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Topic: QJET Fuel Air

in Forum: C3 Engines


QJET Fuel Air

Posted: 1/14/06 8:07pm Message 1 of 5
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ORLANDO, FL - USA
Joined: 12/11/2002
Posts: 459
Vette(s): 1980 L82 Dark Metallic Green Coupe, Gymkhana Suspension, AM/FM/CB, GM ZZ383....nice....

Started adjusting the Qjet air fuel today using the vacuum method. I ended up at 10.5 turns out on both sides with 18.5 vac at 800RPM in drive.

Q. Does this range of number of turns out seem normal for a QJET? A tuning article I read said to start at 3 turns out (holley?) and turn in from there?

Q. I actualy reached 18 on vac at 8 turns out on each, should I back off to close to 8-9 turns?




 
1980 L82 (5069 made), Dark Green Metalic (844 made)
Gymkhana Suspension, AM/FM/CB, Sporting a ZZ383......... 
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QJET Fuel Air

Posted: 1/14/06 8:19pm Message 2 of 5
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Duncanville, TX - USA
Joined: 11/8/2003
Posts: 20214
Vette(s): #1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/ Am-Fm/map light National/Regional/Chapter NCRS "Top Flight" #2-1985 Bright Red/Carmine Cp.L-98/auto Member: NCRS, NCRS Texas, Corvette Legends of Texas
Every carb, and the engine it is on, will take a different adjustment to get it right on. I have found, on MOST applications w/Quad, that 3-4 turns out from bottom, will give the best performance. There is always gonna be an exception, and there is the variable of carb size vs engine size, cam size, exhaust, etc. etc. Just turn them to get the best vac. reading, and idle quality. The adjustments ONLY effect idle. Anything over 1000/1200 rpm, and the carb has already switched over to the power enrich circuits/jets.
You're getting there!!


Joel Adams
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QJET Fuel Air

Posted: 1/14/06 9:52pm Message 3 of 5
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BINGHAMTON, NY - USA
Joined: 7/19/2003
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Wow I didn't think you could turn them out that far,like Joel said 3to4 is usually all you need to get it right,I think if I turned mine out 10 turns they would fall out


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QJET Fuel Air

Posted: 1/15/06 9:22am Message 4 of 5
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Duncanville, TX - USA
Joined: 11/8/2003
Posts: 20214
Vette(s): #1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/ Am-Fm/map light National/Regional/Chapter NCRS "Top Flight" #2-1985 Bright Red/Carmine Cp.L-98/auto Member: NCRS, NCRS Texas, Corvette Legends of Texas
Ron, I think you may have a few screws loose, anyway...

I have a sign in my shop that says..."Loose Nuts Tightened Here!"


Joel Adams
C3VR Lifetime Member #56    

My Link


(click for Texas-sized view!)
             NCRS

"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"

QJET Fuel Air

Posted: 1/15/06 6:47pm Message 5 of 5
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ORLANDO, FL - USA
Joined: 12/11/2002
Posts: 459
Vette(s): 1980 L82 Dark Metallic Green Coupe, Gymkhana Suspension, AM/FM/CB, GM ZZ383....nice....

I found an older post with a response from Ken which indicated I should locate the best vacuum, then find the dead spot, and then back down to the point where the best vacuum started. Done.

My final numbers were 5.5 turns out on each with 17" vacuum at 750-800RPM in drive with vac advance connected.

What seemed strange is that the idle screw is barely touching so I can't lower the idle any further with this setup. I also rechecked the timing for max vacuum and test run. Some bucking so I backed down a hair on the timing, now seemed to run strong.




 
1980 L82 (5069 made), Dark Green Metalic (844 made)
Gymkhana Suspension, AM/FM/CB, Sporting a ZZ383......... 

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