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Discussion Starter #1
Hi,

Fredrik from MapTun advised me to change the Spark Plugs of my Viggen to NGK BCR8ES, or if I couldn´t get those, BCPR7ES-11.

He explicitly told me not to use PFR7H-10 or PFR6H-10 (=Saab recommendation)as those would sometimes detect knocking even if there is none.

What do you think?

Yours,

Philip
 

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Fredrik has also made the same recomendation to me for my 9000 (normally BCPR7ES). The way NGK number their plugs is that cooler ones have a higher number.

The BCR8 has a significantly shorter nose than the 7, and is a much more efficient conductor of heat. Thus the plug operating temperature is lower, which amongst other things, helps to reduce the risk of detonation.

The NGK website has really good info on spark plug theory here

{edit} I forgot to say that my understanding of the reason for the Viggen using the platinum NGK plugs was to extend the life under higher performance conditions. Personally I don't have a problem with paying £10 or so every 6,000 miles or so for a new set of plugs...
 

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I think MapTun is dead on about the PFR7-H10's. When I tried them in my Viggen regardless of what the actual hp was, it put down significantly less. To the tune of 20-30 less hp even on cool days. (the g-tech could have easily exagerrated that figure and I won't argue with that, but I could feel a difference). It makes sense that it's detecting knock when there is none. That would explain a lot. Otherwise I can't understand why a cooler plug would run worse even on a hot day. I may try the plugs they reccomend and see if it makes a difference here on warm days. I think it would be awesome if it really made a change for the better on warm days. I could definetly use that.
 

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Discussion Starter #4
Hi,

I just phoned up five (!) car parts suppliers until I found one who said he could order the BCR8ES plugs for me. Let´s see if he is right about that

Thanks for your input!

Yours,

Philip
 

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Discussion Starter #5
He was wrong ... just phoned me that he couldn´t get them. Now I ordered them at another supplier who told me thar he would get them in three days...

Any ideas where I could get those plugs?

Yours,

Philip
 

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I just spent a while on the phone trying to locate some BCR8ES plugs. Maaaan those are hard to find. NAPA is actually going to call NGK because in their product listings, that part number isn't available. I'll probably end up ordering it from that website you showed. Hopefully they deliver to the US too since our sparkplugs.com doesn't have em.

p.s. I think I might know why the PFR's detect knock when they shouldn't. Maybe I'm wrong here, but platinum is an N2O catalyst. If you put a platinum wire in a chamber with N2O it'll get hot, sometimes even glow red or white. N2O is a naturally produced gas in combustion, and it's that brown haze you see as smog. The Ionization Gap Sensor that Saab uses to detect knock is in some ways dependant on heat. The heat around the spark plug ionizes the gap, which allows a small amount of current to flow before ignition. The computer detects this and realized that cyllinder is about to knock, or will be sensitive to knock if high boost, and full ignition advance is continued, and thus retards ignition/boost. The platinum spark plug may act like a catalyst to the N2O (NO2 even though produced in the exhaust will linger in the cyllinder because not all of the exhaust gasses are discharged) which would cause it to really heat up and CERTAINLY would set off the ionization gap sensor. The platinum surface of the spark plug would be like the surface on your catalytic converter, which is very hot and as a result highly ionized. Makes some sense doesn't it? ALSO ... you cannot use platunum plugs with Nitrous Oxide for presumably the same reason. The engine could very well ignite the N2O before it's supposed to!
 

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Discussion Starter #10
Originally posted by Cosmic Blue 9-5:
[qb]Try www.spark-plugs.co.uk they have
Part No. BCR8ES Part Code 5430 Price Inc VAT £2.80 each[/qb][/b]
Hi,

I found just this address searching for the plugs. I will try them if the second supplier should not succeed.

Thanks a lot!

Yours,

Philip

P.S. Interesting theory, Adrian. You should join our Saabscene-Trip to the Nürburgring in September if you can arrange to fly over to good old Europe
 

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OooOoo. I wish I could. Pretty tight budget this year though. Maybe I can talk my ex gf into it aye? lol She's always wanted to go to Europe and just inherited about $893,000 from her grandfather. lol Oh well, she doesn't even want to spend the money because she feels like it's not really hers. Must be the only person on the planet who could inherit almost a million bucks and not want to spend a single penny of it. And ty about the theory Phillip! I feel almost stupid for not thinking of it earlier. I've known for some time how the IGS on the Saabs work, and that N2O is in exhaust gas, and that platinum catalyzes it, but I just never put the three things together before. Does anyone know if Iridium would work any better than platinum? So far people have been running Iridium plugs in Nitrous cars and not had any issues. Plus it should last longer than the BCR8ES's in theory. Does cost a bit more though sadly. I guess it's probably not a great idea. But let me know if anyone tries it!
 

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Ok I juuuuust got the call back from NAPA. They don't sell the BCR8ES in the united states. NGK called them back and said it was an exclusively European plug. You lucky blokes. Hopefully sparkplugs.co.uk will deliver here. *crosses fingers* It's either that or try the $12 a piece iridiums. Wish me luck either way.
 

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Originally posted by Adrian W:
[qb] Hopefully www.sparkplugs.co.uk will deliver here.  *crosses fingers*  [/qb][/b]
Yes they ship to the USA!
International Shipping
International shipping by Royal Mail airmail is currently available in two world zones: 'European destinations' and 'Rest of the World' (including USA). Please ensure that you select the appropriate shipping zone in your shopping cart when placing an order.
International orders of a high value may require a signature on delivery.
 

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Originally posted by Cosmic Blue 9-5:
[qb]Are you "performance chaps" suggesting we replace our plugs with these in all models?............and why?    [/qb][/b]
Nope, they will probably be too "cold" for non-tuned models, or even those in a mild state of tune. Take a look at my NGK link above for more info...
 

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Hmmm ... I've seen that NGK post before. Read it quite a while. It would be my understanding that the combustion temperature (I have some good reasons for this, but I don't want to inflict my reasoning on anyone who doesn't ask for it LOL) would be more dependant on compression and intake temp than boost pressure. You should be able to use any plug that your combustion temperature can burn the carbon off of. And considering the price, it could be worth trying once, and keeping it for a while then checking occasionally to see if they foul. I could see the colder plugs fouling someplace like Sweden in the dead of winter. Which is probably why you shouldn't use them anywhere like that. But if you live someplace relatively warm (like me) cooler plugs should be safe year round.

Also ... again considering the price you could try a couple different sets out. If you live somewhere cool, try the warmer BCPR7ES-11's first. If you live somewhere warm, try the 8's first. Then just read the plugs after maybe 100+ miles or so and see if they're too hot or too cold. Since it's only one heat range you should be able to get away with it without any real risk.

But hey if it's a stock car, and you live in Europe, odds are, going to a cooler plug will give you 0 hp and cost you $ .... not much purpose in that is there?
 

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When I went to my dealer to get some new plugs, they told me that Saab no longer uses the BCPR-7ES. They said that they only sell the BCPR-6ES now. I put them and have had no issues on my 1999 9-3S tuned to 260 hp. I think the 8 heat range plugs may be too cold for most of our applications, as the 7s seem to be for some people.
 

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Perhaps the 2.0 turbo runs cooler? It does have half a compression point lower than the 2.3 Perhaps they are too rich. I'll have to buy both sets and see which works better. Thanks for the input! It's much appreciated.
 

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I've heard of Saab recommending the NGK 6 range for Turbo owners who don't
much , so as to avoid the fouling that they were getting on the 7 series.

Not many cars use 8's as standard (except the old R5 Turbo...). I've one car that uses 5's!!

Andrew
 

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Discussion Starter #19
Hi,

now a technical question: when you change your plugs, do you apply any of the following substances:

Molykote - to the thread
Krytox - to the insulation rubber
Dielectric grease - to the tip

???

Yours,

Philip
 

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I have a picture of a "perfect" PFR7-H10 (well the master tech at the Saab dealer Mr. Finn said this is what plugs should look like) The NGK is on the right:

http://groups.msn.com/TheSaabGuy/saabsando...oto&PhotoID=111

On the left is a Denso. The Denso is out of my 1992 900 non turbo. I decided just for the heck of it to try putting the PFR7-H10s in it. I know I know ... it's way too cold a plug for that car. (though the emmissions guy said it had a high combustion temp, and was running lean
) Oh well, it's just for temp purposes. Kinda for fun to see if it makes a difference in that car. Eventually I may take the old PFR6-H10's out of the Viggen and put them in it to see if they're warm enough for it. The Viggen's IGS may not like platinum. But perhaps the older Saab won't be so picky. I'd hate to waste two $50 sets of plugs.

It's a shame I have to take these headers off that car to get it to pass smog. I rather like them tried to paint them with some high temp header paint, but it just burnt off and turned white. They're made by S&S. Got em for $20 at the junkyard off another Saab.

http://groups.msn.com/TheSaabGuy/saabsando...oto&PhotoID=109

Back in this car's hayday it could actually peg the speedo well past 130 mph. Not too bad for a naturally aspirated 2.1L with just headers, muffler and a K&N eh?
 
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