Re: Race Header Benefits?

[William J Erikson <williamjosiah@juno.com>]

Now THERE is some hard data! Good to see!
It also makes me feel good, because I have an AutoTech Tri-Y header
sitting in my garage.
I didn't expect the increase in low end.
Just curious, do you happen to have an estimate, from this experience,
how much difference there is between a completely stock setup on an '84
GTI (single outlet manifold, cat, 1 7/8" exhaust, normal muffler) and a
Tri-Y with good 2" mandrel-bend exhaust, like TT's?
	Thanks much,
	Josiah



On Sun, 18 Jul 1999 19:57:22 -0500 "H Jones" <hjones1@airmail.net>
writes:
>I have tested 3 different exhaust manifolds on my Scirocco and here 
>are my
>results....
>
>1. "Tri-Y" - marked increase in low to mid-range power, very minor
>improvement in hp above 5700 rpm
>
>2. Stock VW Dual Down-Pipe Manifold - Similar results as the Tri-Y, 
>with a 1
>to 2 hp drop across the power-band (The Tri-Y did slightly better)
>
>3. 4 into 1 Equal Length System - The best over-all performance, with 
>much
>better top-end (over 5700 rpm) results. Without a doubt, the best 
>solution
>for a hi-rev race application!
>
>My choice was the 4 into 1 system! If the primary application was for 
>street
>driving, I would opt for the tri-y (more low end torque and MUCH 
>cheaper).
>
>All three manifold systems were tested with a 2" diameter exhaust, 
>with no
>cat and no muffler. All test were conducted on the same dynometer over 
>a 2
>day period.
>
>The header / manifold is vital for making hp, but don't overlook the 
>exhaust
>system (down-stream of the manifold) design. I have run 4 different 
>exhaust
>system designs and the one that makes the most hp runs 30" perfectly
>straight from the end of the header and then angles (hard) to the 
>driver
>side, exiting just aft of the driver and before the rear wheel.  This
>exhaust system is LOW, extremely loud and does not come even close to 
>being
>street legal, but many of the lessons can be applied to a 
>street-legal
>exhaust system (the section just aft of the header junction should be
>STRAIGHT for at least 30").
>
>Harry
>
>----- Original Message -----
From: T Berk <tberk@mindspring.com>
>To: <scirocco-l@scirocco.org>
>Sent: Sunday, July 18, 1999 6:44 PM
>Subject: Race Header Benefits?
>
>
>>
>>
>> Listers,
>>
>> My '81 came w/ a 4 into 1 header installed. I have since swapped in 
>a
>> GTI 1.8 liter engine. The only other mod at the moment is a K&N 
>filter.
>>
>> I have at my disposal a dual exhaust and wondering what the header
>> benefits me- high RPMs with more flow? Greater torque? Loss of low 
>end?
>>
>> tia,
>> TBerk
>>
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