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Hi, does anyone have Dwell settings for The Red Audi R8 coil packs (part Denso #673-9302)?
I don't know very much about these coils or Dwell settings in general. Are dwell settings something that should be supplied by the manufacturer? Or are they something that should be tuned?
Any help is greatly appreciated. Thanks
You can use oscilloscope to detection it.This technology include standalone courses.
The R8 coils do not need much dwell at all for most applications but they can be cranked up to produce really good ignition energy if needed. Be aware they pull significant current so your wiring needs to be capable.
For most NA and mild boost applications they only need about 1.6ms at 14V - they are pulling about 8A already at that! At 2.5ms they are pulling about 16A each. They saturate at about 12.8ms pulling 18A.
Here is the dwell table from the last time I used them in a mild turbo road engine ~1.4Bar.
Another table here: https://www.50ignite.com/installation-manuals/
"Cannot be run off the mill with ECU’s that cannot handle low input resistance"
How to know which ones are those Ecu's?
You will need an ecu with ignition drivers that can do 20mA at 5V minimum. Most of the common consumer level ecus can, many of the megasquirt variants can’t. If in doubt you will have to query your ecu manufacturer.
Do you have dwell settings for the U5015 Coils (NGK48042) used on TFSI and Lamborghini Gallardo ?
They should be similar to red R8 ones but i cant find good information about dwell vs bat voltage settings....
Adam Walmsley, what spark duration are you using with the coil table you posted, and what spark plug gaps?
If running less than 2.0 ms of dwell and any less than 1.0mm of plug gap my engine misfires all over the place.
With these settings it still misfires under anything else than the lightest load.
I never had any issues with the D514a coils I used previously, only replaced for packaging reasons.
Do these apparently "weaker" R8 coils generally need more spark advance?
My ECU is a Vi-PEC V44
"what spark duration are you using with the coil table you posted," Spark duration will not come into effect with direct spark/COP. It generally only comes in to effect on a distributor V8 where you run out of cycle time at high RPM for full dwell and spark. Set it to 1 or 1.5ms will do.
"If running less than 2.0 ms of dwell and any less than 1.0mm of plug gap my engine misfires all over the place. With these settings it still misfires under anything else than the lightest load." Are you sure reducing spark plug gap gives you more misfires? - It would normally have the opposite effect. What fuel, boost & Lambda are you running? I have personally only used these on relatively mild turbo road engines and didnt need anymore than 1.6ms. They will continue making more spark up to about 10ms though if your wiring is capable.
Adam, thanks for your message.
The engine is a new build, still being run in with no boost, and was running fine (whilst continually alternating light load and engine braking to seat piston rings) for the first non-stop 300 km drive with 0.7mm of spark plug gap, then a few days later, with absolutely nothing changed in the settings, started to misfire whilst cruising for no apparent reason. I then increased plug gap to 0.9mm, which allowed me to get back going but it was still occasionnaly misfiring the more I would increase load (again still running under vacuum). I then increased plug gap to 1.0mm which helped a little further. I am now at the stage of putting more load but it keeps misfiring again, without even being able to run any boost, and it seems to me now that increasing plug gap any further is not going to solve the issue.
Running fresh Euro 98 unleaded with an AFR of 14.7:1 under vacuum, enriching to ~14.0/13.5:1 when nearing atmospheric pressure. Running it any richer under vacuum makes no difference.
For what it's worth the exact coils I am running are the NGK U5015 (the black top ones used on the Lamborghini Gallardo rather than the "bling" red tops used on the Audi R8), and NGK e-mailed me that the correct dwell for those was 1.7 ms, which is pretty much the value where the pointer sits in the coil dwell table you posted under "normal" running conditions, i.e. a stable battery voltage of ~13.5 V on my car.
If your problem was due to “weak ignition coils”, then reducing the plug gap would help (you need less energy to jump a smaller gap). So the fact you are observing the opposite effect suggests it is not an ignition energy problem. I would say you are fouling spark plugs due to them being too cold in heat range. Increasing the gap increases the spark voltage and allows it to “burn through” the contamination. If you are running cold plugs try a standard heat range for your run-in. Once you are driving it harder later you will be getting things hot enough to run a cold plug.
I am running NGK BPR7ES spark plugs. They are not fouled at all, and if anything they look a little whiter than they should when running at stoich, but the engine runs like a sewing machine under vacuum, at least when it's not misfiring whenever I open the throttle a "little too much".
I know of a guy running a similar engine with the same BPR7ES plugs and without getting any misfiring issues.
For reference, in standard normally-aspirated guise and with a static compression ratio about 3 points higher than what I have now, my engine is supposed to run on BPR5ES.