|
|
|
08-14-2009
|
#1 |
|
Join Date: Mar 2008
Location: England
Posts: 219
|
why the different plunums
sure this is not a new question but ouldnt find an answer in search
why is there a difference....is one better than another |
|
|
|
08-14-2009
|
#2 |
 
Join Date: Mar 2007
Location: Crystal Lake, IL
Posts: 7,194
|
Re: why the different plunums
Stock one on the left has individual runnners, the one on the right has had the primary and secondary runners merged together or siamesed for greater flow. The siamesed runners are not a stock option, most were done by Jeal or other tuners.
__________________
LGAFF 90 #966-150K miles-sold 92 #234-sold 1987 Callaway TT #17 1991 ZR-1 #1359 |
|
|
|
|
08-14-2009
|
#3 |
 Join Date: Jan 2004
Location: Portland, OR
Posts: 1,057
|
Re: why the different plunums
The full siamese plenum pictured on the right can support a higher volume of air than the stock plenum casting will allow. It is a fairly pricey mod and is best suited for use on highly modified engines - usually strokers.
__________________
Robert ZR-1 Net Registry Oregon State Director 91 ZR-1 #431 Black/Black LPE 368 |
|
|
|
|
08-17-2009
|
#4 | |
 
Join Date: May 2008
Location: Mauriceville, Texas
Posts: 179
|
Re: why the different plunums
Quote:
Also, are siamesed plenum's made from stock plenum's with aluminum/metal filler, or some type of fiberglass or bondo as a filler in the valley's between the runners? Are siamesed plenum's...besides the runners...typically ported also?
__________________
Clint aka billybaloneey '94 - C4 ZR-1 #445 - Black/Black '05 - C6 silver/black 6sp '85 - C4 white/graphite (almost done) automatic '78 - C3 silver/black (a work in progress) automatic |
|
|
|
|
|
08-17-2009
|
#5 | |
|
Join Date: Jan 2004
Location: Portland, OR
Posts: 1,057
|
Re: why the different plunums
Quote:
A fully siamesed plenum is made by cutting out the outside center sections of the two side by side runners then welding in some curved sheet aluminum in its place. Some have metal filler added to the outside to smooth out the appearance. Typically these types of plenums have some agressive porting involved as well. Here are a few pics of a full siamese job in progress.   
__________________
Robert ZR-1 Net Registry Oregon State Director 91 ZR-1 #431 Black/Black LPE 368 |
|
|
|
|
|
08-17-2009
|
#6 |
|
Join Date: Mar 2008
Location: England
Posts: 219
|
Re: why the different plunums
I thought l had thrown in a post on the dropped plenum....but it seems to have vanished
see the DRM website and the pic of the LT5 with the huge injector ram pipes ..... pretty sure they are on a low 'dropped' plenum |
|
|
|
|
08-18-2009
|
#7 | |
 
Join Date: Jun 2005
Location: pittsburgh
Posts: 4,632
|
Re: why the different plunums
Quote:
__________________
It's not the car, it's the people - Doug Johnson 90 r/r "KEYS ON" nick named "T.L.B" |
|
|
|
|
|
08-19-2009
|
#8 |
Join Date: Nov 2008
Location: Grand Rapids, MI
Posts: 384
|
Re: why the different plunums
Found these pictures online of the motor Corey Henderson built for Bonneville. Siamese ports and dropped plenum. Hope he doesn't mind me posting these!
   
|
|
|
|
|
08-14-2009
|
#9 |
|
Join Date: Jun 2005
Location: pittsburgh
Posts: 4,632
|
Re: why the different plunums
wait till ya throw in the dropped plenums
__________________
It's not the car, it's the people - Doug Johnson 90 r/r "KEYS ON" nick named "T.L.B" |
|
|
|
|
08-14-2009
|
#10 |
|
Join Date: Aug 2005
Location: north of montreal
Posts: 510
|
Re: why the different plunums
dropped plenum ????
bj |
|
|
|
 |
|
|
Hybrid Mode
