Accel pump distributor nozzle advice needed
Thread Starter
Pro
Joined: Dec 2005
Posts: 709
Likes: 1
From: Lakewood Colorado
Accel pump distributor nozzle advice needed
On 396. Getting some sag at first throttle. Engine dies if I'm not careful. Especially when warm. In Holley 670CFM. OEM accelerator pump.
Current nozzle is 32. Straight type. (Tube type gives me fits when cruising speed vacuum comes up.)
Dont know if it matters but I live in Denver so higher altitude.
Will 35 remedy problem or should I go to 37 or 40?
Or is secret just to get all three and see what works?
Current nozzle is 32. Straight type. (Tube type gives me fits when cruising speed vacuum comes up.)
Dont know if it matters but I live in Denver so higher altitude.
Will 35 remedy problem or should I go to 37 or 40?
Or is secret just to get all three and see what works?
Racer
Joined: Apr 2006
Posts: 477
Likes: 43
From: Millbrae California
i would stay with the .032 and use a pink cam if the carb does not have one plus put 2 or 3 - 3/32" flat washers on the duration spring on the pump arm. this is a old Barry Grant trick when he was modifying holley carbs to make the pump more active, this way the pump squirts instead of just compressing the duration spring and slowly squirting the fuel thru the pump nozzle.
also be sure you have a good ignition spark advance curve (12 initial with 36 or so total timing not counting the vacuum advance)
also be sure you have a good ignition spark advance curve (12 initial with 36 or so total timing not counting the vacuum advance)
Drifting
Joined: Jul 2002
Posts: 1,944
Likes: 20
From: The only Corvettes in Highett Victoria
the answer.........
Vettecrazy,
If you still have trouble with that good advice, there is only one answer, Lars.
Although he no longer does this work while he fixes up his Vette, maybe you could offer to help him with his car and he might look at your carb?????????
Won't hurt to ask.
Regards from Down Under
aussiejohn
If you still have trouble with that good advice, there is only one answer, Lars.
Although he no longer does this work while he fixes up his Vette, maybe you could offer to help him with his car and he might look at your carb?????????
Won't hurt to ask.
Regards from Down Under
aussiejohn
Tech Contributor
Joined: Aug 1999
Posts: 14,380
Likes: 6,390
From: At my Bar drinking and wrenching in Lafayette Colorado
If this is a 670 Holley, is it a Street Avenger...? The Street Avenger carbs are jetted extremely lean in order to get CARB approval. Run the float levels so the fuel is starting to spill out the level holes. Check to see if you are exposing more than .020" of your transition slots where you currently have your idle speed set. You may need to crack your secondary idle speed up a tad in order to drop the primary side down to .020" exposure. I've never had to change squirter size on a Street Avenger once it was correctly set up.
More importantly, as Henry points out, check that timing. Up here you need to be running no less than 36 total with 16-or-so initial inorder to get good throttle response and to eliminate the off-idle hesitation.
Just bring it over and I'll show you how to set it up.
More importantly, as Henry points out, check that timing. Up here you need to be running no less than 36 total with 16-or-so initial inorder to get good throttle response and to eliminate the off-idle hesitation.
Just bring it over and I'll show you how to set it up.
Thread Starter
Pro
Joined: Dec 2005
Posts: 709
Likes: 1
From: Lakewood Colorado
Thanks Lars. I'd love to get advice from the master, let alone have a chance to meet. Thank you for the offer, and if it still stands would like to determine how and when that I could bring it by.
Much obliged!!!!
Much obliged!!!!
