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Switching to speed density 94 LT1

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Old 03-20-2007, 05:49 PM
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Switching to speed density 94 LT1

What needs to be done to switch to speed density mode in the PCM? Tunercat has an option to goto speed density mode. Is just flip the flag, unplug MAF and reflash? Or is there something else that needs to be done?
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Old 03-20-2007, 05:53 PM
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Thats all you have to do
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Old 03-20-2007, 06:35 PM
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I have seen where people talk about copying the high octane stuff to the low octane table, thats not needed with the tunercat flag?
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Old 03-21-2007, 01:38 PM
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yep, just flip the SD flag and go.. be aware that the factory VE tables need alot of work with a modified motor.. just download VEmaster EE and a copy of datamaster EE, let your engine go into closed loop, log a quick drive, run the log and a saved copy of your bin through VE master, smooth it, reburn and repeat as meany times as needed to get those BLMs in line.
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Old 03-21-2007, 01:41 PM
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Originally Posted by Paul94Z
yep, just flip the SD flag and go.. be aware that the factory VE tables need alot of work with a modified motor.. just download VEmaster EE and a copy of datamaster EE, let your engine go into closed loop, log a quick drive, run the log and a saved copy of your bin through VE master, smooth it, reburn and repeat as meany times as needed to get those BLMs in line.
VEMaster by default targets 124 as the BLM is this a good target?
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Old 03-21-2007, 03:52 PM
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once I read in the documentation why he targeted 124 by default but I forget the specifics.. I think it has something to do with the transition to WOT
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Old 03-21-2007, 03:58 PM
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found this over on corvetteforum
"VeMaster's default BLM target is 124, but you can raise that if needed. Just remember you want your BLMs to stay a bit below 128, so when you go into PE mode they will lock-in at 128."
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Old 03-21-2007, 05:57 PM
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Ugh VEMaste+Datamaster == bad tune. I run VEMaster with freescan and it does minor adjustments and the tune works
I ran it with Datamaster and the car wouldn't rev over 2k in neutral and drove like ****.
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Old 03-21-2007, 07:51 PM
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I would suggest making a copy of your tune before you run vemaster on it so you can then compare the two to see the changes inside of tunerpro or tunercat.. remember that the blm's bottom at 108.. so if it does on a certain cell you can only correct for a 15% variance between each log and tune.. takes a few times to get it close and a dozen more to get it perfect..
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Old 03-21-2007, 08:08 PM
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Originally Posted by Paul94Z
I would suggest making a copy of your tune before you run vemaster on it so you can then compare the two to see the changes inside of tunerpro or tunercat.. remember that the blm's bottom at 108.. so if it does on a certain cell you can only correct for a 15% variance between each log and tune.. takes a few times to get it close and a dozen more to get it perfect..
Well VEMaster made the car immediately undriveable whereas using freescan has made changes but the car has remained driveable
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Old 03-22-2007, 10:46 AM
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hmm, have you compared a before and after VE to see what it did? You really need to open it in tunerpro, manually smooth large spikes and then use the smooth function in the toolbox to make it perfect.. this way you will not feel any jerking as the pcm pulls VE data from the different cells
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Old 03-22-2007, 11:12 AM
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Originally Posted by Paul94Z
hmm, have you compared a before and after VE to see what it did? You really need to open it in tunerpro, manually smooth large spikes and then use the smooth function in the toolbox to make it perfect.. this way you will not feel any jerking as the pcm pulls VE data from the different cells
http://breakherthewang.com/SDTune2_vem.txt
This is the results of using freescan

http://breakherthewang.com/SDTunetest_vem.txt
This is the results of DataMaster.
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Old 03-22-2007, 11:56 AM
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Originally Posted by LiENUS
Well VEMaster made the car immediately undriveable whereas using freescan has made changes but the car has remained driveable
GIGO. I found that if you just dump a complete datalog into VEM that you'll get crap out of it. You need to preselect the data, either by being very careful with how you operate the car while logging, or by filtering the data afterwards.

For me it was easier to just do it all in excel, where I can tweak things to my liking, rather than guessing at what if any input filtering VEM is doing.
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Old 03-22-2007, 04:09 PM
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I don't think the problem is with VEM, I've run dozens of logs through it to get a VERY nice tune.. my gues is that if it is the factory VE table it will be far off if any significant engine mods have been performed (cam). You also must be sure you are free of vacuum leaks and have accurate O2 readings, no exhaust leaks, etc to perform this recalibration. Double check your injector constant and cylinder volume is correct as well. What are your mods anyway? Something's def not right:

cell[1400][70] 78.1 1.03 80.9
cell[1400][75] 78.5 1.03 81.2
cell[1400][80] 78.9 0.895 70.7
cell[1400][85] 79.3 0.756 59.8

The VE should only go up as MAP increases, not down.

Have you visually looked at the graph of your new BINs? You will probably see that it contains alot of pits and peaks.. it must be smooth in the end.

Last edited by Paul94Z; 03-22-2007 at 04:19 PM.
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Old 03-22-2007, 04:16 PM
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Originally Posted by Paul94Z
I don't think the problem is with VEM, I've run dozens of logs through it to get a VERY nice tune.. my gues is that if it is the factory VE table it will be far off if any significant engine mods have been performed (cam). You also must be sure you are free of vacuum leaks and have accurate O2 readings, no exhaust leaks, etc to perform this recalibration. Double check your injector constant and cylinder volume is correct as well. What are your mods anyway?
Relatively stock, asside from gutted cat and removed MAF. the MAF was removed because the engine runs better with it removed. It was breaking up on the top-end felt like a dead opti but cleared up as soon as MAF was unplugged. Hence the SD switch. Cleaning the MAF actually fixed it but i'm not a fan of MAF style setups i'd rather be in speed density mode. The block I believe was factory replaced I don't believe it has been bored over but I didn't check when I had the oil pan off (Didn't even bother to look at the mains to see if 4 bolt or 2 bolt. I think the block was replaced because there is no vin derivative on the side of the block.
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