Qjet starving with 383
12-22-2011, 01:25 AM
#1
Qjet starving with 383
Anyone have experience with a qjetted 383? The problem i'm having is that ever since i swapped in the 383, the qjet stumbles for a couple of seconds after going from 1st to 2nd, and 2nd to 3rd for a few seconds during WOT. (revs stumble at 4000-4500 rpm) and then rip to 6000 rpm.
It feels like it's starving for fuel, but i run a holley blue electric, which worked flawlessly with my 355.
Any thoughts?
Heads are RHS 200cc, comp cams 280 hydraulic roller, weiand dual plane. All these parts were on the 355.
It feels like it's starving for fuel, but i run a holley blue electric, which worked flawlessly with my 355.
Any thoughts?
Heads are RHS 200cc, comp cams 280 hydraulic roller, weiand dual plane. All these parts were on the 355.
12-22-2011, 02:50 PM
#2
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Car: 82 Berlinetta/57 Bel Air
Engine: LS1/LQ4
Transmission: 4L60E/4L80E
Axle/Gears: 12B-3.73/9"-3.89
I ran a qjet on a 396. Didn't have starvation problems.
Couple of things come to mind. 1) Larger needle/seat assy - http://www.summitracing.com/parts/EDL-1980/ - I used one in my qjet; 2) the secondary air valve is closing or partially closing during the shifts. Try adjusting the AV tension first by loosening it until you get a little bog going to WOT, then tightening it until it goes away. This may allow the AV to stay open during the shifts (or open more quickly after the shift). With a T5, you're on borrowed time behind a 383, so you may want to consider a double pumper Holley type carb.
Couple of things come to mind. 1) Larger needle/seat assy - http://www.summitracing.com/parts/EDL-1980/ - I used one in my qjet; 2) the secondary air valve is closing or partially closing during the shifts. Try adjusting the AV tension first by loosening it until you get a little bog going to WOT, then tightening it until it goes away. This may allow the AV to stay open during the shifts (or open more quickly after the shift). With a T5, you're on borrowed time behind a 383, so you may want to consider a double pumper Holley type carb.
12-22-2011, 03:27 PM
#3
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Car: 1985 IROC
Engine: 305 TPI
Transmission: 700R4
Re: Qjet starving with 383
If this happeneing during shifts at WOT then its more likely your air valve. Its likely to tight and will only open properly with higher airflow.
Adjustment is easy.
what carb is this? part number? what did it come off of?
Adjustment is easy.
what carb is this? part number? what did it come off of?
12-23-2011, 05:29 PM
#6
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Car: 91 Camaro RS
Engine: empty bay (for now)
Transmission: Built T-56
Axle/Gears: 3.42 stock posi disc
Re: Qjet starving with 383
nothing. he was just warning you the t5 isnt built to handle a low hp 350, let alone a 383. and double pumper carbs tend to work better on performance oreinted vehicles than the vac secondary ones.
12-24-2011, 12:45 AM
#7
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Car: 82 Berlinetta/57 Bel Air
Engine: LS1/LQ4
Transmission: 4L60E/4L80E
Axle/Gears: 12B-3.73/9"-3.89
A mechanical secondary (double pumper) Holley carb allows you to "granny shift" without this sputtering after shifting.
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