carlo Posted May 29, 2003 Share Posted May 29, 2003 Hey all, I changed my spark plugs to NGK iridium (.8 gap), and am finding that at idle and down low the car seems lumpy.. Almost like I have put a new cam in it, also I have noticed the exhaust note seems to have more definition (for lack of a better word).. The car seems to be running well, its just down low and off boost it feels weird. Any suggetsions as to what this could be.. Is it just the new plugs (the old ones where very old a shitty), maybe a timing thing?? Cheers Link to comment https://www.sau.com.au/forums/topic/17047-spark-plug-question/ Share on other sites More sharing options...
Guest RedLineGTR Posted May 29, 2003 Share Posted May 29, 2003 how was the car, before you changed the plugs. Do you run higher than average boost if not why gapping them so small. Did you screw the new spark plugs in properly, were all connnections cliped in properly? Link to comment https://www.sau.com.au/forums/topic/17047-spark-plug-question/#findComment-352768 Share on other sites More sharing options...
Doctor Posted May 29, 2003 Share Posted May 29, 2003 Try turning the top of the plug so it faces the injector. Link to comment https://www.sau.com.au/forums/topic/17047-spark-plug-question/#findComment-352770 Share on other sites More sharing options...
rb25 Posted May 29, 2003 Share Posted May 29, 2003 This is like a misfire at idle and is ok. My 33 does the same on a .76 gap 6heat copper plug - not burning fuel as well as it could at idle but never misses a beat on full boost @ high rpm. Running a cold plug doesnt help the idle either. Link to comment https://www.sau.com.au/forums/topic/17047-spark-plug-question/#findComment-352786 Share on other sites More sharing options...
Doctor Posted May 29, 2003 Share Posted May 29, 2003 I changed from 7's to 6's yesterday and my god what a difference. Better start up, idle as smooth as power delivery more linear. Link to comment https://www.sau.com.au/forums/topic/17047-spark-plug-question/#findComment-352792 Share on other sites More sharing options...
rb25 Posted May 29, 2003 Share Posted May 29, 2003 6 are better for street use IMO. They run warmer and burn fuel more efficiently. Link to comment https://www.sau.com.au/forums/topic/17047-spark-plug-question/#findComment-352798 Share on other sites More sharing options...
carlo Posted May 29, 2003 Author Share Posted May 29, 2003 The car was fine before the change, but it seems more responsive post change.. the car runs about 9psi of boost. Link to comment https://www.sau.com.au/forums/topic/17047-spark-plug-question/#findComment-352809 Share on other sites More sharing options...
Zahos Posted May 30, 2003 Share Posted May 30, 2003 Originally posted by Doctor I changed from 7's to 6's yesterday and my god what a difference. Better start up, idle as smooth as power delivery more linear. Then try going to 5's. I just went from a heat range of 5 to 6 and I dont like it! I'll be going back down to a heat range of 5 again, so much smoother.... Link to comment https://www.sau.com.au/forums/topic/17047-spark-plug-question/#findComment-353190 Share on other sites More sharing options...
JL Posted May 30, 2003 Share Posted May 30, 2003 What spark plugs are the best to buy and what should I get 5's 6's or 7's. I have a 32 gts-t lightly modded, Cheers JL Link to comment https://www.sau.com.au/forums/topic/17047-spark-plug-question/#findComment-353195 Share on other sites More sharing options...
Zahos Posted May 30, 2003 Share Posted May 30, 2003 lightly moded = BCPR5E I am guestimating I am sitting at around the 170 - 180rwkw mark, and my car runs best with these for street use. Link to comment https://www.sau.com.au/forums/topic/17047-spark-plug-question/#findComment-353207 Share on other sites More sharing options...
JL Posted May 30, 2003 Share Posted May 30, 2003 What brand of plugs are BCPR5E Zahos? Link to comment https://www.sau.com.au/forums/topic/17047-spark-plug-question/#findComment-353313 Share on other sites More sharing options...
Zahos Posted May 30, 2003 Share Posted May 30, 2003 NGK Do a search, you'll find this is topic is covered extensively.... Link to comment https://www.sau.com.au/forums/topic/17047-spark-plug-question/#findComment-353319 Share on other sites More sharing options...
Doctor Posted May 30, 2003 Share Posted May 30, 2003 Zahos do you find that its threshold to detonate has lowered? Do temps run a little higher? Link to comment https://www.sau.com.au/forums/topic/17047-spark-plug-question/#findComment-353393 Share on other sites More sharing options...
Zahos Posted May 30, 2003 Share Posted May 30, 2003 I found that once the car warmed up, idle was smoother, and that the plug didnt foul as quickly. It also significantly reduced the misfire at the 5000rpm mark seen by R33's with VVT (not that it applies to you ). So in answer to your question, yes! Temps were just the same, noticed no difference. Link to comment https://www.sau.com.au/forums/topic/17047-spark-plug-question/#findComment-353419 Share on other sites More sharing options...
JL Posted May 30, 2003 Share Posted May 30, 2003 Thanks for your help Zahos, Cheers JL Link to comment https://www.sau.com.au/forums/topic/17047-spark-plug-question/#findComment-353448 Share on other sites More sharing options...
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