Thread: engine mods??
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Old 11-21-2013, 12:34 PM   #39 (permalink)
beatr911
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Join Date: Feb 2008
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B2300 - '96 Mazda B2300 SE

Focus - '05 Ford Focus ST

The red car - '00 Honda Insight
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Quote:
Originally Posted by renault_megane_dci View Post
How about shaving the head and advancing the cam to restore initial timing ?
Wouldn't it be better overall (high rpm included) ?

Yes you could do that to increase compression and restore the cam timing to stock. He wants to boost low/mid output though and is not interested in high rpm. So just advancing the cam will increase both compression and low/mid output.



That's a good one, thanks !
Step one, tune carb and step two work on plug gap, right ?
Yes. But depending on how finely tuned you want to go, a larger gap will also burn a very slightly leaner mixture without misfire. So jet (with O2 feedback device), tune plug, try one step leaner (with O2 feedback device). We're really splitting hairs here so it's probably only beneficial if you already have the leaner jets for the last step. Humidity, barometric pressure and temperature also play a role and will adjust your mixture a tiny bit for you.

Also, carfully cut back the ground strap on the plug so it covers about 1/4-1/3 of the center electrode. It exposes the spark a little more. Google pictures of the Autolite AR103 sparkplug. The key for our use is the ground strap design. This plug alone was good for about 4% or ~1.5mpg over the double planinum plugs on my Focus.
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Last edited by beatr911; 11-21-2013 at 12:53 PM..
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