I'm just starting to collect together the parts I need to make up my engine loom for my yb powered mk1 .
I'm using a race technology dash so I will be adding in the extra wiring for all the addition sensors
For the crank , cam and map sensor is it best to twist the cables or use shielded wire to stop interference
Also is knock sensor required ( my existing loom does not have it )
Can the ignition amps be located inside the car ? I'm using MSD wasted spark .
Can the coil pack be mounted to engine under inlet manifold as I'm trying to make it look clutter free
Thanks

 

A lot will depend what ecu you are using.

For any rotational/pulsed signal and VR sensor then yes it should be twisted and screened

Others less important, but it would be good practise to twist wires to items.

Knock sensor will depend on your ecu

Amp can go anywhere, but the route from amps to coils will be high current/high interference potential wires, so wise to isolate them from any sensor wiring.

Coilpack can be mounted anywhere really, avoiding extreme heat etc

 

I'm using L8 ecu with msd closed loop map
coil pack / ignition amp wiring will be shorter than using a standard loom and msd adaptor loom so I don't see any issues there .
looking at a standard wiring loom diagram it only show the map sensor to use shielded wires . I could be wrong .

 

there was a topic recently on some wiring. Strangely teh Cossie uses a screened map sensor wiring.

That is very unusual for any automotive application to do that, but MSD said it was very important.

But there are no downsides to twisting and screening where appropriate. And VR signals like crank/cam, absolutely should be twisted and screened.

 

Yeah I agree with that . any idea where to buy correct gauge twisted screaned cable . 2 core and 3 core ?

 

Raychem 55 military spec cable is what you need.quite dear but the business as regards quality,reliability,interference resistance and voltage drop minimisation.throw it into Google and see where you can purchase.theres a few places in the uk

 

ok thanks for the advice . is 20 awg correct size ?

 

Correct for what ? Depends on the amount of current you are wiring for.

For sensors and very low current items, it would be fine though.

As for Raychem etc etc...it's also easy to go overboard. Depends on your budget, not everyone requires an ultimate spec setup when even the OEM dont use such cable

But any decent thinwall automotive type cable will be fine for most.

 

Yes for all sensors injectors etc in loom I will run separate lives for injectors ,Idle valve , air injectors , O2 sensor etc .
I have found some 2 core and 3 core shielded cable from rs components . I can get for free thin wall single cables . . the price of raychem is a bit high . especially as in want to build 2 looms . and most aftermarket looms are not built with raychem . but undo know a couple of aircraft engineer so I will see if I can source from them .

 

There is no need for separate lives for those items and it will make any loom far bulkier.

just make sure the shielded cable you refer to is also twisted, at least for the crank/cam sensor wiring.

But places like CarBuilderSolutions, or Vehicle Wiring Products, Simtek etc etc will all sell various wiring.

 

ok thanks for the advice very helpful 😀

 

I have just been looking at a loom that I bought new last year from a well known company . Not any wires are shielded or in twisted pairs . Do some manufacturers not believe it necessary to do it ? car has been running fine since fitted .
Also is octain and engine check wiring plugs required ?
thanks