20v Silvertop stock ignition timing and fueling maps

[Lykowsky]

Hello,

I'm building wiring harness from scratch for 20v ST in ae86 zenki chassis to run Ecumaster EMU standalone.

I would like to speed up a bit and put factory ignition and fueling maps as a good starting point, because at the moment only changes to engine are:
COPs, Hall sensors for camshaft and crankshaft trigering, EGT thermocouple, wideband O2 sensor, open velocity stacks 70mm.

At the beggining I will not use factory VVT'i, it will be replaced by adjustable pulley for both inlet and exhaust.

I will also run 4-1 exhaust header with 2.5 inch exhaust - I'm bit worried that will be too much in diameter but we will see.

For near future I have planned to use factory inlet BT camshaft as it has bit bigger lift and will not require valve springs upgrade.


Did anyone download Ignition and fueling from stock ECU?
I also would be happy to have tables showing values to put manually into new ECU.


Best regards
Lykowsky

[Project D]

I highly doubt you will find anybody with a stock 20v silvertop map.
Stock ECU calculations on the silvertop are based on air flow meter (AFM), so going open ITB means going with a manifold air pressure sensor (MAP) or, even more likely because of the ITB, Aplha-N (TPS based) instead of the AFM, so you would have to start form scratch anyway.
Honestly the hardest part with a standalone ECU is the initial setting.
If you can get past that and once the car start, time to go to the dyno for a proper calibration.

[jondee86]

Found these at the bottom of my sock drawer Said to be Blacktop base
maps. Extremely basic and don't look like they will do any harm unless you
go crazy driving on them. But should be good enough to get the engine
running...




Based on 290cc/min injector size and set up for a TPS only tune. The fuel
map is in milliseconds, but I also have it as a V.E. map if that is any help.
As said TPS will be by far the easiest way to tune your engine. Just make
sure you have a WBO2 gauge so you can monitor the AFR and keep the
mixture on the rich side. No running less than 14.5:1 AFR when warm until
you can get it tuned.

Disclaimer: I have not used this tune. Use it at your own risk.

Cheers... jondee86

[Lykowsky]

Wow, much appreciated, to be honest I was losing hope that anyone will respond on this. Thank you

ECU that I currently plan to use allows some extended tuneability, I red quite few articles already mentioning that Alpha N is one of the options.
However Alpha N has some downsides especially when car is used for daily driving with different weather conditions, partially you can manage this issue with Barometric correction from MAP.
I'm also worried with Alpha - N behaviour on part throttle operation.
I will plan at the beginning with MAP and will see how it behaves.

Regarding AFR I believe software provide ability to switch on alarm when running above certain set value.

@Jondee86
Can you also share V.E map please?

Lykowsky

[jondee86]

This is the VE version of the ms fuel map shown above...



Looking at it seems that the whole map could be could be lowered by
20 to bring the numbers down to a more realistic level. However, with VE
maps the actual numbers are not important. It is the shape of the map...
the ECU calculates the correct fueling based on the input settings you
have entered, and the map just shows a picture of how the fueling varies
across the rpm/load range.

As an example, my s/c engine runs on a VE map that does not go higher
than 55 at any point (don't ask me why) Starting from scratch an
engine will usually run if you make a VE map with the first row at 50% and
the last row at 80% and adjust from there using the WBO2 gauge.

Tuning ITB's using MAP for load axis works well for idle and low throttle
openings if you have a stable MAP signal (averaged across all 4 throttles
and damped). But because the MAP signal drops rapidly as the throttles
open, the MAP signal will usually be at 100kPa by about 30-35% TPS.

Tuning by TPS does not work so well at idle and low rpm but works much
better for medium and high throttle openings as the fuel load is varied by
the throttle opening all the way to 100% TPS. The ideal situation that is
adopted by many ECU's these days is to have a "blend" of MAP and TPS
load control. MAP control at low throttle gradually changing to TPS as the
throttle opening increases... best of both worlds

Cheers... jondee86

[oldeskewltoy]

For comparison... (16V smallport) ignition map. WOT = 105% on left column, the car idles @ about 50-55 on the left column



my fueling map will not be of any use to you as I run a single t/b, so I run a MAP fueling system.