Hi guys. I am looking for some feedback from those with tunes and/or tune shops regarding your own experiences with spark plugs. The pluses, minuses etc etc..

I've read a few threads now reporting how the stock plugs don't hold up for too long once a tune file has gone in and there seems to be a lack of information giving explanation for why different plugs are better used in favor of simply replacing stock plugs for stock again.

So, i have listed a few questions for those that are hopefully able to provide quality answers:

1) What is it about the stock plugs that actually cause them to burn out faster once a tune has been added.

2) Do the stock plugs life become shorter again once the car has had turbos and intercoolers added or, is the life expectancy the same as what you would get with a base stage 1 tune?

3) What are the symptoms leading up to a plug change? Also do symptoms occur suddenly out of the blue or does the engine lose power progressively at a rate where you don't notice it, and then suddenly one day you notice the engine is down on power? Or how does it go, and?Or, what is it that actually happens that alerts you its time for a plug change?

4) What is the best plug to use for a tuned car and, is there an optimum plug (brand/type) to use depending on the level of tune you have?

5) Once the plugs are changed for a different type better suited to a tune file, if you switch the file back to the stock tune file will the engine perform differently in any way?

6) Will the tune perform better immediately once you change the plugs even though the stock plugs are still perfectly fine? Or do the stock plugs physically have to be on the way out to notice any benefits from a change in plug type?

7) Does the plug type also vary depending upon the octane of fuel you plan using mindful most tunes have different 93 and 100 file settings?

8) Once the stock plugs are changed out, what is the life expectancy of the new/different type plugs? Or will they burn out at the same rate as a new set of stock plugs.

Any quality info would be appreciated .

Thanks in advance .

 

I will try to answer

1) What is it about the stock plugs that actually cause them to burn out faster once a tune has been added.

That's true and im not sure why they burnt quicker after tune




2) Do the stock plugs life become shorter again once the car has had turbos and intercoolers added or, is the life expectancy the same as what you would get with a base stage 1 tune?

No..It is same if u have stg1 or +700hp kit




3) What are the symptoms leading up to a plug change? Also do symptoms occur suddenly out of the blue or does the engine lose power progressively at a rate where you don't notice it, and then suddenly one day you notice the engine is down on power? Or how does it go, and?Or, what is it that actually happens that alerts you its time for a plug change?

Yes u will feel that ur car ran SLOWER after that u will get drop boost issue..etc



4) What is the best plug to use for a tuned car and, is there an optimum plug (brand/type) to use depending on the level of tune you have?

Denso pk20pr-p8, gapped to .025”.


5) Once the plugs are changed for a different type better suited to a tune file, if you switch the file back to the stock tune file will the engine perform differently in any way?

It should be fine no matter if it is stock or tuned



6) Will the tune perform better immediately once you change the plugs even though the stock plugs are still perfectly fine? Or do the stock plugs physically have to be on the way out to notice any benefits from a change in plug type?

The car should ran perfect if get new OEM sparkplugs or Denso and u should feel the differance directly



7) Does the plug type also vary depending upon the octane of fuel you plan using mindful most tunes have different 93 and 100 file settings?

We used OEM sparkplugs and Denso with 93, MS103, MS109 and C16 and no problem.



8) Once the stock plugs are changed out, what is the life expectancy of the new/different type plugs? Or will they burn out at the same rate as a new set of stock plugs.

We change plugs every 3000 mile

 

omg, 3000miles! not a big deal in most cars, but when it is as involved as this car it is a bit of a bigger deal!

fwiw, Todd says the stock plugs gapped down to 0.025 are fine with 700+hp the denso are one stop "hotter" or is it "cooler"? whatever, they are one step more "aggressive".

 

1. Due to the additional heat caused by increased boost and fuel, there is a higher potential for pre-ignition/detonation.

2. Yes

3. There will be a loss of power, depending on the surrounding circumstances (driving style and use) it can happen quickly or slowly. There are other tell tale signs, under load the engine might stumble, if the plugs are in really bad condition the idle could be affected. At this point you definitely will have through a code.

4. Ideally one step colder than the factory plugs.

5. There shouldn't be much of an issue, typically if the plugs are too cold it will lead to fouling. Although I don't believe one level of a heat range will be enough to cause them to foul in this particular instance.

6. Spark plugs don't increase horsepower, they merely allow the motor to operate more efficiently.

7. Can you elaborate more on what you mean by plug type? Are you referring to the manufacturer? The heat range? The metal?

8. That all depends on your driving style.

 

I'm assuming you don't work on Porsche's?

 

Paul, PM quattrogeek. He bought my Ruf 550 conversion 997TT. He picked up over 150 whp after swapping plugs, coils and cleaning out the MAFs. The car had progressively lost power, and the AFRs started to run high.

- bob

 

An interesting read if you haven't read it:

https://www.6speedonline.com/forums/...97-turbos.html

and for the record, a stock 997 GT2 requires plug change every other year or 12K miles...twice as often as a stock 997TT. Nearly identical engine, but different turbos and ECU programming.

bob

 

Thanks for your responses guys. Alex's (sharkys) report is telling as well. Its good to know whats in store once a tune has taken hold. To know what plugs are available and the life expectancy depending upon the level of tune is good also...the available brands and gap settings etc. It seems going by GT2's stock requirement for plug changes at 12k indicates higher boost/performance changes the game for the plugs quite a bit. So am i right to assume that a car that does moderate street driving (WOT where possible) and a few track days may be lucky to get 10k between plug changes?

Just a few more questions..
Which plugs last longer at .025? The oems or the Denso's...and are there any other brands? Also what gap do the oem plugs use if used with the stock tune file?

Thanks.

PS. shotcaller re your 3000km change outs. Am i to assume you are running a very high hp tune with big boost? I understand that abnormal combustion temps can be a big problem for components other than just plugs. Any thoughts or experiences there?


PS looks like i better get ready for another poke from the dealer....arrrg.

 

It is 3000 mile not 3000km and that's on tuned cars or high hp cars

Keep in mind that Denso has longer life than OEM sparksplugs

I told u what Todd K recommend

 

Yes 3000ml is around 5000kms....but still not a long time between changes....and its a big job too.

So how much longer would you say the denso's last in comparison?

I missed that. So what did Todd K say?

 

Not sure but u still can use them until u feel ur car loss power

Todd K recommend to change then every +3000mile or 5000km.

 

There is no way someone recommended you to change your plugs every 3k, that is just crazy.

On a tuned car (not engine built) I have heard from many of the tuners that every 20k is good. If the car is stock then every 40k is the Porsche recommendation, on a tune every 20k should suffice.

If your changing your plugs every 3k (shotcaller) you might as well think about buying a dealership or Pcar shop.

 

I had AWD change my plugs (against their recommendation but I was very insistent) to Denso IK22 and sure enough they don't seem to work very well. Below 4krpm the car stutters and stumbles a lot. Up top the plugs seem to work OK as we got 593hp/602tq at the wheels. But, I'll be going back to Denso PT20 after talking with Todd @ EvoMS.

I'll also have AWD install the EvoMS HDE coils just to make sure I'm getting enough spark now. If I remember correctly, Todd said that all I lacked for the 775 kit was the coils and the inlet pipes (which are also going to be installed at AWD).

 

I also have the IK 22 Denso plugs & seem to notice some stuttering at low rpm & especially on deceleration ,i wonder if my plugs are wrong or just need replacing i must have at least 5-6 k on them.

 

In my case it was noticed in very short order. I have much less than 1k mi on the car since the plugs went in. I was warned and now I have to pay for not listening.