Quadrajet Problem Solving > Dialing in your rebuilt Quadrajet carburetor

Qjet going lean at part throttle acceloration

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mertz28:
The spacer is a Hamburger that is 4 hole but tappers at the bottom and has a little bit of an opening between the to sides of the dual plan.  Like this: http://www.jegs.com/i/Hamburger's/497/3211/10002/-1?CAWELAID=1710687312&CAGPSPN=pla&catargetid=230006180000514790&cadevice=c&gclid=Cj0KEQjw0POdBRCq3arGgYD05pMBEiQAmiUeTiV5jk--xElV8mEXCX6oH-SOkmp4hFCBHQpcXF9cT4EaAine8P8HAQ   Mine is for a spread bore.

I will try running it without and see how it does.  I did notice that it seemed to reduce performance a little when I first put it on but I was hoping to get some more torque with it.

Cliff Ruggles:
I drove my car to the track for Friday night "test and tune" and ran 7.25 @ 96mph with a stock intake and no spacer on it.  I seriously doubt if  your mild set-up would benefit anyplace from a spacer.  I've tested all sorts of them on my set-up, and to date have ran the best ET with no spacer at all.  About all I see with spacers is at most a little more MPH and slower 60' times.  In other words more power up near the shift point, and less low speed power.....Cliff

mertz28:
I thought I had it made when I was finally able to burn rubber with my 72 C20 truck (350/350 and 4:10). It was going a little lean before it kicked in so Cliff suggested I tighten up the spring on the secondaries. I finally got around to doing that and I did some minor adjustments to the APT and now it is back to it's old self. When I power brake it it stays lean and will rev to 1850 but it will not stand up and even attempt to brake the tires lose. I put the secondary spring back to were it was and got the APT back close and still nothing. I would appear that the secondaries aren't opening. I certainly don't hear the rush of air. What could be causing this? What could keep the secondaries from opening? I am using a narrow band a/f gauge but will hook up my Innovate to readjust the APT. When I get on it it doesn't instantly go rich but that might be the gauge. During power braking when I was able to brake the tires lose it would go to 11.6 and under but now it stays around 13. For some reason it doesn't seem to be getting fuel.

Cliff Ruggles:
How much did you tighten up the spring?  Adjustments made there should be about 1 screwdriver blade thickness at a time, or no more than 1/8th turn until secondary transition is smooth and there is no felt transition at all.

Did you get rid of the spacer yet?  I've ran into all sorts of "issues" with secondary transition and performance trying to use spacers.  They increase plenum size, and can cause some "reversion" which effects secondary transition.  I would NEVER use one on any "mild" set-up for any reason.  They will also cause further issues in cool/cold weather due to lack of thermal efficiency.......Cliff

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