Cliff's Quadrajet Parts and Rebuild Kits

General Category => Quadrajet Carb Talk and Tips => Topic started by: 77cruiser on October 18, 2015, 05:19:14 AM

Title: Loses 30 hp with air cleaner?
Post by: 77cruiser on October 18, 2015, 05:19:14 AM

Have a 421 sbc on the dyno & when I put a Moroso drop base air cleaner assembly on it we lost over 30 hp.
What is the proper shaped base for a Qjet?
Here are 2 pulls lost 25 hp with ac.
When I put in a richer rod it loses more with the ac assembly. But the sensor is showing it going leaner with the ac on.

http://myweb.midco.net/77cruiser/Dyno%20CV%20rod.jpg
http://myweb.midco.net/77cruiser/CV%20rod%20B%20hanger.jpg

Title: Re: Loses 30 hp with air cleaner?
Post by: 73ss on October 19, 2015, 05:32:29 PM

That's odd. Looks like the right side is leaning out a lot more then the left side. did you have a air filter in the cleaner? turbulence?

Title: Re: Loses 30 hp with air cleaner?
Post by: 77cruiser on October 19, 2015, 05:39:11 PM

Had a filter in It was a Moroso drop base deal, 14 x4. Act weird with a screen top velocity stack on it too.

Title: Re: Loses 30 hp with air cleaner?
Post by: Cliff Ruggles on October 26, 2015, 03:43:30 AM

Drop base air cleaners move the lid closer to the carb.  Try a taller air cleaner element in it and see if it helps....Cliff

Title: Re: Loses 30 hp with air cleaner?
Post by: 77cruiser on October 26, 2015, 05:33:42 PM

When i went back last week we tried everything we had available. 25 hp down over no ac.
Pics of a couple of ac we tried. they had 4 inch filter installed. Really hurt when I got beat by the Holley, not really but if I could match the no ac power with one on it would be nice.
I don't know how much power is lost but the AFR varied quite a bit side to side with the Q but not the Holley.

http://myweb.midco.net/77cruiser/100_3908.JPG
http://myweb.midco.net/77cruiser/100_3909.JPG
http://myweb.midco.net/77cruiser/Best%20Chuck%20Nyuten.jpg
http://myweb.midco.net/77cruiser/Best%20Qjet%20no%20AC.jpg
http://myweb.midco.net/77cruiser/Best%20Qjet%20w%20AC.jpg

Title: Re: Loses 30 hp with air cleaner?
Post by: qjetsrule on October 27, 2015, 08:02:23 AM

what was done to the quadrajet? I hope it's not the one you're showing in the pictures.

Title: Re: Loses 30 hp with air cleaner?
Post by: 77cruiser on October 27, 2015, 08:11:19 AM

That would be for the sleeper look  ;)

Just this.  http://myweb.midco.net/77cruiser/Q%20Jet%20E%20Tubes-1.jpg

Title: Re: Loses 30 hp with air cleaner?
Post by: Cliff Ruggles on October 28, 2015, 03:09:42 AM

If you are seeing a power difference and fuel curve not smooth or out of range the q-jet isn't up to par or fuel delivery inadequate for what you are doing.

I've been on the dyno with quite a few engines over the years, and have yet to get outrun by a Holley or anything else on a dual plane intake.   On single plane intakes it takes at least a 1" spacer to run with a square flange carb as the huge secondary plates stick too far into the plenum areas when using a spread bore carburetor.....Cliff

Title: Re: Loses 30 hp with air cleaner?
Post by: qjetsrule on November 07, 2015, 08:47:37 AM

did you try your combination with a filter lid such as a k&n? it might help if you have low hood clearance and require a drop base air cleaner. good luck

Title: Re: Loses 30 hp with air cleaner?
Post by: 77cruiser on November 07, 2015, 01:37:47 PM

Yup we tried the filter lid K&N can't remember if we tried it with all the bases though.