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Forced Induction ?: X-Flow versus JH head
- Subject: Forced Induction ?: X-Flow versus JH head
- From: scirocco-al@insight.rr.com (scirocco)
- Date: Mon, 17 Feb 2003 16:17:26 -0500
- References: <NFBBIFEIOLEKBIKOONPOAEMBHCAB.sfwilliams@comcast.net>
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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
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.
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:
a) flow reasons
b) turbo fitment
c) *much* less heat transfered to the intake manifold from the blazing =
hot turbo and manifold
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>Yes, but less RPM =3D less exhaust gas =
velocity and=20
less efficiency. Also expecting the turbo to produce power over a =
shorter=20
RPM band would probably increase turbo lag. Beyond that the cart =
V8=20
engines turn around 14,000 RPM and the old F1 turbo cars turned I =
think=20
around 12,000. Having a larger RPM band to work with the and =
the=20
correct gears in the tranny will give you more of a window to drive the =
motor in=20
rather than just a window from around 2500 to 5500 RPM that will be =
partially=20
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>
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<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 title=3Dsfwilliams@comcast.net =
href=3D"mailto:sfwilliams@comcast.net";>Scott F.=20
Williams</A> </DIV>
<DIV style=3D"FONT: 10pt arial"><B>To:</B> <A =
title=3Dscirocco-al@insight.rr.com=20
href=3D"mailto:scirocco-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 face=3DArial color=3D#0000ff 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=20
lifters.</FONT></FONT></FONT></DIV>
<DIV><FONT face=3DArial color=3D#0000ff size=3D2></FONT> </DIV>
<DIV><SPAN class=3D850240716-17022003><FONT face=3DArial =
color=3D#0000ff=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 the=20
point of revving higher when increased volumetrica efficiency can be =
had by=20
turning up the boost? The cross flow head is superior for turbo use =
because=20
of:</FONT></SPAN></DIV><SPAN class=3D850240716-17022003><FONT =
face=3DArial=20
color=3D#0000ff size=3D2></FONT></SPAN></DIV>
<DIV><SPAN class=3D850240716-17022003><FONT face=3DArial =
color=3D#0000ff=20
size=3D2></FONT></SPAN> </DIV>
<DIV><SPAN class=3D850240716-17022003></SPAN><SPAN=20
class=3D850240716-17022003><FONT size=3D+0><FONT face=3DArial =
color=3D#0000ff=20
size=3D2>a) flow reasons</FONT></FONT></SPAN></DIV>
<DIV><SPAN class=3D850240716-17022003><FONT size=3D+0><FONT =
face=3DArial=20
color=3D#0000ff size=3D2>b) turbo fitment</FONT></FONT></SPAN></DIV>
<DIV><SPAN class=3D850240716-17022003><FONT size=3D+0><FONT =
face=3DArial=20
color=3D#0000ff size=3D2>c) *much* less heat transfered to the intake =
manifold=20
from the blazing hot turbo and manifold</FONT></FONT></SPAN></DIV>
<DIV><SPAN class=3D850240716-17022003><FONT size=3D+0><FONT =
face=3DArial=20
color=3D#0000ff size=3D2></FONT></FONT></SPAN> </DIV>
<DIV><SPAN class=3D850240716-17022003><FONT size=3D+0><FONT =
face=3DArial=20
color=3D#0000ff 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=20
wanted."</FONT> </DIV>
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