View single post by Judson Manning
 Posted: 08-27-2008 05:06 pm
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Judson Manning

Joined: 03-14-2005
Location: Atlanta, Georgia USA
Posts: 406
This is an update after we put John Cronin's rebuild on the DynoPak last week.

John went with an extremely 'streetable' combination of 107 cams 104^ HTD sprockets fed by Dellortos and breathing through the standard tri-Y header.  I'll get around to posting the actual torque, HP and air-fuel ratios graphs one of these days.

The results showed an almost perfectly flat torque curve from 2500rpm to just over 5200rpm.  The intermediate dip in the curve corresponds to a/f ratios dropping to 11:1 from an ideal (full power ideal that is) 12.5:1.  The dip is right in the middle where the carbs are running out of the range of the a/c and idle jets suggesting the 145 mains are a tiny bit rich at full throttle.

For comparison my 2.2 running essentially 104 cams on 135 mains showed a steep  rise from 2000rpm to over 5000rpm.  That was until we smoked the clutch!  A dynoPak WILL find the weak point in your driveline.  At full throttle my a/f ratio was skirting the low 12:1 range.

The more dyno runs we get across the country and more data we collect on various combinations will most definately help us find better and better jet combinations.  Anyone else have dyno data they can share???