Hey guys, It has been quite some time since I have lurked these forums. I am happy to say I finally got myself into a Porsche. I picked up a 01 996 Turbo last month. It is an AWE Stage 2 car with GT2860R turbos, GIAC tuned, Upgraded diverters, AWE exhaust, AWE headers, etc. It seems to boost to 1.3ish bar and is said to have around 580whp and 570wtq according to dyno sheets provided by the seller. It had 26k miles and I have already almost put 1000 miles on the car. I am going to be changing the oil and doing spark plugs and possibly coils (the last time coils were done was 2009).

My question is what plugs should I use when I do the swap? It looks like AWE/GIAC used stock plugs for it. I was told by a trusted tuner on Rennlist that OEM FR6LDC plugs gapped at 0.030" Would it make more sense to use a step colder plug like the BRF7ix? I know there are some guys with modded cars here. I just want to get the best plugs for this car to ensure its going to run as good if not better than it does now. It runs well now only at idle I get an occasional stumble but I was told that this is inherent on 996TT cars and sometimes gets a little more noticeable when modded.

Also, none of the coils are cracked but would it make sense so change them due to time?

Any help is very much appreciated. I really love the car and want to treat it well and have many years of happiness with it.

 

It would appear the stock plugs appear to be up to the task. I believe the factory plugs are extended tip which tend to run "hot" at low engine speeds which helps keep the plugs "clean". But at higher engine speeds the tip is exposed to the incoming charge and this helps keep the tip temperature reasonable even when the engine is working hard.

As for the occasional stumble...

New O2 sensors at 132K miles perked up my Turbo's stock engine. While in the case of the sensors I was prompted to replace these due to a CEL related to an O2 sensor error (bad heater) the engine was not manifesting any signs of any issues.

Also, I can tell you with my stock Turbo even though the coils were not manifesting any signs of any issues -- IOWs no misfires -- new coils really perked the engine up.

Sure, I had these changed at around 140K miles rather than 26K miles but a modified engine could do with fresh coils at even in your car's case at 26K miles.

My Turbo engine never stumbled but it would idle in such a way to cause the transmission rattle when I rolled up to a stop with the transmission in neutral and my foot off the clutch pedal. I could "stop" this by pushing the clutch pedal all the way down then releasing it. But I could bring the rattle back with a bit of engine revving.

Figured this was just a trait of the car. But at some point -- I can't tell you if it was after the new sensors were installed or after the new coils were installed -- the rattle was gone. The rattle was a sign the engine was not idling as smoothly as it should have been.

 

I run NGK BKR7E at 1.2 bar. I was told not to run the platinum tipped version. I do change mine every season.

 

my car w 16/24's has the equivalent bolt ons you mentioned and i've been running the fr6 bosch plugs ( or beru = same ) for a decade in two different 96t's. my tuner always recommended .028. so, same, pretty much. remember, the car when first released in '01 porsche used a "5" heat range. they later upgraded in "02" to the "6" and the fr6 is also the gt2 factory installed plug. so, fr6ldc is fine. you could use the bosch gt2rs plugs but i doubt highly you'd notice any difference except in cost. i wouldn't fiddle with em, as they are pre gapped out of the box but that's up to you. i've changed plugs probably at least 6 times in the past 9 years in this car and that's as good as you'll get or need. if you run hard you'll burn plugs faster than if you "put around".

i generally change them at 15k miles and it always noticeably improves performance. coils? every 3rd plug change religiously ( 3 x in 9 years ). whether they need em or not.

coils are relatively cheap. you're "there" when you change the plugs. so yeah, change em. 10 years on those is enough, plus you're establishing a baseline for YOUR car.

enjoy.

 

Might consider changing the plugs more often. With my Turbo I had the plugs changed a number of times and on schedule. In one case -- shortly after I bought the car -- I had them changed due to time the car certainly didn't have the miles to warrant replacing the plugs. But in cases where the plugs were changed on time or miles I never noticed any change from the engine. (Same with my Boxster and the plug change schedule was 60K miles.) Kind of disappointing in a way but in a way a good sign too in that the plugs were still even with all the miles on them still performing well.

Based on my experience with my Turbo I'd say replacing the coils every so often is probably a good decision. As I mentioned in an earlier post replacing the coils at around 140K miles perked the engine up some. In hindsight I probably should not have waited that long. But I didn't want to fall into the trap of replacing things like coils with no indication such action was necessary. But a modified Turbo engine places a bigger demand on the coils (along with everything else) so coils want to be in tip top shape.

 

The trusted Rennlist tuner you're referring to recommends a lot of stuff which you can take with a grain of salt. People needlessly overcomplicate stuff. Install FR6LDC plugs out of the box and call it a day. I've never ever gapped the FR6LDC and have run them for years on a stock block 3.6 and also on built 3.8 and 4.0 race Mezgers. Zero issues, ever.... They are pre-gapped and not really designed to be messed with anyway. If you wanted to install a step colder plug for some reason, I would go with a 996Cup plug.

 

aside from the plug question,
if your running such big turbos at 1.3 bar, do you have after market injectors, because if not I would very careful continuing as is... I see running lean conditions all the time... you do not have the fuel to support it PERIOD...