10-17-2007, 10:41 AM
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#6
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AF Enthusiast
Join Date: Sep 2005
Location: Aurora, Colorado
Posts: 1,134
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Re: What is that butterfly thingy
They affectivly change the size of the intake runners as Tom said. HERE is a post about it recently on planetisuzoo.
Here's the relevent replies about it..
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Originally Posted by BigSwede
I think that engine has dual length intake runners...long ones for torque at low rpm and short ones for hp at high rpm...I forget the break point where the butterflys change over, might be around 3000 rpm.
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Quote:
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Originally Posted by "JLEMOND
HEY STEVE ,YOU ARE CORRECT IN THAT THE EARY DOHC ENG DID NOT HAVE DUAL RUNNERS , JUST DUAL INLET INTAKES , THAT UNTILL ABOUT 3600 RPM THEY STAYED CLOSED , AND THEN OPENED TO LET MORE AIR IN , UNTILL THAT RPM ONLY HALF OF THE INTAKE VLV ARE RECEIVING AIR ,FROM THE PLENUM TO HELP WITH LOW SPEED DRIVEABILITY, AND TORQUE, ODD PART, THE SOHC ENG USED THE SAME NO OF VAVLES AND DIDNT USE THE AIR CONTROL VLVS, AT ALL THEREBY RECEIVING AIR IN ALL 12 VLVS ALL THE TIME , ON THE 98 AND LATER ENGS THEY DID GO TO THE DUAL INLET RUNNERS , AND THEY WORK JUST AS YOU SAY, LONG RUNNERS UP TO ABOUT 3600 RPM AND THEN SW TO SHORT RUNNERS FROM THERE ON HI TORQUE AT LOW RPM AND HP AT THE TOP END , POOR MANS SUPERCHARGER , PIONERED BY CHRYSLER WITH THE RAMCHARGERS ENG IN 1960 , EXCEPT THEY DIDNT USE THE LOW AND HI SPEED RUNNERS , LIKE THE LATER ENGS , LONG RUNNERS FOR THE BIG CARS AND THE SHORT RUNNERS FOR THE DRAG CARS . THOSE LONG RUNNERS HAD AN EFFECT IVE LENGTH OF ABOUT 44 IN LONG JERRY
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__________________
--Dave
1999 Rodeo LS 3.2 4x4 5 Speed
32x11.50-15 BFG T/A KO
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There is a very fine line between "hobby" and "mental illness." - Dave Barry
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