Rtek Forum Discuss the Rtek 2.0 and other Rtek ECU's

Ignition dwell

Old 05-29-09, 08:54 AM
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Ignition dwell

Is ignition dwell adjustable through the rtek?
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Old 05-29-09, 06:49 PM
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No it's not.
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Old 05-30-09, 03:48 PM
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Well that sucks. Maybe that's something that could be looked into for a future upgrade?
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Old 05-30-09, 07:39 PM
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You are the only person thats ever asked for that feature since we started in 2003. Thats not to say it's a bad feature, but my limited knowledge of ignition systems (Please enlighten me if you think otherwise) tells me the gain is not worth the effort. You're better off getting an MSD box.
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Old 05-30-09, 07:51 PM
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what is stock dwell?
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Old 06-01-09, 09:21 AM
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Originally Posted by turbo2ltr View Post
You are the only person thats ever asked for that feature since we started in 2003. Thats not to say it's a bad feature, but my limited knowledge of ignition systems (Please enlighten me if you think otherwise) tells me the gain is not worth the effort. You're better off getting an MSD box.
It's not to say that not having it is a bad thing. Stock dwell settings are perfectly fine with stock coils and an MSD box used with them is a good upgrade. The only reason I asked was that it leaves the door open for alternative ignition coils later on. Specifically the LS7 coils since their dwell requirements are so different. If someone were to just swap coils to other units and not adjust dwell, they probably wouldn't get anything beneficial out of it and would probably get worse performance. The stock 2nd gen coils are actually quite nice. Better than even most aftermarket units. The LS7 coils are just awesome though!

NoviceRotaryTech: Stock dwell isn't a set number. Well actually it is but it isn't. There is a base minimum and maximum dwell setting but there is a correction table. Depending on voltage and rpm, the ecu will make adjustments to the base number. They are typically expressed in % of original value. It may be less or it may be more. Dwell is basically the amount of time the coil is allowed to rest and recharge between firings. Obivously as rpm's rise, the available amount of total dwell time available decreases. This also has to change with voltage as a lower voltage will take longer to get the coil charged back up.

Ignition systems are actually quite interesting but not terribly simple. I'm far more comfortable telling people how to tune fuel and timing than I am telling them how to play with dwell. You need to think about things such as wasted spark and multiple discharge setups. Is one intense spark really worse than several? To answer that you need to think of how the flame front in the engine propagates as well as how it does it under different rpms and loads. How does wasted spark and firing the leading coils twice as often as non wasted spark affect total coil output due to necessary dwell settings? You get the idea.

No big deal if it isn't available. It's something I like to play with but most people don't. The rtek is still a very nice easy thing to work with compared to the alternatives.
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Old 06-03-09, 10:51 AM
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if the OEM coils weren't so good people would be more interested in a dwell feature. Their design is such that a simple ignition amplifier solves most ignition problems on the car. I feel like you are applying some of the issues with the Renesis coils to a platform just doesn't have that problem.

The Power FC for example can change dwell on OEM coils (2nd and 3rd gen) but it doesn't matter much because people just hook up HKS Twin Powers and those dynamically change dwell somehow.
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Old 06-03-09, 02:44 PM
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I know how to wire in the LS7 coils in non wasted spark mode through 2 stock 2nd gen trailing ignitors on a stock ecu. The issue becomes that I want to adjust the dwell accordingly but can't. I agree the stock coils are pretty darn good with an ignition amplifier but I also want a stronger trailing spark without having to revert to 3 ignition amplifiers to do it as I want to run negative split in cruise with very lean a/f ratios. I need a good solid trailing light off to get what I want.
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Old 06-04-09, 10:11 AM
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I went with the HKS twin power on my FC, which also amplifies trailing spark and is just a small box about half the size of one MSD. It's only 5 wires: Leading has 1 wire and trailing has two wires, both spliced in with no wires cut. Then there is a power and ground wire. They recommend you wire the power wire into the leading coil.



I ran that at 21psi no problem. It's not cheap, but it's cheaper than 3 MSD boxes, way less wires, and much cleaner. The box is listed as 91mm (L) x 80mm(W) x 34.5mm (H). I had relocated my battery, so I installed the Twin power behind the driver side headlight. There was an empty M6 bolt hole there into which I installed a stud. Then I glued some rubber feet to the bottom of the box to dampen vibration and bolted it down.

Anyway, it's something to consider. I would never have 3 MSD boxes in my car either.
Attached Thumbnails Ignition dwell-fc_twin_power.jpg  
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Old 06-04-09, 03:44 PM
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The twin power definitely looks like a nice option and definitely simpler than 3 MSD boxes. Then again if I could run a twin power along with LS7 coils and then have proper dwell control for those coils...
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Old 05-01-15, 07:44 AM
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Will the Rtek/Stock ECU run these?

https://www.rx7club.com/3rd-generati...-992444/page2/

Looks like an interesting upgrade.
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