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Forced Induction ?: X-Flow versus JH head
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Without arguing about the validity of any of your statements, I will say =
I can't see how any of them apply to the hydraulic vs. solid lifter =
issue. For a street engine the hydraulic lifters are more than able to =
handle the RPM that the rest of the engine can sustain without any =
significant differences in valve lift, duration or acceleration. I know =
for a fact the hydraulic lifters are good for 6500 RPM. How fast exactly =
did you think this essentially stock VW engine would need to turn?
Dan
----- Original Message -----=20
From: scirocco=20
To: Scott F. Williams ; scirocco=20
Sent: Monday, February 17, 2003 5:17 PM
Subject: Re: Forced Induction ?: X-Flow versus JH head
Yes, but less RPM =3D less exhaust gas velocity and less efficiency. =
Also expecting the turbo to produce power over a shorter RPM band would =
probably increase turbo lag. Beyond that the cart V8 engines turn =
around 14,000 RPM and the old F1 turbo cars turned I think around =
12,000. Having a larger RPM band to work with the and the correct =
gears in the tranny will give you more of a window to drive the motor in =
rather than just a window from around 2500 to 5500 RPM that will be =
partially consumed by getting the turbo up to speed.=20
=20
My .02 cents.
Alan=20
----- Original Message -----=20
From: Scott F. Williams=20
To: scirocco=20
Sent: Monday, February 17, 2003 11:14 AM
Subject: RE: Forced Induction ?: X-Flow versus JH head
"Scirocco" wrote:
> I'd stick with the JH head. What you would gain from the cross =
flow design you would more=20
> than loose from the hydraulic lifters.
=20
The hydraulic lifters are only a liability at very high rpms. =
Spinning the motor that fast isn't a requirement for a turbo motor. =
What's the point of revving higher when increased volumetrica efficiency =
can be had by turning up the boost? The cross flow head is superior for =
turbo use because of:
=20
a) flow reasons
b) turbo fitment
c) *much* less heat transfered to the intake manifold from the =
blazing hot turbo and manifold
=20
With all these factors considered, it is fairly evident that the =
cross flow design provides far more benefits than whatever minor penalty =
the hydraulic lifters impose.
--
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."=20
-
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<DIV><FONT face=3DArial size=3D2>Without arguing about the validity of =
any of your=20
statements, I will say I can't see how any of them apply to the =
hydraulic vs.=20
solid lifter issue. For a street engine the hydraulic lifters are more =
than able=20
to handle the RPM that the rest of the engine can sustain without any=20
significant differences in valve lift, duration or acceleration. I know =
for a=20
fact the hydraulic lifters are good for 6500 RPM. How fast exactly did =
you think=20
this essentially stock VW engine would need to turn?</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>Dan</FONT></DIV>
<BLOCKQUOTE dir=3Dltr=20
style=3D"BORDER-LEFT: #000000 2px solid; MARGIN-LEFT: 5px; MARGIN-RIGHT: =
0px; PADDING-LEFT: 5px; PADDING-RIGHT: 0px">
<DIV style=3D"FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV=20
style=3D"BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: =
black"><B>From:</B>=20
<A href=3D"mailto:scirocco-al@insight.rr.com"=20
title=3Dscirocco-al@insight.rr.com>scirocco</A> </DIV>
<DIV style=3D"FONT: 10pt arial"><B>To:</B> <A=20
href=3D"mailto:sfwilliams@comcast.net"; =
title=3Dsfwilliams@comcast.net>Scott F.=20
Williams</A> ; <A href=3D"mailto:scirocco-l@scirocco.org"=20
title=3Dscirocco-l@scirocco.org>scirocco</A> </DIV>
<DIV style=3D"FONT: 10pt arial"><B>Sent:</B> Monday, February 17, 2003 =
5:17=20
PM</DIV>
<DIV style=3D"FONT: 10pt arial"><B>Subject:</B> Re: Forced Induction =
?: X-Flow=20
versus JH head</DIV>
<DIV><BR></DIV>
<DIV><FONT face=3DArial size=3D2>Yes, but less RPM =3D less exhaust =
gas velocity and=20
less efficiency. Also expecting the turbo to produce power over =
a=20
shorter RPM band would probably increase turbo lag. Beyond that =
the cart=20
V8 engines turn around 14,000 RPM and the old F1 turbo cars =
turned I=20
think around 12,000. Having a larger RPM band to work with =
the and=20
the correct gears in the tranny will give you more of a window to =
drive the=20
motor in rather than just a window from around 2500 to 5500 RPM that =
will be=20
partially consumed by getting the turbo up to =
speed. </FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>My .02 cents.</FONT></DIV>
<DIV> </DIV>
<DIV><FONT face=3DArial size=3D2>Alan</FONT> </DIV>
<BLOCKQUOTE dir=3Dltr=20
style=3D"BORDER-LEFT: #000000 2px solid; MARGIN-LEFT: 5px; =
MARGIN-RIGHT: 0px; PADDING-LEFT: 5px; PADDING-RIGHT: 0px">
<DIV style=3D"FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV=20
style=3D"BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: =
black"><B>From:</B>=20
<A href=3D"mailto:sfwilliams@comcast.net"; =
title=3Dsfwilliams@comcast.net>Scott=20
F. Williams</A> </DIV>
<DIV style=3D"FONT: 10pt arial"><B>To:</B> <A=20
href=3D"mailto:scirocco-al@insight.rr.com"=20
title=3Dscirocco-al@insight.rr.com>scirocco</A> </DIV>
<DIV style=3D"FONT: 10pt arial"><B>Sent:</B> Monday, February 17, =
2003 11:14=20
AM</DIV>
<DIV style=3D"FONT: 10pt arial"><B>Subject:</B> RE: Forced Induction =
?: X-Flow=20
versus JH head</DIV>
<DIV><BR></DIV>
<DIV>
<DIV><FONT color=3D#0000ff face=3DArial size=3D2><SPAN=20
class=3D850240716-17022003>"Scirocco" wrote:</SPAN></FONT></DIV>
<DIV><FONT face=3DArial><FONT color=3D#0000ff><FONT size=3D2><SPAN=20
class=3D850240716-17022003>> </SPAN>I'd stick with the JH =
head. What=20
you would gain from the cross flow design you would =
more <BR><SPAN=20
class=3D850240716-17022003>> </SPAN>than loose from the hydraulic =
lifters.</FONT></FONT></FONT></DIV>
<DIV><FONT color=3D#0000ff face=3DArial size=3D2></FONT> </DIV>
<DIV><SPAN class=3D850240716-17022003><FONT color=3D#0000ff =
face=3DArial=20
size=3D2>The hydraulic lifters are only a liability at very =
high rpms.=20
Spinning the motor that fast isn't a requirement for a turbo motor. =
What's=20
the point of revving higher when increased volumetrica efficiency =
can be had=20
by turning up the boost? The cross flow head is superior for turbo =
use=20
because of:</FONT></SPAN></DIV><SPAN =
class=3D850240716-17022003><FONT=20
color=3D#0000ff face=3DArial size=3D2></FONT></SPAN></DIV>
<DIV><SPAN class=3D850240716-17022003><FONT color=3D#0000ff =
face=3DArial=20
size=3D2></FONT></SPAN> </DIV>
<DIV><SPAN class=3D850240716-17022003></SPAN><SPAN=20
class=3D850240716-17022003><FONT size=3D+0><FONT color=3D#0000ff =
face=3DArial=20
size=3D2>a) flow reasons</FONT></FONT></SPAN></DIV>
<DIV><SPAN class=3D850240716-17022003><FONT size=3D+0><FONT =
color=3D#0000ff=20
face=3DArial size=3D2>b) turbo fitment</FONT></FONT></SPAN></DIV>
<DIV><SPAN class=3D850240716-17022003><FONT size=3D+0><FONT =
color=3D#0000ff=20
face=3DArial size=3D2>c) *much* less heat transfered to the intake =
manifold from=20
the blazing hot turbo and manifold</FONT></FONT></SPAN></DIV>
<DIV><SPAN class=3D850240716-17022003><FONT size=3D+0><FONT =
color=3D#0000ff=20
face=3DArial size=3D2></FONT></FONT></SPAN> </DIV>
<DIV><SPAN class=3D850240716-17022003><FONT size=3D+0><FONT =
color=3D#0000ff=20
face=3DArial size=3D2>With all these factors considered, it is =
fairly evident=20
that the cross flow design provides far more benefits than whatever =
minor=20
penalty the hydraulic lifters impose.</FONT></DIV>
<DIV></FONT></SPAN><FONT size=3D2>--<BR>Scott F. Williams<BR>NJ =
Scirocco=20
nut<BR>'99 Subaru Impreza 2.5 RS<BR>Mazda 323 GTX turbo "assaulted"=20
vehicle<BR>Golf GTI 16v "rollycar"<BR>ClubVAC: "Roads found. Drivers =
wanted."</FONT> </DIV>
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