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Discussion Starter · #1 ·
Just a question out of curiosity really.

On my '89 2.0 FPT, with a red DI cartridge, the handbook recommends a plug gap of .9 to 1.0.

Later cars using the same red DI appear to use a gap of 1.1.

Did Saab find that 1.1 was better for the DI or are later cars with the 1.1 recommendation fundamentally different?

And no, I don't know when the recommendation changed.If anyone else does, it might answer the question

I'd be interested to hear your thoughts.
 

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Not sure, but the Haynes seems to only recommend something other than NGK and says "refer to other manufacturer for gap of their plug" or something like that.

I ended up with something inbetween and settled for a "loose" 40 thou (only had imperial feelers when fitting).

Seems to run well enough with that gap.

BTW MY96 2.0LPT.


Pete
 

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Haynes seems to be affiliated to 'Chumpion' so only list those.

I've set my Aero to 1.0mm just to be different, and someone here a while ago speculated that a salightly smaller gap would giver slightly better power and torque and the slight expense of emmisions and possibly low end pickup.

As I'm now running slighty higher boost (but not Bubbles levelsd...) I thought I'd err on the side of caution and allow for some plug gap errosion over 12 months.

Andrew
283.1bhp (or it was....)
 

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Discussion Starter · #4 ·
Thanks for the replies.
I'm running at 1.0 too, with no noticeable problems. What the optimum setting is for the DI is the big question.
I'd be interested to know if Saab ever issued a service bulletin, upping the gap from .9 to 1.1 for the red DIs.
My existing DI is 14 years old and still running happily so far, so I think I'll just leave it at 1.0.
 

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hmm my old '90 2.0fpt red di would misfire on full boost at anything over 0.8mm and by 1.0mm was undriveable.. spoke to saab and various plug manufacturers - never ever figured out why.
the plugs also blew open and closing them gently never restored the performance - it used to eat a set of plugs every 3k.. yes, 3k.
was a hoot to drive though - i just used to buy plugs in packs of 24 from a friendly garage always kept a spare set and a torx key in the boot in case the misfire suddenly appeared. i can still remember the burnt fingertips.....
 

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Welcome to Saabscene Rhino.

Sounds like you old 2.0fpt was a plug beast!!

I change the plugs on my 2.3 carly every 24K and I think that;s a heavy user as it doesn't make the last 6K.

I hope you changed those hot plugs carefully as the alloy heads and steel plugs expand at different rate and can mess the soft alloy threads up if not careful.

Andrew
who used to have a 900T with 1 locktight'd plug
 

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haha wondered if youd spotted that - i meannnt the torx key in the boot and the plugs used to live in a special plastic (lunch) box under the bonnet so they were at near engine temperature (tried so many different things to sort it - buying plugs was the cost effective answer). it might sound daft carrying warm plugs but it would just die on you and new plugs always did the trick. it humourously ate a set of those max power approved electrode plugs in an awesome 150miles. ha.
my current 2.3fpt going in tomoro for cat removal and other tinkerage.. i cant wait!
(said by an obvious mentalist who's just spent a fortune on fully replaced timing&balance gear)
ill get an avatar of my trusty barge soon.....
 

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I got talking to a very helpful NGK rep at the motorcycle show (he also looked after cars). He said 3 & 4 electrode plugs were for economy and longer service life, but they might even make the performance worse.

My bid : NGK BCPR7ES with 1.1 mm gap

Champion are poo and can't be used in any of my vehicles.

Tried 0.9 but engine felt a bit more hessitant (or perhaps i dreamt it)
 
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