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Wiring questions and advice?

Old 10-09-14, 04:45 AM
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Wiring questions and advice?

Doing a 13b-rew swap in a friends FB. Haltech sprint re ecu, and basically no factory wiring. He's using 850cc primaries, and 2000cc bosch injectors. So to power them, we should just run one single relay to all 4 injectors? Whats the best way to split one output wire from the relay to 4 separate wires for each injector? The same thing for the coils too, but for the coils (aem smart coils), can we use one relay for all of them or do they require too many amps meaning one relay for each coil?

What connectors do you guys use? What quality butt connectors and all that do you recommend?

Sorry this is our first time wiring like this so any tips and pictures will be helpful. Thanks!
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Old 10-10-14, 03:44 PM
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Old 10-10-14, 05:40 PM
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Mazda uses 1 relay (the EGI main relay) to power both the coils and the injectors. Mazda splits the switched wire of the relay into a Black/Yellow wire that powers just the injectors, and then the Black/white wire that powers the coils, bac valve, and all the emissions solenoids. Mazda uses a separate fuse for each wire.

so that is how Mazda did it, if you wish you are free to design something different.

it is perfectly acceptable to split the wires earlier, and have 2-3 relays, one for the injectors, one for the ignition, and one for other stuff (bac, boost control, etc). i would suggest that you fuse each one like Mazda did.

Mazda usually splits the wires with a crimp, although its acceptable to solder as well. soldering is solid, so if it is placed in a place where it needs to bend/vibrate, it can crack.

to size the relays/fuses you can either use Mazdas sizing, or you could do the maths and come up with some current numbers, the AEM coils should have a data sheet telling you how many amps they need, multiply by 4, to get all of them, and then you want some extra margin, so maybe add 20% and size the wiring appropriately.
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Old 11-01-14, 07:41 PM
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Thanks! Whats the recommended way to split one wire to say 4 power wires for injectors?
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Old 11-03-14, 06:54 AM
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Butt splice. 14g into 4x 20g. I prefer to use non-insulated crimp splices and then cover the joint in double wall, adhesive lined heat shrink. Soldering works well, if it's done correctly.
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Old 11-07-14, 06:54 PM
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Definitely follow what Ludwig said. It's the only way to go.
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