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Re: Race Header Benefits?



I'm racing DSP, which says no cams, so I can't do that. I have a K&N
(0.5bhp? : )     ) and I'm going to be installing a Golf throttle body
and port-matching it to the intake (is this legal for DSP, guys?) at the
same time as I install the header.
	-Josiah



On Sun, 18 Jul 1999 22:26:38 -0500 "H Jones" <hjones1@airmail.net>
writes:
>Data is critical and the dyno does not lie. Luckily I have access to 
>an
>excellent in-ground dyno that was purchased from an auto emissions 
>testing
>facility which went belly-up (warms my heart).
>
>My application is pretty unique and may not completely apply to your 
>84 1.8.
>My car is a 1.6L 1980 Scirocco, prepared for SCCA ITC racing. The 
>rules
>limit engine modifications, but the exhaust manifold & system are
>unrestricted (except exit point and db levels).
>
>The Auto-Tech Tri-Y is one of the three systems that I tested (and ran 
>on
>the car for a year and a half). I like the Tri-Y, it is cheap, it is 
>light
>and it DOES give more hp. A good "tuned" 4-into-1 header is going to 
>cost
>$500 and the best one that I have seen is manufactured by BSI. If you 
>have
>the $$$ and your car will be running in the higher rpm range, get the
>4-into-1.
>
>The key to gaining more hp with your header / exhaust system is to 
>change
>more than just the exhaust system. Get the engine breathing better. 
>Get a
>cam that "matches" your desired exhaust system & intake system. I run 
>a
>"real" G-Grind (it passes the Scruiteneer's dial test), everything is 
>match
>ported, the injection system is modified & adjustable (dialed it in 
>based on
>extended exhaust gas temps @ 6000 rpm) and the distributor is fully
>mechanical & recurved (UK spec 1.6L GTi unit).
>
>Get the engine breathing, on the intake side and the exhaust side.
>
>----- Original Message -----
From: William J Erikson <williamjosiah@juno.com>
>To: <scirocco-l@scirocco.org>
>Sent: Sunday, July 18, 1999 9:19 PM
>Subject: Re: Race Header Benefits?
>
>
>> 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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>> >>
>> >>
>> >
>> >
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>> >
>>
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>

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