I love my Qjet
Melting Slicks
Joined: Mar 2005
Posts: 2,838
Likes: 10
From: Austin TX
I'm forever telling people that if you're going with a vacuum secondary carb, a Q-Jet is better than a Holley,..easier to tune, meters more conistantly throughout, flows plenty (750 cfm), and better mileage.
Then the same people look at me like they're waiting for a punch line.
The Holley has one advantage,..larger fuel bowls, but that can be overcome with a larger needle/seat assy and some other tricks.
Then the same people look at me like they're waiting for a punch line.
The Holley has one advantage,..larger fuel bowls, but that can be overcome with a larger needle/seat assy and some other tricks.
Safety Car
Joined: Dec 2004
Posts: 4,071
Likes: 0
From: San Diego CA
Originally Posted by 73, Dark Blue 454
I'm forever telling people that if you're going with a vacuum secondary carb, a Q-Jet is better than a Holley,..easier to tune, meters more conistantly throughout, flows plenty (750 cfm), and better mileage.
Then the same people look at me like they're waiting for a punch line.
The Holley has one advantage,..larger fuel bowls, but that can be overcome with a larger needle/seat assy and some other tricks.
Then the same people look at me like they're waiting for a punch line.
The Holley has one advantage,..larger fuel bowls, but that can be overcome with a larger needle/seat assy and some other tricks.
Drifting
Joined: Mar 2005
Posts: 1,806
Likes: 3
From: Burlington WI
News to me.....
Originally Posted by Kalway
Qjets aren't vacuum secondaries, though...
http://www.tocmp.com/manuals/Carbs/R...20complete.pdf
Here is some interesting reading on the operation of the Q-Jet.
Pages 11 and 12 describe the vacuum operation of the air valves for the secondaries.
Last edited by fl_rider; Apr 13, 2006 at 06:06 AM.
Melting Slicks
Joined: Mar 2005
Posts: 2,838
Likes: 10
From: Austin TX
Of couse a q-jet is a vacuum secondary carb,..the butterflies on top the secondaries sense the vacuum signal and meter the air and fuel accordingly. How quick or slow it opens is very adjustable,..there's a little set screw on the passenger side of the butterfly shaft. If it opens too fast, she'll bog,..to late, poor performance,..just right will put a big smile on your face.
Lack of this knowledge is the biggest reason people struggle with q-jets.
A mechanical secondary carb uses throttle linkage/movement for opening and metering of everything in the primary and secondaries.
Lack of this knowledge is the biggest reason people struggle with q-jets.
A mechanical secondary carb uses throttle linkage/movement for opening and metering of everything in the primary and secondaries.
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Melting Slicks
Joined: Feb 2003
Posts: 2,529
Likes: 27
From: Auburndale Florida
2025 C2 of the Year ('64-'66) Finalist - Unmodified
St. Jude Donor '03-'05-'06-'07-'09
Originally Posted by Kalway
I'm hoping lars will chime in and back me up on the q-jet not being a vacuum secondary...
Lars is the expert...he can explain it better
I love my Q-jet. For years I thought Holley was the only way to go....know better now. Better low and mid range, throttle reponse and economy
I am fortunate Lars tuned mine about a month ago.
Thread Starter
Instructor
Joined: Feb 2005
Posts: 173
Likes: 0
We tuned that holley up and down and just couldn't get it to do anything major, no matter what we did. It just wouldnt respond. I don't know whether someone else did the tuning on the Qjet but to my knowledge it hasn't been out of the box in at least five years...Bolted right on and I haven't gotten enough of it since. 
Team Owner
Joined: Jul 2001
Posts: 61,415
Likes: 478
From: Here to make friends
St. Jude Donor '11, '16-'17
Originally Posted by fl_rider
Maybe you could illuminate us all.
http://www.tocmp.com/manuals/Carbs/R...20complete.pdf
Here is some interesting reading on the operation of the Q-Jet.
Pages 11 and 12 describe the vacuum operation of the air valves for the secondaries.
http://www.tocmp.com/manuals/Carbs/R...20complete.pdf
Here is some interesting reading on the operation of the Q-Jet.
Pages 11 and 12 describe the vacuum operation of the air valves for the secondaries.
Team Owner
Joined: Jul 2001
Posts: 61,415
Likes: 478
From: Here to make friends
St. Jude Donor '11, '16-'17
Melting Slicks
Joined: Mar 2005
Posts: 2,838
Likes: 10
From: Austin TX
Some people call a quadrajet an "air valve",..that's fine although the little diaphragm on the side of your carb that controls the upper secondary butterflies (air valves) open and close based on vacuum. Also,..some would call air being sucked into an engine "vacuum".
Not an arguement that will solve anything (I must have too much time) but here's some support for my side:
http://www.hemmings.com/index.cfm/fu...article_id/498
http://www.carcraft.com/howto/57178/
http://www.arkansaspontiacs.org/tech...ockyQ-jets.htm
But we agree in principle,..love me some q-jet!
Wes
Not an arguement that will solve anything (I must have too much time) but here's some support for my side:
http://www.hemmings.com/index.cfm/fu...article_id/498
http://www.carcraft.com/howto/57178/
http://www.arkansaspontiacs.org/tech...ockyQ-jets.htm
But we agree in principle,..love me some q-jet!
Wes
Last edited by 73, Dark Blue 454; Apr 14, 2006 at 12:15 AM.
