I was, as usual, just spot checking different threads in the Forced Induction forum a week or two ago and there was a discussion about a topic (the name of which escapes me now and hence, the reason I'm posting this thread) that touched on some timing setups some of you good people were using. One of the respondents, I cant remember his user name but he has red pickup truck in his signature, posted some of his Holley Terminator timing setting via screen shots. I've been running E85 for the past several years but haven't really done much on the spark tables, tending to focus more on the VE tuning with my HPTuners. While looking at this gents timing, I thought, "wow. .. .that's all super aggressive, compared to mine". The Holley X, Y axis is based of the KPA and RPM axis, while HPTuners uses Cylinder AirMass vs RPM. I pulled one of my more lengthy scans down into a spreadsheet and ran some analytics on the data to try to correlate the KPA of the scan to the rows associated cylinder air mass. After I had that, I hand typed in the screen shots KPA/RPM from the holley into a separate spreadsheet. Then I created some code in PL/SQL to match them up as well as I could to represent what's in the HPTuners rows and columns. I had to be a little creative to fill in the RPM columns because Holley, rather than using 200 or 400 RPM increments, has uneven breaks like 267,533,1067, 1333, etc. On those, I just averaged between the HPtuners columns that incompassed the Holley columns. At any rate, I then created a spreadsheet to receive the current HPTuners spark table, the Holley based timing setup, a set of columns from the scanners spark logging, then a section that contained potential revisions. The logic in that section first compares the scanner/log output to see if that cylair/rpm cell was hit, if so, it checks to see if the Holley derived cylair/RPM cell is of a higher value that my current tunes cylair/RPM value. If it is, in adds 1 to the current tunes cell value. This new value appears in the 'revised' section. If the test is 'not true', then the original cell value from the current tune appears. I then upload the revised tune to my PCM, take a test drive , logging the drive and then repeating the process.

So far, so good .Runs great and no knock retard incurred as of yet although I've only had three drive cycles, iterations. But the reason I'm posting this as much as anything else, do you guys know whom I'm talking about with the red pickup in his sig? I think he's running twin turbos and has a wicked fast truck. As I mentioned, his timing setup looked far more aggressive than any others I'd seen.
Thanks,
Dave

 

I’m guessing you’re looking for DBRODS. He’s a smart cat.

 

You nailed it. That's the guy....

 

Agreed his table is more aggressive than some. As you know, read the plugs and sneak up on it. Every engine has a sweet spot and you can skip right over it if you get too greedy. For instance, we recently ran a buddy’s engine on an engine dyno and we found .5° either way cost power (and you’d tell me I was lying of I told you how much!). It’s all about cylinder pressure and it can be “finicky” if you will.

 

Dang. As little as .5 difference? Thats incredible. Ive read over the years about the process of getting a good plug reading. At the same time, reading "don't go on a full tilt pass and then shut off the engine immediately. Doing so will cook the oil in the turbos journals". Kinda stuck on what to do regarding that.

I'll amend my utility to add .5 at at time instead of 1. Thanks for the tip!

 

I’d still go a degree at a time. Remember, this was on an engine dyno and it was easy to see gains/losses. May not be that easy to see testing with acceleration, chassis dyno, etc.