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Dialing in your rebuilt Quadrajet carburetor / Re: Edelbrock Performer RPM 1910 idle tuning for more cam.
« Last post by avmechanic on June 19, 2025, 08:43:23 PM »
I have not modified my carb as far as drilling out any orifices. I was just going by the info in Cliffs book as I am away from home and can not go check my carb right now. Cliffs info lists the Idle Bypass air as .110" but the idle channel restrictions as .055".
Greg
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Quadrajet Carb Talk and Tips / Re: Quality, reliable mechanical fuel pumps
« Last post by quadrajam on June 19, 2025, 03:06:32 PM »
I just googled it. Thats a nice pump AND it has a bypass port.
That may be your ticket Cadman. Had I known about it I may have....hmmmm..
too late now,gone electric.

QJ
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Quadrajet Carb Talk and Tips / Re: Quality, reliable mechanical fuel pumps
« Last post by lightning boy on June 19, 2025, 01:31:14 PM »
RobbMC makes a nice mechanical fuel pump. Not cheap though.
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Diagnose a Quadrajet carburetor problem / Re: 17084226 tip in
« Last post by quadrajam on June 18, 2025, 02:57:53 PM »
I agree with Kenth. Should be good.

QJ
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Diagnose a Quadrajet carburetor problem / Re: 17084226 tip in
« Last post by Kenth on June 18, 2025, 01:20:27 PM »
It´s the result with tip-in that counts and with a slight rpm pick-up with the APT 1 turn up and no driving issues i would say it´s good as is.
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Diagnose a Quadrajet carburetor problem / Re: 17084226 tip in
« Last post by 65malibu on June 18, 2025, 04:47:46 AM »
I did check when the needle hanger starts to move when I had it apart and the pin starts to make contact around 1 1/2 turns from the bottom.
Should I go down on the jet size to bring the needles up more into the taper?
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Dialing in your rebuilt Quadrajet carburetor / Re: Edelbrock Performer RPM 1910 idle tuning for more cam.
« Last post by Kenth on June 18, 2025, 12:52:59 AM »
The 1910 has .055" idle bypass air from "factory".
Are, yours modified?
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Diagnose a Quadrajet carburetor problem / Re: 17084226 tip in
« Last post by Kenth on June 18, 2025, 12:47:10 AM »
At 1 turn they are as low as they can be.
The APT starts rising the piston/rods at 2 turns up from bottom.
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Quadrajet Carb Talk and Tips / Re: Quality, reliable mechanical fuel pumps
« Last post by quadrajam on June 17, 2025, 05:32:31 PM »
I fought this same demon for years. Engine heat boiling the fuel in the pump. The key
is having sufficient bypass flow to displace the boiling fuel with cooler fuel from the tank.
 
 In answer to your question I don't think there is a high performance 3 port fuel pump.
You may need to use a performance pump, 80-100 GPH and come up with your own
return bypass petween the pump and carb.
  Is your existing return to the tank free and unrestricted?

I finally had to revert to an in-tank pump and return line with a bypass regulator
under the hood. No more problems. I really wanted to keep my mechanical pump.
I HATED the idea of an in tank pump. I even passed on a really good deal on
a 880 block because of no fuel pump provision.

 QJ
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Dialing in your rebuilt Quadrajet carburetor / Edelbrock Performer RPM 1910 idle tuning for more cam.
« Last post by avmechanic on June 17, 2025, 04:57:21 PM »
Hello.
I have an Edelbrock Performer RPM 1910 Qjet on my Buick 455. I have had this carb for years and it is an excellent performer. A number of years ago I gave it a rebuild and Cliff built me a kit to help tune it better for my engine. That engine was a basically stock 70' Stage 1 455 with factory Stage 1 cam. It had a particularly rich idle. Cliff sold me some primary metering rods and idle tubes to tune it along with the rest of the rebuild kit. It worked fairly well. Now forward ahead to today and I just dropped in a fresh 455 with some more performance modifications done to it. This engine is also a 70' 455. Heads are ported with Stage 1 valves. I am still using stock pistons but did all I could to get the compression as close as possible to true 10:1. In the end it calculated out to 9.89:1. I am running quite a bit more cam than the factory Stage 1 cam it had before. This is a TA C113. It is 229/243 at .050 on a 113 lobe separation installed 3 degrees advanced. Lift is right at .500" on both intake and exhaust. This cam has 11 degrees of overlap. I am also running a TA SP1 single plane intake now.  I just got the engine in and running before I had to leave for a work shift away. The cam broke in nicely and I managed several trips out driving with it. Performance seems excellent. I have some tuning to do yet though. Particularly idle. I do not have a lot of control of the idle circuit with the screws and can not get it to idle down well with the speed screw. I am pretty sure the butterflies are open a little to get the idle air needed. Unfortunately I ran out of time to deal with it before I had to go away for work. I am trying to come up with a plan to sort it out when I get back. Cliff's book shows .110" idle bypass air on the 1910. I can look to confirm that when I get back home. My thoughts are I need just a hair more bypass air. I do have a air fuel ratio gauge in the car and where I got the idle to work best was showing about 13.5:1 when warm but it is quite lean until the engine is warm. The idle is pretty rough and not always stable RPM wise. The cam is not huge so I should be able to get it to idle a little smoother than it is. I am at about 800 in gear and close to 1000 in park. Do you have any suggestions on what to try? I thought to increase the bypass air to .120" then try to tune. I am also thinking of moving the vacuum advance to manifold rather than ported. Current timing is 15 initial 19 mechanical for 34 total on the MSD distributor. Thanks in advance for any advice.
Greg
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