8D/DA2/DA3 - v2.11 - 10/14/03
EE - v1.33 - 12/16/01
8D: 90-91 Corvette, 90-92 Camaro/Firebird (L98)
DA2: 92-93 Corvette (LT1)
DA3: 93 Camaro/Firebird (LT1)
EE: 94-95 Corvette, Camaro/Firebird, Impala, and other LT1-based B-bodies. Note that the VE tables are used only in the backup Speed Density mode on these cars (i.e. as long as the maf is plugged in and working, VEMaster will have no apparent effect.) You can also explicitly enable SD mode via Tunercat or LT1Edit.
The 8D/DA2/DA3 VEMaster only supports the logging software Datamaster.
The info below applies to the older (EE) version of VEMaster, but the idea is still the same.
VEMaster is designed to improve the drivability of LT1-based GM vehicles that have been modified with a high-performance cam and/or cylinder heads. The program uses a log file created by the user driving the car under normal conditions. This log file must currently be made by using the commercial Datamaster software or the freely available Freescan. The program also requires a pcm image file created by Tunercat. LT1-Edit users can convert their .lt1 files to Tunercat .bin files using the TuneConv program.
VEMaster parses the logged data file using only closed-loop, part-throttle data. The LT1 computer has 16 closed-loop fuel trim cells. Each of these cells contains 2 pairs of learns: a long-term left-and-right pair (a.k.a. BLM) and a short-term left-and-right pair (a.k.a. INT). For each VE cell in the VE tables, the program grabs the average BLM from the fuel trim cell the VE cell lies in, interpolating if necessary. The pcm bin file is modified, so be sure to make a backup copy before you run the program.
Since this program was designed to improve drivability and not top-end power, I recommend tuning no higher than the default setting of 3000 rpm. There are two reasons for this. One, any time you swap in a more radical cam for the stock cam, your VE will suffer at lower rpm's. However, at higher rpm's, the more radical cam will first equal, then exceed, the volumetric efficiency of the stock cam. At these higher rpm's, though, it is safe to assume one will be operating at W.O.T., and the fuel can more easily be controlled by adjusting the Power Enrichment table. Second, the fuel trim cells in stock form end at 2000 rpm. So from 2000 rpm on up, you only have that one set of learns. Presumably, most of the data (and driving) you will be doing will be closer to 2000 rpm than not. Therefore, the accumulated learns your car has in the 2000+ rpm cells will mostly be based upon data in the 2000-3000 rpm range, and thus should not be applied to higher rpms.
VEMaster was developed using MS Visual C++ 6 under Windows 2000. It has been tested on Windows 2000, Windows NT 4, and Windows 98.
VEMaster is released under the GPL and as such is open source. I intend to post the source code on the site soon - in the meantime I would encourage interested parties to email me requesting a copy. As I have an LT1 (see above) it is really not worth it for me to further develop VEMaster. However I would be willing to help any qualified individual who did.
VEMaster software is freeware. It comes with no warrantly, explicit or implied. Always examine the log file VEMaster creates to see what changes it has made to the pcm image file. Open the image file in Tunercat (or LT1-Edit) and make sure everything looks okay. I will not be held responsible for damages resulting from the use of the program. Use at your own risk.