Thread: Spark Plug Pics
View Single Post
GJF GJF is offline
Slantnose from HELL
GJF's Avatar
Join Date: Dec 2004
Posts: 809
No problem Don,
One problem you will see is if you go too big on the gap on boosted cars, the boost can and will actually blow the spark out. So even though the larger gaps give a better spark even with enhancers the spark can be extinguised. I run twin 300+ DFI boxs on my car and found on theNGK BKR9EIX plugs the .030 gap might have been too much @1.1-1.2 bar. The motor was acting as if it was lean popping. I had a set of Bosch W4CS which are 1 range hotter than the NGK's. I gapped them at .025 instead of .030 and haven't had the problem since. I was thinking of possibly trying the NGK's again with the gaps closed up to .025 just to see if it was the plugs heat range or the .005 gap difference.
For your wasted spark I would stay at .020-.025. Even with the enhancer boxes the larger recommended gap seems to be too much.
I'm using the siemens 1000cc injectors, they just don't like under .250. I am at low 13 to mid 13 at idle and cruise and in the 11's on boost. It isn't thay big a deal the only way it would become a problem is if I couldn't get it to idle without loading up. I have a good idle @ 850 RPM and a steady MAP reading. that is all anyone could ask for.
On a side note at what RPM are your EVO cams falling off?
87 911 Carrera platform
Twin Garrett's, Big Valve, Xtreme Cylinder Heads, JB Racing cylinders and machine work, custom JE pistons, GT2 EVO cams, GT3 oil pump, modified 3.2L intake, 80mm TB, custom Intercooler, equal length headers, DFI, KEP Stage 2 custom twin disc, G50 custom gear set, LSD, Tilton trans pump, Fluidyne cooler
Old 06-01-2008, 07:50 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #5 (permalink)