91 vs 93 octane and spark plugs

Bagelfast · 07-21-2009, 02:35 PM

It seems some people feel that 20k miles on a tuned car seems to be the time to change the plugs on our cars.

But it also seems guys running tunes on 91 octane vs 93 octane guys seem to have more issues?

I have ran stock for about 8k miles. Then ran a tune for 5k and now another tune for about 7k, im about at 20k miles on 93 octane all else stock, HPFP failed about 2k miles ago but the car runs good and strong from what i can tell. Any tell tale signs plugs are failing? i get no misfires, run smooth through the rpm band and such.

David 12 · 07-21-2009, 05:25 PM

Your probably fine then as far as the spark plugs go. Rough idle, hesitation, CEL (indicating a misfire in a cylinder) are all signs. I changed mine at 20k tuned so you should be okay for another 5k to 10k.

It seems like race gas and octane booster accelerate the wear process.

Lotus99 · 07-21-2009, 06:54 PM

Quote:

Originally Posted by 1LUMI335

But it also seems guys running tunes on 91 octane vs 93 octane guys seem to have more issues?

I'm not clear on what you're saying. Guys on 91 have more problems or guys on 93?

07-21-2009, 02:35 PM	#1
Bagelfast Lieutenant Colonel 125 Rep 1,546 Posts Drives: BMW Join Date: Sep 2008 Location: USA iTrader: (0)	91 vs 93 octane and spark plugs It seems some people feel that 20k miles on a tuned car seems to be the time to change the plugs on our cars. But it also seems guys running tunes on 91 octane vs 93 octane guys seem to have more issues? I have ran stock for about 8k miles. Then ran a tune for 5k and now another tune for about 7k, im about at 20k miles on 93 octane all else stock, HPFP failed about 2k miles ago but the car runs good and strong from what i can tell. Any tell tale signs plugs are failing? i get no misfires, run smooth through the rpm band and such.
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07-21-2009, 05:25 PM	#2
David 12 Major 130 Rep 1,048 Posts Drives: 2019 BMW X5 50i BSM, M Sport Join Date: Jan 2007 Location: Omaha iTrader: (0)	Your probably fine then as far as the spark plugs go. Rough idle, hesitation, CEL (indicating a misfire in a cylinder) are all signs. I changed mine at 20k tuned so you should be okay for another 5k to 10k. It seems like race gas and octane booster accelerate the wear process.
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