Discussion in 'Intake Systems , Fuel Systems and Related' started by Maniacmechanic1, Jan 1, 2019.
I Love the Holley 770 Cfm Street Avenger Carb 4150 with Vacuum secondary I use on my '63 Gp.
Only weak link I have found is the electric choke.
Best vid I have found for Holley choke tips.
Choke is coming off too early for cold Midwest winters here at -20 F to 32 F.
Going to try out the Holley choke delay Heat Dyne thermistor sensor.
The Olds 425 wants 1/8" inch initial choke opening as the guy explains towards the end of the video.
If it does not work out then I will install a Holley manual choke pull cable.
One area where a Quadrajet is superior ...factory hot air chokes worked flawless in Midwest winters provided all working and dialed in.
Also to get that Initial 1/16" - 1/8" choke opening on an electric choke equipped Holley 4-bbl you need to index the choke cover to its lowest or past marks so there is no heavy tension on the choke plate at cold temps.
Close to EFI performance.
Cold winter starts ease and drive away Notta yet.
I received the Holley Choke Delay kit.
Going to install today and test try it out.
Also came in is a New Remy CS144 Alternator I am going to build 1-wire hookup with a Moroso 5 inch billet aluminum drive pulley. For extended high rpm race 6000+ in my Trans Am.
Another CS144 is coming also in.
Going to build 1-wire.
Use a reproduction L88 427 DZ302 3-5/8" O.D. Drive pulley.
Build for a member when he is ready.
Use the 1963 Gp with its Olds 425 V8 to test both out and charge voltage current characteristics with different driven pulley ratios.
Thinking L88 DZ302 pulley best for most here.
Thrown alternator belts has happened to me dozens of times.
Can happen serpentine belt layout also.
I calculated the cost of an Holley Sniper EFI and found out that I have to drive nearly 8 years to get the cost in for fuel economy.
The cold start is one + on the EFi side.
I use only manual chokes, trouble free and "self tuning" by cable.
The Holley Sniper is the best bolt on EFI you can buy.
Getting down to 15F tonight.
Be able to test again the Holley Elecrodyne heat sensor I installed last Sunday..
Be Best if it was -20 to -30 F.
All those aftermarket EFI systems have to be tuned for real cold Midwest, East Coast and Europe winters.
Sit in the vehicle up to 1/2 - 1 hour with a laptop outside no heat.
Dial it in.
Here are now 37F
Its better on cold air temp startups at 20 F.
Still not right.
Holley 4150 Street Avengers are documented as not having Choke Pulloffs like all Rochestor Quadrajets had.
But that is not true researching last night.
There is a tiny vacuum piston inside of the electric choke housing & tiny crankshaft and connecting rod link.
Bend the rod to make adjustments.
Also a hidden external bleed screw on some models to adjust vacuum pulloff rate or strength on engine startup.
The Olds 425 ci V8 has cubic inches and the engine wants air.
With the air cleaner off and 1st startup cold the engine burbles from too rich AFR.
Get out and move the choke air blade manual with my fingers and the engine instant smooths out to EFI Smooth running warmup.
Backed the choke coil spring cover off clockwise so near all tension is gone and markings are now off scale.
Holley has a forum....little help.
Forum is dead. Not enough guys working it like Grumpys here.
Googled with Key words.
Team Camaro & Team Chevelle Forums I found long lost hidden information Needed.
Most guys say theses Holley Electric chokes are garbage & have been since the mid 1970's.
Keep trying to get it right.
Can always install a manual choke cable.
But in Doomsday scenario.....getting shot at & need to fire gunshots back & need to move 100-130 mph in the 1963 Pontiac Grand Prix.....No time to Fiddle with a manual Choke Cable.
Foot on the Floor & Do Not Lift for anything.
Just like Drag Racing.
I fiddled with the Electric Choke on the 770 CF Holley Street Avenger carburetor after work tonight.
Removed the choke housing & resealed the vacuum passage with a New Cork gasket I had.
The vacuum air bleed screw for the choke pulloff piston was covered in Epoxy glue. I had to slowly pick it away.
Then I discovered it was nearly shut closed by Holley when it was made. Just 1/2 turn out.
Adjusted 3 turns out & Fired up the Pontiac.
Took off running & the choke air blade was open much further ! The vacuum choke break hidden works !
Fine tuned the choke & warmed up nice like a New Car with EFI !
One single old timer on another forum left enough info....Team Camaro.
No one at Holley even knows today !
Great solution, the screw looks like the same on secondary throttle stop.
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