Anyone doing a 2 BAR SD tune yet??

[Redline Motorsports]

We just finished installation of a APS TT kit on my 2006 ZO6. GM High Tech Magazine was here for the last two days documenting the install for an upcoming article.

Next week I planned on getting into the tune and was looking for some "heads up" on the 2 BAR SD issues that may arise that differ from the LS1/LS6 methods.

I assume forced OL, disable MAF, create BEN factor maps, log, copy/paste, regenerate coefficients and rewash should be the basic concept.

Any pointers would be appreciated!

Howard

[johnv]

Done an L76 E38 .
removed the air flow meter and fitted a screw in IAT sensor.
2 bar MAP sensor of course
disable fuel trims
MAF disabled
running in open loop
Set up injector tables for 60 lb mototrons


Auto VE wouldn't work for me, for some reason we were getting commanded AFRs between 1.5 and 2.5:1, pid was not working properly so BEN correction factors were miles out.

So had to do it the hard way:crash:

You will notice with the VVE table when you make changes in one area and then generate coeficients, that you don't get exactly what you have asked for and the table becomes blended to a large degree so you have to keep massageing the table bit by bit to get there.

Took me nearly 50 flashes:music_whistling_1: but ended up with a good result, picked up 80 RWKWs (107rwhp) over the MAF tune that was in it.

You don't have as much control over the timeing in boost as you do with the LS1 COS , pretty much need to use the last row in the spark table and tune to your max boost , so your giving a bit of timeing away at lower boost levels.

Cheers
John

[Redline Motorsports]

Done an L76 E38 .
removed the air flow meter and fitted a screw in IAT sensor.
2 bar MAP sensor of course
disable fuel trims
MAF disabled
running in open loop
Set up injector tables for 60 lb mototrons


Auto VE wouldn't work for me, for some reason we were getting commanded AFRs between 1.5 and 2.5:1, pid was not working properly so BEN correction factors were miles out.

So had to do it the hard way:crash:

You will notice with the VVE table when you make changes in one area and then generate coeficients, that you don't get exactly what you have asked for and the table becomes blended to a large degree so you have to keep massageing the table bit by bit to get there.

Took me nearly 50 flashes:music_whistling_1: but ended up with a good result, picked up 80 RWKWs (107rwhp) over the MAF tune that was in it.

You don't have as much control over the timeing in boost as you do with the LS1 COS , pretty much need to use the last row in the spark table and tune to your max boost , so your giving a bit of timeing away at lower boost levels.

Cheers
John

Thanks John!

Good things to point out to save some azz breaking. The thing with turbo cars is that they are only in small area of the 1 BAR as it doesn't take much throttle effort to see positive boost.

As far as timing......once the motor maxes the timing table I'll have to default to the last column. I wonder if I can use some of the adder tables to control the timing even further....

Howard

[GMPX]

B5155 might assist is bringing the timing back to an area you can tune under boost. If you made it 0.50 in theory you are halving the g/cyl value used in the timing tables.

When manipulating the VVE table you do need to keep in mind that changing just one or two cells in a zone will have very little (or no) effect once the coefficients are generated. You need to think beyond one or two cells. Just experiment yourself, select all the cells in one small zone, reduce it by 10% then generate the coefficients and look what happens, the outer cells will hardly change whereas the center ones will. It's like having severe smoothing applied. Once you get used to that concept it should be pretty simple to manually create the shapes you want.
Also keep in mind you can change the zone map and RPM values to allow greater control in to boost. For example on the LC3 S/C Northstar they moved the high MAP zones to 120kPa.

Also, before you start tuning, select the entire VVE (use the 2 or 3bar one) and add just 1 to the whole table and generate the co-efficients. Trust me, doing that will save you some major headaches thanks to a bug in the ECM code.

Cheers,
Ross

[Redline Motorsports]

Ross,

What is adding one doing???

Also can you use the 1 BAR VVE table to dial in the N/A areas and then select the 2 BAR VVE and dial in the rest? Just wondering if this will give better resolution for cruise and underboost and then it will condense it into the 2 BAR map.

Can the MAF remain with the 2 BAR method?? I don't see why at MAF hertz's that are below the max it shouldn't work like normal but what would happen if the MAF maxes but the 2 BAR is still reading? How is this factored into the fueling calculation?

Howard

[Delco]

Adding 1 forces the coeficiens o be recalculated removing a GM error problem

No it will make no difference just cause a problem if you go from 2 bar vvt to 1 bar vvt as it wil recalcuate taking into no regad the boosted section and stuff up your tuning

[Redline Motorsports]

Adding 1 forces the coeficiens o be recalculated removing a GM error problem

No it will make no difference just cause a problem if you go from 2 bar vvt to 1 bar vvt as it wil recalcuate taking into no regad the boosted section and stuff up your tuning

So this is a flat "1" added to the entire table prior to making changes?

Is this a 1 time add or does it get done prior to every regen? It is only 1 so its not a big change but I can see how it can wake up the regen process.

Howard

[GMPX]

Flat 1 to add, so it really makes zero difference to the actual numbers considering they will range from 1500 - 2500.
It's a one time only change, once it's been done on that tune you don't need to worry about it again.

Cheers,
Ross