light duty alt for 2004 miata
I'm considering swapping out the heavy (18#) and heavy duty (80amp) alternator on my 2004 miata track day car for a lightweight alt.
The problem that am considering, is that the OEM alternator uses a phase/driver circuit (in which half of the regulator resides in, and is controlled by the ecu). I would like to swap in a self regulated "one wire" alt and merely unplug the ecu connectors; but am unclear if this would merely send a code, or if the car might not run. Has anyone tried this? |
Tons of NBs have done this. There's a few dozen threads on the subject here.
https://www.google.com/?gws_rd=ssl#q...miataturbo.net |
Thank you. I was able to get a decent diagram from a couple of the threads.
However, I'm still wondering what will happen if the ECU alt leads are left unplugged? In reviewing the search, I haven't seen anyone swap a self regulated alt for a P/D alt and still retain the OEM ECU. |
unplug your current alternator and find out.
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Originally Posted by Braineack
(Post 1231116)
unplug your current alternator and find out.
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Why bother keeping the stock ecu? The 8-10lbs you save from the alternator is kind of a drop in the bucket compared to the like 10hp you get from a standalone.
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Originally Posted by Leafy
(Post 1231378)
Why bother keeping the stock ecu? The 8-10lbs you save from the alternator is kind of a drop in the bucket compared to the like 10hp you get from a standalone.
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Originally Posted by G3ML1NGZ
(Post 1231440)
Are you telling me there are 10hp simply to be gained from a better tune on a stock car? or is my sarcasm meter broken?
No, that's what he's telling you. |
Originally Posted by G3ML1NGZ
(Post 1231440)
Are you telling me there are 10hp simply to be gained from a better tune on a stock car? or is my sarcasm meter broken?
|
Originally Posted by Leafy
(Post 1231378)
Why bother keeping the stock ecu? The 8-10lbs you save from the alternator is kind of a drop in the bucket compared to the like 10hp you get from a standalone.
I did just replace the PD alternator with a standard lightweight. I used a small NDIF/nippendenso internal fan and set it up with a standard regulator... set it to 14.7 V. It charges great, but does cause a dash charge indicator light to light up. With the ck engine, airbag, batt and the occasional the abs lighting up the dash kinda looks like a Christmas tree. |
then you didnt mod the wiring properly.
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Originally Posted by Braineack
(Post 1231655)
then you didnt mod the wiring properly.
...Unless, of course, you are being serious? It looks like the charge indicator light (brn/red) comes off the ecu, and I believe that this is fed by the phase/driver circuit (gry, gry/red). I suppose that I could try to hook up a method to simulate the signals that the P-D portion of the circuit would normally see, rather than just unplugging the connector as I have done. Also, I need to mention that the only new light is the ck batt light. The others have been on because of previous lapses in judgement (gutting airbags, re-chipped ecu and poor braking skills) For the moment: Leaving for the track tonight... and the car charges/runs! |
The alternator worked perfectly over the event this weekend.
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1 Attachment(s)
Originally Posted by speedj
(Post 1231685)
...Unless, of course, you are being serious? It looks like the charge indicator light (brn/red) comes off the ecu, and I believe that this is fed by the phase/driver circuit (gry, gry/red). I suppose that I could try to hook up a method to simulate the signals that the P-D portion of the circuit would normally see, rather than just unplugging the connector as I have done. https://www.miataturbo.net/attachmen...ine=1431964594 i.e., mod the wiring correctly. |
Originally Posted by Braineack
(Post 1232366)
or just do this:
https://www.miataturbo.net/attachmen...ine=1431964594 i.e., mod the wiring correctly. |
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