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  #11  
Old 09-18-2017, 08:42 PM
SuperNovaSS SuperNovaSS is offline
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Awesome Eric. I love reading your posts! Keep up the good work.


Jason
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  #12  
Old 10-28-2017, 09:33 PM
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VintageMusclecar VintageMusclecar is offline
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I pulled my trusty 3310 Holley off and installed my "mule" 7045228 Quadrajet on Project Hoopty Thursday. I had to swap out the primary throttle shaft for one equipped with a lever for a 350 Turbo kick-down cable, but other than that the swap was relatively uneventful.

Initial impressions: The QJet idles MUCH better than the Holley, and off-idle was silky smooth yesterday--more on that below in a moment. The electric choke on the QJet works perfect--the one on the Holley was a little temperamental at times.

I'll be doing a new mileage loop with the QJet shortly--didn't get to do one with the Holley after the rear end swap--couldn't keep our toes outt'a the grill.

Today I figured I'd take advantage of this brisk fall air to give ol' Hoopty a chance to stretch it's legs a little again.

2.2 0-30 and 5.5 0-60 with the shifter left in drive, 4800 rpm up-shift (need to tweak the governor springs/weights for a 5500 rpm up-shift), and with a bit of a hesitation at the hit. I need to open up the choke pull-off orifice restriction a bit to allow the secondary air doors to open a little quicker. I had the air door spring at 1 turn on the dyno (trying to keep it from going pig rich on initial load) which resulted in one hell'uva bog at the hit in the car. I backed it off to 1/2 turn which made a HYOOGE improvement, but there's still a bit of a sag at the hit.

Nothing I can't tune out with a little more work, all part of the game.

The carb is still a bit lean on idle and off-idle transition--the cool weather today really made this noticeable. Even after idling for ~1 minute with the choke on, it would die when putting it into gear. I had to give it about 2 minutes warm-up time to be able to go into gear w/o stalling.

I gave the idle mixture screws another ~5/8 turns out each to give it a little more fuel off idle and it made a noticeable improvement. I'll probably wind up opening up the down channel restrictions a little further, and I may also restrict the idle air bleed channels a little. Again, nothing a little tweak or two can't cure.

I'm positive this little heap can hit a sub 2 second 0-30 once I get rid of the bog, and with a little more rpm on the up-shift and a couple other minor tweaks I can see a high 4 second 0-60 w/o too much trouble. IMO that's pretty damned good for a mild 358" small block in a driver wagon.

I'm having a ball with this damned thing.

More later.
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  #13  
Old 10-29-2017, 10:14 PM
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Braved the chill this morning and pulled the QJet off for the needed tweaks.

-Restricted idle air bypass circuit. Note: most "rebuilders" block this circuit off completely with lead plugs, which causes an excessively rich idle and transition circuit. Most stock engines run fine with this circuit as-delivered, but I find restricting the circuit instead of blocking it off provides better results.

-Swapped choke pull-off for one I modified for a replaceable restrictor to fine tune secondary air door opening rate

-Swapped primary jets from 74 to 72 (stock is 71) (49 PMR-stock)

~1/2 dozen test drives playing with pull-off restrictor sizes and secondary air door tension, have about 90% of the bog out.

The carb now idles perfectly with the choke on, and I can drop it in gear and drive it w/o it trying to stall out now. Idle only drops ~150 rpm where it was dropping 250+ before.

The car is so much crisper and more responsive with this carb on it it's not funny--and I had the Holley pretty well dialed in. I think I'm going to build a later model unit (no aneroid) to test with next. QJets are without a doubt a serious bitch to dial in compared to a Holley, but man they run so damn nice when you get them dialed in.

More later.
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  #14  
Old 10-30-2017, 05:33 AM
SuperNovaSS SuperNovaSS is offline
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Eric,

I love reading these posts. Please keep it up.

Thanks,

Jason
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Old 10-30-2017, 06:55 PM
earntaz earntaz is offline
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Quote:
Originally Posted by VintageMusclecar View Post
Braved the chill this morning and pulled the QJet off for the needed tweaks.

-Restricted idle air bypass circuit. Note: most "rebuilders" block this circuit off completely with lead plugs, which causes an excessively rich idle and transition circuit. Most stock engines run fine with this circuit as-delivered, but I find restricting the circuit instead of blocking it off provides better results.

-Swapped choke pull-off for one I modified for a replaceable restrictor to fine tune secondary air door opening rate

-Swapped primary jets from 74 to 72 (stock is 71) (49 PMR-stock)

~1/2 dozen test drives playing with pull-off restrictor sizes and secondary air door tension, have about 90% of the bog out.

The carb now idles perfectly with the choke on, and I can drop it in gear and drive it w/o it trying to stall out now. Idle only drops ~150 rpm where it was dropping 250+ before.

The car is so much crisper and more responsive with this carb on it it's not funny--and I had the Holley pretty well dialed in. I think I'm going to build a later model unit (no aneroid) to test with next. QJets are without a doubt a serious bitch to dial in compared to a Holley, but man they run so damn nice when you get them dialed in.

More later.
I love it when I hear folks calling these carbs a "Quadra-junk" -- GM stuck a ton of money in development of the QJ. In the right hands it works damn good. If I remember right Ford used a version of it and Chyrsler Corp also. TAZ ...
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