is Necessary for tunerpro, comes with tunercats.
Where to buy: http://www.tunercat.com/winflash_des...lash_desc.html $20
For changing actual tune file;
Pick one:
Tunercats
Where to buy: http://www.Tunercat.com $160
OR
Lt1edit obd1
Where to buy: http://www.Carputing.tripod.com $200
Or
Tunerpro RT
Where to buy: Http://www.TunerPro.net $Free, $30 to eliminate 10 second delay window
Datalogging (recording car running to watch tune actually running in car)
Freescan
Where to buy: http://www.andywhittaker.com/en-gb/ecu/freescan.aspx $Free
Or
TTS datamaster
Where to buy: http://www.ttspowersystems.com/DataMaster.html $119
Or
Tunerpro RT
Where to buy: http://www.Tunerpro.net Free, $30 to eliminate 10 second delay window at startup.
Or
LT1edit
http://www.Carputing.tripod.com $50 upgrade to their tuner for datalogging.
BLM locker:
Xcel file downloaded for free.
I got it here: http://www.taekwondoplus.org/z28/WOT...cker_Setup.zip
If/When that stops working, PM me, and I'll email it.
Wheel/tire/rearend calculator (if not built in to tuning software):
Xcel file downloaded for free.
PM me, and I'll email it.
Extras
Wideband O2 sensor (for recording actual air/fuel)
Innovate lc-1
Where to buy: http://www.innovatemotorsports.com/products/lc1.php $199 OR eBay Price: $180
Basic setup:
Proper cable
laptop
tune software w/ pcm flash or winflash seperate
datalogger
A wideband setup is ideal to monitor actual Air/fuel for fine tuning fueling. It is NOT advised to tune your fueling without one, though it can be done to an extent. Make sure you can datalog the wideband with RPM as this is important. It is possible to wire the LC1 and other wideband sensors into the A/C pressure sensor to have TTS Datamaster datalog your AFR directly. http://www.camaroz28.com/forums/showthread.php?t=535603
GETTING STARTED
First things to do:
Set up all the software you'll be using on your computer.
For setting up Tunerpro RT: http://ltxtech.com/forums/showthread...RT-V5-Tutorial Thank Gregrob for the writeup.
Set up a couple folders for your datalogs and for tunes. I save my previous two tunes in case what I changed is detrimental. (it's happened!)
Either find a starter PCM .bin file (Or .LT1) to start with or pull your own off your car. I would also look into a mail tuner to give you a good starting point to fine tune further. A mail tuner can also provide you with a stock tune file based off your VIN.
If you are using your current tune as the starting point, use winflash or your tuning software to "read PCM." Save the file somewhere as your stock tune so you can always go back to it or look at it if you end up changing something you shouldn't. KEEP IT SAFE!
Using the BLM locker program, Lock WOT BLMs. This keeps your AFR at WOT constant. With an unlocked BLM, your WOT AFR will vary depending on where your tune was at when you went WOT.
Reprogram the PCM in your car with this tune.
Next thing decide what you want to tune. WOT, or cruising/daily driving.
You need to use your datalogging software to scan your car driving in the conditions you want to tune in. If you are doing a WOT track style tune, ideally you want to make sure you are in open loop while tuning. When you go into WOT you go into a set P.E. mode so it's not all important but your run up until PE mode will be based off your open loop tune.
POWER TUNING FOR THE TRACK
This should be done at the track for safety sake and to make sure the driving conditions are accurate to a track run. Most of the time if you try to tune for this on the street you won't be able to get the lower RPMs due to WOT traction issues on the street.
After you datalog a run or two check your table "spark advance vs map vs rpm." STARTING IN THE LOWER RPMS, Look at where in your run you experienced knock retard and find the corresponding cells in the tune (based off of the MAP and RPM). I pulled only a degree or two at a time to see when the KR disappeared. Usually if you pull as much timing to equal the KR timing pulled it's actually more than you need to pull and you'll notice you can add timing back if you go too much. Do this wherever you see KR in your datalog. Get this as close as you possibly can. Timing is very important for power. Generally speaking every degree of timing pulled due to knock retard equates to roughly 1-3hp. If you can tune out your KR and run full timing without KR pulling any this will result in the most power gains in your tune.
If you have KR that you can't seem to get rid of, or if you think you've pulled an excessive amount to keep from knocking it may be helpful to change your AFR. Without a wideband this is not recommended.
Tuning your AFR richer or leaner can add considerable power as well depending on how far off your tune is at the start.
In the lower RPMs sometimes adding additional fuel can have a cooling effect on the intake charge and actual lower knock. If you add too much however it will lower power by flooding the engine.
I started my AFR tuning by logging my wideband and making a table of where my tune was commanding the AFR to be and where it actually was at. I noticed the tune was commanding an AFR of 11.7-12.0 and it was actually running within about a tenth or two of that.
There are two tables that control commanded AFR at WOT. They are "%change to AFR at WOT vs rpm" and "%change to AFR at WOT vs coolant temp"
I made an excel spreadsheet to calculate it for me to tell me my commanded afr. The way to calculate commanded AFR: Commanded AFR = 1+( (ECT%+RPM%)/100 )
Graph this out based off of what engine coolant temp range you usually run at with the values in the RPM range... so you have a line graph of your AFR vs RPM at the coolant temp you run at. Then decide what AFR you want to run at vs RPM.
I did a very rough tune on mine for about 12.6 in the lower RPMs gradually increasing to about 13.0 at about 4000rpms and then leaned it out slowly toward 13.5 in the higher RPMs. Some people will tell you to go for a solid number the entire RPM range usually somewhere in the 13.5-12.7 range for NA cars. I wanted a bit more fuel in the lower RPMs to help eliminate knock. (it did so VERY effectively in my case)
Doing this type of AFR tuning is not ideal but if your tune is relatively close (commanded vs ideal) this can be quite effective at fixing it. There is another way to adjust your fueling at WOT which is by reading your AFGS in your datalog and finding the corresponding table in your MAF table and adjusting it by a % at a time until your commanded AFR is equal to your actual. This would be helpful with fine tuning AFR as well.
Doing these two adjustments (timing and AFR) will net you the most substantial of your gains. If you gain nothing here, chances are you're doing it wrong or there was nothing to gain!
Another thing that can help with your WOT run is your shift points. For figuring out ideal shift points, you need to dyno the car. Find out where your peak power is made and set your shift point about 400rpm higher.
When you are setting this there are two tables that control shift points. One is based off of MPH and the other is RPM based "kickdown normal mode shift rpm threshold" and . BOTH have to be "hit" in order for the PCM to tell the tranny to shift. If you change one and not the other it may or may not have the desired effect. With the two tables you adjust them up or down the desired RPM or MPH based off your dyno. DO NOT set them exactly where you want them to shift as it takes a while for the transmission to actually shift after it's been told to. My car shifts 500rpm after it's commanded to. So by datalogging you can figure out what setting you need to have to get the desired shift point.
Torque Converter Clutch Lockup. "TCC WOT forced lock speed threshold vs gear" Some people will have the TC lock up at WOT in third gear to raise trap speed. I had mine set to about 10mph after the shfit to third and have changed it to about 3mph after the shift now. I do not know how much if any affect it had on performance, but my car has been running better and better. I can't attribute it to the TCC change as I did some other changes as well. I assume it was negligible if anything.Last edited by LSWHO; 01-03-2012 at 05:17 PM.
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The Following User Says Thank You to LSWHO For This Post:
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05-21-2011, 11:07 PM #2
Tuning Glossary:
AFR: Air/Fuel Ratio
ALDL cable: cable connects car to computer
.bin file: this is your actual tune file in the PCM
BLM: Block Learn Multiplier, A block of information the PCM uses on the fly to adjust your AFR to 14.7 as best it can for optimum gas mileage/emissions/power.
BLM Locker: Locks WOT BLMs at 128. Eliminates variables at WOT in your AFR.
Datalogger/Datalogging: Recording live engine data for playback, or software to do so.
.LT1 file: this is your actual tune file in the PCM in lt1edit.
Narrowband O2 sensor: What your car uses stock to read AFR. Inaccurate for tuning and has a narrow readable band.
OBD1: On board diagnostics port, this type was used pre 96
OBD1.5: Term used to describe an OBD1 car that uses an OBD2 cable port. STILL OBD1
OBD2: 96+ OBD2 cars must use OBD2 software/hardware or convert to OBD1 (1.5)
PE: Power enrichment, a mode your PCM enters at WOT to control fueling.
PCM: Powertrain Control Module, this is your cars computer
Wideband O2 sensor: Accurately reads your AFR in a broad range.
WOT: Wide open Throttle.Last edited by LSWHO; 05-22-2011 at 12:53 PM.
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05-21-2011, 11:19 PM #3
Converting a 96/97 obd2 car to obd1.
Doing it yourself requires two parts.
1. An obd1 lt1 PCM. This can be flashed to work with your car. (auto or manual, different car, and gearing)
2. An obd1 knock SENSOR. NOT KNOCK MODULE.
Also mail order tuners offer PCMs modified to work with obd2 knock sensors. This makes them plug and play.
Madtuner.com does it for $250.
The PCM is located on the passenger side of the engine bay next to the firewall. It is held in place by 2 10mm bolts and four red safety clips and 4 color coded main connectors.
The Knock sensor is on the drivers side of the engine block below the exhaust manifold.Last edited by LSWHO; 05-22-2011 at 12:34 AM.
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05-22-2011, 03:02 PM #4
nice right up......i plan to do what you said a good mail order tune and then start tunning my self(if i dont go ls1 pcm).....since my car will go from stock motor to pretty moddified....i would think though bolt on cars can skip the mail order tune right? just h/c or cams ,injector swaps....things like that is when you recommend a mail order tune?...agian good right up...
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05-24-2011, 05:56 PM #5
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06-01-2011, 07:22 PM #6
LSWHO Good stuff. Since LT1 tuners are getting hard to find this is a great start towards creating many DIY tuners. Keep it coming.
95 Impala SS Clone
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06-01-2011, 11:16 PM #7LTXTech Sponsor
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Thanks for the write up. I sent a PM and am looking forward to more LT1 tuning tips. Local LT1 tuners are non-existent, so it looks like I have to do it myself. At least until I do the LS1 PCM swap.
-David-
1985 Camaro Z28 (Under Construction)
1994 Firebird Formula - LT1/4L60e (The Daily)
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06-02-2011, 10:44 AM #8
Thanks guys, ask your questions in this thread so the info is there for future readers and so I can update the thread as well. Muddy, I PM'd you back.
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06-02-2011, 05:23 PM #9
Great thread, can we (I) get a copy of your "I made an excel spreadsheet to calculate it for me to tell me my commanded afr. The way to calculate commanded AFR: Commanded AFR = 1+( (ECT%+RPM%)/100 )"
I'm a Tunercat / Datamaster User myself, total admitted newb. I know my way around computers and electronics, and that has helped me approach tuning carefully.
I was able to solve my inconsistent ET's. Had a .4 to .5 spread when i bought the car, now down to a .01 or less after a few months, but I have not tried to tinker with the Engine tune itself, to up the HP. Not sure I want to, damn car gets 25-26mpg highway as it sits! PE settings only LOL!
BTW, for WOT Shifting with an A4, After I tested every which way, the only table it cares about is the MPH table, For example, this works for me for shifts @ 5150. I bumped the 2 thresholds to 6000 across the board, and it still shifted right on the mph, every time. Exchange a few emails with TC, with my logs and such attached. And he concurred, it worked off of MPH only. TC gives great support!
Kickdown Mode Up/Down Shift Points
Shift MPH
Normal Hot Cold
1->2 36 36 83
2->3 67 67 81
3->4 120 120 85
2->1 19 19 83
3->2 57 57 81
4->3 94 94 85
Kickdown Normal Mode Shift RPM Thresholds
Shift RPM
1->2 5000
2->3 5000
3->4 5000
Kickdown Mode Shift RPM Thresholds Vs. Mode
Shift Mode
Hot Cold
1->2 5000 5000
2->3 5000 5000
3->4 5000 5000
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06-02-2011, 09:08 PM #10Lurker
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kick ass. my tuning software should be here any day now.
Kyle
just ur everyday slow LT1. wanna try her out?
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