I tested a set of Denso Iridium spark plugs on my 996tt. I drove about 400 miles and removed them. The problem was at 3/4 to wot a very pronounced stagger was induced. When I removed them the stagger disappeared. The plugs were burning correctly according the electrode color.

 

I know I'm almost 2 years late, but thanks for the info!

- KJ

 

what heat range were they? 6 or 7

 

CJV,

Denso's website said the correct part would be the "Denso Iridium IK20".

Is this the part you used?

Thanks,
KJ

 

It has been a long time since I used that plug. I didn't throw them away. If I can find them I will get the number. It was the plug they recommended at the time. I was not the only one who had the same problem. If I remember correctly, the electrode is recessed along with being far thinner.

As I said back then, the color of the plug was correct. It was not burning too hot or cold. It simply introduced this studdering problem.

 

Thanks CJV, you saved me from wasting my time with these!

- KJ

 

We can always count on Chad for questions regarding just about anything, he has done everything from soup to nuts on KA.

 

The problem with Denso Iridium plugs is that they often quote cross-over part numbers that are not direct replacements. Often the heat range changes, the plug reach, or other characteristics are not the same as a stock plug as I found out in my Viper and Lamborghini. I had them send me suppoedly 'exact crossovers'. The car lost about 20hp at the wheels. When I compared them to the stock plugs, the reach was about 1/4" less than a stock one; meaning the plug was getting pulled out of the combustion chamber.

 

i am running the Uber Power ZR8 and they work great but you have to replace them every 10000 miles to get the best performance.

 

uber power zr8? is that a 8 heat range?

 

What are the standard replacement plugs reccomended?

Mike

 

make sure you get Bosch FR6s guys..

Don't get the Berus. They suck ***.

 

What exactly do u run in ur car... since ur boosting so high... u must fowl the fr6s all the time... or do u use a different heta range plug?

 

Actually I do man. But as long as they last.. they're good They last longer than the Berus...

 

did u ever hear of the UBER POWER ZR8 PLUG?
OR BETTER YET... IS THERE "FR7" TYPE OF PLUG? THAT WILL FIT OUR TTs... I folwed my Berus twice in a month when I was running 23 psi.
what happens is a stutter under full throttle.