8mm plug wires worth it?

[AC_Schnitzel]

I'm replacing items under the hood from a tune-up/upgrade perspective.

Car is a bone stock 88 super eta with plans to make it a "2.7i" and then prep for turbo in the future.

Are upgrading to 8mm spark plug wires worth it? What can I expect to gain from a performance stand point?

Thanks in advance.

[ak-]

IMO, nothing for a street car.

Wires carry electric current. You can think of electric current in wires as synonymous to water in water pipes. The bigger the pipe (cross sectional area), the less resistance the water sees getting from point A to point B.
So, the bigger cross sectional area of the wire (8mm vs 7mm), the less resistance the current fights trying to get to the spark plug.

If you like math:
Resistance = (resistance of wire)(length of wire)/(cross sectional area)

Resistance of wire is always a constant considering whatever material is used. Just use 1 for this example.
Length of wire is the same when purchasing 8mm vs 7mm, so you can see the bigger cross sectional area is the only thing reducing resistance after you work your math out.


So, the way I see it is that if for whatever reason there needs to be a lot more current fed into the motor for X reason, there is no need to go bigger wires, but it's always nice to have more than what you need. Like an extra large soda for your burger when a medium is cool too.

[LowR3V'in]

how much shorter does the 7mm plug wire need to be to
handle the same amount of juice of an 8mm wire.

[roguetoaster]

Depends entirely on the actual spec of the wire AFAIK. But in some cases it could be a 15-20% difference in resistance, at least according to reference tables, and keeping in mind that I'm no electrical engineer.

There's also sheathing, insulation/shielding, and connector types/fitment to consider when choosing one wire set over another.

[DesertBMW]

8mm means the insulation is 1mm thicker. It has nothing to do with performance. Internal wire is the same.

[e30davie]

People seem to make oodles of horspower on the stock ignition system, i would wait until you reach the limit before spending any more on thicker wires.

I personally would go down the route of removing the distributor and fitting either 3 or 6 seperate coils (wasted spark) then the wires are shorter. then you don't need thick ones as you have gained the same thing from shorter cables.

[LowR3V'in]

stock wire from the junkyard is probably fine in a stock engine but since where on the topic
i was looking up what the best wire was an basically moroso blue max with the insulation sleeve was the "best" overkill but so are my coils.

make them yourself it is very very easy.

[ak-]

8mm means the insulation is 1mm thicker.

If this is true, then the only claim the vendor should be making is that their wire suppresses electromagnetic interference better than stock.

Also, yeah there is no performance gain. Current is going to flow regardless to make spark just as much as the engine needs.
There is no such thing as 'more flow! more hp!'.

For the wire length question, just plug and chug the numbers with the equation I provided assuming you want the same Resistance. Make Res of wire variable 1 or 10, doesn't matter.
What you have there is already over kill considering length and the assumption of wire gauge being thicker along with more sheathing.

[AC_Schnitzel]

Gotcha. So it seems the consensus is that there is no significant difference (especially for a street car).

Why do brands like IE or BavAuto charge a premium for these then? Is it more of a placebo?


Sent from my iPhone using Tapatalk

[TobyB]

Durability 'may' improve.

The center conductor 'may' have lower resistance: stock carbon wires are moderately high,
compared to copper.

None of this really makes much HP difference at all until you hit 45 psi of boost and
your mixture is so dense it won't light...

t

[LowR3V'in]

good point how much resistance is there in jumping the gap or jumping the gap at 30psi boosted.
the little difference in the wire resistance doesn't look to me like it really matters n/a.

What i was looking at in wires is the one with the least RF noise and those blue max where the ticket.

[TobyB]

Ooo, lots of the 8mm 'low resistance' wires will be way RF-noisier than stock-

the stock carbon makes a pretty poor antenna compared to copper!

t

[jeffnhiscars]

I remember buying a coil of copper spark plug wire and and boxes of 100@ end fittings and caps for all of $20. I lost track of how many sets of wires I made before I lost track of the bits but to this day I just can't bring myself to pay what they want for new wires.