Holley tuning help
#962250
03/30/11 12:57 AM
03/30/11 12:57 AM
|
Joined: Jun 2007
Posts: 1,184 clarks summit pa
73cuda340
OP
super stock
|
OP
super stock
Joined: Jun 2007
Posts: 1,184
clarks summit pa
|
I have a 1985 w150 with a 318 that has a 650 double pumper, edelbrock air gap and headers with a full three inch exhaust, other than that it's stock. Im getting a very bad bog starting off and if I floor it the truck will stall. I have to feather the gas to get it moving and the it runs ok. I checked for accelerator pump shot and I get a shot as soon as I hit the throttle. The timing is at 14 inital and 34 total. I just swapped to the four barrel and am trying to get it sorted out. Any help appreciated.
1973 Cuda 528 all aluminum Hemi, 4 speed, 3.23 Sure-Grip,
(JA5) Silver Frost Metallic
1973 Challenger Rallye 340
1985 W150 Power Ram prospector
1986 Camaro IROC-Z 305 tpi
|
|
|
Re: Holley tuning help
[Re: ireland383]
#962252
03/30/11 07:58 AM
03/30/11 07:58 AM
|
Joined: Oct 2003
Posts: 21,345 Marysville, O-H-I-O
70Cuda383
Too Many Posts
|
Too Many Posts
Joined: Oct 2003
Posts: 21,345
Marysville, O-H-I-O
|
having to feather it, as in, pumping the gas when starting off? sounds like you need MORE pump shot.
I would start out by changing the size of the nozzle on the pump shot, one or 2 sizes bigger so that you get more fuel, faster. then you can start playing with the cams on the pump shot too if you need more duration of pump shot.
I had the same problem on a holley DP. I had to pump the gas 3 or 4 times to get the RPMs up without stalling it. went up a few sizes in nozzle, and also changed the cam so that I got a longer duration shot, and the problem went away
**Photobucket sucks**
|
|
|
Re: Holley tuning help
[Re: fox]
#962254
03/30/11 10:38 AM
03/30/11 10:38 AM
|
Joined: Nov 2005
Posts: 1,943 San Angelo, Texas, U.S.A.
1968RR
top fuel
|
top fuel
Joined: Nov 2005
Posts: 1,943
San Angelo, Texas, U.S.A.
|
Off-idle bogs often mean that you're running rich. You need to make sure that 1. you're idle mixture screws are adjusted properly 2. you have correct power valves, and 3. your jetting is right. The first two things can be done with a vacuum gauge and a little patience. The third requires trial-and-error and a lot more patience. ![](/ubbthreads/images/graemlins/Twocents.gif)
"When I'm in a slump, I comfort myself by saying if I believe in dinosaurs, then somewhere, they must be believing in me. And if they believe in me, then I can believe in me." - Mookie Wilson
|
|
|
Re: Holley tuning help
[Re: 70Cuda383]
#962257
03/30/11 01:16 PM
03/30/11 01:16 PM
|
Joined: Feb 2005
Posts: 5,221 Branson, Mo.
joedust451
super gas
|
super gas
Joined: Feb 2005
Posts: 5,221
Branson, Mo.
|
Quote:
I had the same problem on a holley DP. I had to pump the gas 3 or 4 times to get the RPMs up without stalling it. went up a few sizes in nozzle, and also changed the cam so that I got a longer duration shot, and the problem went away
Sounds like the carb had internal issues, maybe even vacuum leaks & you did a "bandade" fix, unless you had a high dur. cam & low manifold vacuum, there should be no reason an OOTB holley (properly sized) should need any more then Idle screw adj. & maybe a minor jet change, even with high dur. cams/low man. vacuum i can tune in a holley with minimal changes in squirters/cams IF the timing curve is set right.
|
|
|
Re: Holley tuning help
[Re: 73cuda340]
#962260
03/31/11 07:32 PM
03/31/11 07:32 PM
|
Joined: Jun 2007
Posts: 1,184 clarks summit pa
73cuda340
OP
super stock
|
OP
super stock
Joined: Jun 2007
Posts: 1,184
clarks summit pa
|
Not sure on jet sizes or size of the squirters or the power valve. I haven't had this apart yet.
1973 Cuda 528 all aluminum Hemi, 4 speed, 3.23 Sure-Grip,
(JA5) Silver Frost Metallic
1973 Challenger Rallye 340
1985 W150 Power Ram prospector
1986 Camaro IROC-Z 305 tpi
|
|
|
Re: Holley tuning help
[Re: greenpigs]
#962263
04/01/11 02:01 PM
04/01/11 02:01 PM
|
Joined: Jun 2007
Posts: 1,184 clarks summit pa
73cuda340
OP
super stock
|
OP
super stock
Joined: Jun 2007
Posts: 1,184
clarks summit pa
|
I adjusted the mixture screws and it is a little bit better now, but the bog is still there and now I have a little hesitation on the top end.
1973 Cuda 528 all aluminum Hemi, 4 speed, 3.23 Sure-Grip,
(JA5) Silver Frost Metallic
1973 Challenger Rallye 340
1985 W150 Power Ram prospector
1986 Camaro IROC-Z 305 tpi
|
|
|
Re: Holley tuning help
[Re: 73cuda340]
#962264
04/01/11 03:59 PM
04/01/11 03:59 PM
|
Joined: Feb 2005
Posts: 5,221 Branson, Mo.
joedust451
super gas
|
super gas
Joined: Feb 2005
Posts: 5,221
Branson, Mo.
|
Quote:
I adjusted the mixture screws and it is a little bit better now, but the bog is still there and now I have a little hesitation on the top end.
Go invest in a holley tuning book or 2, i own 3 of them, read em, then read em again. If you know the fuel system is good, the ignition/timing curve is good & no vacuum leaks, THEN look at the carb, most problems are blamed on the carb, because thats the 1st. thing you see when looking at your engine, but most problems are elsewhere.
|
|
|
Re: Holley tuning help
[Re: 73cuda340]
#962265
04/01/11 07:51 PM
04/01/11 07:51 PM
|
Joined: Jan 2003
Posts: 1,100 Fort Lauderdale
Dave440
super stock
|
super stock
Joined: Jan 2003
Posts: 1,100
Fort Lauderdale
|
My ![](/ubbthreads/images/graemlins/Twocents.gif) First off....for a late model low compression engine with a stock cam in a heavy vehicle... a double pumper and air-gap intake is not the way to go. You want torque to get you off the line. That intake is rated 1500-6500 for a reason. You're hurting off the line torque and wasting fuel with an air gap. Plus ...double pumper carbs are meant to sit on top of a race engine with generally low vaccum signal and lumpy cams. Theyre jetted richer and also idle richer = wasted fuel. A regular Performer intake (NOT RPM or Air Gap RPM) and vacuum secondary carb is all you need for that setup and will provide more torque at lower rpm. If its a new intake and you can swap it for a performer....do it. Go with a 600 vac sec holley or Edelbrock 625/650 AVS carb and you'll be much happier. Of course.... theres always a Performer intake and Demonsizzler prepped Thermoquad! Small primaries = Gas mileage and Gobs of low rpm torque + Large vacuum secondaries for when your foot gets happy! ![](/ubbthreads/images/graemlins/drive.gif)
|
|
|
Re: Holley tuning help
[Re: Dave440]
#962266
04/01/11 08:44 PM
04/01/11 08:44 PM
|
Joined: Jun 2007
Posts: 1,184 clarks summit pa
73cuda340
OP
super stock
|
OP
super stock
Joined: Jun 2007
Posts: 1,184
clarks summit pa
|
I knew before hand that it wasnt the perfect combination for my setup. I only used this carb and intake setup because I already had them laying around as extra parts. Anything is better than the stock 2 barrel setup that was on it as that needed a complete rebuild. It was running so rich that your eyes would burn standing next to it and you could basically watch the gas gauge go down. The truck runs 100 times better than it did. The only problem is if I try to get on it quick it will bog down bad until I get moving. I just want to try to get this fine tuned for now until I get my 340 finished to put in it.
1973 Cuda 528 all aluminum Hemi, 4 speed, 3.23 Sure-Grip,
(JA5) Silver Frost Metallic
1973 Challenger Rallye 340
1985 W150 Power Ram prospector
1986 Camaro IROC-Z 305 tpi
|
|
|
Re: Holley tuning help
[Re: Dave440]
#962267
04/01/11 09:20 PM
04/01/11 09:20 PM
|
Joined: Feb 2005
Posts: 5,221 Branson, Mo.
joedust451
super gas
|
super gas
Joined: Feb 2005
Posts: 5,221
Branson, Mo.
|
Quote:
My ![](/ubbthreads/images/graemlins/Twocents.gif) Plus ...double pumper carbs are meant to sit on top of a race engine with generally low vaccum signal and lumpy cams. Theyre jetted richer and also idle richer = wasted fuel.
Not true.
|
|
|
Re: Holley tuning help
[Re: joedust451]
#962271
04/02/11 10:23 PM
04/02/11 10:23 PM
|
Joined: Jan 2003
Posts: 1,100 Fort Lauderdale
Dave440
super stock
|
super stock
Joined: Jan 2003
Posts: 1,100
Fort Lauderdale
|
Quote:
I think you will have to richen up the transition circuit to cover up the hole between the accelerator pump shot and transition into the main circuit. Usually enlarging the idle restriction and maybe the power valve restriction in the metering plate by a few thousandth should help
I would agree with those mods...EXCEPT...this isn't the motor that carb is going to end up on...(assuming the 650dp is goin on the 340 when its done? I could be wrong in ASSuming there) ...plus its a one way street if you drill the PVCR larger and it doesnt fix the problem or worse...end up drilling too large and it results in a rich condition. Or ends up fixin the problem on the 318 and it doesnt run right on the next motor it goes on. Then your stuffing bent pieces of wire in the pvcr to try to reduce the flow thru an oversized hole or buying a new metering block...etc...
I always like to start with external easily reversible changes like accel pump adjustments, plastic cam changes and engine timing FIRST.
Its also possible the PVCR size is fine but it needs a power valve that opens sooner than the stock 6.5. Maybe an 8.5 or 10.5 depending on engine vacuum at idle and cruise. Its all trial and error....and can get expensive parts wise but if youre stickin with Holley carbs then you end up with a collection of parts you can use to experiment with on most 4150 series carbs in the future (power valves do eventually get hard though- ive got a collection of petrified valves).
As for drilling...I only go drilling idle bleeds, fuel bleeds and PVCRs as a last resort...and its usually bcus the carb selection was wrong.
I'm also guilty of the "spending lots of time tryin to make carbs and manifolds you have lying around work right" scenario than I'll ever admit too. Oh mannnnn I just did.... DOH!!!! ![](/ubbthreads/images/graemlins/rant.gif)
Make adjustments, change parts...or drill baby drill... I guess it all depends how much time, money and patience you have ![](/ubbthreads/images/graemlins/wrench.gif)
As always.....YMMV
|
|
|
Re: Holley tuning help
[Re: 451Mopar]
#962273
04/03/11 02:27 AM
04/03/11 02:27 AM
|
Joined: Feb 2007
Posts: 1,025 Las Vegas, NV
dodgeboy11
super stock
|
super stock
Joined: Feb 2007
Posts: 1,025
Las Vegas, NV
|
I tried the larger squirters with limited success. To start, jet that puppy bigger 2 to 4 sizes per jet (primary and secondary) if the problem gets less, you need more fuel from the accelerator pumps. I believe the 650 comes with 31 nozzles standard. Going bigger doesn't help as the 30 cc pumps don't have enough volume per stroke to spray the fuel in as it is needed. I put dual 50 cc pumps on mine with 31 nozzles and I used the brown pump cam, turned it so it was about to push the accelerator pump lever, marked it and drilled my own hole. Hesitation went away for me. You need more fuel, the manifold is fairly big for that combo, it has no exhaust crossover to heat anything so it needs more fuel. This is all assuming the engine is happy and the carb is as well.
|
|
|
Re: Holley tuning help
[Re: joedust451]
#962276
04/03/11 01:03 PM
04/03/11 01:03 PM
|
Joined: Jan 2003
Posts: 538 PA
maxwedge1
mopar
|
mopar
Joined: Jan 2003
Posts: 538
PA
|
having been down this road before putting a hirise dual plane and vac secondary 600 on a previous stock 2bbl with 2.76 gear. It killed the off idle and bottom end.
assuming the carb is ok..my cure was alot of time experimenting on initial timing the idle mixture and timing curve. getting a clean idle with alot of initial and lighter spring for quicker advance was the fix but you have to deal with pump gas and pinging issues also if your to agressive.
need to limit total advance also since alot of initial and the lite springs will put total to high.
more gear would help if you are running "hiway" gears now.
Last edited by maxwedge1; 04/03/11 01:11 PM.
|
|
|
Re: Holley tuning help
[Re: maxwedge1]
#962277
04/08/11 11:00 PM
04/08/11 11:00 PM
|
Joined: Jun 2007
Posts: 1,184 clarks summit pa
73cuda340
OP
super stock
|
OP
super stock
Joined: Jun 2007
Posts: 1,184
clarks summit pa
|
Havnt had a chance to work on the truck for a while but I found out that the miss and hesitation up top was from when I found out that I forgot to hook up the vacuum advance back up and then after hooking it up I checked the timing again and the total was at 52 degrees. Guess Ill have to lower the initial a little to get it back down.
1973 Cuda 528 all aluminum Hemi, 4 speed, 3.23 Sure-Grip,
(JA5) Silver Frost Metallic
1973 Challenger Rallye 340
1985 W150 Power Ram prospector
1986 Camaro IROC-Z 305 tpi
|
|
|
|
|