Alright, my car is finally starting to come together, now I just gotta get it running it's best:-) So here's the deal: my car seems to run Ok right now, but when I go from aroun 1/4 throttle to WOT, my car stalls for a sec, and then picks up. And when I'm accelerating, the RPM's seem to flutter. One of my mechanic friends suggested plugging the vacuum advance off the distrubeter to the carb. He said in some of his high-performance cars it seemed to help a lot. (but he is a mustang guy:-) Any thoughts?

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1986 Z28
383 ci Stroker, Dart Sportsmen 2 heads, roller rocker arms, Crower Hot Street Beast cam, edelbrock 750cfm carb and performer rpm intake, Corvette Servos, shift kit and 2600 rpm stall convertor, 3.73 gears and Eaton limited slip posi rearend.

 

Come on guys, little help?

 

I say, go ahead and plug it. But if your car explodes don't blame me.

 

lol Thanks for the advice. Anyone else?

 

If the hesitation occurs at the moment you nail the pedal, problem might be accelerator pump shot.

There are two places to hook up vacuum advance, full time (below the blades) and ported (above the blades). I prefer full time cause when you floor it, vacuum under blades drops to near zero, and you get no vacuum advance. With ported you get vacuum above the blades (in the throttle bore) when blades are open and airflow gets going, causing vacuum advance to add timing. Add this to the mechanical advance caused by the distributor weights kicking out, and you get too much total timing, which kills high rpm power.

 

wow I've never heard of that before. I definately have to try that out b/c I've been having some issues w/ my carb doing the same thing as newby. I've adjusted my accelerator pump and checked the timing and now I'll try this

thanks

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Jay
black 85 Z28 - waiting on a new paint job, then she'll be real purty
87 Chevy S10 Blazer- 2.8 liters of pure fury

Jay's Website
yahoo im: wildcat856
AIM: Jayman85Z
Homer no function beer well without
check out GMPerformance.org

 

Wow, thanks. Definately something I need to check out.

 

In the old days, manifold vacuum was the norm, not just for the reason listed above. It helped engine run cooler. Ported is a child of emissions control era.

http://www.randomunity.com/superrod/...distribut.html

One caveat: high compression engines sometimes had a slight ping when you nailed throttle at low rpm, cause vacuum didn't kick out soon enough. Hallmark of nasty musclecar engines of the 60's. Solved by adjustable vacuum cannisters.

 

Plugging the vacuum advance into a different port won't make the bog go away. Your problem is in tuning the carb (accelerator pump and squirter size being the #1 suspects).