Spark plugs ... Need resisted ones ..... HELP! !!

[Slatter]

Hi guys

Im part of the emerald buy and htey have told me i have to use Resisted spark plugs.

Currently im using B7ECS ngks in my engine as thats what john eales reccomended.

However ngk dont do a BR7ECS !

Anyone use resisted plugs in their cars ????

Slatter

[griffter]

I've used BPR6ES in my 4.3 V8. They're the standard Range Rover plug. They have a projected electrode ('P'), run a little hotter ('6') and are resistive ('R'). Can't say whether or not they'd be suitable for your application, but have a play here:

http://www.ngkpartfinder.co.uk/cars_commercial.php

and optionally purchase here:

http://www.mister-solutions.co.uk/bpr4es---br10ecs...

[trackcar]

cant you just use the 5k resistive vauxhall plug heat extenders rather than the cheap non resistive things that are popular aftermarket replacements? i can't imagine you'd need more than that coupled with the std resistivity of the plug leads. Ive fitted many emeralds and never needed extra resistance from resistive plugs yet over and above the items mentioned above.

[Slatter]

Well id never heard of using resited plugs because i thought the leads were. But leoni at emerald has said i will definitly need them :S

[tempus]

Hello,BR7ES is probably as near as you will get but phone them on 01422 281001 and ask would be your best bet.Tempus

[That Daddy]

BPR7ES available all day long,correct heat range and NGK(most important)i use the BP7ES my leads are resistor type so dont need the R plug.

[Slatter]

I phoned NGK they werent exactly that helpful but they said BR7ES im going to go and try and find one at a motorfactors and see how different the S ( 2.5mm centre electrode) is different to the CS ( Low angle ground electrode)

[rev-erend]

Ask why !

I thought the reason for resisted plugs was RF supression.

If you locate the coil packs and HT leads away from other sensitive wiring (e.g. crank trigger) then I don't think there will be a problem.

[GreenV8S]

rev-erend said:

Ask why !

I thought the reason for resisted plugs was RF supression.

That's the main reason on mainstream cars, but there seems to be a common problem with aftermarket systems using direct driven coils, where the voltage spikes on the low tension side of the coil are enough to upset the ECU. It seems that incresing resistance on the HT side smooths out the voltage spike on the LT side and alleviates the problem.

[thenick]

I also spoke to Leoni about this, apparently we need resistive spark plugs and high impedance injectors in order to reduce interference. She didn't really know why but said she had been told to pass on the message from Karl. I have yet to check both parts but the injectors are just run with an inline resistor if they are not resistive. The spark plugs i'm not sure about, other than they need to have an R in the code! If you find out which plugs are going to be best for the job, please post the code up here so everyone can follow suit!

[GreenV8S]

I don't think this is anything to do with the injectors, it's purely about the ignition coil flyback voltage. As an aside though, if you have low impedance injectors these would normally be driven via a peak-and-hold driver rather than a simple square wave - if you just drive them through a resister you won't get the response time improvements that these injectors are intended to provide.

[Slatter]

Been doing some research today

B7ECS that most TVR's run that are listed by NGK and it seems non standard rv8s normally use

B = 14mm Thread diameter
7 = Heat
E = 19 mm thread reach
CS = Low angle ground electrode

The closest i have found are BR7ES ...

These dont have the low angle grond electrode and instead have a Standard 2.5mm centre electrode.

I dont know if its critcal we have a Low angle ground electrode or not.

Ive been told to ring TVR power and try and find out exactly why tvrs run the B7CES 's and hence why the low angle ground electrode.

[tempus]

resistor plugs tend to burn slightly hotter at the tip,this cuts down on fouling,ecu producers utilize this when designing them,modern ones can make them as matched pairs with specific resistances.Tempus

[Slatter]

Right ive been on the phone to TVR power and now have a greater understanding. I explained what the situation was and there reply was .... we have done loads of engines and remaps with Emerald ecu's .... they just use the B7ECS and resisted leads.....

The BR7ES plugs wont be as good, they told me why but its hard to explain so ill try and do some pictures and diagrams later.

Might be worth phoning emerald up though and asking them if the leads are resisted.....

[Slatter]

Right guys ive drawn a little diagram on PAINT !! that should help to show the differences between B7ECS and BR7ES plugs aparted from being resisted the differences are the tapered part and the electrode that you should be able to see from the diagram ....

You will have to click on the "full size" button to see it clearly

http://s156.photobucket.com/albums/t13/novasport13...

[GreenV8S]

tempus said:

resistor plugs tend to burn slightly hotter at the tip,this cuts down on fouling,ecu producers utilize this when designing them,modern ones can make them as matched pairs with specific resistances.Tempus

That's interesting to know. I guess it's something to do with the 'shape' of the spark (current versus time). Does it make any difference whether the resistance comes from the plug or from the leads?

[rev-erend]

trackcar said:

cant you just use the 5k resistive vauxhall plug heat extenders rather than the cheap non resistive things that are popular aftermarket replacements? i can't imagine you'd need more than that coupled with the std resistivity of the plug leads. Ive fitted many emeralds and never needed extra resistance from resistive plugs yet over and above the items mentioned above.

If Jools does not need them .. then perhaps Leoni was passing on a glib generalisation from Karl...

[thenick]

Well what she said to me was that you either need resistive spark plugs or a source of resistance beforehand ie: resistive leads. So it is probably worth asking them if the leads provided are resistive. If not, could we just use resisted plug extenders from NGK?

On the injector front, she said they needed to be either high impedance injectors or needed to have resistors placed in-line to achive a resistance of around 10-12 ohms rather than the normal 2-3. Not sure why though!

[Slatter]

Ive found what we need ....

http://www.spark-plugs.co.uk/graphics/images/plugc...

and main page here ...

http://www.spark-plugs.co.uk/pages/pricing/ngk_plu...

[thenick]

So we need B7ECS spark plugs with SB05E resisted extenders right?