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JBL930 JBL930 is offline
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Join Date: May 2006
Location: UK
Posts: 1,172
The 993t is single plug, with just one coil. The coil is mounted with the terminals facing up, and without the seal around the intercooler they are right in the path of any water coming in. Now i know that it's water that is killing the coil, i can make sure that doesn't happen again by shrouding it.

I was just wondering whether i could/should aim for a better spark at the plug.

To give you some idea why i am thinking about this, i have been chasing an odd boost issue for some time, my map should give me 1.1bar, and when it's running well it does, and pulls really strong.
But sometimes the car acts up, only boosting to 0.8bar, like at the last VMax event. It can run like this for a while, and then suddenly and for no apparent reason it will go back to a proper 1.1bar.
I hadn't noticed that it was connected to the rain, but looking back it makes perfect sense. I set off for Le Mans last week and the car was running strong, we drove through a shower and after the shower it was only boosting to 0.8.
We drove further and there was a major downpour, after that i was lucky to see 0.5bar and was spluttering as soon as boost started to build. It seams stupid now, but i still hadn't put two and two together, i thought the ECU was acting up, and i had two spares with me, but they didn't help, changed the DME relay, that didn't help. Then i'd go around and check connections on everything, MAF sensor etc.... and then it would fire up.....idle for a while, then idle badly, then be fine. I'd go for a spin and it would boost a little, maybe 0.5bar and then splutter, but off boost it seamed fine. Then without warning it would die all together, no sign of life. Leave it for an hour and it would start again. Really odd behaviour...

New coil fitted and my mechanic said it's back to being scary fast, he said he was shocked how much quicker it feels than when he first fitted the bigger turbos a month or so ago.
Which in turn has me thinking if the spark makes SO much difference, how can i go about having the absolute best possible spark with my stock set up.
I wonder if, even in new condition, my coil simply isn't up to the job. I'd rather have something that was running at 75% of it's capacity when under full demand from me, if that makes sense?

Is it just the coil that makes the spark? Is there such a thing as too much spark?
87 930, 993 turbo engine, RS Tuning 520PS/515lbf-ft, Arrow Rods, ARP hardware, Solid lifters, G50-50, RS Flywheel, 890nm Sachs clutch, RSR coil overs all round, 993 C4 calipers front, 930 fronts on the rear, Ruf Speedlines.....
Old 540 BMW, XB12S Modified, for being a total hooligan
Old 06-19-2010, 05:06 AM
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