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Puny fuel injectors
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Demetri, plug in the following numbers at
<http://www.rceng.com/technical.htm#WORKSHEET>:
700hp
6 fuel injectors
.60 brake specific fuel consumption
.80 max injector duty cycle
57.2psi fuel pressure (the same as Josh, btw)
Hit the calculate button and what do you get? Those injectors must be 76.44
lbs/hour (803cc/min) to make that kind of power safely. What does that tell
you? The performance of Porsche's highly developed 911 twin turbo motor is
bound by the same laws of physics as everybody else's. The math that we've
applied to this situation holds up just fine.
Or, with a little bit more analysis you can see how much fuel flow it takes
for the Porsche to make each single horsepower unit:
700hp/ 6 cylinder = 116.67 hp per cylinder
803cc per injector/ 116.67hp = 6.88cc to generate 1 hp
Meanwhile, Josh is claiming:
approx. 325hp/ 4 cylinders = 81.25hp per cylinder
310cc per injector/ 81.25hp per cylinder = 3.82cc to generate 1hp
So, although the 911 Turbo's specific output is around 31% greater than the
1.8T (81.25hp/117hp = .69), Josh is claiming that his motor is 44% more
efficient at making power (3.82cc/6.88cc = .56). DOES THIS MAKE ANY SENSE AT
ALL? How can his motor be radically more efficient yet far less powerful
when corrected for the number of cylinders? For an easy comparison, that 911
motor would output a "mere" 487.5hp if its specific output matched Josh's
1.8T .
Something is terribly wrong with this picture. What is it?
--
Scott F. Williams
NJ Scirocco nut
'99 Subaru Impreza 2.5 RS
Mazda 323 GTX turbo "assaulted" vehicle
Golf GTI 16v "rollycar"
ClubVAC: "Roads found. Drivers wanted."
Demetri Raptis wrote:
You guys got me to look at some articles for some twin turbo 911s, and
they run 75 lbs/hr injectors to make 700 horses. I would think josh is
right.
demetri
--Boundary_(ID_zFzNXznU48JeBHzC0KzmvA)
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<DIV><SPAN class=670111215-14062002><FONT face=Arial color=#0000ff
size=2>Demetri, plug in the following numbers at <<A
href="http://www.rceng.com/technical.htm#WORKSHEET";>http://www.rceng.com/technical.htm#WORKSHEET</A>>:</FONT></SPAN></DIV>
<DIV><SPAN class=670111215-14062002><FONT face=Arial color=#0000ff
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=670111215-14062002><FONT face=Arial color=#0000ff
size=2>700hp</FONT></SPAN></DIV>
<DIV><SPAN class=670111215-14062002><FONT face=Arial color=#0000ff size=2>6 fuel
injectors</FONT></SPAN></DIV>
<DIV><SPAN class=670111215-14062002><FONT face=Arial color=#0000ff size=2>.60
brake specific fuel consumption</FONT></SPAN></DIV>
<DIV><SPAN class=670111215-14062002><FONT face=Arial color=#0000ff size=2>.80
max injector duty cycle</FONT></SPAN></DIV>
<DIV><SPAN class=670111215-14062002><FONT face=Arial color=#0000ff
size=2>57.2psi fuel pressure (the same as Josh, btw)</FONT></SPAN></DIV>
<DIV><SPAN class=670111215-14062002><FONT face=Arial color=#0000ff
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=670111215-14062002><FONT face=Arial color=#0000ff size=2>Hit
the calculate button and what do you get? Those injectors must be 76.44 lbs/hour
(803cc/min) to make that kind of power safely. </FONT><SPAN
class=670111215-14062002><FONT face=Arial color=#0000ff size=2>What does that
tell you? The performance of Porsche's highly developed 911 twin turbo motor is
bound by the same laws of physics as everybody else's. The math that we've
applied to this situation holds up just fine.</FONT></SPAN></DIV>
<DIV><FONT face=Arial><FONT color=#0000ff><FONT
size=2></FONT></FONT></FONT> </DIV>
<DIV><FONT><FONT><FONT face=Arial color=#0000ff size=2>Or, with a little bit
more <SPAN class=670111215-14062002>analysis </SPAN>you can see how much
fuel flow it takes for the Porsche to make each single horsepower
unit:</FONT></FONT></FONT></SPAN></DIV>
<DIV><SPAN class=670111215-14062002><FONT face=Arial color=#0000ff size=2>700hp/
6 cylinder = 116.67 hp per cylinder</FONT></SPAN></DIV>
<DIV><SPAN class=670111215-14062002><FONT face=Arial color=#0000ff size=2>803cc
per injector/ 116.67hp = 6.88cc to generate 1 hp</FONT></SPAN></DIV>
<DIV><SPAN class=670111215-14062002><FONT face=Arial color=#0000ff
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=670111215-14062002><FONT face=Arial color=#0000ff
size=2>Meanwhile, Josh is claiming:</FONT></SPAN></DIV>
<DIV><SPAN class=670111215-14062002><FONT face=Arial color=#0000ff
size=2>approx. 325hp/ 4 cylinders = 81.25hp per cylinder</FONT></SPAN></DIV>
<DIV><SPAN class=670111215-14062002><FONT face=Arial color=#0000ff size=2>310cc
per injector/ 81.25hp per cylinder = 3.82cc to generate 1hp</FONT></SPAN></DIV>
<DIV><SPAN class=670111215-14062002><FONT face=Arial color=#0000ff
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=670111215-14062002><FONT face=Arial color=#0000ff size=2>So,
although the 911 Turbo's specific output is around 31% greater than the 1.8T
(81.25hp/117hp = .69), Josh is claiming that his motor is 44% more efficient at
making power (3.82cc/6.88cc = .56). DOES THIS MAKE ANY SENSE AT ALL? How can his
motor be radically more efficient yet far less powerful when corrected for the
number of cylinders? For an easy comparison, that 911 motor would output a
"mere" 487.5hp if its specific output matched
Josh's 1.8T .</FONT></SPAN></DIV>
<DIV><SPAN class=670111215-14062002><FONT face=Arial color=#0000ff
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=670111215-14062002><FONT face=Arial color=#0000ff
size=2>Something is terribly wrong with this picture. What is
it?</FONT></SPAN></DIV>
<DIV><FONT size=2>--<BR>Scott F. Williams<BR>NJ Scirocco nut<BR>'99 Subaru
Impreza 2.5 RS<BR>Mazda 323 GTX turbo "assaulted" vehicle<BR>Golf GTI 16v
"rollycar"<BR>ClubVAC: "Roads found. Drivers wanted."</FONT> </DIV>
<DIV><FONT size=2></FONT> </DIV>
<DIV><SPAN class=670111215-14062002><FONT size=2>Demetri Raptis
wrote:</FONT></SPAN></DIV>
<BLOCKQUOTE dir=ltr
style="PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #0000ff 2px solid; MARGIN-RIGHT: 0px">
<DIV class=OutlookMessageHeader dir=ltr align=left><FONT face=Arial size=2>You
guys got me to look at some articles for some twin turbo 911s, and they run 75
lbs/hr injectors to make 700 horses. I would think josh is right.</FONT></DIV>
<DIV><FONT face=Arial size=2>demetri</FONT></DIV></BLOCKQUOTE></BODY></HTML>
--Boundary_(ID_zFzNXznU48JeBHzC0KzmvA)--