RE: performance mods

[ANDREW_ATWELL@HP-PaloAlto-om20.om.hp.com]

The throttle body is what controls the air flow into the intake manifold for the
motor.  In US cars it is restricted, ie. it isn't as large and doesn't allow as 
much air to flow.  The european cars have a larger throttle body that alows for 
better flow.  The larger throttle bodys (T-body) are available from Nuespeed, 
Advanced Motor Sport, etc.  Any T-body for the VR6 will work, I don't think 
there is much difference between brands, just price.  Shrick was the first to 
produce performance camshafts for the VR6 and now they are also availible from 
Abt, and TT.  What a cam shaft allow for is changing the profile of the valves 
opening and closing.  A high duration cam shaft (ie. high numbered 268, 276 
etc.) means that the cam will hold the valve open longer.  This is necessary for
power at higher RPMs. Cam shafts will increase horse power at the high end of 
the RPMs, at the cost of reduced hp at the lower RPM's, and a rough (lopey) 
idle.  Cam shafts can totally transform a motor, making it feel like a 
completely different motor.  So.... cams for the VR6 exist in 260 and 268.  The 
260 will be milder, providing modest power increases at higher RPM, without much
loss in low RPM and only slightly changing the idle.  A 268 cam will really 
boost high RPM power, noticeably decrease low end and give a bumpy idle.  
HOWEVER, these are still street cams and will not be as drastic as racing cams.
They are a great boost for a motor.  The VR6 was probably purposely under camed 
for emmissions reasons (love that EPA).  The addition of a cam will really wake 
it up.  Biggest draw back is the price!  While the VR6 cams are $1100 the 8v 
cars cams can be had for $199. Not really fair.  So I'm waiting for the prices 
to come down.
andy

______________________________ Reply Separator _________________________________
Subject: RE: performance mods
Author:  Non-HP-Ng.Kevin (Ng.Kevin@nationscredit.com) at HP-PaloAlto,mimegw6
Date:    11/5/97 3:36 PM


     
Ok, so what type or model of throttle body is recommended (and reliable)?   
I've heard Shrick cams being mentioned in several articles in EC   
magazine. Any real-life comments on their performance? And what do the   
"268" and "2__"  types stand for?
Thanks again.
     
Kevin
     
 ----------
From:  jettaglx[SMTP:jettaglx@igtc.com] 
Sent:  Wednesday, November 05, 1997 12:35 PM 
To:  Ng, Kevin
Cc:  jettaglx
Subject:  Re: performance mods
     
     Before bothering with a header I would go with suspension work.   
 Then
     again before a header for engine mods go with a throttle body and 
     cams.  The header alone will not make much (if any) differnece in 
     power.
     andy