928 S4 = BOSCH Platinum Fusion Iridium Spark Plug WGR7DQI 4510
09-07-2011, 08:20 PM
#31
Done With Sidepatch
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09-16-2011, 10:07 AM
#32
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Just switched my 4-prong iridium plugs out for Roger's 3-prong NGKs and there is a noticeable difference! Car runs fantastic. The 4-prongs only had 15k miles on them and no unusual deposits or wear, but clearly the GTS is happier with the ones Roger recommends.
Interesting to think, I bought the 4-prongs back in 2007 when I first got the car, and before I ever heard of Roger Tyson or Rennlist. Have sure come a long way since then!
Interesting to think, I bought the 4-prongs back in 2007 when I first got the car, and before I ever heard of Roger Tyson or Rennlist. Have sure come a long way since then!
09-16-2011, 02:50 PM
#33
Burning Brakes
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09-16-2011, 06:48 PM
#34
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Hi All 
I know a fair amount about plugs for my 928, because I have run a LOT of different ones for my Nitrous.....what follows does not apply to GTS cars... but it does to any 16 valve plus most S4`s..
Multiple electrode plugs were not designed for 16 v 928s and give absolutely nothing apart from extended life, and as anyone who uses their 928 as I do as a daily driver, you should be changing your plugs yearly...
Also I would NEVER EVER fit a set of plugs I cannot gap with feeler gauges.
Either Bosch or NGK are fine...
I used to run NGK BP6ES (not BPR6ES as not worried about electrical suppression - thats all the R means)
When I moved up in Nitrous power, I needed one heat range colder , so BP7ES , then as more power added , BP8ES then finally to an Ngk C9 (bike racing plug) for my high speed runs and drag racing with large amounts (over 500) of Nitrous.
So basically anyone with a standard 928 16 valve then personally I would recommend BP6ES or WR7DC...
Supercharged or Turbocharged then BP7ES OR BP8ES.
Every heat range in an NGK plug gives roughly 70 degrees more temperature.
Hope this helps...
Oh and plugs do NOT all come gapped the same in the box....use a set of feeler gauges and set them yourselves..
All the best Brett
I know a fair amount about plugs for my 928, because I have run a LOT of different ones for my Nitrous.....what follows does not apply to GTS cars... but it does to any 16 valve plus most S4`s..
Multiple electrode plugs were not designed for 16 v 928s and give absolutely nothing apart from extended life, and as anyone who uses their 928 as I do as a daily driver, you should be changing your plugs yearly...
Also I would NEVER EVER fit a set of plugs I cannot gap with feeler gauges.
Either Bosch or NGK are fine...
I used to run NGK BP6ES (not BPR6ES as not worried about electrical suppression - thats all the R means)
When I moved up in Nitrous power, I needed one heat range colder , so BP7ES , then as more power added , BP8ES then finally to an Ngk C9 (bike racing plug) for my high speed runs and drag racing with large amounts (over 500) of Nitrous.
So basically anyone with a standard 928 16 valve then personally I would recommend BP6ES or WR7DC...
Supercharged or Turbocharged then BP7ES OR BP8ES.
Every heat range in an NGK plug gives roughly 70 degrees more temperature.
Hope this helps...
Oh and plugs do NOT all come gapped the same in the box....use a set of feeler gauges and set them yourselves..
All the best Brett
05-06-2013, 08:03 AM
#35
Bringing this topic up. I have problems with my S4 running rich on idle and HC at 200 ppm. On revs its good and car performs nicely.
One reason is NGK BP6ES plugs. Switched back to Bosch WR7DC+ 'es (10tkm on them) and car runs better. Amazing. I have never seen a n/a engine that is this picky to plugs! Will do some work on exhaust and go to emissions test again.
One reason is NGK BP6ES plugs. Switched back to Bosch WR7DC+ 'es (10tkm on them) and car runs better. Amazing. I have never seen a n/a engine that is this picky to plugs! Will do some work on exhaust and go to emissions test again.
05-06-2013, 09:49 AM
#36
Three Wheelin'
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Bringing this topic up. I have problems with my S4 running rich on idle and HC at 200 ppm. On revs its good and car performs nicely.
One reason is NGK BP6ES plugs. Switched back to Bosch WR7DC+ 'es (10tkm on them) and car runs better. Amazing. I have never seen a n/a engine that is this picky to plugs! Will do some work on exhaust and go to emissions test again.
One reason is NGK BP6ES plugs. Switched back to Bosch WR7DC+ 'es (10tkm on them) and car runs better. Amazing. I have never seen a n/a engine that is this picky to plugs! Will do some work on exhaust and go to emissions test again.
You have a problem with that reading...its NOT the plugs, whichever make you use....
When was the car last serviced ? dizzy caps/rotor arms last CHANGED ? Air filter last CHANGED ?
Etc etc...
All the best Brett
05-06-2013, 10:54 AM
#37
Chronic Tool Dropper
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Bringing this topic up. I have problems with my S4 running rich on idle and HC at 200 ppm. On revs its good and car performs nicely.
One reason is NGK BP6ES plugs. Switched back to Bosch WR7DC+ 'es (10tkm on them) and car runs better. Amazing. I have never seen a n/a engine that is this picky to plugs! Will do some work on exhaust and go to emissions test again.
One reason is NGK BP6ES plugs. Switched back to Bosch WR7DC+ 'es (10tkm on them) and car runs better. Amazing. I have never seen a n/a engine that is this picky to plugs! Will do some work on exhaust and go to emissions test again.
Many folks report good results using the NGK BPR6ES plugs (vs the non-resistor version you mentioned).
05-06-2013, 12:47 PM
#39
I've changed the wires with plugs but rotors and arms did not arrive yet. Also the air filter is in the next batch.
Here in Finland we take emissions tests every year and last year this car passed them with flying colors.
Also I need to edit this a bit. In fact the mixture wb02 at end of the pipes show lean mixture but HC is high - due to fact that there is unburnt fuel. I belive it goes so that exhaust pipe leaks before car's own lambda and it sees that there is too much air and increases the gas. The AFR is about 15 on idle so that's actually lean, not rich, sorry to confuse on that.
I'm going to take out the exhaust next weekend if my GTS stuff comes from UK in time. The rest of the stuff (distributor caps and arms plus new set of WR7DC+'es and filter) will find their way in as soon I get them.
Here in Finland we take emissions tests every year and last year this car passed them with flying colors.
Also I need to edit this a bit. In fact the mixture wb02 at end of the pipes show lean mixture but HC is high - due to fact that there is unburnt fuel. I belive it goes so that exhaust pipe leaks before car's own lambda and it sees that there is too much air and increases the gas. The AFR is about 15 on idle so that's actually lean, not rich, sorry to confuse on that.
I'm going to take out the exhaust next weekend if my GTS stuff comes from UK in time. The rest of the stuff (distributor caps and arms plus new set of WR7DC+'es and filter) will find their way in as soon I get them.
05-06-2013, 01:01 PM
#40
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W7DTC was only used in the 92 to 95 GTS - 928 wise that is
__________________
Does it have the "Do It Yourself" manual transmission, or the superior "Fully Equipped by Porsche" Automatic Transmission?
George Layton March 2014
928 Owners are ".....a secret sect of quietly assured Porsche pragmatists who in near anonymity appreciate the prodigious, easy going prowess of the 928."
Does it have the "Do It Yourself" manual transmission, or the superior "Fully Equipped by Porsche" Automatic Transmission?
George Layton March 2014928 Owners are ".....a secret sect of quietly assured Porsche pragmatists who in near anonymity appreciate the prodigious, easy going prowess of the 928."
05-06-2013, 04:19 PM
#41
Chronic Tool Dropper
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I've changed the wires with plugs but rotors and arms did not arrive yet. Also the air filter is in the next batch.
Here in Finland we take emissions tests every year and last year this car passed them with flying colors.
Also I need to edit this a bit. In fact the mixture wb02 at end of the pipes show lean mixture but HC is high - due to fact that there is unburnt fuel. I belive it goes so that exhaust pipe leaks before car's own lambda and it sees that there is too much air and increases the gas. The AFR is about 15 on idle so that's actually lean, not rich, sorry to confuse on that.
I'm going to take out the exhaust next weekend if my GTS stuff comes from UK in time. The rest of the stuff (distributor caps and arms plus new set of WR7DC+'es and filter) will find their way in as soon I get them.
Here in Finland we take emissions tests every year and last year this car passed them with flying colors.
Also I need to edit this a bit. In fact the mixture wb02 at end of the pipes show lean mixture but HC is high - due to fact that there is unburnt fuel. I belive it goes so that exhaust pipe leaks before car's own lambda and it sees that there is too much air and increases the gas. The AFR is about 15 on idle so that's actually lean, not rich, sorry to confuse on that.
I'm going to take out the exhaust next weekend if my GTS stuff comes from UK in time. The rest of the stuff (distributor caps and arms plus new set of WR7DC+'es and filter) will find their way in as soon I get them.
Exhaust leaks upstream of the oxy sensor tend to be leaks of higher-pressure exhaust gasses out to atmosphere. Unless you have an exhaust system that does an exceptional job of extracting burned cylinder gasses (and therefore drawing air in through any leak), you can practically discount the idea of air leaks giving you a false lean reading.
