Cliff's Quadrajet Parts and Rebuild Kits

Quadrajet Problem Solving => Dialing in your rebuilt Quadrajet carburetor => Topic started by: Mr48willys on October 22, 2012, 06:04:25 PM

Title: Stock APT and idal mixture screws setting
Post by: Mr48willys on October 22, 2012, 06:04:25 PM

Hi
    Does anyone know what the stock setting for the APT and the idal mixture screws are. I live in California and need to pass smog. Trying to get it back to stock as close as possible to pass smog. By the way it is on a 1981 Chevy blazer 305. Also if anyone has any tips for smog and the carb I wouk love to know about them

Thanks for any help

Title: Re: Stock APT and idal mixture screws setting
Post by: Shark Racer on October 23, 2012, 11:16:26 AM

Personally, I'd run the car on a smog dyno and dial in the APT at 25mph on the dyno, then set the idle mixture screws.

Title: Re: Stock APT and idal mixture screws setting
Post by: Cliff Ruggles on October 26, 2012, 09:45:53 AM

Set the idle mixture screws for best idle quality at the leanest settings.

Set the APT using the "tip-in" procedure in our book.

This will put both idle and part throttle on the edge of lean, and should get it thru emissions....Cliff

Title: Re: Stock APT and idal mixture screws setting
Post by: Freddiesbuick on December 03, 2012, 05:32:19 PM

Quote from: Cliff Ruggles on October 26, 2012, 09:45:53 AM

Set the APT using the "tip-in" procedure in our book. This will put both idle and part throttle on the edge of lean, and should get it thru emissions....Cliff

What "tip-in procedure"? What book....( I have the Rochester Quadrajet Carburetors book)?  ???

Title: Re: Stock APT and idal mixture screws setting
Post by: Ethan1 on December 03, 2012, 06:27:12 PM

Quote from: Freddiesbuick on December 03, 2012, 05:32:19 PM

What "tip-in procedure"? What book....( I have the Rochester Quadrajet Carburetors book)?  ???

 From the front of Cliff's website:

 (http://www.cliffshighperformance.dreamhosters.com/images/book_large.jpg)

Title: Re: Stock APT and idal mixture screws setting
Post by: Freddiesbuick on December 03, 2012, 06:53:20 PM

Quote from: Ethan1 on December 03, 2012, 06:27:12 PM

From the front of Cliff's website...

Yes I have that book but I don't recall seeing anything about a "tip-in" method for APT. In fact, I spent a lot of time reading chapter 6 about the power piston just looking for that specific info. Perhaps I missed it?  ???

Title: Re: Stock APT and idal mixture screws setting
Post by: Shark Racer on December 04, 2012, 06:39:24 PM

I believe it's in the performance modifications, it's an inset/sidebar. Look for a picture of a carburetor with a hand held over the primary flaps.

Title: Re: Stock APT and idle mixture screws setting
Post by: Freddiesbuick on December 05, 2012, 05:03:30 AM

Pg. 99, (chapter 6). Found it! Thanks! ;D