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HP Tuners
2008 chevy trailblazer_ss_1ss
37 Posts
Discussion Starter #1
Over the past couple of years GM has changed their coding from what most had become accustomed to with LS1's...some of their changes have been for the better(MAF limits moved upwards for many 08' models) and others for the worse(IFR table limited to 63.5 lb/hr & Fan temp turn ons start at 192*F) what we've tried to do is take the best of what GM offered & improve on them :chug:

Our final hopes with this Custom OS is that you'll be able to run anything from a standard 1 bar maf tune all the way to 2.5 bar utilizing a REAL VE table that we've all come to know and love, we've also doubled the max airflow limit of the maf for guys that want to stick with a maf tune!

Anyways here's the skinny on the rest of the features as posted on our forum

Hi guys,

Some of you are aware that we have been working on a 2.5bar solution for the E38 ECM's that no longer have a VE table. After a few issues, I completed the last internal devtest session today where finally everything worked as planned on the dyno :D

We've incorporated a number of powerful new features that brings the HP Tuners solution well ahead of any stock operating system solution. Here's a quick rundown on the features, some of which will be familiar to those that have used our enhancements before.

This E38 enhancement contains the following features:
- 2.5 bar (255 kPa) max MAP sensor support (calibration capability for GM 0-5V linear MAP sensors)
- Rescaled MAF High Freq table supports up to 15400 Hz with 300 Hz resolution, also supports airflow up to 1024 g/sec
- New VE tables with 33 x 33 cell resolution each and configurable MAP and RPM axes (choose your own resolution)
- Charge Temperature based VE multiplier table, configurable axis
- TPS based VE multiplier table, 33 x 17 cells with configurable TPS and RPM axes
- MAP referenced Boost Enrich table
- Boost Enrich MAP threshold and hysteresis value
- Both MAF and Speed Density mode supported
- Boost based fuel cut, selectable MAP threshold cuts fuel to all cylinders when exceeded
- Rescaled fan temperature axis 163-250F (73-121C), stock is 192-250F (89-121C)

The MAF High Freq table has been rescaled to 5800-15400Hz at 300 Hz resolution and the maximum airflow limit for this table has also been adjusted to allow up to 1024 g/sec (instead of the stock 512 g/sec). This is excellent news for boosted applications that want to retain the MAF but reach higher than the stock 12200Hz and 512 g/sec limits.

There are three new VE tables. Two Normal tables (one for the intake manifold control open and another for closed) and one Displacement On Demand (DoD) VE table. For vehicles that do not have intake manifold control and/or DoD it is a good idea to set all three VE tables the same. There are also VE multiplier tables that can be used to change (multiply) the VE value based on Charge Temperature (Manifold Air Temperature) and TPS/RPM. The TPS Multiplier table can be useful for tuning large camshafts. On various tables the RPM/MAP/TPS axes are fully configurable, you can set the resolution to suit your application. The defaults are suited up to around 10psi boost (175 kPa) with 5 kPa MAP resolution and 200 RPM resolution from 400-6800 RPM.

Boost enrichment functions as per our other enhancements, with an enable MAP, hysteresis and Boost Enrich table. Boost enrichment also triggers open loop fuelling. The ECM will use the richest of the PE table and the Boost Enrich table values when fuelling.

The new Boost Fuel Cut feature will cut fuel to all cylinders whenever boost is above the enable MAP value. There is also an enable/disable option for this feature. It is a complete fuel cut to all cylinders when active. This could be used by engine shops who supply turbo chargers with electronic boost controllers to protect against customers winding the boost up higher than the engine internals can handle. It could also be used as a valet tune kind of feature.

Overall, the devtest results are very promising with the folks looking in on the testing very happy to return to "normal" VE table style tuning, the HUGE tables, the awesome flexibility and customization possible with the configurable axes and also looking forward to the possibilities of extended MAF tuning with exotic MAFs or maybe even the new LS3 MAF. The fan axis lowering is also one that was well received!

As i mentioned above, at present we will start out with a limited beta for the Aussie VE Holdens with a specific operating system ID (covers most if not all VE's). Assuming the limited beta goes well then after SEMA we will begin the large'ish task of integrating all the E38 and E67 OS's we currently support for the US and other markets. I would like to offer a US beta also initally, but with the many deadlines to meet before SEMA this is the best plan we could make.


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