Julian, don't mean to rebut your point, but correct plug gap is very important on a Trionic car, there is this quote from Dr Boost who heads trionic development at Saab in Sweden on Saabnet.com :If the 9000 is the same as the 9-3, the plugs gap spec. is 0.9mm - 1.1mm. For longer plug life you are therefore better off gapping the plugs closer to 0.9mm. If you leave them at 1.1mm they soon go out of spec.
I have heard various dealers complain of Trionic 5 'eating plugs' and I'm sure it's because they lob 'em in straight out of the box on the top end of the gap spec.[/b]
Simple....(I'll give you the short version, it's late here in Sweden)
A wider gap will of course produce a longer spark.
As you know that air/fuel mixture needs to be exposed of the HOT spark, the HEAT will start the flame.
The larger area of exposure the better, "as a general rule of thumb".
As the pressure raise, during hi boost conditions, the voltage need will also raise. IF you have got an ignition system with too low voltage, there will be no combustion, since there will be no spark across the gap.
I have had NO probs with the plugs gapped to 1.10 mm, even at H/O applications, well that is if 350 bhp is H/O for you....
Last but not least, there is no connection between having the plugs gapped to 1.10 and premature DI failure.
Do I make myself clear enought ?
The 1.10 (compared with 0.85) will NOT make the DI cassette to work harder.
I tried to explain that earlier last week or so, see if you can find that thread, or else ask again[/b]
For safety's sake, yes, that is the correct assumption. The key element in the NGK spec is the "R", standing for "resistor", which is key to the successful operation and longevity of the DI system. There are undoubtedly other manufacturers who make resistor spark plugs, but they're yet to become widely known in the Saab world if they do make a compatible one... the only upgrade I know of is the NGK platinum range, which offer longer life and more consistent performance.Originally posted by dicreamio:
[qb]I guess I can assume even Bosch plugs are no good?.
I do follow that advice, but I am happy to check the plugs on my Aero regularly to make sure they don't get too wide. Many people (including Saab dealers) will simply follow the Saab service schedule which, unbelievably, doesn't recommend checking the spark plug gaps at all between changes at 36,000 mile intervals. Under these conditions, it is safer to start at the minimum setting and hope that after 36K miles, they're still within spec.Originally posted by Friberg:
[qb]When DrBoost is saying that the car runs better with the gap set to 1.1mm I don't see any reason for not using his advise[/qb][/b]
Yeah... for the once like us who are driving tuned Saabs the spark plugs don't last very long. 10000km/6000 miles are a good time to change.Originally posted by Mark E:
[qb]I change mine every 6000 miles... but then they probably have a harder life than most :fawlty: [/qb][/b]