Starter amp draw Z22?

[Lockleaf]

I'm working on some modifications to my wiring harness and want to do the actual math to see what gauge wires to use, plus a couple other components that are draw specific.

 

So

 

How many amps does a z22 starter draw?

 

Or where might I search for this info? My work computer doesn't have it and my Google fu has failed me.

[Lockleaf]

Ok found some info telling me it draws 1.4Kw.

 

1400 watts/ 12 volts = 112 (ish) amps

 

My tester at work, when I tested a new one, showed the high draw limit as 120 amps for this starter.

 

So 120 is the high draw number number I'm going with, unless someone sees an issue with that.

[DanielC]

A starter, like any electric motor draws whatever current it needs based on the load on it.  Greater load, more current. 

All wires have some resistance, even big starter wires.  The current the starter draws through any cable causes a voltage drop.  Greater current, greater voltage drop.  Smaller cables, greater voltage drop.

 

When there is greater voltage drop through the cables, the starter motor compensates by turning slower, and drawing more current.

 

If the starter cables are "too big", there is less voltage drop.  The starter responds by turning faster, and that in turn means the starter draws less current.  Less current being drawn from the battery means the battery voltage is higher.  This mean the system voltage is higher, there is more voltage available for the ignition circuit.  The engine cranking at a higher RPM, with more ignition voltage starts sooner.   A sooner starting engine draws the battery down less than one you have to crank for a long time to get it to start.  This means the alternator has less work to do.

 

Long story short, I made my own battery cables for my stock 521.  I used 2/0 cables.

[shacks510]

Welding cable

[DanielC]

Welding cable is a good choice. 

By the way, the thing that is hardest on a starter is excessive heat.  Heat is created by higher current flow.  Big thick cables that allow a starter to turn faster, and draw less current, and create less internal heat, make the starter last longer.

[Lockleaf]

Cool. Thanks for the ideas. Soon as photobucket is done sucking I'm posting some wiring ideas to my half pint build thread that brought this question up.

[banzai510(hainz)]

I don't get what your after that the Japanese enginnering haven't thought thru already?????

[datzenmike]

Bigger is better but don't forget that in a circuit the current is the same anywhere in that circuit. If you put in a thick positive cable it will still be limited by the thinner ground cable.

[banzai510(hainz)]

Buy bigger No engineering to think about

[thisismatt]

I don't get what your after that the Japanese enginnering haven't thought thru already?????

 

Really?  These were economy cars to begin with, and although their quality surpasses a lot we see now and since then, they still didn't use the best they could have. 

[banzai510(hainz)]

Im sure the stock cables cables are been changed out since then. Buy the molded lead ends USA Made ones at O rileys.   Never had a proplem Most  ends with corrossion that's cause .

proplems. Run a good battery and use a battery hold down

[datzenmike]

They were at least adequate. Same with tires but you may get better performance with today's tires. Heavier cable will have less resistance to current flow. Less resistance equals less generated heat. Usually starting only takes a few seconds so not a big concern. But if  you have a starting problem some day, a smoking cable shouldn't be part of it. 

[Lockleaf]

If you want to know what I'm doing Hainz, go check out my build thread. Half pint - z22 swapped goon.

 

Thanks again guys.

[datzenmike]

Only way to go wrong is to get a smaller cable than the one used on that starter.

[DanielC]

You have to remember Japanese engineers would probably like to put bigger battery cables on the Datsuns.

But Japanese accountants look at every part in a car, and have this thought.  If we can save a tenth of a yen on this part, and we make 1,000,000 cars that use this part, we save a of of money.

Copper is expensive.

[banzai510(hainz)]

at work we use a FLUKE 400a Amp meter to wrap around the cable to check. But this is a 300$ item Cheaper to just buy a 8ga Exide cable. and buy a gear reduction starter.

update:

read your OTHER thread There is a remote battery with selinoid kit Datsport used to sell but not listed anymore

[Charlie69]

Lockleaf here is something to research.  What is the purity/quality of the copper used in wiring 40 years ago compared to today?  Number strands and the diameter of the strands and the quantity also make a difference in the rating of a wire/cable.