Battery compensation tables, specifically coil dwell table

Discuss which Sensors work best with these ECUs and share how you are using inputs and outputs
Simon P.
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Re: Battery compensation tables, specifically coil dwell tab

Post by Simon P. »

Edited as per DTAS54 request.

One of the byproducts in the case of pulleys case is that changing the ratio changes the accessories speed, ie the alternator, PS and WP. And in my case slowing the alternator (not my intention, just a consequence of changing the pulley ratio) has created a situation in which at low engine speeds (below 1400RPM) I experience lower than "normal" alternator voltage which I feel may be affecting spark energy in my fixed dwell application. And thus the reason I feel adjusting dwell through the compensation table could be beneficial in my case. Certainly not to make more power, just to smooth out an already decent tune.
Last edited by Simon P. on Wed May 02, 2012 10:28 pm, edited 1 time in total.
DTAS54
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Re: Battery compensation tables, specifically coil dwell tab

Post by DTAS54 »

(edited to remove pulley specific dialogue)

It is a good idea to price check the motorsport versions if that is the only way to get the specs... but that is going to cost a lot I'm sure, compared to finding the data and using the ones we have.

Simon, Steve, and all the others.... I jumped on the grenade and started a thread in Everything Else where we can discuss the relative merits of parasitic reduction.

I would encourage posters in this thread to edit out the stuff on pulley systems and their merit to stay on topic, and move the conversation over there.

This is not helpful to the issue of how to use DTA's feature of variable dwell based on voltage.

Speaking for myself, as well as Simon, we both appreciate the depth of knowledge in the forum about engine management, and would like this dialogue to stay focused on the subject at hand.

The relative merits of parasitic reduction could fill a forum on its own, so there is a place for it elsewhere.

Thanks in advance.
Last edited by DTAS54 on Wed May 02, 2012 9:34 pm, edited 1 time in total.
Simon P.
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Re: Battery compensation tables, specifically coil dwell tab

Post by Simon P. »

Certainly fine with me, I was just explaining why I had the idle low voltage condition in the first place, not trying to convince anyone to strip the paint from their car :lol:
Lumley32, I do have a scope and would be very interrested in you explaining how I can measure dwell at different voltages to build a usable table for my coils. Your input on how to do this "safely" would be most appreciated.
VR6Turbo
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Re: Battery compensation tables, specifically coil dwell tab

Post by VR6Turbo »

DTAS54 wrote:Those Bremi coils for the R32 look very similar to the BMW coils, just a different connector. They seem to be used across a variety of VAG&P engines, much like the BMW which is across many engines too.
Yeah I've noticed modern German engines seem to share a lot of parts these days. Hell, I'll bet VW / Audi / BMW / Mercedes engines are all cast at the same foundary and are supplied with parts by the same OEM manufacturers :lol:

Anyway, if you manage to find any info on your coils, please let me know. I had no luck at all with Bremi. No response to emails or voicemails.

Another common Bremi coil is the 1.8T pencil coil, which also operates in the 2-4ms range, which is on the data sheet Stevie kindly provided on page 1. You can see the abrupt shut off at 4ms precisely, and is also when you get a warning about coil damage in DTASwin....when you exceed 4ms.

As for the pulley debate and what not. Is this not what race cars all about? The last tenth? Is that not what F1 is all about? The kers system giving just that little extra to get past an opponent?

It's easy to be dismissive but this is why we choose standalones in the first place. We don't want to be restricted to a locked down OEM computer, because let's face it, if we all had basic needs and no need to play around with dwell, why aren't we just using factory computers?
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86sixsix
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Re: Battery compensation tables, specifically coil dwell tab

Post by 86sixsix »

DTAS54 wrote:Simon, Steve, and all the others.... would everyone be willing to delete the pulley nonsense from this thread to retain its value, and I'll jump on the grenade and start a thread elsewhere where we can discuss the relative merits of parasitic reduction? I know I'd be happy to edit and clean up the thread, this has gotten way off topic.
get what you like deleted for me, kids - my cars all work perfectly...
Renault 1.6 K7M, '92 Clio 16v shell, Rotrex C30-74, S40, Faceache, Sh***er, YouTube Blue Shed Channel
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86sixsix
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Re: Battery compensation tables, specifically coil dwell tab

Post by 86sixsix »

cheers for the PM DTAS54 - to answer your query openly - no - i'm not even half as old as you are - everybody is dude, kids, guys, boys n girls etc, etc...
Renault 1.6 K7M, '92 Clio 16v shell, Rotrex C30-74, S40, Faceache, Sh***er, YouTube Blue Shed Channel
lumley32
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Re: Battery compensation tables, specifically coil dwell tab

Post by lumley32 »

long story short you measure the current going into the coil as its charging the current rises from 0 to say 7 amps then levels out, the dwell should be slightly more then the time that the current is rising.

have a look at the pic its from the pico scope web site, that's what i use (i borrow it from my local collage) as you can see this coil is beaing over charged and will get hot!! once the coil has saturated (peek current draw) it will not produce any bigger a spark no matter what you do!

hope this makes scene!

as for the pullys (i no off topic) after talking to a friend of mine i now understand, nothing to do with drag, all about not over speeding the aulnator
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Simon P.
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Re: Battery compensation tables, specifically coil dwell tab

Post by Simon P. »

Interresting... Do you limit input current or let it rise freely and let the coils natural inductance control inrush? I have a good DC power supply but I think it's limited to 10 amps or so...
stevieturbo
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Re: Battery compensation tables, specifically coil dwell tab

Post by stevieturbo »

You have no way to limit input current. Once the coil is charged, it's charged.

A bit like filling a bucket of water with a hose. 12v is the water pressure and the bucket can only accept so much water. Once full it's pointless filling any further
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ignitionautosport
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Re: Battery compensation tables, specifically coil dwell tab

Post by ignitionautosport »

Bosch igniters often have current limiting built in depending on model, [edit: oops must learn to read other posts haha]
Last edited by ignitionautosport on Fri May 04, 2012 5:16 pm, edited 1 time in total.
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