Holley ultra 650 double pumper review tuning and needed help
07-31-2014, 12:12 PM
#1
Racer
Thread Starter
Holley ultra 650 double pumper review tuning and needed help
I have been running a jegs remanufactured qjet for the past year. The only adjustment I made to it was adjusting the mixture screws for highest vacuum reading. The qjet has performed well is all aspects . my only complaint is it seems rich. Heavy exhaust smell at idle and black soot on the sides of my car. Looking for easier adjustability ... Hopefully! I chose the holley 650 ultra double pumper.
Specs are
1980
New build this spring
350
99% street
9.2 comp
Edelbrock performer 2101
HEI
Obx sidemount headers 1 7/8" primaries
Dart SHP 180 heads mild ported
Comp cams xr276hr 224/230 dur hyd roller
4 speed
3.07 gears
Timing
15 degrees @ 750 rpm
35 degrees @ 3000 rpm
+ 20 degrees manifold vacuum advance
Idle vacuum 14"
210 psi cranking compression
Stock delco fuel pump 6-7 psi
Qjet
Starts and idles well
Great throttle response driving
Never bogs backfires stumbles.
Pulls hard to 5800 rpm where it seems to flaten out, probally do to the intake manifold.
650 ultra dp
Lars sent me his papers on holley setup.* Wanting to learn as I go I installed the holley with the out of the box settings to see the difference after tuning to Lars papers .* I fabed a new fuel line. Then after installing the carb I noticed the secondary linkage hits the hot air block off plate on the intake. Installed a 1" open space to cure the interference. I am also using a adjustable throttle bracket and checked that the secondaries are fully opening . then I installed a lower profile air box/ air cleaner to fit the volley carb and to allow everything to fit under my 1980 stock hood.
Holley ultra 650 dp jetting out of the box
63/73 main jets
6.5 power valve
28/31 nozzles
Green cam primaries
Pink can secondaries
Cam screws in #1 hole
With everything installed it fired immediately. I adjusted idle to 750 rpm and adjusted the mixture screws for highest vacuum reading. Vacuum with the holley is the same as the qjet 14"
I noticed out of the box all the mixture screws were at a different number of turns. Holley's response is the carb is wet flowed on a bench and the screws are adjusted for equal flow and does not mean they will have the same number of turns out. As a note to achieve my highest vacuum reading the mixture screws were only 1/4 of a turn out from seated. At a half turn out the idle went to hell. With the qjet my mixture screws were 3 turns out for max idle vacuum .
Test run 1 out of the box holley settings
Carb is very responsive and does not have heavy exhaust fumes at idle as before . under normal driving the carb performs very well. BUT has a stumble/bog on quick throttle movement but it does recover quickly and pulls harder then it ever has. The stumble/bog is less noticeable @ idle but still there none the less. I figured I'd have some tuning to do. Cams and nozzles ... Butt dyno say the holley feels much quicker then the qjet except for the split second bog. Where the qjet feels very smooth the holley feels very aggressive. From a 1000 rpm rolling start the qjet will just pull hard, the holley (after the bog) will burn the tires.
Test run #2
Pull the carb and set it up to Lars papers.
My finding on the box holley setup. Found the secondary idle completely closed showing no transfer slot and the front open showing half or more of the transfer slot.
Floats set wrong, front too low rear to high. Pump nozzles in wrong places, holley had the 31 on the primary and the 28 on the secondary .
I set the secondary idle screw for .020 transfer slot showing same with the primary . checked pump arm clearance .015 at full throttle. Switched nozzles so the 28 is on the primary and the 31 is on the secondary. Adjusted the floats to the center of the sight glass.
It started immediately set mixture screws for the highest vacuum. The mixture screws are now 1 full turn out vs 1/4 of a turn as with the holley settings. Idle is much smoother than with the holley settings throttle resppnce is much crisper. BUT still has the same bog/stumble as with the box stock settings. Will be changing nozzles and pump cams this weekend to try and cure the bog issue. With the holley I seem to need less throttle opening to take off normally from a stop light then with the qjet. My spark plug color looks good and I haven't noticed any surges or backfires while cruising. I have not drove it many miles as of yet though.
With these changes the engine is still pulling hard at 6000 rpm where I let off..carb spacer and different air cleaner assemble..can't say which or all has helped the upper rpm range. This is defiantly not a bolt on and go carb as my qjet was but I am enjoying the tuning and learning I am getting.
Advise on tuning my setup, jetting pump cams nozzles ect would be very helpful. Reading the forum has helped me all the way thru this build.
As a side note the air box I bought allows me to run a 1" spacer on the performer intake with 5/8" hood clearance so a performer rpm would fit under a stock 80 hood. The performer rpm will be part of next winters project. I will post updates from the pump can and nozzle changes I make to rid the bog.
Specs are
1980
New build this spring
350
99% street
9.2 comp
Edelbrock performer 2101
HEI
Obx sidemount headers 1 7/8" primaries
Dart SHP 180 heads mild ported
Comp cams xr276hr 224/230 dur hyd roller
4 speed
3.07 gears
Timing
15 degrees @ 750 rpm
35 degrees @ 3000 rpm
+ 20 degrees manifold vacuum advance
Idle vacuum 14"
210 psi cranking compression
Stock delco fuel pump 6-7 psi
Qjet
Starts and idles well
Great throttle response driving
Never bogs backfires stumbles.
Pulls hard to 5800 rpm where it seems to flaten out, probally do to the intake manifold.
650 ultra dp
Lars sent me his papers on holley setup.* Wanting to learn as I go I installed the holley with the out of the box settings to see the difference after tuning to Lars papers .* I fabed a new fuel line. Then after installing the carb I noticed the secondary linkage hits the hot air block off plate on the intake. Installed a 1" open space to cure the interference. I am also using a adjustable throttle bracket and checked that the secondaries are fully opening . then I installed a lower profile air box/ air cleaner to fit the volley carb and to allow everything to fit under my 1980 stock hood.
Holley ultra 650 dp jetting out of the box
63/73 main jets
6.5 power valve
28/31 nozzles
Green cam primaries
Pink can secondaries
Cam screws in #1 hole
With everything installed it fired immediately. I adjusted idle to 750 rpm and adjusted the mixture screws for highest vacuum reading. Vacuum with the holley is the same as the qjet 14"
I noticed out of the box all the mixture screws were at a different number of turns. Holley's response is the carb is wet flowed on a bench and the screws are adjusted for equal flow and does not mean they will have the same number of turns out. As a note to achieve my highest vacuum reading the mixture screws were only 1/4 of a turn out from seated. At a half turn out the idle went to hell. With the qjet my mixture screws were 3 turns out for max idle vacuum .
Test run 1 out of the box holley settings
Carb is very responsive and does not have heavy exhaust fumes at idle as before . under normal driving the carb performs very well. BUT has a stumble/bog on quick throttle movement but it does recover quickly and pulls harder then it ever has. The stumble/bog is less noticeable @ idle but still there none the less. I figured I'd have some tuning to do. Cams and nozzles ... Butt dyno say the holley feels much quicker then the qjet except for the split second bog. Where the qjet feels very smooth the holley feels very aggressive. From a 1000 rpm rolling start the qjet will just pull hard, the holley (after the bog) will burn the tires.
Test run #2
Pull the carb and set it up to Lars papers.
My finding on the box holley setup. Found the secondary idle completely closed showing no transfer slot and the front open showing half or more of the transfer slot.
Floats set wrong, front too low rear to high. Pump nozzles in wrong places, holley had the 31 on the primary and the 28 on the secondary .
I set the secondary idle screw for .020 transfer slot showing same with the primary . checked pump arm clearance .015 at full throttle. Switched nozzles so the 28 is on the primary and the 31 is on the secondary. Adjusted the floats to the center of the sight glass.
It started immediately set mixture screws for the highest vacuum. The mixture screws are now 1 full turn out vs 1/4 of a turn as with the holley settings. Idle is much smoother than with the holley settings throttle resppnce is much crisper. BUT still has the same bog/stumble as with the box stock settings. Will be changing nozzles and pump cams this weekend to try and cure the bog issue. With the holley I seem to need less throttle opening to take off normally from a stop light then with the qjet. My spark plug color looks good and I haven't noticed any surges or backfires while cruising. I have not drove it many miles as of yet though.
With these changes the engine is still pulling hard at 6000 rpm where I let off..carb spacer and different air cleaner assemble..can't say which or all has helped the upper rpm range. This is defiantly not a bolt on and go carb as my qjet was but I am enjoying the tuning and learning I am getting.
Advise on tuning my setup, jetting pump cams nozzles ect would be very helpful. Reading the forum has helped me all the way thru this build.
As a side note the air box I bought allows me to run a 1" spacer on the performer intake with 5/8" hood clearance so a performer rpm would fit under a stock 80 hood. The performer rpm will be part of next winters project. I will post updates from the pump can and nozzle changes I make to rid the bog.
07-31-2014, 12:37 PM
#2
Instructor
I just upgraded to a Holley 670 Street Avenger with Vacuum Secondaries and replaced an older BG Road Demon. I have a similar motor with a TH400 and 3.73 gears. I found the same issues you had with the adjustment on the secondary throttle blades and the idle mixture screws. My floats were okay though and my choke worked perfectly. My accelerator pump arm was in alignment and needed no adjustment. I do not have the bog problem, mine accelerates beautiful.
07-31-2014, 03:54 PM
#3
Le Mans Master
You said you already had a takeoff stumble? Why would you install a smaller accelerator pump shooter in the primary barrels if you had a stumble in the initial opening of the throttle blades? Put back the larger shooter nozzle in the primary side....possibly go to a 35 nozzle. There are 2 settings on the pump cam one brings in the shoot a little later. You might want to try the other cam position. Buy a book on Holley tuning!
One other thing you might want to try.....ditch the vacuum advance on your distributor and run mechanical only sometimes the low RPM vacuum fluctuations can wreck havoc on vacuum advance timing. Your rear differential should be a 3.55 gear set in my opinion but what's a guy like me know?
One other thing you might want to try.....ditch the vacuum advance on your distributor and run mechanical only sometimes the low RPM vacuum fluctuations can wreck havoc on vacuum advance timing. Your rear differential should be a 3.55 gear set in my opinion but what's a guy like me know?
Last edited by Solid LT1; 07-31-2014 at 03:57 PM.
07-31-2014, 04:15 PM
#4
Racer
Thread Starter
You said you already had a takeoff stumble? Why would you install a smaller accelerator pump shooter in the primary barrels if you had a stumble in the initial opening of the throttle blades? Put back the larger shooter nozzle in the primary side....possibly go to a 35 nozzle. There are 2 settings on the pump cam one brings in the shoot a little later. You might want to try the other cam position. Buy a book on Holley tuning!
It doesn't stumble during normal take off or normal cruising. Reving while parked it doesn't stumble unless I get in to the secondary's. While driving any quick throttle movement makes it stumble. I ordered 33, 35, 37, and 40 nozzles along with a pump cam kit.
Going to change the screw positions tonight. book is on order.
07-31-2014, 06:11 PM
#5
Racer
Thread Starter
Still need to hook up the air inlet tubes .
Disconnected and capped vacuum advance. No change in the stumble, response wasnt, crisp and car sounds blubbery with out the vacuum advance.
Disconnected and capped vacuum advance. No change in the stumble, response wasnt, crisp and car sounds blubbery with out the vacuum advance.
Last edited by Flyinace3; 07-31-2014 at 06:15 PM.
07-31-2014, 06:28 PM
#6
Le Mans Master
My 600 dp also had the bog and it was due to an over-rich condition from the squirters (based on A/F ratios from chassie dyno runs). I reduced mine to the smallest (22s) and reduced the cam to cure the problem.
08-01-2014, 01:16 AM
#7
Racer
Thread Starter
Thanks for the info I didn't think about it being a over rich stumble... I should have ordered smaller nozzles as well. Which pump cams did you end up using?
08-01-2014, 01:16 PM
#8
Le Mans Master
IIRC, pink. Also, IIRC, when I did a lot of pump shot testing, I found that the #1 and #2 cam settings did the opposite of what is published and the "higher" setting gave the smaller shot.
I was able to remove the squirter and "thread" a plastic dropper that had calibrated marks into the fitting and physically see how big the shot was for the various cam and positions. I was going to produce a kit to do this, with a drain-back valve to the float bowl after each shot, and market it, but it never happened. I knew that if the product caught on, the "big boys" would move in and undercut me with their Chinese crap.
I was able to remove the squirter and "thread" a plastic dropper that had calibrated marks into the fitting and physically see how big the shot was for the various cam and positions. I was going to produce a kit to do this, with a drain-back valve to the float bowl after each shot, and market it, but it never happened. I knew that if the product caught on, the "big boys" would move in and undercut me with their Chinese crap.
Last edited by toddalin; 08-01-2014 at 01:24 PM.
08-01-2014, 09:40 PM
#9
Racer
Thread Starter
IIRC, pink. Also, IIRC, when I did a lot of pump shot testing, I found that the #1 and #2 cam settings did the opposite of what is published and the "higher" setting gave the smaller shot.
I was able to remove the squirter and "thread" a plastic dropper that had calibrated marks into the fitting and physically see how big the shot was for the various cam and positions. I was going to produce a kit to do this, with a drain-back valve to the float bowl after each shot, and market it, but it never happened. I knew that if the product caught on, the "big boys" would move in and undercut me with their Chinese crap.
I was able to remove the squirter and "thread" a plastic dropper that had calibrated marks into the fitting and physically see how big the shot was for the various cam and positions. I was going to produce a kit to do this, with a drain-back valve to the float bowl after each shot, and market it, but it never happened. I knew that if the product caught on, the "big boys" would move in and undercut me with their Chinese crap.