LS2/LS7 coils and DWELL Time

[STATUS]

I would expect a faulty coil or wiring issue.

Not having any issues with LS2 coils on standard coil maps from 04Uxx.

At what power? Pretty common to misfire above 400awkw

[bachig24u]

I would expect a faulty coil or wiring issue.

Not having any issues with LS2 coils on standard coil maps from 04Uxx.

At what power? Pretty common to misfire above 400awkw

I haven't bothered to measure the power but they haven't blown a 60A circuit yet, I allow 10A/Coil.

LS2 or even LS1 coils will run 1000+hp drag engines wherever you measure it.
quality of coil, plug gap, fuel type or mixture density & compression have bigger influences than awkw or any hp number.

[STATUS]

I would expect a faulty coil or wiring issue.

Not having any issues with LS2 coils on standard coil maps from 04Uxx.

At what power? Pretty common to misfire above 400awkw

I haven't bothered to measure the power but they haven't blown a 60A circuit yet, I allow 10A/Coil.

LS2 or even LS1 coils will run 1000+hp drag engines wherever you measure it.
quality of coil, plug gap, fuel type or mixture density & compression have bigger influences than awkw or any hp number.

I know we have no issues, we have even made 1007hp on std oem coil packs, i was referencing to the std 04Uxx dwell maps... they tend to missfire on cars making over 400awkw on std dwell maps usually due to the boost required to make that power on a pair of small turbos... quick tweaks make good inroads.

[bachig24u]

STATUS post your quick tweaks so Bgytm can get on with troubleshooting the real issue.

[rick88ss]

STATUS post your quick tweaks so Bgytm can get on with troubleshooting the real issue.

I would like to know too so I can correctly setup the dwell time when I install my LS2 D514A coils

[Bgtym]

table may dwell duty cycle is in degrees of crankshaft rotation as Apexi PFC ?





table in nistune almost similar. perhaps slightly different algorithm for calculating the charging time.

[Matt]

No, it doesnt match that at all

Dwell vs RPM table is an internal table to counteract the reduction in CAS pulse length (used for calculating dwell) when RPMs increase.

ECU internal pulse processor chip uses a counter (triggered by the CAS signals). As engine RPM increases, CAS signals are shorter, so the pulse time decreases. The dwell vs RPM table is used to counteract this to maintain a consistent dwell time over the entire RPM range.

Would not recommend changing this table, unless you want more/less dwell in a certain RPM section (adjustable by percentage of change)

Dwell vs Volt table is used to increase dwell time when battery voltage not as high.

Default dwell time is about 3ms or so using these default tables. Nistune reports the dwell time on the core ECUs we support. The dwell vs volt table can be modified by a percentage to offset the default dwell time to suit different coils

[unkn0wn]

Default dwell time is about 3ms or so using these default tables. Nistune reports the dwell time on the core ECUs we support. The dwell vs volt table can be modified by a percentage to offset the default dwell time to suit different coils

Hi Matt,

When doing consult data of a s13 sr20det today, dwell time was showing 0.00 - does this feature work on this ecu?

cheers, christian

[Matt]

Make sure ECU is in 'tuner mode'

Yes coil reporting time is enabled for this ECU

[unkn0wn]

Make sure ECU is in 'tuner mode'

Yes coil reporting time is enabled for this ECU

Hi Matt,

I tried again tonight, still nothing showing.
I did a screen capture, but it seems it did not work

The car has AEM smart coils and is missing the standard Igniter - would this cause an issue?

[Matt]

The parameter is there but value was 0. I found incorrect memory address was used for this ECU

I'm doing a new update this week after a few more changes so I'll include it with this build

[unkn0wn]

Just to get back to you, I was able to pull up dwell time on the s13 sr20det after the update.

It fluctuates much more than i had anticipated, especially when backing off from WOT seems to spike.

Playing with the voltage offset was able to increase the dwell time average, while also increasing the spiking.
Is there another table to help adjust the throttle input vs dwell time? to help get the number to a more static fixture?

[Matt]

That is the only number I can get from the ECU (as part of its dwell calcs). Only using a scope and directly looking at the pulsewidth itself to get a clearer picture

Work with the average. I wouldnt worry about the spikes in reporting (decel will cause a large change in numbers so may upset the calculations I use)

[Bgtym]

Matt can you help with the connection coils LS-2? possible problem in the control signal, increasing Dwell Tim does not give result.

The LS2 built in coil igniters (the amplifier that drives the coil's primary current based on the sequencer signal) will follow the sequencer signal pulse width. When the signal from the sequencer is high (3 to 5+ Volts - with very little current from the controller, a few dozen milliAmps), the coil current will be building. When the signal from the sequencer is pulled low (shut off), the coil will spark. The duration of the signal from the sequencer determines the dwell (though the coil igniter limits this to no more than ~8 milliseconds).

http://www.megamanual.com/seq/coils.htm

[Matt]

I'm not sure how I can help with this one?