Spark plugs for megajolt
Turbo Mini Forums

Can anyone please give me a reasoned explanation why it is recommended that we use resister type plugs for Megajolt systems ?.

I have two sets of Champion NYCC plugs which I found able to resist a high speed misfire under full boost better than most, when using the standard M/T distributor and would like to use them.

Resistor plugs prevent electrical noise in both the ECU circuitry and TV/ Radio reception.

You can use either resistor type leads OR resistor plugs, NOT both. Most modern leads are non resistive so you need a resistor plug. If you use a non resistive plug and non resistive leads, you can overheat the ignition coil and perhaps damage the ignition driver in the ECU, that is because the overall resistance is too high allowing a greater current/ voltage at the plug and ECU. You'll get a good spark, but the ignition components might not like it and your neighbours will hate you for ruining their TV reception during Corontaion street.

Thanks Sprocket - did you mean "too low" in the third line rather than too high, as I am confused otherwise ?.

I have silicon leads - no idea if they are resistive or not - how do I tell ?

Got to get this right in my mind as I,m going to the RR on Wednesday and dont want to get anything wrong in case I damage not only my wallet.

No he does mean too high, resistive plugs and leads increase resistance overall.

Sorry to persist on this but I do want to understand. If there are NON RESISTIVE leads and or plugs, how does this INCREASE the resistance ?

I can understand that if the resistance is too low it might allow damage to other components.

Sprockets original comment about reducing electrical noise is also understood (I think !)

I think Tadge has it right.

i belive Colins post should read....

Resistor plugs prevent electrical noise in both the ECU circuitry and TV/ Radio reception.

You can use either resistor type leads OR resistor plugs, NOT both. Most modern leads are non resistive so you need a resistor plug. If you use a non resistive plug and non resistive leads, you can overheat the ignition coil and perhaps damage the ignition driver in the ECU, that is because the overall resistance is too LOW allowing a greater current/ voltage at the plug and ECU. You'll get a good spark, but the ignition components might not like it and your neighbours will hate you for ruining their TV reception during Corontaion street.

Yes mistake on my part and should read as Joe has kindly edited for me :$

Glad I now understand -thanks to all for your patience.

i think youll find that most modern ht leads do have a bit of resistance in them tadge , its generally about 5 to 12k ohms .

i v found that ,even with coiled stainless choking type msd leads , i needed to run the resistor plugs so i didnt interfere with the computer on the car ,and also to be safe for other computers ill be fitting this year .


oh ,when are you coming out in my car ???lol

Edited by robert on 28th Feb, 2010.

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

Propper boost control ?

OK, got that, thanks

Thought I would let you get it up (to 200 BHP that is ) to allow for my bulk before coming over.

Actually, let me get mine RR,d and see if the weather perks up a bit and I,ll be in touch -I hadn,t forgotten.

Which RR are you going to on Wednesday Dave and any idea of what you're expecting ?

Richard.

Minivanless, but reluctantly happy living with the decision. There'll be another one day.
http://www.youtube.com/profile?user=minimadmotorman#p/u

Richard I,m going to Lynx AE in north Bucks. Jon Lee there seems to know a good deal about A series, SU,s and turbos ans he is interested in my car so it all looks good.

As to what figures to expect, I had dreamed of about 140 but Jon says this is highly unlikely - we shall see. Whatver the figures as long as it drives right I shall be happy.

how did it go ? success ?

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

I wasn,t going to admit this but it was almost a total bust. Jon Lee is a great guy and really seems to know his stuff and was very patient with me but he could not do much as the MJ refused to play -no spark. It ran yesterday on MJ , but I drove it there(and back!) on the distributor.

All we managed to prove was that my fuelling was spot on, to my amazement, and that the distributor is knackered.
I did see a little over 100 gee gees at 5000rpm on 7lbs, which is pathetic.
However Jon says he has not ever seen the sort of figures I see on here, so unless someone else goes there with a known quantity I will never know.

He and I are both keen to re-visit when I sort the MJ, but right now the only thing that is stopping me setting fire to the car is the fact it might burn down the workshop and my bikes with it.

Must go now, my tears are watering down the scotch

Oh bummer

Go in, have a cup of tea, and come back to it at the weekend

Edited by robert on 3rd Mar, 2010.

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

Robert do you have a graph for everything? Most recent posts seem to feature one of your graphs!

Interesting point about spark plugs, I hadn't considered the need to change them when megajolting. Something else to add to the shopping list.

Edited by minimole23 on 3rd Mar, 2010.

Nice to get some encouragement, but the comparison that I make is that the original M/T made 93 bhp and I have spent time and money on a decent head and cam, plus an intercooler and a bigger exhaust - and all for 7 bhp ?.

I,ve been casting glances at the Polestar ecu, which looks like a very simple system compared to piggybacking the MJ on to the Edis -has anyone on here used them ?

Schrödinger's cat - so which one am I ???

Maybe but the Metty made it at 6130 rpm, back at 5000 rpm I'd hazard a guess that it was only making about 75 bananas so you're considerably up on Rover.

Edited by Rob H on 3rd Mar, 2010.

turbo 16v k-series 11.9@118.9 :)

Denis O'Brien.