The Holley "Trick Kit" literally

slimbo

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May 21, 2007
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made my own tuneable pvcr. went up to a .070 pvcr with a set of brass set screws that i can interchange. opening up the pvcr and going down on the main jet lets me get 15-16 mpg out of a 550 horse small block with 4.10's. its nowhere near the mileage i can get with fuel injection but its good enough for me. been reading alot on carb tuning lately and coupled with a good afr meter it will make you insane chasing the perfect tune. im almost there!
 

NoMoore

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May 26, 2006
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slimbo5 said:
made my own tuneable pvcr. went up to a .070 pvcr with a set of brass set screws that i can interchange. opening up the pvcr and going down on the main jet lets me get 15-16 mpg out of a 550 horse small block with 4.10's. its nowhere near the mileage i can get with fuel injection but its good enough for me. been reading alot on carb tuning lately and coupled with a good afr meter it will make you insane chasing the perfect tune. im almost there!

Cool! Would you care to share the info on what tap you used, was it an end tap? What size, and where did you get the set screws? Anything else you could add for the masses to read? Did it take much messing around to get it right?

Pics would be great too. It would be nice to start adding some stuff like that to this thread.

What afr meter are you using? Innovate?
 

slimbo

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May 21, 2007
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using an innovate meter. the power valve channel restriction (pvcr) is the two small holes behind the power valve that actually add fuel when the valve opens. by making that larger and the jets smaller you can taylor how well your car runs at part throttle (as long as its running on the mains,usually 25-2700 and up) while still getting all the fuel it needs under wot. for the pvcr i use brass 8/32 set scrws 3/16 in length and drill to the size needed. right now i am at .070 with a 72 main jet which is equal to a 87 jet when they are combined. i dont use a bottoming tap i just tap a little at a time so the set screw fits tight when fully seated. next time i have my carb apart i will take some pics for ya. i get my set screws at mcmaster-carr.
 

383malibufiend

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Mar 27, 2006
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lots of good reading here guys. blew some things i thought were true out of the water.
 

NoMoore

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Thread starter
May 26, 2006
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slimbo5 said:
using an innovate meter. the power valve channel restriction (pvcr) is the two small holes behind the power valve that actually add fuel when the valve opens. by making that larger and the jets smaller you can taylor how well your car runs at part throttle (as long as its running on the mains,usually 25-2700 and up) while still getting all the fuel it needs under wot. for the pvcr i use brass 8/32 set scrws 3/16 in length and drill to the size needed. right now i am at .070 with a 72 main jet which is equal to a 87 jet when they are combined. i dont use a bottoming tap i just tap a little at a time so the set screw fits tight when fully seated. next time i have my carb apart i will take some pics for ya. i get my set screws at mcmaster-carr.

Thanks for the response!!


Here is what I believe to be the formula for getting jet size close when changing PVCR's.


A=Pi*r^2
Total area=(Pi*((Jet Diameter/2)^2))+(Pi*((PVCR Diameter/2)^2))

I just made that up, is it right?
d=r*2
 

slimbo

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i have no idea ow to read those formulas...lol. i use demons jet flow chart and its been damn near perfect every time.
 
A

Anonymous

Guest
Holley

I could not agree with you more about the marketing angle. I have a question about adjustable air bleeds. They are on most of their full race carbs but they tell you not to touch them. As far as I am concerned they will have an effect on calibration and the fuel "curve" but they say do not touch. BS !!!! I personnaly think that alot of hi perf manufactuers use the same angle and prey upon the male ego and just plain ignorance to sell their crap.
Buyers beware !!
HAPPY HOLIDAYS
MIKE
 

NoMoore

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Thread starter
May 26, 2006
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Re: Holley

plooker said:
I could not agree with you more about the marketing angle. I have a question about adjustable air bleeds. They are on most of their full race carbs but they tell you not to touch them. As far as I am concerned they will have an effect on calibration and the fuel "curve" but they say do not touch. BS !!!! I personnaly think that alot of hi perf manufactuers use the same angle and prey upon the male ego and just plain ignorance to sell their crap.
Buyers beware !!
HAPPY HOLIDAYS
MIKE

LOL, right on. I'd trade adjustable air bleeds for adjustable ifr's and pvcr's in a heartbeat.
 

RatDime

Frequent Racer
Oct 24, 2006
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does anyone know what the stock boosters are on a 750 dom carb by chance? .025? I need to know front and back thanks
 

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