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I've been away from this group for a while, but looking to get back involved.
I've had enough of my qjet and it's vacuum secondaries. I'm looking at going to a Quick Fuel 750. I live in MN and don't drive it much below 40F degrees.
I'm trying to decide if I should go with a choke or not? My friend has a 69 BBC that he has disabled the choke for years and seems to start and idle ok (I've sent him an email to confirm).
I have the 65-72 drop base made for the Holley dpumper. I'm also upgrading my performer intake to the air gap. Hood clearance is always an issue on these cars, and while I have a SBC 406" I have the BBC hood. Things should fit based on my estimates.
Looking at either this one: SS-Series Carburetor Black Diamond, 750cfm
I live in Canada and do not have a choke . First one was a holley 650 now running Quick Fuel 750 . Just have to warm up for 2-3 minutes in mornings and good to go.
From: At my Bar drinking and wrenching in Lafayette Colorado
Originally Posted by StingrayLust
I've had enough of my qjet and it's vacuum secondaries.
You do know that a Q-Jet does not have vacuum secondaries, and is rated at 750 cfm... Correctly set up, it will run equal to any of the aftermarket carbs. But regardless... run any carb you're comfortable with setting up and tuning. Any of the performance carbs will run as well as the Q-Jet if correctly tuned.
You do know that a Q-Jet does not have vacuum secondaries, and is rated at 750 cfm... Correctly set up, it will run equal to any of the aftermarket carbs. But regardless... run any carb you're comfortable with setting up and tuning. Any of the performance carbs will run as well as the Q-Jet if correctly tuned.
Lars
Yes I'm aware that the bottom of the secondaries are mechanically opened, but there is still that top flap. I've adjusted the spring several times and I still have problems getting it to open when I think it should. I've timed my vacuum release cam arm to make sure it's opening quick, but I think there are times where the vacuum raises too high between 1st and 2nd and keep the top flap closed even if the bottom secondaries are open.
My problem is one that I posted on soon after I put my 406" motor in during the Spring of 2015. I can get the secondaries to open in 1st, but then no matter how hard I step on it in 2nd, after a fairly quick/normal shift, they will hardly ever open in 2nd. It's highly frustrating to know I've got more power but I can't access it on demand.
It's a done deal, I'm switching. I'll be keeping it as it's original, but I've had enough.
And it's not just about the performance, which is the key right now, but it's the hard starts where fuel is going somewhere else: evaporation, sucked back down to pump, leaks onto intake, etc. Some of that I know won't be cured by switching carbs, but besides trying a different carb, I'm at wits end and EFI is just a bit too much $ for me right now.
I live in Canada and do not have a choke . First one was a holley 650 now running Quick Fuel 750 . Just have to warm up for 2-3 minutes in mornings and good to go.
Qveld, that's exactly the kind of feedback I was looking for.
My buddy who I mention in the post said that Spring/Fall he has to keep the foot on the gas for a bit longer to keep it going, but in the summer he doesn't have a problem.
When I 1st set mine up I set the choke to stay open. I blocked the cross over so no extra heat under the carburetor.
It would always start but would die over and over unless I keep my foot on the accelerator.
So I got around to connecting the choke wire and adjusted it. Now I can fire it up and wait until it gets enough heat to idle on it's own. So I fire it up, jump out get my glasses, jacket, what every and I'm good to go.
The main advantage to a choke, other than convenience is avoiding pumping a lot of raw fuel into a cold motor. That practice dilutes the oil and wears the rings
I don't run a choke on either of my vettes. The Quick Fuel I ran on the 6t8 didn't even have the choke horn which I heard ups the cfm to 780. The 6210 spreadbore on the 69 has the choke disconnected, just takes a little longer to warm up before I can drive it. T
From: Some days your the dog and some days your the hydrant.
Royal Canadian Navy
No choke here either. If the car is tuned properly, it will run fine after a minute or two in summer weather. You would need to pump the carb many, many times to contaminate the oil. Starting a no choke carb with one or two shots of the pedal is all I need to do. No different than starting a qjet that requires the same method.
No choke here either. Starts and runs fine down to 40 something degrees. I kept the high idle functioning so it still has high idle when cold just without the choke. Once it warms up the normal throttle stomp sets the idle back down.
Another trick is to turn on the AC. The Idle kick up solenoid holds the idle higher as well, and is adjustable to your liking. Then when the engine is warmer turn off the AC.
New carb time
