carb tuning ???
#1220082
04/21/12 09:37 PM
04/21/12 09:37 PM
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Joined: Nov 2004
Posts: 3,517 pacific northwest
Stroker Scamp
OP
master
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OP
master
Joined: Nov 2004
Posts: 3,517
pacific northwest
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using and A/F meter my idle is at 18-20, I only have the screws out one turn, other question is whats the best # to look for in the upper RPM range? race motor C-12 fuel, Im just testing parked for now but im getting a 10-11 at 4K, carb is a Holley 950 HP, seemed to think it was 12.5 range, any input would be great, as you can tell im just learning this stuff, Thanks Mike
footbrake N/A SB 408 Scamp 10.10 @ 132 street/strip 73 Duster 340 street strip 12.79 @ 105
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Re: carb tuning ???
[Re: Stroker Scamp]
#1220085
04/22/12 12:48 AM
04/22/12 12:48 AM
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Joined: Jan 2003
Posts: 5,486 SoCal
Brian Hafliger
master
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master
Joined: Jan 2003
Posts: 5,486
SoCal
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Quote:
using and A/F meter my idle is at 18-20, I only have the screws out one turn, other question is whats the best # to look for in the upper RPM range? race motor C-12 fuel, Im just testing parked for now but im getting a 10-11 at 4K, carb is a Holley 950 HP, seemed to think it was 12.5 range, any input would be great, as you can tell im just learning this stuff, Thanks Mike
Idle screws out 2-2 1/2 turns, block rear power valve and start with 87, 2.5 PV in front and 77 jet. I recommend .035 squirters, and blue pump cams front and rear. Make sure you crack the rear throttle blade enough to let air by the blades. OOTB they are seated in the bores and won't properly allow idle adjustments. A 950 is just too small for that engine though IMO... Brian
Brian Hafliger
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Re: carb tuning ???
[Re: Brian Hafliger]
#1220086
04/22/12 01:16 AM
04/22/12 01:16 AM
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Joined: Nov 2004
Posts: 3,517 pacific northwest
Stroker Scamp
OP
master
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OP
master
Joined: Nov 2004
Posts: 3,517
pacific northwest
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Quote:
Quote:
using and A/F meter my idle is at 18-20, I only have the screws out one turn, other question is whats the best # to look for in the upper RPM range? race motor C-12 fuel, Im just testing parked for now but im getting a 10-11 at 4K, carb is a Holley 950 HP, seemed to think it was 12.5 range, any input would be great, as you can tell im just learning this stuff, Thanks Mike
Idle screws out 2-2 1/2 turns, block rear power valve and start with 87, 2.5 PV in front and 77 jet. I recommend .035 squirters, and blue pump cams front and rear. Make sure you crack the rear throttle blade enough to let air by the blades. OOTB they are seated in the bores and won't properly allow idle adjustments. A 950 is just too small for that engine though IMO... Brian
currently running 84 squared no power valves, pretty sure 35 for squirters, think i have a cam kit, boy i should have done this long ago,,, brian wont turning it out to 2 1/2 fatten up the idle?
footbrake N/A SB 408 Scamp 10.10 @ 132 street/strip 73 Duster 340 street strip 12.79 @ 105
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Re: carb tuning ???
[Re: Big B]
#1220090
04/24/12 12:25 AM
04/24/12 12:25 AM
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Joined: Nov 2004
Posts: 3,517 pacific northwest
Stroker Scamp
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OP
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Joined: Nov 2004
Posts: 3,517
pacific northwest
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is the higher the # fatter or leaner?
footbrake N/A SB 408 Scamp 10.10 @ 132 street/strip 73 Duster 340 street strip 12.79 @ 105
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Re: carb tuning ???
[Re: Cab_Burge]
#1220092
04/24/12 12:31 AM
04/24/12 12:31 AM
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Joined: Mar 2003
Posts: 2,516 PA
moparacer
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master
Joined: Mar 2003
Posts: 2,516
PA
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At 18-20 I bet that thing is sipping air somewhere.
Is this with open headers/collectors?
67 Barracuda street/bracket car 11.27-119 68 Dart 502 BB 8.70s-152 414 cid SB Dragster 7.65-174
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Re: carb tuning ???
[Re: Stroker Scamp]
#1220094
04/26/12 10:15 PM
04/26/12 10:15 PM
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Joined: Nov 2004
Posts: 3,517 pacific northwest
Stroker Scamp
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master
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OP
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Joined: Nov 2004
Posts: 3,517
pacific northwest
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another dumb question but how much does the A/F change under load going down the track?
footbrake N/A SB 408 Scamp 10.10 @ 132 street/strip 73 Duster 340 street strip 12.79 @ 105
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Re: carb tuning ???
[Re: Stroker Scamp]
#1220095
04/27/12 12:01 AM
04/27/12 12:01 AM
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Joined: Aug 2003
Posts: 43,251 Bend,OR USA
Cab_Burge
I Win
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I Win
Joined: Aug 2003
Posts: 43,251
Bend,OR USA
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Quote:
another dumb question but how much does the A/F change under load going down the track?
It depends on the fuel system and carb., if it goes lean from the start line to the end of the run then look at what is casuing it. I've seen it caused by the fuel filter being to fine, to small of needles and seats, .110 versus .120 Not big enough pickup in the tank, not big enough fuel line to the front, not good enough fuel pump, fuel regulator too small and the list goes on
Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
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