EFI ignition maps

[dap930]

Kenik,

Since your at 8.3 CR, I think it is a good starting point for twin plug. At 8.3:1 your effective CR is going to be higher when you get into boost. You can add 3 or 4* in the 65KPA and below rows for your cruise areas as you will want lean mixtures (at least 14.7:1) here for MPG. You can safely add 2* to your 195KPA row. I run a little more advance than you, but I am only 7:1 CR at best after mods when I rebuilt my 3.0 liter.

[IMR-Merlin]

Originally Posted by dap930

Kenik,

Since your at 8.3 CR, I think it is a good starting point for twin plug. At 8.3:1 your effective CR is going to be higher when you get into boost. You can add 3 or 4* in the 65KPA and below rows for your cruise areas as you will want lean mixtures (at least 14.7:1) here for MPG. You can safely add 2* to your 195KPA row. I run a little more advance than you, but I am only 7:1 CR at best after mods when I rebuilt my 3.0 liter.

my car runs like **** with anything above 13.5 AFR... goes into lean misfire.

[kenikh]

I'm starting out pig rich for initial startup safety margin.

[jpnovak]

Kenik,

There is an asterisk* at the bottom that says initial advance 8 deg. Are these numbers actual +8?
if so, then not so conservative for Twin plug.

[kenikh]

Originally Posted by dap930

Kenik,

Since your at 8.3 CR, I think it is a good starting point for twin plug. At 8.3:1 your effective CR is going to be higher when you get into boost. You can add 3 or 4* in the 65KPA and below rows for your cruise areas as you will want lean mixtures (at least 14.7:1) here for MPG. You can safely add 2* to your 195KPA row. I run a little more advance than you, but I am only 7:1 CR at best after mods when I rebuilt my 3.0 liter.

This will be an interesting exercise. My cams are have lower dynamic compression than most turbo cams, so went with higher static CR pistons to make up the difference, off idle. If you look at the spreadsheet below, you'll quickly see the fine interplay that exists between static compression, dynamic compression at idle and dynamic compression at full boost.

My hypothesis is that one can make qualified ballpark estimates on tuning parameters from superficially different configurations, so long as you have the full complement of compression calculations as basis.

(ignore the head volume values - I fudged them to get the desired calculated static CR values, for simplicity's sake)

[kenikh]

Originally Posted by jpnovak

Kenik,

There is an asterisk* at the bottom that says initial advance 8 deg. Are these numbers actual +8?
if so, then not so conservative for Twin plug.

Good question - I pulled this out of the text/print file. I'll look at the tune file (other laptop) later to confirm. If so - good catch, Jamie. That said, the cited tune is from a single plug motor on pump premium, so we'll see what it really means

[kenikh]

Just notice my calcs above use 7.5:1 as the stock 3.3L 930 static CR, instead of 7.0:1. Dynamic CR of a stock 930 @ 7:1 static CR is:

@1.0 BAR - 12:25:1
@.08 BAR - 11:00:1

[Tippy]

To your point, 114 lobe separation bleeds off cylinder pressure designed for turbo/SC's/nitrous applications....

[dap930]

Merlin,

Something must be amiss. What injectors are you running, Hi or Low Z, dead time? Is it stumbling during throttle change? Or just acting like lean surge? I believe your are full sequential if I remember correctly.
I just reviewed some datalogs I did the other day. I am seeing 14.5 - 14.7 @ 2500 rpms in third gear (about 50 mph). Throttle response is excellent. I could go leaner but I do not want to add any unneeded heat to an air cooled engine.

[IMR-Merlin]

Originally Posted by dap930

Merlin,

Something must be amiss. What injectors are you running, Hi or Low Z, dead time? Is it stumbling during throttle change? Or just acting like lean surge? I believe your are full sequential if I remember correctly.
I just reviewed some datalogs I did the other day. I am seeing 14.5 - 14.7 @ 2500 rpms in third gear (about 50 mph). Throttle response is excellent. I could go leaner but I do not want to add any unneeded heat to an air cooled engine.

I am not full sequential and running 60# injectors. Anything around 14.0-14.5 it starts to misfire and buck. I am out straight with work for the next 10 days. I have a new turbo coming in next month, I will have time to play then.. plus the air gets cooler

[dap930]

Merlin,

OK, I was just thinking that your injector settings may be off some, which is magnified when injectors open more than once per engine cycle. When you get misfires, AFR's start reading richer when in fact they are not. Your 14.0 to 14.5 could be a lot leaner than what shows. Just a thought when you can get back to it.

[kenikh]

The base tune is now loaded to the ECU. I used Windows 10, so for all of the doubters, it's all about the USB to serial adapter. If you're having issues, buy this:

Keyspan High Speed USB to Serial Adapter(USA-19HS) | Tripp Lite

Manipulating Wintec 4 on a fast, modern computer is refreshing.

[JJ 911SC]

Originally Posted by kenikh

The base tune is now loaded to the ECU. I used Windows 10, so for all of the doubters, it's all about the USB to serial adapter. If you're having issues, buy this:

Keyspan High Speed USB to Serial Adapter(USA-19HS) | Tripp Lite

Manipulating Wintec 4 on a fast, modern computer is refreshing.

kenikh,

Very interesting... 2 years ago I bought a new computer (window 8) but it would not connect via the USB 3 ports. Actually, the computer I'm using (Vista) will only connect on the USB 2 port and not on the USB 3 port. I end-up returning it the next day.

Just to make sure before I spend more $$$, what computer is the W10 loaded on, using the Keyspan High Speed USB to Serial Adapter(USA-19HS)?

Thanks

JJ

[kenikh]

Microsoft Surface 3 and Surface 3 Pro both worked like gangbusters with Windows 10. I've also bought a serial to Bluetooth adapter for the Tec3R. Will be testing that soon with my Dell Venue 8 Pro. A wireless tablet dashboard... The mind boggles at the prospect!

[JJ 911SC]

Originally Posted by kenikh

Microsoft Surface 3 and Surface 3 Pro both worked like gangbusters with Windows 10. I've also bought a serial to Bluetooth adapter for the Tec3R. Will be testing that soon with my Dell Venue 8 Pro. A wireless tablet dashboard... The mind boggles at the prospect!

Looking forward to hear the result.

[kenikh]

Originally Posted by jpnovak

Kenik,

There is an asterisk* at the bottom that says initial advance 8 deg. Are these numbers actual +8?
if so, then not so conservative for Twin plug.

I confirmed this setting's meaning with Richard Clewett - that 8 degrees is from the initial advance setting, which he says is for cranking below 500 RPM when cold.

[kenikh]

Did a little bit of tweaking-by-phone with Richard as well on the timing. He felt the higher Kpa values were far too low and the car would run like crap. So we bumped everything up to 20, per below. Plan is turn her over tomorrow and start tuning.

[jonfriedline]

Does anyone have any EFI maps for an 86 930 efi project?

[proffighter]

not 86 but 81 (does not matter I guess). about 95% tuned, so on your own risk:



from another pelican fellow or me, can't tell anymore:

[proffighter]

hmm png not shown. so here it is: