Ferris decided to buy into the hype and try out a set of irridium spark plugs. So last weekend we installed them. Overall install impressions, Prophet_S4 hit it on the nose when he said, "it's not difficult, just a pain in the ***!" Here's the pics:
First step is to remove all the plastic engine covers. We started on the airbox side because it is a little easier to get to. You will see the coilpacks that cover the plugs.
Unplug the connectors by lifting the silver tab. There are two bolts holding the coil packs in place. once you remove them the coilpack will slide out.
You will need a long rachet extension to get the plugs out.
Here's what it looks like with all three coilpacks removed.
Here's a side by side of the new and old plugs. You can't see in this pic but the diode on the irridium plug is tiny!
After you have gapped the plugs (we gapped at 30) and installed them, slide the coilpacks back in, bolt down and reconnect the plug.
Here's a tip, when reinstalling the airbox, make sure your thumb isn't in the way of the clips. They pack a mean punch as Ferris found out the hard way!
Getting to the drivers side plugs is a little more difficult because the coolant reservoir is in the way. We unscrewed it but left the hoses intact and moved it out of the way.
We had to move it around depending on which plug we needed to get at.
In some cases you will need someone to hold the reservoir when removing and installing the plugs.
All in all it took us about 45 minutes to an hour to do the whole job. It will go a lot faster the next time we do it (on my car). As for the performance difference with the irridium plugs, i'll let ferris comment on that.
Please make this a FAQ! Exactly as is would be great.
00 Nogaro, MTM springs, UUC short shifter@40%, SSRs with PP S03s (245/40-17), rolled fenders, StopTech Brakes, Trailer hitch for bike rack, K04s, AWE downpipes, new and improved MAF....284 gms/second.
Well yes I bought the hype and I'm sure most of it is.. However let me explain the reasoning...
I always noticed slight hesitations esp in the upper rev limits. Then it occurred to me the more boost and or compression, humm for some reason my car puts out 1 bar of boost I think I'll have the dealer check into that for me, the more voltage is needed to produce a nice arc. This esp true in the higher rev range when the coils must charge and discharger faster, leaving more room for misfires. Now to compensate for this, one could lower the gap, which as a general rule, would mean less power or lower the power needed to produce a spark. Problem one was no hard data on the required voltage and what the coil packs produce. So with no knowledge of what we had or what the ignition system could produce my search ensued. I came across Iridium plugs, which seemed to be embraced by another AWD/TURBO group, the VR-4s. So I researched it, Iridium has a resistivity of ~5 micro ohms and with a high strength manufactures are able to make a very fine tip, I believe it was .04 MM. They also sport a U Groove, but I think that's snake oil, much like the ****fires.. Anyway compared to our stock platinum with a resistivity of 10 micro ohms, I figured I could run a stock or large gapping. So after much debate I decided to take the $100 plunge. I went with a stock gapping of .032 in and the same heat range as stock.
Once installed and fired up, I got 0 misfires on cylinders 1-3 and 5 & 6, but 4 sported 6 or so I think the problem was the antisieze compound. After about 3 minutes at idle I had 0 misfires across the board. Unfortunately the weather prevented any g-tech runs before and after so we have no hard data. But after about 1500 miles the car seems have no hesitation, infact I think the falling off in the upper range is nonexistent at this point. Idle is also alot smoother, no more bouncing tach, it's basically locked at 800.
The only draw back is that the VR-4 people notice a crack insulator when running 18-22PSI of boost, I honestly doubt I'd run that so no worries and I'll check in another 1500 miles.
My vote is if you have 2 hours and 100 to blow it's worth it.
The BMW M Roadster, if you have the means I highly suggest you pick one up. It's so choice....
2001 M Roadster
2001 S4 Avant
2008 Yamaha FZ6