The official EFI Ignition map sharing thread

[mikedsilva]

Originally Posted by Dr J

The physics of this is as follows:
Best power is obtained when the maximum cylinder pressure happens around 15 deg after top dead center (ATDC) (due to mechanical leverage of rod to crank). When the spark plug lights up, it takes some time for the flame front to travel across the cylinder. As RPMs go up, you advance timing to fire earlier, say 25 deg before top dead center (BTDC). This gives more time for the flame front to travel so that max cylinder pressure happens 15 deg ATDC.

With a single plug in the center, the flame front has to travel half the diameter in all directions. In our cars, the plug is off center, so it takes even longer to travel in one direction.

With twin plug, you start two flame fronts so you get peak cylinder pressure faster because the flame front travels half the distance. The result is that you do not need to fire so early. Hence, you decrease advance. In fact, keeping the same advance can cause the engine to work against itself, generating peak pressure when the piston is still traveling up or around TDC, where you are stressing the piston, rod, and crankshaft rather than using that pressure to turn them.

For the sake of completeness of this explanation, I would mention that other things that affect the speed of the flame front are air fuel ratio, manifold pressure from turbo/supercharging and things like water-methanol injection.

Thanks for this John.

[JohnJL]

Anyone got an official 993 ignition map in table form?

Couldnt find...saw Steve's chart and some linear ones but nothing in table format like the MS3/Rasant/etc

[Cheshire Cat]

Originally Posted by JohnJL

Anyone got an official 993 ignition map in table form?

Couldnt find...saw Steve's chart and some linear ones but nothing in table format like the MS3/Rasant/etc

Not a complete map but should work to start with http://forums.pelicanparts.com/porsche-911-technical-forum/1034061-wanted-3-6-twinplug-timing-map.html#post10515583

[lvporschepilot]

Suppose I should post this here as well. This is pretty close since I swapped to ~25lbs late 90s Corvette injectors (Bosch 0280155931) with Bosch 044 fuel pump @ 65psi. These injectors flow somewhere around 30lbs at this pressure. I may have some more room for ignition timing but don't want to push it until I get it on the dyno. I added a bit more timing while logging but fuel table did not want any more or less fuel. I figure less timing is better if it's not asking for fuel changes.

74 Carrera with RS flares


Engine build:
2.8 twin plug, ITB (Triumph). AEM Infinity 506
Rasant cam and crank sensor (ZF Hall)
10.5:1 JE pistons, standard included rings
92mm Mahle liners, Millenium tech restored
DC65 cam
39/38 ports. standard valve sizes
Carillo rods
964 oil pump (I see about 18-19lbs oil pressure, digitally measured, idle)
Euro racing headers
aluminum flywheel
M & K 2 in 1 out


currently running NGK 8 heat range, but I think those might still be a bit too hot reading after hot run, going to try 9s

These heads, even with 39mm intake port andvery long duration cam, seem to max flow somewhere between 6000-7000rpm. idles ok around 1200. Wants very little fuel due to cams which have tons of overlap. Very streetable engine though, easy.

[Thomas Owen]

Hello everyone, and thanks for all those that have posted and contributed.
Here is my setup, so hopefully someone can get me something to start the car:

1992 3.6, freshly rebuilt and completely stock internally
46mm pmo itb from Rasant
Infinity 6/8h
TPS, MAP, Crank sensor
Built the harness myself
Bosch coil on plug

What else am I missing here? Can anyone supply me with software to get it running?

Thanks
Thomas

[Dr J]

Hello Thomas. If you got your kit from Rasant contact them and see if they have one. Andrew is quite helpful.

[lvporschepilot]

Originally Posted by Thomas Owen

Hello everyone, and thanks for all those that have posted and contributed.
Here is my setup, so hopefully someone can get me something to start the car:

1992 3.6, freshly rebuilt and completely stock internally
46mm pmo itb from Rasant
Infinity 6/8h
TPS, MAP, Crank sensor
Built the harness myself
Bosch coil on plug

What else am I missing here? Can anyone supply me with software to get it running?

Thanks
Thomas

Andrew has a really good base map to get you going.



Anyone else try Link's ECUs? I saw their software at a tuner now and it is a sharp system. Same connectors as Motec otherwise.

[dap930]

Thomas,

If you visit Steve Wong's web site, 911chips.com, you will find some ignition map information for the 964 and 993. I thought about posting some of that information here, but it appears to be copyrighted.

[pampadori]

I recently made an alternate tune for my car that is...lets say a bit more juvenile.

Anyone want to guess what outcome i was going for? Clue - If it was a Japanese car, you could fairly call it a ricer mod! not sure how that translates to German car culture.

[Cheshire Cat]

Originally Posted by pampadori

I recently made an alternate tune for my car that is...lets say a bit more juvenile.

Anyone want to guess what outcome i was going for? Clue - If it was a Japanese car, you could fairly call it a ricer mod! not sure how that translates to German car culture.

considering ign retard on 0 throttle it`s pop`n`bang tune ))

[Hi_Fi_Guy]

Originally Posted by pampadori

I recently made an alternate tune for my car that is...lets say a bit more juvenile.

Anyone want to guess what outcome i was going for?

Does it spit flames on decel?

[pampadori]

@CheshireCat and @Hi_Fi_Guy you're both right. I had to turn off my decelFuelCut to get the most pops and bangs and fire from it. Otherwise the fuel cut kills all the fun. It makes your car very noticeable when you're engine braking beside other cars with their windows down!
I should get a trim pot switch so i can flick back and forth from the regular, more polite tune and the pop n bangs tune.

I also picked up an ethanol sensor that I need to install. not boosted yet or anything that needs e85 but it would be interesting to know what I just pumped into my tank.

What I still haven't been able to figure out is how to get my two-step to sound like a modern 911 Turbo S's launch control. Mine just sounds like blarp........blarp........blarp.......blarp. I want more of a ga.ga.ga.ga.ga.ga.ga.ga.

[lvporschepilot]

Originally Posted by pampadori

I recently made an alternate tune for my car that is...lets say a bit more juvenile.

Anyone want to guess what outcome i was going for? Clue - If it was a Japanese car, you could fairly call it a ricer mod! not sure how that translates to German car culture.

You doin it all loco ese. I'm not mad. Could be fun right

[vanda]

Hello guys,

I am a huge reader of this formum for a couple of years and the read fixed a lot of questions so far

I am running the following gear:
86 3.2 internals stock euro spec
taylor made 48mm ITBs
Alpha N engine control
EMU Black ECU
Equal lenght headers with stock heat exchangers
964 exhaust

after 2 years fighting all kinds of issues and different ECUs I am super happy with the result now. But one worry is somehow left:

My fuel tables look super lean, but the spark plugs and the Lambda say ist fine, even still a bit rich. All other tables look way richer...

Do I need to worry for some reason or did i miss something?

Happy for any response!
Thanks

Attached are my ignition and fuel tables based on TPS/ RPM

[chrisbalich]

Your axes being reversed what most of us run is playing games with my brain.
But if you can only go 20 cells in Y and 16 in X, I understand why you did it.

[Westbound]

Hi my names Jeff and I’m new to this forum, but not new to Porsches. I worked with Chris Flavell ( fetuhoe ) at Fenn Lane, where I started this project 5 years ago.

Here’s my hardware and I’m ploughing through the maps trying to get it running better.

Useful information on here, I clearly need to add more advance to my ingnition at 2000 rpm

Now that’s a job for Monday



Engine is a 2.7 911/81 totally standard with 98mm tall manifolds with injectors in the base, with high butterfly throttle bodies 41mm with 955i injectors and shafts.

All the Aluminum parts, manifolds and throttle bodies I’ve had cast and machined in the U.K., all the linkages are laser cuts, and the cross tube is a based on the Weber one.

I’ll add my maps, once they are sorted.

[Cheshire Cat]

Originally Posted by vanda

Hello guys,

I am a huge reader of this formum for a couple of years and the read fixed a lot of questions so far

I am running the following gear:
86 3.2 internals stock euro spec
taylor made 48mm ITBs
Alpha N engine control
EMU Black ECU
Equal lenght headers with stock heat exchangers
964 exhaust

after 2 years fighting all kinds of issues and different ECUs I am super happy with the result now. But one worry is somehow left:

My fuel tables look super lean, but the spark plugs and the Lambda say ist fine, even still a bit rich. All other tables look way richer...

Do I need to worry for some reason or did i miss something?

Happy for any response!
Thanks

Attached are my ignition and fuel tables based on TPS/ RPM

Ha! I have the same ECU! Wondering about your start up and warm up fueling... What do you use to control your idle?

[vanda]

Originally Posted by Cheshire Cat

Ha! I have the same ECU! Wondering about your start up and warm up fueling... What do you use to control your idle?

Since I am running ITBs I don't run any mechanical helpers or motors.
I run a few correction tables for fuel and ignition which do a fabulous job. Idle is way better then before switching to ITBs. The correction tables below is what helps a lot

Idle Trgt: Target Idle in correlation with temp
Idle ign contol: any deviation from target idle will be corrected via advance
idle ign VS CLT: advances my ignition based on temp
warmup enrichment: just a bit more fuel based on temp

Those settings helped a lot for start up and idle.

Best!

[Cheshire Cat]

Originally Posted by vanda

Since I am running ITBs I don't run any mechanical helpers or motors.
I run a few correction tables for fuel and ignition which do a fabulous job. Idle is way better then before switching to ITBs. The correction tables below is what helps a lot

Idle Trgt: Target Idle in correlation with temp
Idle ign contol: any deviation from target idle will be corrected via advance
idle ign VS CLT: advances my ignition based on temp
warmup enrichment: just a bit more fuel based on temp

Those settings helped a lot for start up and idle.

Best!

You are legend sir! What kind of power have you made if measured? Is your 3.2 from 3.2 Carrera or bored out 3.0 aka 3.2ss?

[Showdown]

Hi all,

I’m in the process of tuning my 77 2.7 x-factory EFI ITB conversion and would like to see some others for comparison. I’m working through some stumbles during acceleration and just need something to compare to.

Thanks in advance!!