Author Topic: anyone wanna guess at my dyno numbers??  (Read 6607 times)

Offline challydust

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Re: anyone wanna guess at my dyno numbers??
« Reply #45 on: July 12, 2010 - 01:19:06 PM »
your powervalve is really determined and needs to be set by what you vac is in gear idling and warmed up! (I think you have auto?)
you have and 8 jet spread which is really about the max you wanna go with a power valve
your airbleeds? that cant be right... this is a 2 circuit carb right and you are saying your 4 air bleeds up front are all 75's and the 4 rears are all 70's? no way that can be right! for example my air bleeds are 28 for the highs and 65 for the idle... the idle bleeds are the 2 outer ones up front and rear and the highs are the 2 inners front and rear!

BG will get you squared away  :2thumbs:   yes my power valve was set at the manifold vaccum....honestly cant remember if we checkit in gear though....i thought it was at idle around 9 or 1000 rpm....it had a 4.5 pv in it...once we took the vac measurment...i put a 3.5 in it.......the heads are not aluminum...there steal 452  worked over.......NO aluminum heads here......as far as the airbleads ill check again...im pretty sure those are correct numbers...  this is why i need to take this car to someone that reallyknows these carbs ,ect....i do not....the car is an auto too...i think...its too rich in the idle circuit.....when im rolling and stomp it...it doesnt belch fuel.....now when i did run the dyno at full throttle...it was puttin some smoke out??...would ther be a diff from the street to the dyno though....wouldnt it be the same deal...




Offline moper

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Re: anyone wanna guess at my dyno numbers??
« Reply #46 on: July 13, 2010 - 11:56:55 AM »
I would like to know what the idle rpm is, what the vacuum level is in gear, and those cylinder pressures. What convertor and gearing do you have (sorry if I missed that). Lastly, if you have the vacuum gage out already, stick a long hose on it and tape it to your windshield, then drive the car and record the vacuum levels and rpms for idle in gear, light throttle cruise, and part throttle light acceleration. These numbers will help indicate what parts of the carb and timing curve to tweak. Also, you need to remember you really have a stock stroke 440 there. It's in a B wedge block, but it's a 440 bored .060 over. So the theory of "A stroker will eat up cam duration" and huge power numbers simply don't apply. That being said I've pulled over 440 to the tires with less cam and compression from pump gas 440s so I do think it's a little soft.
What I see that I question:
1. A low number PV for that combo. I've run hydraulic flat tappets in 440s with similar specs (9-10:1 static ratios) and seen idle in gear vacuum around 9", 12-13 out of gear at 800rpm. If the power valve is too low, while it will stay shut at idle, both light throttle acceleration and transition from part to wide open throttle may have lean spots. Once ping or detonation starts, they will not stop until the throttle situation is changed. Lean helps create hot spots in the big chambers and they start to ping.

2. FBOs curve IMO is a little odd. With a true 10.5:1 and that cam, I'd expect initial timing to be less, and the advance to be faster. If you have a tight convertor, gearing is moderate (say higher than 3.55:1) and the stall is lower than 2500, a slower advance helps you. If the gearing is more aggressive, or the convertor stalls to 2800 or more, you should be able to bring the advance in much faster. So again, I'm not sure what his line of thinking was.

Offline challydust

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Re: anyone wanna guess at my dyno numbers??
« Reply #47 on: July 21, 2010 - 11:48:49 AM »
these are what my plugs look like