Holley 4150 tuning
Thread Starter
Pro
Joined: Aug 2000
Posts: 713
Likes: 105
From: Winston-Salem, NC, USA
Holley 4150 tuning
I've been tuning my carb, and was curious as to what folks with SB's, mild cams, and 4150's were running for jets and power valves - I've been running
Primary - 64
Secondary - 68
PV - 6.5
I am still rich in general, and I have a dead spot when I accelerate from a cruise at 2000 RPM with about 13" of vacuum - the dead spot I think indicates that I'm going momentarily lean from the secondaries cracking and no fuel flowing "instantly" (don't have a shooter on the secondaries).
Well, what I did last night was change the following -
Primary - 60
Secondary - 64
PV - 8.5
Logic here is, I need to lean out in general, but, I need to richen the mixture when the secondaries are openning (transition).
2 things - was wondering what other folks are running for jets/PV's and also, what are some indications that I'm too lean other than it running poorly and checking plugs? I've heard that there's a high RPM popping sound with a lean mixture, but, have never experienced this,...
Thanks in advance!
Primary - 64
Secondary - 68
PV - 6.5
I am still rich in general, and I have a dead spot when I accelerate from a cruise at 2000 RPM with about 13" of vacuum - the dead spot I think indicates that I'm going momentarily lean from the secondaries cracking and no fuel flowing "instantly" (don't have a shooter on the secondaries).
Well, what I did last night was change the following -
Primary - 60
Secondary - 64
PV - 8.5
Logic here is, I need to lean out in general, but, I need to richen the mixture when the secondaries are openning (transition).
2 things - was wondering what other folks are running for jets/PV's and also, what are some indications that I'm too lean other than it running poorly and checking plugs? I've heard that there's a high RPM popping sound with a lean mixture, but, have never experienced this,...
Thanks in advance!
Melting Slicks
Joined: Mar 1999
Posts: 2,845
Likes: 2
From: Apex NC
Re: Holley 4150 tuning (72greg)
I would help you here, my Brother, but I know squat about Holley's :D
How did it run with the new combo of smaller jets and larger power valve? Other signs of a lean mixture would be the water temp running higher, and at the extreme some bucking at cruise speeds.
Shannon
PS - check the post about the Wilson event tomorrow. I'm sorta going along.
How did it run with the new combo of smaller jets and larger power valve? Other signs of a lean mixture would be the water temp running higher, and at the extreme some bucking at cruise speeds.
Shannon
PS - check the post about the Wilson event tomorrow. I'm sorta going along.
Drifting
Joined: Nov 2000
Posts: 1,390
Likes: 39
From: North Brunswick NJ
Re: Holley 4150 tuning (72greg)
72Greg,
I am running a 3310-6 Holley that was converted to a 4150. My primary jets are71 and the secondaries are 76. You need to check your timing with a good variable advance timing light to make sure you are burning your fuel properly.
You dont mention the size of your carb, but idle circuits that dont have enought air will cause rich conditions and fouled plugs. Off idle problem my be related to the timing if not chck the clearences on the accelerator pum.
Car Craft magazine has a great basic tunning section on carbs this month.
Ed
I am running a 3310-6 Holley that was converted to a 4150. My primary jets are71 and the secondaries are 76. You need to check your timing with a good variable advance timing light to make sure you are burning your fuel properly.
You dont mention the size of your carb, but idle circuits that dont have enought air will cause rich conditions and fouled plugs. Off idle problem my be related to the timing if not chck the clearences on the accelerator pum.
Car Craft magazine has a great basic tunning section on carbs this month.
Ed
Racer
Joined: Apr 1999
Posts: 422
Likes: 3
From: Oxford MI
Re: Holley 4150 tuning (72greg)
I run 68 and 76 with 8.5 pv. I found the lean pop more noticable at idle. I now adjust my idle mixture at 900 to 1000 rpm for the best drivability. I was always lean in this range when I made the adjustment at idle rpm(750).
Thread Starter
Pro
Joined: Aug 2000
Posts: 713
Likes: 105
From: Winston-Salem, NC, USA
Re: Holley 4150 tuning (BB2B)
it's a 600CFM carb,....
sb69coupe - I got it slapped back on last night around 9:15pm and had to make some adjustments - it was running very poorly initially because the accelerator pump adjustment was whacked,...I'm going to mess with it during lunch (one of the +'s of working from home!, ;) )
sb69coupe - I got it slapped back on last night around 9:15pm and had to make some adjustments - it was running very poorly initially because the accelerator pump adjustment was whacked,...I'm going to mess with it during lunch (one of the +'s of working from home!, ;) )
Drifting
Joined: Mar 2001
Posts: 1,395
Likes: 6
From: Indiana
Re: Holley 4150 tuning (72greg)
I am running with 68 prim and 76 sec on my 650dp. I drove around with a vacuum gauge to see what the car did under normal circumstances before settling on the 6.5 power valve. It seems to run pretty good now,even though I liked the feel of the 85 power valve a little better, but I was looking for better milage than 8mpg :bb My plugs seems to indicate that I am a bit rich since making the change to 68 pri from the 65's that I had in not too long ago. I am now changing my cam so I will wait before rejetting again.
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