10mm leads on a 4 litre

[Excitedoldgeezer]

As the subject describes, is it worth fitting the 10mm act leads on a 4litre chim? Do people notice a difference? Or is it better to just have the standard 8mm replacements

[blitzracing]

Waste of time, 8mm is fine on a stock ignition system.

[blueg33]

I got 10mm leads for a good price (kit car show) so I fitted them. Made no real difference but looked good

[Transmitter Man]

blitzracing said:

Waste of time, 8mm is fine on a stock ignition system.

Nah, bigger is better

I'm running Taylor Ignition 10.4's on both my cars: http://www.taylorvertex.com/Products/index.cgi/thu...

Phil

[blitzracing]

Its complete urban myth, the wire insulation thickness simply dictates how much peak HT the lead will take before it breaks down. On a stock RV8 system if all well it peaks out at between 10 and 20 kv, as once the spark starts to burn the HT voltage wont go any higher. On top of this the available HT voltage drops off quite sharply anyway as the engine RPM rises as you only have one coil supplying 4 sparks per revolution, so the coils dwell time becomes quite short. You only need "race" leads if you are running such things as high turbo boost pressures, nitro, LPG, as these effect the peak voltage needed to ignite the spark in the first place, none of which apply to most TVRs. It wont do any harm running 10mm leads, but don't believe the hype that its worth extra BHP over decent stock OEM leads.

[Kitchski]

blitzracing said:

Waste of time, 8mm is fine on a stock ignition system.

[Transmitter Man]

Of course I agree with 8mm is more than ample from a performance standpoint however the large leads are a talking bs point

Who said anything about one coil. I have two coil packs, soon to to be eight coils.

Phil

[blueg33]

Transmitter Man said:

Of course I agree with 8mm is more than ample from a performance standpoint however the large leads are a talking bs point

Who said anything about one coil. I have two coil packs, soon to to be eight coils.

Phil

But Mark said this - so he was talking about 1 coil etc

blitzracing said:

Waste of time, 8mm is fine on a stock ignition system.

[blitzracing]

I would think that the plug firing voltage would go up if you are using wasted spark, as you now have to jump the air gap between 2 plugs at the same time, but I doubt its that much more than a system with one coil and a distributor, as you have the rotor gap to jump as well as the spark gap in this system. The firing voltage is pretty variable at the best of times as it goes up with more air (ie higher compression) and fuel. Typically if say it takes 15kv to fire the plug at idle, it may take 20-22kv to fire it under full load. In the case of the Lucas single coil system, the coil will deliver about 35kv when open circuit, and although this drops as RPM rise's, it never drops below the voltage needed to fire the plug. I see your race leads are rated to 102kv so I think you are safe insulation wise however many coils!

[Excitedoldgeezer]

Ok so the general view is with my one coil on a standard 4 litre set up (as much as you can say they are standard) 8mm is more than enough and the 60 quid or so difference is better spent elsewhere. Just got to work out where :-)
Cheers
Steve