Toymods Car Club Inc: Tech & Conversions => 7MGE Compression Ratio

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oldcorollas
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Kita-Ku, Sapporo, Japan
Registered:
January 2003

Re: 7MGE Compression Ratio - How High ??	Mon, 28 July 2003 04:10

although it's a pain, you could always go half way and then get more machined off later. much more work, but as ya say, aint no going back (without a thick copper gasket). well, bikes with high overlap run up to abut 13:1, some of the euro cars are running around 11:1. in my rolla (4K) i have 275/285 cams (solid lifter) which have 65 deg overlap and high lift rates. i have 10.2:1 CR only run mobil 8000 (or occ. optimax if i have to) and currently have stupid amounts of advance. something like 20-25 deg static and 35-40 all in. i have not been able to get it to ping yet even with 35 deg static advance. just makes it harder to start and loses much power. the combustion chambers have been seriously smoothed compared to stock, but it's still a crappy chamber (tho it is about 1/3rd squish area with 0.8mm squish (32 thou) i'm sure the bigger than stock overlap gives me lower dynamic compression at low revs (135-140psi cranking speed) but at high rpm, the dynamic compression should be as high if not higher than stock?? i'm thinking of at least 10.5:1 next time, with a smaller overlap cam, but i guess our motors are pretty different as i have bore of 76.5mm.... at worst if you go maybe 0.5 points too high you could always go a 1.2-1.5mm copper gasket. Cya, Stewart [Report message to a moderator]

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