Thanks guys - Ray - the air coming in is underhood air, so it's fairly warm. The secondary cam is new, but I havent measured hangar height (I'll check that) Walt - Thanks for your input...the float level is at .425, but I can play with that and see if it makes a difference. I did replace the accell pump assembly with one from Cifff Ruggles with a stiffer spring and cup garter, it did make a difference but not at the same throttle point I'm having the issue at. Ken thinks it may be in the down channel restriction - mine are at .040, Cliff's book calls for .046 or better in his performance "recipes", Ken thought .050 would do the trick. Gonna try that next. I'm also surprised by RPM curves (see attached) I had an issue with fuel supply mid way through first gear, and with the secondary air valves when second gear hit but I worked through those and most of the runs are similar to the AFB. I would have thought the QJet would have built more RPM in second gear with the larger secondaries, and that may be so with richer rods. But take a look at the attached chart - the black line is a typical AFB run, the colored lines are the QJet runs. The part that surprised me is that the carb is falling on it's face off the line, and losing that second is killing times straight on through. Funny thing is I'm not feeling it in the seat of my pants. I ran heavy for traction (fuel and toolbox) and the car launched clean, just hazing the tires. There is a slight delay for the secondaries to come in, but it just feels like transition, not a bog. I'm launching at a high enough RPM where it's on the main metering system, so the off idle stumble isnt coming into play...I'm going back a size leaner on this rebuild, but it still shouldnt do that. And the car pulls so strong I'd swear it was faster. I'm interested in your thoughts.
I realize the chart is too small to read - PM me if you want to see a larger version and I'll e-mail it to you
Been messing with the Q-Jet again...tore it down and decided to go all out and re-calibrate some stuff (build 2)- car ran even better, but the lean stumble was more pronounced so I richened up the off idle circuit a touch more (build 3) Now, the car runs awesome - great throttle response, got rid of the lag at tip in, fantastic idle and good vacuum but it's even slower. I'm not too worried though, I think I know why. If I'm right, I richened the primary side so much that I'm now too fat on the secondary side. It's also much slower to rev, so I'm gonna try to go back to leaner secondary rods and see if that balances it out...they say go fatter until you go slower, and then back it off and I may be at that point. it does smell kinda rich, but no smoke or plug fouling. I can tell I need to bring the secondaries in sooner anyway - I'll attach the RPM curves, an example of the 2nd build curve is in black, the 3rd build curve is in red Here's the specs - the 2nd and 3rd builds are patterened after Cliff Ruggles book - I may have made a mistake opening the lower air bleed to .070 as I got confused over which bleeds I was looking at.. More to come - [TABLE="width: 373"] [TR] [TD="width: 189, bgcolor: transparent"][/TD] [TD="class: xl24, width: 88, bgcolor: transparent"]Stock [/TD] [TD="class: xl24, width: 76, bgcolor: transparent"]1st Build [/TD] [TD="class: xl24, width: 72, bgcolor: transparent"]2nd Build [/TD] [TD="class: xl24, width: 72, bgcolor: transparent"]3rd Build [/TD] [/TR] [TR] [TD="bgcolor: transparent"]Fuel Inlet [/TD] [TD="class: xl24, bgcolor: transparent"][/TD] [TD="class: xl24, bgcolor: transparent, align: right"]0.135 [/TD] [TD="class: xl24, bgcolor: transparent, align: right"]0.135 [/TD] [TD="class: xl24, bgcolor: transparent, align: right"]0.135 [/TD] [/TR] [TR] [TD="bgcolor: transparent"]Float Level [/TD] [TD="class: xl24, bgcolor: transparent, align: right"]0.250 [/TD] [TD="class: xl25, bgcolor: transparent, align: right"]0.425 [/TD] [TD="class: xl29, bgcolor: transparent, align: right"]0.425 [/TD] [TD="class: xl25, bgcolor: transparent, align: right"]0.030 [/TD] [/TR] [TR] [TD="bgcolor: transparent"]Idle Tube [/TD] [TD="class: xl24, bgcolor: transparent, align: right"]0.033 [/TD] [TD="class: xl25, bgcolor: transparent, align: right"]0.035 [/TD] [TD="class: xl29, bgcolor: transparent, align: right"]0.035 [/TD] [TD="class: xl29, bgcolor: transparent, align: right"]0.035 [/TD] [/TR] [TR] [TD="bgcolor: transparent"]Idle Channel Restriction [/TD] [TD="class: xl24, bgcolor: transparent, align: right"]0.040 [/TD] [TD="class: xl24, bgcolor: transparent, align: right"]0.040 [/TD] [TD="class: xl25, bgcolor: transparent, align: right"]0.046 [/TD] [TD="class: xl25, bgcolor: transparent, align: right"]0.052 [/TD] [/TR] [TR] [TD="bgcolor: transparent"]Upper Air Bleed [/TD] [TD="class: xl24, bgcolor: transparent, align: right"]0.050 [/TD] [TD="class: xl24, bgcolor: transparent, align: right"]0.050 [/TD] [TD="class: xl24, bgcolor: transparent, align: right"]0.050 [/TD] [TD="class: xl24, bgcolor: transparent, align: right"]0.050 [/TD] [/TR] [TR] [TD="bgcolor: transparent"]Lower Air Bleed (upper) [/TD] [TD="class: xl24, bgcolor: transparent, align: right"]0.070 [/TD] [TD="class: xl24, bgcolor: transparent, align: right"]0.070 [/TD] [TD="class: xl24, bgcolor: transparent, align: right"]0.070 [/TD] [TD="class: xl24, bgcolor: transparent, align: right"]0.070 [/TD] [/TR] [TR] [TD="bgcolor: transparent"]Lower Air Bleed (lower) [/TD] [TD="class: xl24, bgcolor: transparent, align: right"]0.060 [/TD] [TD="class: xl24, bgcolor: transparent, align: right"]0.060 [/TD] [TD="class: xl25, bgcolor: transparent, align: right"]0.070 [/TD] [TD="class: xl29, bgcolor: transparent, align: right"]0.070 [/TD] [/TR] [TR] [TD="bgcolor: transparent"]Mixture Hole [/TD] [TD="class: xl24, bgcolor: transparent, align: right"]0.086 [/TD] [TD="class: xl25, bgcolor: transparent, align: right"]0.094 [/TD] [TD="class: xl25, bgcolor: transparent, align: right"]0.094 [/TD] [TD="class: xl29, bgcolor: transparent, align: right"]0.094 [/TD] [/TR] [TR] [TD="bgcolor: transparent"]Primary Jets [/TD] [TD="class: xl24, bgcolor: transparent, align: right"]0.074 [/TD] [TD="class: xl24, bgcolor: transparent, align: right"]0.074 [/TD] [TD="class: xl29, bgcolor: transparent, align: right"]0.074 [/TD] [TD="class: xl29, bgcolor: transparent, align: right"]0.074 [/TD] [/TR] [TR] [TD="bgcolor: transparent"]Primary Rods [/TD] [TD="class: xl24, bgcolor: transparent, align: right"]0.045 [/TD] [TD="class: xl24, bgcolor: transparent, align: right"]0.045 [/TD] [TD="class: xl24, bgcolor: transparent, align: right"]0.045 [/TD] [TD="class: xl25, bgcolor: transparent, align: right"]0.043 [/TD] [/TR] [TR] [TD="bgcolor: transparent"]Secondary Well restriction [/TD] [TD="class: xl24, bgcolor: transparent, align: right"]0.028 [/TD] [TD="class: xl24, bgcolor: transparent, align: right"]0.028 [/TD] [TD="class: xl25, bgcolor: transparent, align: right"]0.032 [/TD] [TD="class: xl29, bgcolor: transparent, align: right"]0.032 [/TD] [/TR] [TR] [TD="bgcolor: transparent"]Secondary POE Restriction [/TD] [TD="class: xl24, bgcolor: transparent, align: right"]0.052 [/TD] [TD="class: xl24, bgcolor: transparent, align: right"]0.052 [/TD] [TD="class: xl24, bgcolor: transparent, align: right"]0.052 [/TD] [TD="class: xl24, bgcolor: transparent, align: right"]0.052 [/TD] [/TR] [TR] [TD="bgcolor: transparent"]Secondary Tube Restriction [/TD] [TD="class: xl24, bgcolor: transparent, align: right"]0.025 [/TD] [TD="class: xl24, bgcolor: transparent, align: right"]0.025 [/TD] [TD="class: xl25, bgcolor: transparent, align: right"]0.036 [/TD] [TD="class: xl29, bgcolor: transparent, align: right"]0.036 [/TD] [/TR] [TR] [TD="bgcolor: transparent"]Secondary Rods [/TD] [TD="class: xl26, bgcolor: transparent"]AK- .0567S [/TD] [TD="class: xl26, bgcolor: transparent"]AK .0567 S [/TD] [TD="class: xl27, bgcolor: transparent"]CK .0527 L [/TD] [TD="class: xl28, bgcolor: transparent"]CK .0527 L [/TD] [/TR] [TR] [TD="bgcolor: transparent"]Secondary Valve Opening [/TD] [TD="class: xl24, bgcolor: transparent, align: right"]1.188 [/TD] [TD="class: xl25, bgcolor: transparent, align: right"]1.130 [/TD] [TD="class: xl25, bgcolor: transparent, align: right"]1.130 [/TD] [TD="class: xl29, bgcolor: transparent, align: right"]1.130 [/TD] [/TR] [TR] [TD="bgcolor: transparent"]Secondary Hanger [/TD] [TD="class: xl26, bgcolor: transparent"]M [/TD] [TD="class: xl26, bgcolor: transparent"]M [/TD] [TD="class: xl28, bgcolor: transparent"]M [/TD] [TD="class: xl28, bgcolor: transparent"]M [/TD] [/TR] [/TABLE]
I'm hesitant to post this here, with your past small screw driver mishap and all... :idea2: but it may be something to check easily while your under the hood next time... *Make sure you have someone with you to Hold the Brakes* and insert the straw slow and easy... I posted this on lemmy-67's Quintet thread as well... Saw this tip on the net and thought I'd share it. To check the power piston spring with the engine running at idle and in gear (get someone to help or set parking brake for this) take a straw and slide it down the vent tube on the carb. (Note: this will only work on q-jets where the power piston is directly under the vent tube) If the power piston spring is to strong vs. engine vacuum, the power piston will bounce up and down raising and lowering the straw erratically with the engine idling in gear. With the engine idling and the correct spring for the engine vacuum, the power piston should stay down, only rising if the throttle is opened to reduce engine vacuum. This should be checked with the engine fully warmed up by running approx. 10 minutes to make sure that the choke is off.
