I've been working on tuning my 355 superram R-trim setup with a Haltech E6K, and here are the current spark and fuel base maps that I'm running on. I was wondering if someone could give me some pointers and general comments if these are looking correct so far. The engine seems to be running rich but still acceptable. I'm using 52pph injectors. You guys experienced with this, do any obvious flaws jump out at you?

 

Why is the timing at 15 degrees from 500 to 1500 rpms, and up to -50 kPa? If it's for starting, the HEI ignition module runs at 10 degrees (IIRC) until it hits a certain rpm (i.e. engine starts running, above cranking rpm), and then the ECM's timing control (timing map) takes over.

Also, generally as the rpms increase, the mixture inside the cylinder gets more turbulent, and timing requirements decrease, so you'll see on others timing maps that the timing tends to decrease as rpms climb. YMMV.

How much boost are you planning on running? I see the timing decrease stops at 100 kpA, so I'm guessing 14 psi?

What injectors are you running? If it's high impedence, I don't know of many that can open/close faster than about 1.6ms, which may give the idle some instability. Tune that by ear and WB02.

 

Thanks for your comments!

I have a cranking table that locks the timing at 15 degrees on startup, and it is activated too. Based on your comments, the HEI module isnt paying attention to ECM timing control until above cranking RPM, so the ecm timing map in this area and the cranking map is not really used. My MSD 6AL might also be introducing some timing advance at cranking speeds, but I have not verified this. The engine starts easily right now, but I will change the timing map just to make it right. A starting point is 4 degrees by 500, then 8 degrees by 1000, and 10 by 1500?

My timing is not decreasing as rpms climb. What is a typical slope?

I've seen boost as high as 19psi at high rpms and no load (tire spin). Under load I see about 15 lbs max.

I'm running standard TPI high impedence 52pph injectors made by accel. Does it appear that I have oversized the injectors? What's a good do not exceed pulse width on these injectors?


My wideband should be here by this weekend. Could you give me an idea of what a/f ratios I should be targeting during different conditions?

 

That and Duty cycle..

 

Most forced induction guys aim for around 11.5 to 12:1 when under boost. For cruise, you can run 14.7

Are the numbers in your fuel map pulse width? Most domestic efi systems use Volumetric Efficiency for the fuel map.

That e6k has a lot of resolution. My Big Stuff 3 has less than half that many cells. Are the axes configurable? Is there anywhere I can download the software to have a look at the features?

 

Thanks!! The numbers in my map are pulse width in ms (not VE, but one can be derived or estimaged from the other). The axes are configurable by selecting the use of a 1, 2, or 3 bar map. The load axis self-configures to 32 equal increments of the sensor range. For my case, a 3 bar map, each cell jump is 9.677 kpa. If the sensor reads between any two cells, the computer linearly interpolates between the two table values. It's really a great method!

As far as rpms, you can choose between 32 cells divided into 0-10,500 rpm or 32 cells divided into 0-16,000 rpm. People use the 16,000 rpm resolution to run motorcycles and rotary engines, etc. Again, the same linear interpolation method applies.

Yep! You can download all of the software at www.haltech.com. They have the software for all of their DFI models up online. Although the e6k software appears lame at first, it's super powerful I think!