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Shawn

Registered: 05/13/12
Posts: 3
Reply with quote  #1 

Hi got some questions.........   went to track and jetted carb up to 12-sizes.  did not chang "Nothing.  even changed timing from 29"degrees up to 45"degrees pretty much ran the same.  Im lost. got any suggestions?  by the way its a big block chevy 605 cubic inch . with an e85 sv1 carb.  Thanks: shawn part no:30105

PRO-SYSTEMS

Moderator
Registered: 12/16/11
Posts: 1,418
Reply with quote  #2 
It sounds fuel delivery related. 

As you go up in jet if there is fuel in the bowl, it will keep getting richer and richer.

What was your fuel pressure at an  idle?  What was it at wide open throttle at the finish line.

DO you have any 02 data?

Thanks.

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Patrick James-President
PRO-SYSTEMS

Moderator
Registered: 12/16/11
Posts: 1,418
Reply with quote  #3 
Note: I accidentally deleted his post that denoted he was running 15-16 psi downtrack.

Shawn,

15 to 16 lbs.  Thats too much.  You are flooding it out.

Here are the directions that came with the regulator in a nutshell.

Set the idle at 7 psi and you are looking for 11 psi max going down the track.

Anything over 11 psi and the needle and seats can't fight it and will just pour fuel into the engine so jetting will have no effect.

Also be aware that at 13 psi or higher brass floats can crush on any carb equipped with brass floats.  When the fuel initially bursts in the bowl area at 13 psi or higher the air can't escape fast enough and it will flatten the middle of brass floats on any carb.  You then lose float drop as the float will only wiggle in its hinge due to the bend in  its body and won't fully open and you lean it way out.

So high pressure can both flood and lean out any carb.

Inspect the carb for damage and drop your pressure to the recommended range.





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Patrick James-President
Shawn

Registered: 05/13/12
Posts: 3
Reply with quote  #4 

Thanks for the tip....... Ill check it all out.  i have a magnafuel 500 a pump.  so just turn the pump down?

PRO-SYSTEMS

Moderator
Registered: 12/16/11
Posts: 1,418
Reply with quote  #5 
Your pump is OK,  turn your vacuum operated regulator down so that it carries 11 psi down track.  Typically a base setting of 7 will give you a 4 lb raise of pressure when you go to wide open.  But for some reason you are gaining double that.  So drop your base idle setting back to 3-4 that should give you 11-12 down track.

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Patrick James-President
Shawn

Registered: 05/13/12
Posts: 3
Reply with quote  #6 

That worked....!  Sweet.  Thanks alot man. I thank you for your help...

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