EFI University

[BluByU]

I have an M800 and I've been thinking of changing over to some low impedence injectors. My question is how do I determine if my wire size is large enough for peak/hold. 4amps at 12v should be 48watts right... some of the calculations out on the net differ on the safe and unsafe side. Its currently 8 feet of 20gauge.

[FraserGT]

The M880 is basically the same ECU but with an Autosport connector.

The maximum size wire that the M880 can take is 22awg, so for your injectors 20awg wire is more than capable of handling the current.

[John at J&S]

Blu:

The injector may dissipate 48 watts, but the wires won't.

4 amps peak injector current is the spec you are looking at.

Table 3 on this Belden page shows AWG 22 could handle 11 amps:
http://www.belden.com/pdfs/MasterCatalogPDF/PDFS_links%20to%20docs/03_Hook-Up%20&%20LeadWire/3.28_3.32.pdf

Note this is for a single wire. Derate as shown when bundling wires, since they heat each other.

[BluByU]

[figgie]

Wow

so belden reaffirmed what I knew to be true.

Given the same wire size. The max amperage rating of the wire is dependant on the sheething (PTFE 22 awg comes in at 10amps and probably 11 amps since there is a 50 degree seperation between PTFE and Silicone!) and number of wires in a bundle.