Hey Guys,,Yes,more spark plug stuff.....First,,,I "talked" with Bosch people today and They said The FR5 LDC is the plug for our Turbos...So,all I know is that I have in my car and have seen every one saying the FR6LDC is the plug....Right??.........In Bosch,the 5 is colder then a 6...As we all know....lol....when you add boost you would like a cooler plug OR atleast stay the same,,,But then why do we get advised always to run a 6 which is hotter??.....Please let me in on this reasoning............Also I talked to the Denso people today and they do not list or know anything about a PK20-PR-P8{3245} being or working in a Porsche Turbo??...I turned them on to this site to see it, so they wouldnt think I am a wacko..lol......They also said there plugs should be a 22 range for our turbos,thats colder from them, then a 20.....Yes,I know every thing is not written in stone as a perfect fit or the varabiles change things,,and then there is trial and error.....But I am still confused on running hotter ranges then what those guys recommend on our modified cars............ Did I just open up a NEW can of worms on this old subject??......Sorry,just wanted all of us to be informed.....

 

Wow...I'm confused to say the least..subscribed.

 

Confused on how I wrote this out OR confused with the info I found out?..lol..

 

Your post is perfectly clear! I have to buy new plugs for my next mods round, and I have no idea about what plug should I buy right now... tuners reccommend hotter plugs than manufacturers do, so who's right?

 

I've been told FR6 LDC for the fewest issues. If you change them when you should, no issues. This in the context of stock to "mild" only.

JB

 

IMO, You should run a stock plug unless you are not stock, and run what your tuner tells you to run. My tuner tells me to run NGK and change every 5k miles. I usually change mine sooner, if I am in there...

 

I have run the Denso PK20-PR-P8 (3245) for years with K24/18G turbos, injectors, and other full supporting mods with absolutely no issues whatsoever. The car has run 11.0 in the quarter mile on street tires and trapped well into the 130's with these plugs. They last 10-15,000 miles without any issues...I have always changed them before they needed it, never due to failure of the plug and I have gone 15,000 miles on a set. For K24/18G cars, I would say they are a good choice...

 

Hey John,,Thanks for the info...Thats what I was checking into today,a plug change from my FR6LDC plugs,since I was doing those cats and porting the headers.But when I saw colder numbers recommended on there sites,I was on the phone to get answers on all these popular plugs for our cars......Do you gap yours around .026 to .028??Those are the ones I think I am going to use now.Advanced Auto stores sells them for $6.99 here....The Bosch 6's have not given me any troubles...I can not believe know one has mentioned anything about ever running the next colder ones,5's,with more engine mods and boost??.....Only since they are a long life plug design and a colder one would be advantageous....Unless then they would foul out easier under normal conditions but then why would they be recommended by the company for stockers??

 

Yes, I use them out of the box, but double check the gap before installation. They should be about .027 gap at the K24/18G level.

 

My RUF 550 Rturbo is coming up on the 30K service and I'm going to be doing plugs. Since reading about all these posts about plugs, for what it's worth, I called RUF to find out what they put in their cars and they told me to stick with the OEM Bosch FR6LDC even though the 550 Rturbo runs at higher boost levels......I've got 20K miles on the OEM plugs that were put in there when they did the conversion and the car has NEVER skipped a beat since I've had it....I think sometimes people try to overcomplicate things.........

 

Your car would not skip a beat, you just might not get the timing advance that you would with a colder plug.

 

+1 I got the same advice from Ruf Germany and had the FR6 installed together with the 997 coil packs.

 

No disrespect to anyone here because this forum is wealth of knowledgeable people, but I'd be willing to bet that the Alois Ruf and the gang probably know more about designing and building these cars than most anyone here. I would also be willing to bet that that during the course of their development they probably tried various plugs end ended up sticking with OEM for a reason (probably not that it might be a few bucks cheaper). If they found that a colder plug than OEM was the key to better performance than I'm sure they would have utilized it in their motors. I'm not saying that a colder plug may not be a better way to go in some highly boosted applications where guys are running 1.2 bar +, but in my case with the RUF 550 or for stock / moderately boosted cars, its probably going to be hard to beat the OEM plug. Maybe Porsche got it all wrong too.......

 

good thread I'm subscribed...good to know for my next plug change...

for cars boosting 1.0 bar perhaps stock plugs may be safe, however I wonder if there is an upside to one step colder even on a mildly modded X50 car (tune, exhaust etc...)

 

Hey guys,,,Look what I started again.....lol.....Looking at these two plugs,what a difference in looks....According to the manufactures of the plugs ,these are one step warmer then they recommend for our cars,like I stated at the start.So,they should be close to each other in temp. ranges.The Bosch has a long projected insulator as compared to the very short one on the Denso....From what I know,but I am not an engineer,in an 'aspirated' motor you would like to have a projected insulator to fire the closest you can to the inner center of the charge which makes a better explosion and cleans its self off easier,,,But its in more of a heated area then,,,so,is that good or needed for a modified turbo motor which is forced induction??I think not??But the Bosch has 2 firing straps to jump a gap which helps it not to get blown out as easy,,compared to the Denso's 1........I am going to try the Denso's this time over the Bosch..Hopefully I can say ya or na OR the same.......lol.......