I was hoping by performing direct comparisons on all 4 grades I might be able to learn something about the way they are coping with TFSi fuelling characteristics. When the plugs look as carbon fouled as they did on some of the ones I pulled out of 8P2 something is not 100% right. I've never had a car which leaves so much carbon build up on plugs and through to the tail pipes. They were all fitted to manufacturer torque settings, and run with V-Power / overserviced etc.

In my bike racing days we used to use gunsons colour tune which was essentially a glass spark plug which meant you could see the colour of the spark with the engine running and adjust mixture to fine tune a nice blue flame, it didnt take much to turn a yellow flame blue. these days you could not adjust mixture so you just have to rely on the manufacturers or tuners map to get it right. Z14XE, Z16XE, Z16LET, Z16LER, Z18XE, Z20LET, Z20LEL, Z20LER, Z20LEH, X20XEV, C20XE, C20LET, X25XE, Y26SE, X30XE, Y32SE. My point is that a coil in those days would charge to about 20,000v before discharge and one of the advantages of electronic ignition was the much higher ignition coil voltage which meant you could run much wider plug gaps. The reason for this was the low gap and the high voltage meant that the point at which the spark became a flame was lower ie: lower revs. at 10000rpm a plug needs to put out a individual defined spark about 42 times per second and the smaller the gap the more likely the spark becomes a flame. Things are better today because in days gone by and engine would have 2 sets of points for 4 cylinders so the plugs would fire twice a rev once at BDC and once at TDC near enough so the plugs were firing at 80 times per second.Yes, in the past I've dutifully observed the recommendations about not questioning the fact that every plug has been specifically set up for my own personal needs BUT out of curiosity I actually 'interfered' by rolling my sleeves up and measured the spark gap variation on my last two N18 MCS. All right, I finally got the skinny on the plugs. I have read a lot of posts on this forum about plugs, but ended up calling NGK directly. Here is what I learned:

All the above mentioned NGK spark plugs have a Platinum ring around the electrode tip, NGK also provide the following with an Iridium electrode tip, however be careful as the following have a tip projection of 1mm extra in length over the above!

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A special alloy coating covers the shell of every LPG Laserline spark plug, protecting it from the higher temperatures and the increased risk of corrosion. No other manufacturer currently offers a similar coating. NGK is the brand leader in the UK spark plug market and are the world's biggest supplier to many major car manufacturers. Each and every one of their products are designed to meet the most rigorous standards and are the professionals' choice because of their quality and technical excellence. Their plugs can be found in use by teams in F1, WRC and MotoGP. Put simply, NGK genuine spark plugs are the workhorse at the heart of smooth-running engines around the world.

Ok guys, I see the same questions asked over and over about spark plug selection and fitment, so I hope this information below helps. Do we need to be saved from our own stupidity or are there sound economic reasons to be so meekly 'managed' by manufacturers? However, whilst I believe this may be the case for the 'old skool' turbo charging systems the TFSi system is a very different animal, and the way they system obviously mixes its fuel into the chamber means that maybe the heat issues may not be so prevolent.

So for all those who've spent the last few weeks championing that this is a Revo specific issue...... now maybe the time to reflect and realise your trusty Audi and it's lean burn lump ain't quite as complete a product as you once thought as if it can happen with an MTM map...... Nothing is as clear cut as you may think when it comes to engines and tuning. LPG LaserLine spark plugs are dual precious metal spark plugs specifically developed for gas-fuelled engines. The combustion of gas is different from the combustion of petrol and, therefore requires spark plugs that are specially adapted for these conditions. The gas-air mixtures are more difficult to ignite as more ignition voltage is required and the risk of failure of the ignition coils increases. NGK Laserline spark plugs come with a lifetime of up to 60,000 km, clearly outperforming ?normal? spark plugs. For recommendations as to which plug to choose read this: http://www.audi-sport.net/vb/new-a3...-recommendations-s3-8p-2-0t-oem-modified.html

NGK BKR6EIX Iridium Spark Plugs offer an enhanced spark over the standard items, and are a 'cooler' running plug than standard plugs on 2.0 Turbo Z20LEx models. LPG Laserline spark plugs feature an iridium tipped centre electrode and a ground electrode that contains a platinum chip. The tip of iridium is attached in a specially developed laser welding process patented by NGK. The advantage: These precious metals are resistant to unfavourable conditions in gas-powered engines. The spark gap remains virtually unchanged throughout the entire service life. Megane Petrol Saloon 1.6 16V (LA00, LA04, LA0B, LA11, LA16, LA19, LA1J, LA1K,... 1598cc 79KW 107HP K4M 700;K4M 701;K4M 706;K4M 708;K4M 709 BERU Ultra The brand name spark plug in uncompromising OEM quality! Al well-known international car manufacturers use Beru spark plugs and glow plugs in their vehicles. To retain this high quality level when servicing and repairing gasoline engines, we re The heat range numbers used by spark plug manufacturers are generally the higher the number, the colder the plug.

In both cases these plugs had been factory-fitted and run for ~10 000mls. The electrode gap variation was varied so I (later) cleaned them with a stiff plastic brush and set them 'correctly' (imo) to 0.7mm (advised by a trusted tuning firm) to keep as 'spares'. Gaps ranging from 0.5mm to 1.0mm; can't be right, surely? I think the thing I've noticed since running the 8P2 for 60k (40k at S2 or above) is the condition the plugs were in, and it's not that the plug is damaged in any way, it's the heavy sooting that to me says I'm sure something in the set up is not right, and having tried temperature settings 6 / 7 / 8 it only got worse with colder plugs. Stage 2+ adds 38% more BHP with the additional fuelling, extra air in and out, and to be honest on reflection I feel like a bit of a **** that I didn't think to investigate changing the plug gapping earlier given the way the car was eating plugs (plugs that could be salvaged to run a bit further with a gentle clean up). Scénic Petrol MPV 1.6 (JA00, JA16, JA15, JA19, JA1V, JA2B, JA2C, JA0B,... 1598cc 79KW 107HP K4M 700;K4M 776 NGK Iridium 6 (BKR6EIX) - Recommended OEM temperature grade (in car for 15k on Revo Stg 1 - no issues, removed for stage 2)