I'm new to the Turbo scene but not to building drag cars ( over 20 years of n/a and nitrous cars) but needing help setting up the boosted retard curve on msd 6al2. The setup is a 351w blow through with single 76mm turbo at 10 psi. I'm running a 2 bar msd map and not understanding how to setup the curve on the msd software. With the e85 and distributor locked out Im running 40° total timing and need to pull out 20° ( 2° for every pound of boost ) Can somebody help me out on getting this curve charted out correctly on the msd software? Any sample graphs would be helpful also. Thanks in advance! -Rich

 

You will want to set your curve in the "Boost Retard Curve" table. The X axis is boost in psi, the Y axis is the amount of timing pulled from total.

So Your table would be a straight diagonal line from upper left to lower right if you want it 1:1. So 2.00 psi and 2.0 degrees pulled, 4.00 psi and 4.0 degrees pulled etc.

It will be similar to the table show in the instructions for the box here-

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Sounds good. Should I wait til 4 or 5 lbs of boost before I start pulling 2 degrees? I've heard some people say this.

 

I would start off with 1:1 and then go from there. You may be able to hold off a few psi before you start to pull timing out but I would start conservative.

 

Ok thanks a bunch for the advice

 

Pretty sure 2lbs of boost is at 16.75 on that graph...

 

Pretty sure ain't a good enoigh answer for me. I've had several guys look at it including the shop that's going to dyno it and he he said it looks good. That graph isn't mine anyway

 

I've got it figured out thanks neruve

 

The graph posted is straight out of the instruction manual for the MSD box richstang has. I'm not sure what or how you are seeing 16.75 at 2 psi.

In fact the graph pictured above doesn't pull any timing at all out until after 2.0 psi of boost.


On another note. I'm glad it all worked out for you richstang.

 

because it measures ABSOLUTE pressure...not GAUGE pressure