Subframe is ready to go in!
But before I do that, I am thinking of running the power cable (so I can utilise the clip behind the subframe/firewall).

What gauge wire do I use? Is 8G enough or do I go wih the heavier duty 4G?


4GA OFC Super High Current Power Cable

- Conductor Material: OFC
- Insulation Material: PVC
- Stranding: 7 x 7 x 34/0.127mm
- Wire Diameter: 7.7mm
- Total Diameter: 10mm
- Current Capacity: 110A
- Resistance @ 20°C: 0.00097/M
- Conductivity: 98% up



VS



8GA OFC High Current Power Cable

- Conductor Material: OFC
- Insulation Material: PVC
- Stranding: 7 x 95/0.12mm
- Wire Diameter: 4.05mm
- Total Diameter: 6.5mm
- Current Capacity: 56A
- Resistance @ 20°C: 0.00252ohms/M
- Conductivity: 98%


Or am I on the wrong track all together?

Any help appreciated.

4 gauge or bigger is what you want.
Every time the wire goes through something or is held by a clip, put additional plastic based tube around it locally. New rubber gasket in the boot is a must too.

4G should be the go.

Mini starters are rated at 0.8KW which is (at 12 volts nominal) 66 Amperes at full load. 8G cable is not rated for 66 amps continuously, it could probably handle it periodically...but I wouldn't all the same.

At full load, the 4g wire will lose 0.18 volts along it's length while the the 8G would lose 0.51 Volts. Doesn't sound like much, but it will lose about 19% of the available starting torque because of this small voltage drop.

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SooperDooperMiniCooperExpertEngineering

All garage work involves equal measures of enthusiasm, ingenuity and a fair degree of irresponsibility.

Excellent.. Yeah I thought the 8G would be a big light.
Some places recommend 2G, but at the end of the day, I won't be holding the starter down for any more than the bare minimum - any more and you start heating wires up; the current loss becomes higher and its pointless - if its not starting, there's something wrong!

*off to the shop later to get some 4G*



PS Should i route it before the front subframe goes in or does it not really matter?? Should be able to poke it through the gap shouldn't I?

It is best to route it before the subframe goes in as it is a pretty tight bend through the top of the rear subframeand it goes through a pretty narrow space.

Take a look at a larger size, it will only improve the voltage drop across the cable. Look at it side by side and compare the outer diameters. If its not much bigger overall then it might be worth the hassle.

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SooperDooperMiniCooperExpertEngineering

All garage work involves equal measures of enthusiasm, ingenuity and a fair degree of irresponsibility.

B&S is the new measurement for cable - "gauge" is no longer the industry standard.. apparently!

I have been recommended to run 2B&S - do you think that would be the go?

I think this is one of those situations where size does count. However, the quality of your terminals (& attachment thereof) is also important if you want to reap the benefit of all that low cable resistance.

AWG now defunct? Bugger, another thing to remember

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1967 Cooper S - new front bearings to do.
1965 Cooper S shell - Slow progress. No time or money!
1966 Deluxe- next rustoration!
Mk 2 & XJ6 Jags. Less said the better.

Do you use the 4g with the fine copper strands like I do in car audio? Standard cable for the car has thick strands. I've always wondered and never asked.

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Its cheaper to make it with thick strands, thin stranded wires are typically made for flexibility as the wire is annealed to be repeatedly bent and shaken by vibrations in a car. You can pick it out as they usually specify the number of strands and the area for each in the specifications. The higher the number of strands for a given cable cross sectional area, the more flexible it will be (and more expensive). That's why supercrap cable is so shitty.




Go with what they say, they're the experts willy. As long as it's similar or larger in size to what you have now (actual copper that is) then you will be fine. Like AEG163job says, mind your terminals, and it will work just fine.

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SooperDooperMiniCooperExpertEngineering

All garage work involves equal measures of enthusiasm, ingenuity and a fair degree of irresponsibility.

I used 4G red amp power cable in my clubby, it looks good and delivers the power.

I have measured the current draw when starting a mini and it was about 80 - 90 a using an inductive pick up.

8G handling 56A won't like it.

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Dean Hutton's first car was a Mini.

I use 25mm² welding cable, it's about equivalent to 3G. But more flexible, double insulated and usually cheaper to buy.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.