Drove ‘er to work today with the Q Jet on, idle vacuum is better than the AED, drivability is great, but that’s about it. Even on the highway engine cruising at 3300 rpm, floor it, WUH WAAAAAA, noses over for a split second then goes, NOPE NOT GONNA WORK! I COULD tighten the spring on the doors, but all that will do is eliminate the bog, and then open the secondaries too slow, and Guy will beat me I tested a theory I had but it didn’t hold water. The engine needs the fuel NOW to make power when I slam it to WOT, NOT over a period of seconds. I “think” the issue with the Q Jet other than no accelerator pump on the secondary side is while the small primary’s give good fuel economy and drivability, there’s too much of a difference in size between the primary’s and secondary’s. Also I noticed while on the highway the sensitivity to the throttle is much softer with the Q Jet, it’s super crispy with the AED, same on city streets, with the AED, I go full throttle at 30 mph or less I get sideways, the Q Jet just delivers TOO SMOOTH power, no tire smoke. While it worked fine on my dual plane, it just doesn’t perform well on my single plane. Back on goes my AED DP
Mark see if you can find one of these problems solved 850 competition series problem solved. Great Street Carburetor, and you won’t lose all your gas mileage.
Have you tried launching a little harder to get your 60 ft. down into the 1.75 range? You might just be able to tickle the 12s with just a little more tuning? Re: The Carter Thermoquad, I had one on my Son's GS350 many moons ago and it was truly a great carb. That car went low 14s with 9.8 compression, a KB 118 cam and stock converter.
You'll need to adjust the power piston spring to a softer size for it to work properly. That's your issue
Does your Q-jets air valve flap have square holes to the left and right of the air cleaner stud? These square holes allow the secondary transfer circuit to kick in as soon as the secondary throttle blades crack open which act like a short duration accelerator pump until the main jet discharges kick in.
My converter (JW 9.5”) flashes to 3500 on launch, doubt I could launch harder unless I had more stall. I’ll have to check. But from an overall strictly “performance” standpoint the AED wins I COULD go backwards and try my original iron intake and Q Jet Heck, now I’m thinking again
Is it possible to get more flash stall from the converter by bringing the rpm up against the brakes to 2000 or more??? It might push thru the beams.
If you can hold more than 2000 rpm you should get a better short time. Also, how much air are you running in the MTs? Some have improved their short times with as low as 16 psi. Gotta experiment with that but, you should be able to get better than 1.95 60 ft. for sure.
Did your ET and/or MPH improve from what's in your signature? What rpm did you launch at? I can usually hold about 2500 RPM with my JW 9.5 2800 converter and I don't have disc brakes.
I tried to update my signature but couldn’t figure out how I just bring it up to about 1500 rpm, then it will flash to 3500 when I floor it. I gotta stop being a pussy and giver more
Drum brakes have more holding AND stopping power than discs, the only drawback to drums is they don’t shed heat well, and it’s tougher to modulate them.
Glad you gave it a shot Mark! I finally fired mine up yesterday. Met my buddy with a 2010 Lingenfelter vette and we drove up to a show. On the way we staged on open road at about 25-30mph. I kept up with him and even and hit 6k before I let off. I was pretty happy and surprised at the same time. 6k has been difficult to hit with the qjet and SP3 just like Mark, but different also. A typical WOT for me see's 4k ish before it noses over. Happens from a dead stop or roll "most" of the time. Intermittently I can hit 6k. Last year I ran a fuel gauge through the hood and taped it to the windshield. It drives and accelerates (up to around 4k) at 7psi, then drops down to 2ish. Within the next couple weekends I'm replacing the tank, redoing all the rubber hoses, and adding a RobbMc sender, filter, and pump. All the hoses are brittle and dry rotted anyways so while I'm there I figured I should just do it all. I want to see if that changes anything before I go asking for Mart's Holley
Thanks! I figured I’d try the Q Jet one more time with a few theories, guess it will get boxed up and the AED goes back on! At least I won’t wonder “hmmm, I should try that” On a dual plane the Q Jet ROCKS!
