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Discussion Starter #1 (Edited)
I thought I would post an update on our tuning since there appears to be some confusion, as well as share some details about this engine control management with other forum members.

We've noticed some members wondering as to when tuning will become available. Tuning support for 1996-2006 V8 4.6L engines and five-speed transmissions has been available for a while. When we announced tuning availability for 2004-2006 LH2s, we mentioned that we observed some knock retard on our vehicle. This was not a byproduct of custom tuning - it was observed on the factory calibration. Since then, we've confirmed that a number of vehicles running this engine management system are experiencing the same issue. This means that even when running premium gas, many of you are not seeing the full power the engine should be delivering.

Now a little bit of information on knock retard. This is a function that normally prevents engine damage when engine knock is observed, or in some cases, "guesstimated." What the engine management system does in such cases, is it reduces the amount of final ignition timing, thus reducing delivered power.

I think the following article is a good read for any 2004-2006 LH2 owners:
http://www.autospeed.com/cms/A_1569/article.html

The article mentions an "individual cylinder knock control" feature which is present in these ECMs. In the course of our tuning development, we've studied this technique in great detail and in our opinion, this system is perhaps too sophisticated for its own good. In fact, it is so complex and convoluted, a second processor in this ECM is almost entirely dedicated to it.

Furthermore, this particular ECM has a system in place for judging "ignition efficiency" (the quality of the actual ignition given the fuel used and ambient factors). It has the capability to reduce your engine torque by as much as 60% based on this calculated quality.

To combat some of these issues, one might consider our "knock retard desensitizing" option in a custom calibration, or, in a race-only vehicle, choose to disable the knock retard altogether.

Another observation we've found interesting is that this ECM may have also been intended for the supercharged line because certain parameters are defined to cover over 500 ft. lb. of torque. If some owners would like to do a forced induction conversion, we would be very interested in helping with such a project.

Other areas of interest for us have been developing a Vehicle Theft Deterrent (VTD) bypass solution for retrofit applications and we do believe we have a full solution now. If you have a retrofit application, please let us know.

We're currently developing and testing tuning for the suspension control module as well. We can work with owners who choose to remove the Magneride system from their cars to compensate for the reduced speed range.

Any other changes including tire size/gear ratio changes and all the usual things one looks for in a custom calibration are not an issue.

If you have any questions, please let us know and we will be happy to clarify them for you.

PS: I'd like to mention to moderators that we've attempted to purchase our usual "Authorized Tuner" subscription and it is unavailable. Your "Upgrade" button above points to a dead link. We've used the "contact us" form to notify the forum owners about these issues.
 

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05 STS4
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4,241 Posts
Thank you for coming back and updating all of us. I can't wait for good weather back so I can finished this tcm shift point adjustment and move on to ECM tuning.
 

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2006 STS N* 1SE
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madtuner said:
First of all, before going into further details, I'd like to mention to moderators that we've attempted to purchase our usual "Authorized Tuner" subscription and it is unavailable. Your "Upgrade" button above points to a dead link. We've used the "contact us" form to notify the forum owners about these issues.
...
Sorry to hear about the subscription problems. Please open a new thread in the forum called 'CadillacForum Help Desk'. Most mods like me don't have access to subscriber related functions, but someone in that forum should be able to help you.
 

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2005 STS Northstar RWD
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Another observation we've found interesting is that this ECM may have been also intended for the supercharged line because certain parameters are defined to cover over 500 ft. lb. of torque. If some owners would like to do a forced induction conversion, we would be very interested in helping with such project.
There has been a lot of talk lately of those who have been wanting a bit more power from the Northstar. Hopefully you can find someone near by that will work with you on forced induction.
 

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2006 STS 1SF N* RWD NAV F55
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705 Posts
Madtuner. I am, and previously was VERY interested in your ECM tuning, BUT ! De-sensitizing the knock retard.
These engines NEED to compensate for Ethanol 10%, and/or 87 octane,NOT because the manual says to use 92,
but it is the individual States that put in the Ethanol, and/or the owner puts in 87 octane,and the factory
results are , IT does NOT tear up the engine.So can your de-sensitizing mess up the engine, by letting
it knock ? Also Is the learning procedure reduced,because of your tuning. i.e. VATS/CASE,and the dealer
can do this for you ? Do what ? Please explain.
This is NOT a put down, but an effort to understand the WHOLE operation.
Thanks
 

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Discussion Starter #8
The ECM has the ability to compensate for some ethanol content in fuel. It does not do that primarily through knock retard, so what we call "knock retard desensitizing" would not interfere with that process. This desensitizing can consist in reducing its sensitivity towards picking up [perceived] knock (since there isn't any actual pinging or hesitation when the ECM is retarding the timing) and/or reducing the amount of total timing the ECM is able to pull. Your ECM will still be able to pull timing unless you choose to have knock retard entirely disabled.

No ECM learn procedures are necessary when using our software and cable to load the tuning onto your modules. The same applies if you send in your own modules for programming. CASE/VTD learn procedures are only needed for spare/replacement ECMs.

Our software will also allow you to switch between your stock and custom calibration so that you can compare the difference.

As for a general E85 conversion, that is a possibility with sufficient interest.
 

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08 STS4 V8 1SG & 04 SRX4 V8 & 01 Monte SS
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Have you looked at the 08 ECM TCM at all to see if this is present in 08 as well?
Are you even doing any tuning on the newer ones or are you just letting HPTuners and EFI-Live? Have all the fun?
 

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Discussion Starter #10
We cover the entire Northstar line from 1996. All Northstar products are listed in the Northstar section of our website.

The 2007+ cars as well as the V series run an entirely different engine management system, so knock retard calculations are done in a different manner. The system isn't quite as intrusive and aggressive as on the 2004-2006s.
 

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2005 STS N*, 1SF, 144K mi.
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Thank you, madtuner!

I'm itching to have a 'tighter' transmission, and tweaking the engine tuning can't hurt.

Now...to come up with some more funds.

I need tires, rear struts, a rear wheel...and a large raise!

It appears the load it yourself option actually costs more than a straight exchange. Am I missing something?
 

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Discussion Starter #14
The load-it-yourself option doesn't cost more, unless you choose to keep the cable you receive.

The deposit is fully refundable upon the receipt of the cable (in the same condition as it was sent).
 

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Discussion Starter #16
madtuner,

would it be possible to reprogram the computers for a manual transmission?
That should not be an issue, though I would recommend going with the cable option in that case, since additional tweaks may be needed after the initial calibration.
 

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2005 STS Northstar RWD
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madtuner,

With your better focused insight into the moding, do you know what M/T's may work? While the 5speed A/T is a good trans, I really like rowing my own gears. If they would have offered the car with a manual, I would have found one with that option. Ideally a 6speed manual would be awesome...although I think the new Corvette is going to have a 7 speed :)
 

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Discussion Starter #18
madtuner,

With your better focused insight into the moding, do you know what M/T's may work? While the 5speed A/T is a good trans, I really like rowing my own gears. If they would have offered the car with a manual, I would have found one with that option. Ideally a 6speed manual would be awesome...although I think the new Corvette is going to have a 7 speed :)
You will likely need a number of custom-built parts with any manual conversion. I am not aware of any existing LH2 6-speed conversions, but 4L60E kits have been offered in the past for Northstars. Even with a bellhousing adapter, you would still need to find a suitable clutch and most likely have the input shaft modified.
 

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2005 STS Northstar RWD
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I'm guessing you are correct that there are no LH2 6speed RWD's. CHR Fab makes a bell housing to adapt a Northstar to a manual, but I'm not sure if that is for the LH2 or not. I wonder how different the bell housing is on the 5L50E that was used in the CTS as well. Since the CTS was offered with the same A/T and a manual variant, I wonder if the bolt hole pattern is the same. I recall reading that the FWD Northstar engines had a unique bolt hole pattern for the bell housing, not sure if they carried that over to the RWD.
 
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