Coil packs - R8?

[Shivas Regal]

Hi Guys I need to change coil packs on my motor. I've had heard the R8 ones are a direct replacement and have better/higher resistance.

Can anyone shed some light on this and/or recommend good brand.

Cheers guys

[Mɐʇʇ]

Can't think of any reason to do it, to be honest...replacing coils only adds power if the originals weren't fit for purpose (and would show itself as misfiring under load, or when hot, for example).
So I would stick with stock. (and have, when I replaced all mine)

ECP do some Bremi ones which IMVHO, are good. Product Code 413440400

[Bladerider]

Awesome GTI stock them slightly cheaper as they are a popular upgrade for most VAG cars.

R8 V10 are the best and do have a slight higher resistance rating which means a slightly better spark 5.2 Mohms compared to RS4 3.8 Mohms from memory.

Use them on our tuned japanese motors as well.

J.

[Mɐʇʇ]

So what do we mean by "slightly better spark"? P=IV and V=IR. Or I=V/R, so P=V^2/R.

What this means is that at the same voltage, a higher resistance puts less power into the coil to generate a spark. Are you sure you mean higher resistance?

I was always told that a coil is either man enough for the job - it creates a hot enough spark to correctly ignite the mixture and cause the flame front to propagate - or not. And "not" means the mixture doesn't ignite. So a decent increase above stock horsepower would mean that the dynamic compression ratio increases - hotter spark needed, along with probably a colder plug too.
So I'm not saying it'd never be necessary to upgrade the coils - just that on a stock or stage 1 motor, it'd be a waste of money. Maybe the stock coils don't last so well - that'd be a reason to upgrade I guess. But mine lasted at least 11 years....

Now on a direct injection motor, I guess they could be holding the spark alight for longer (maybe, I've never researched them), and on a turbojet injection motor, all manner of funky stuff could happen. But our motors aren't this.....

Happy for someone to tell me they're running R8 coils on their C5 RS6 and how much better than stock they are on the dyno - and the moment I understand "why", I'll go and buy them myself....

[Shoppinit]

Maybe the bigger spark helps to blast away some of the carbon build up on those V8 FSi engines...

[Bladerider]

LOL

You can carry on playing with Ohms law all you like !!

The higher resistance makes a better spark because (as I understand it) its related to the secondary winding around the coilpack that allows a greater strength field to be available when the primary is collapsed which is what gives a hotter, brighter spark - allowing you to open the gaps on the plugs all other things being equal or keep the gaps the same in a harsher environment in, for example, a higher compression or more densely charged cylinder.

I dont pretend to be a science teacher or jet engine specialist

But yes, higher resistance in this same basic design, matched to the cars ECU and firing/control systems is generally "better"

J.

[Bladerider]

Oh,

And given that they are no more expensive than RS4 ones, are a product that tends to have say a 10year shelf life, and can be had from external vendors at a slightly better price, then I for one am happy with getting them at some point.

What i can definitely say from personal experience is that they make a distinct improvement at 400bhp, 500bhp, 600bhp and beyond in turbocharged 4 & 6 cylinder engines and will be used in my 900bhp engine this year !!

Hope that helps.

[Mɐʇʇ]

What is the distinct improvement and can/has it been measured on a dyno - that's the £64K question for me.
I used to do all manner of things to my cars and then tell myself it made it better. K&N filters for example - that louder induction noise definately always made the car faster...

[Bladerider]

There is more to life than horsepower numbers.

I doubt there is enough improvement from this specific item that you will particularly measure on a Dyno if all other parameters are kept equal on these engines which are in such a relatively low state of tune. But that does not mean that minimal gains are to be ignored or other possible benefits of a cleaner burn are not "worth it" considering as pointed out, that these are not really any more expensive than the standard units in our cars.

Would I go out and buy them tomorrow if my car had only just had stock coilpacks replaced within the last two years ??......No
Would I go out and buy them tomorrow if my car was already tuned a bit but running stock coilpacks ??.....Probably, Ive already spent far more than the £200 the coilpacks cost.
Would I go out and buy them tomorrow if my car had no issues I could detect but didn't know if it had ever had coilpacks ??.....Maybe, depends on how much I enjoy spending on the cars - under £200 for coilpacks that eliminate a possible future failure is probably something I would do. But mainly I think anyone who enjoys these cars regularly end up spending alot more than the coilpacks cost for all sorts of dubious mods and stuff with no discernable "performance improvement" - for example, anything carbon we buy is purely aesthetic, despite carbon items coming from a technology to save weight and increase performance and usually these things cost a fortune !!

As I said - from my own and other tuners experiences, the more normal VAG coilpacks often suffer misfires and reduced performance even at the more modest power levels circa 150bhp/litre. On my SR20 it was ok at 200bhp/litre with brand new TFSI coilpacks but would not get past that point, but switching to R8 coilpacks was fine for over 250bhp/litre and on other engines my tuner has built they were fine beyond this.

I guess it comes down to what you do with your car, what you like spending your money on, what you consider cost vs benefit wise is a good deal, your attitude to what mods are a priority and a whole bunch of other stuff, thats your personal choice. But there have been lots of tests to demonstrate that the R8 coilpacks are an improvement, whether its enough of one for you is dependent on that personal choice.

J.

[V!per]

Awesome GTI stock them slightly cheaper as they are a popular upgrade for most VAG cars.

J.

Can you get me a link to them - can't figure which ones are they

[Mɐʇʇ]

No need to get defensive.

I googled it and I think the answers eventually clear - if you're running a high boost motor the R8 coil produces a slightly hotter spark to help prevent misfiring without having to close the plug gap up. The C5 RS6 doesn't need that, but the coil is a nice red colour which some people like - except you can't really see them under all that OEM carbon.

And, BTW, Anodised & Black Ancantara interior FTW, BYW. Not carbon.

Stuff..

[Bladerider]

No need to get defensive.

Please show me where I was getting defensive ??
I was trying to educate you but I guess you can only lead a horse to water lol

I googled it and I think the answers eventually clear - if you're running a high boost motor the R8 coil produces a slightly hotter spark to help prevent misfiring without having to close the plug gap up. The C5 RS6 doesn't need that, but the coil is a nice red colour which some people like - except you can't really see them under all that OEM carbon.


Oh and Im glad you found on Google what I had already told and typed for your benefit, while you were mistakenly blathering on about Ohms Law while not understanding the simplest principles on how Coilpacks actually work !!

And, BTW, Anodised & Black Ancantara interior FTW, BYW. Not carbon.

I haven't the foggiest what you are talking about, firstly its Alcantara and secondly I don't think interior trims have been discussed in this thread, so I have to admit you've successfully baffled me on that one.

Stuff he obviously wasted his time typing lol

I guess they were right...........

.....you can't fix stupid !! lol

[Mɐʇʇ]

Oh do grow up. I'm sure you a nice enough guy face to face.

[Capt Ric]

Shame, this was an interesting discussion until it turned nasty.

[Mɐʇʇ]

Agreed.

Shame, this was an interesting discussion until it turned nasty.