1994-2002 [Subscribe to Daily Digest] |
The Saab NG900 and 9-3 turbo engines (among others ) use a very sophisticated DI (direct Ignition) cassette as part of the “Trionic” engine management system. Besides providing spark control for each cylinder, the DI cassette and ECU (Engine Control Unit) computer also use the spark plugs to sense knock via the ionization level in each cylinder. So the exact properties of the NGK spark plugs are important to the "Trionic" system operating correctly.
So the answer on spark plugs is while you are able to switch between the NGK platinum and regular ‘copper core’ plugs in the “Trionic” system, using other brands of spark plugs is just asking for check engine lights, misfires, hard starting, and possible DI cassette damage.
For the record I decided to list the current spark plugs recommended by NGK for the NG900 and 9-3 2.0L and 2.3L turbocharged engines (not the 9-3SS). As you can see both heat ranges 6 and 7 are called out. Also note that regular copper plugs, platinum plugs, and iridium plugs are all specified.
I believe the conventional wisdom of the Saabnet (based on a lot of owner input and feedback) still stands.
- Use the inexpensive regular copper BCPR6ES-11 (or BCPR6ES) for primarily city driving as the BCPR7ES-11 tends to show a lot of black carbon deposits on the plug tip.
- Use the inexpensive regular copper BCPR7ES-11 (or BCPR7ES) for primarily freeway, sustained high speed, spirited driving, towing, or when using an upgraded ECU like Speedparts or BSR.
- Replace the spark plugs every 10-15,000 miles, depending on your driving style. The BCPR6ES-11 and BCPR7ES-11 are factory gapped by NGK to .044". The BCPR6ES and BCPR7ES are factory gapped by NGK to .035". The Saab specification is changed over the model years but is generally 1.0mm +/- .1mm (.040” +/- .004”). It is best to gap new spark plugs to the lower end of the tolerance, as the spark gap will increase over the life of the spark plug. Therefore, all the NGK plugs need to be re-gapped to .036" before use in the Saab 2.0L and 2.3L turbo engine.
The cost of the platinum or iridium spark plugs maybe justified if you are paying someone else to do the installation and want to run 30,000 miles between spark plug changes. Otherwise the regular copper plugs perform just as well.
Here are the NGK recommended spark plugs and spark plug gaps for NG900/9-3 2.0L and 2.3L turbo engine by model year (MY) per http://www.ngksparkplugs.com/ application charts as of April 06, 2004.
Prices for NGK spark plugs from http://www.sparkplugs.com/ as of April 06, 2004.
MY1994; all turbo models
BCPR7ES-11 STK# 1095 Gap .040” standard copper plug price $2.24 ea.
MY1995 -1996; all turbo models
BCPR6ES-11 STK# 6779 Gap .040” standard copper plug price $2.24 ea.
BCPR6E-11 STK# 5632 Gap .040” V-Power copper plug price $2.24 ea.
BCPR6EGP STK# 7088 Gap .040” G-Power platinum plug price $2.68 ea.
BCPR6EIX-11 STK# 4919 Gap .040” Iridium IX plug price $6.95 ea.
MY1997 - 1999; all turbo models
BCPR7ES-11 STK# 1095 Gap .040” standard copper plug price $2.24 ea.
MY2000 - 2002; all turbo models (note the use of the newer NGK P/N where BK = BCP)
BKR7ES-11 STK# 2387 Gap .039” standard copper plug price $2.24 ea.
BKR7E-11 STK# 1283 Gap .039” V-Power copper plug price $2.24 ea.
PFR7H-10 STK# 3978 Gap .039” Laser platinum plug price $11.71 ea.
BKR7EIX-11 STK# 6988 Gap .039” Iridium IX plug price $6.95 ea.
REM in Seattle
1998 Saab 900SET; 5-door; Automatic; 68,000 miles
1991 Alfa Romeo Spider; 5-speed; 96,000 miles
1984 Saab 900T; 3-door; 5-speed; 242,000 miles (RIP)
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