When I asked my dealer about he also questioned the same thing. I cant recall seeing the psm light come on but then again i wasn't really looking at the dash at the time. Id just come off a WOT shift from second through third and had released the throttle at @ 6000rpm just on corner approach, shaved all the speed off on corner entry and then accelerated lightly still in third and then felt a very noticeable judder, so i backed right off immediately and then re applied the throttle lighter. Judder stopped. My first thought was the clutch had overheated under all the thrust of the previous WOT burst but then clutch is not very old and is a 764 Sachs. My next thought was the plugs had overheated and were misfiring. It was a very cold morning so the charge was really strong. It didn't leave me all that confident to pick up the pace again.


I don't think intercoolers are a panacea for the plugs however the cooler the IAT the better it is for the longevity of the cylinder components....plugs being one of them. I think the stock coolers are not nearly as efficient in removing heat as the new .2tt coolers so with a tune where the boost and fuel is increased the combustion temps will certainly increase at WOT. Cool the charge/IAT and its a step in the right direction to offset the rigors of the tune, which in true essence will perform better anyway with a cooler denser charge of air.

 

Actually, combustion temps are primarily a function of the amount of air and fuel that combusts and less so on the temp of the air/fuel prior to combustion. The greater the charge density the more thermal energy is produced and thus power. So if power is the culprit in reducing a plug's life then a more efficient IC would facilitate that.

 

Agree TT. Combustion temps primarily are a direct result of the combustion process which occurs from introducing fuel, air, spark and timing to the cylinder. The cooler the IAT charge to the cylinder the more power can be made from the denser charge which on its own allows the introduction of greater and more efficient variables (air, fuel, timing). However, the cylinder components will inevitably last longer if subjected to a cooler intake charge vs a hot IAT charge. And it all becomes a viscous cycle in the sense that the higher the combustion temps the hotter the exhaust temps become and as the exhaust gas passes through the turbine the heat transfer to the compressor becomes greater. So i guess where plugs are concerned, if they are to last longer they need to be in a better environment and none better than a cooler intake type environment that brings about a more efficient combustion cycle.

 

We all know that a modded car has a shorter plug life than stock. A modded car has a more efficient combustion cycle.

 

Not necessarily. And efficiency is determined my more than just power. Optimizing the variables will determine the better efficiency. You could have a tuned car that is hoeing through plugs faster (and cylinder component life) because it has higher IAT's which in turn reduces the ability to optimize the other variables. A tuned car with the more optimized variables will be more efficient that the one that doesn't. Both can make good power over stock. One will be more efficient than the other....and probably make more power too.

 

We may be talking about two different things here. I'm talking about volumetric efficiency or pumping efficiency of the motor. That is directly proportional to power output. Anyhow, there are other variables that affect plug life like the tune itself, spark charge, how rich/lean it runs under full load, etc. But I would argue that any modded car that is putting out significantly more power than stock has a higher volumetric efficiency which would lead to a reduction in spark plug life.

 

In that context i would agree. But the life expectancy of the plug and cylinder components will be reduced determined by the level and type of stress being placed upon them. In certain context stress can be a good thing and, a bad thing...depending upon how it is being applied....as it is in life.
Naturally the greater the power output of the cylinder the greater the need for all variables to be at the optimum to get the best reliability and longevity of the associated components. That doesn't mean that an engine cant make extra power if all the variables aren't at the optimum but things won't last as long as if things were at the optimum.

So, my arument that a plug should last longer still stands on the basis if the tuned engine has everything working for it to the optimum then the plug will last longer than a tuned engine where things aren't.

And I agree that a plug in a tuned engine will never last as long as one in a stock tuned engine but it comes down to the variables that ultimately dictate just how much shorter the plugs like will become.

Maybe what Porsche should do is re- design the engine (move the turbos out of the darn way ) so the plugs can be quickly changed out at every 10,000ks..or whenever....without any fuss.

 

Amen to that brotha!

So in conclusion, there really is not much that one could do in a "somewhat cost effective" way to increase the life span of the plugs on a tuned car... well other than donating your racing gloves, and taking on the job of driving Miss Daisy around.