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Butterflies Dyno Results

New 1/6/05

In the interest of science I decided to get some baseline dyno readings before I begin the task of porterizing my intake, repairing my IMRC, and cleaning the butterflies and secondary valve stems. I got three good runs with butterflies wired open and three with them shut.

The ugly truth:

Best run, butterflies open: 174.6 HP/192.4 TQ
Worst run, butterflies open: 155.8 HP/184.2 TQ

Best run, butterflies closed: 121.8 HP/144.6 TQ
Worst run, butterflies closed. 120.8 HP/139.0 TQ

Known variables: Dyno: Dynojet 248H Ambient temp: 62F, humidity: 71% Fuel: Shell 91/Shell 87 (60/40 mix) Miles since last intake cleaning and plug change: 40k Engine/intake: Original, no mods (except welding) Trans/TC: Original, no mods Exhaust: Original, no mods

Seems a bit anemic compared to other results I've seen posted, but after 138k maybe she's a bit tired, or drive train losses are growing with age. I also have an intermittent rough idle that feels like a coil on its last legs.

I'll go back for another run after the planned rejuvenation and post the results.


-- Mike Testa
 97 VW, 138k Welded

What all do you have planned Mike? Also what were the rpm's when you got these numbers? My G-tech is reading 186HP and I've done a number of things to the car. However I don't put 100% stock in the G-tech. I used it in a friends vehicle that shifted very hard and the G-tech spiked over nothing more than a hard shift. Sure for that split second those hp #'s were at the wheels but that's just not realistic.

Jason Barker

Since the subject of horse power and torque has come up, I have a ?. Is there a way to put an honest 200hp and 200 or more pounds of torque to the wheels without NOS or a blower? And what kind of funds and mods would it take? Now that the cams have come down in price has anyone thought about sending a set off to be added to and reground with more lift and duration?

Jason Barker

Peaks on 32V: HP@5250, TQ@4300 on 24V: HP@4750, TQ@3900

My plans:

Phase I: Clean intake & valve stems, new spark plugs, new rear coils, PCV catch can.

Phase II: Saxectomy/CAI, Chip, Tranny cooler

Phase III: TBD

On Thu, 6 Jan 2005 21:39:53 -0500, jason barker <jandl@ncfreedom.net> wrote: > What all do you have planned Mike? Also what were the rpm's when you got > these numbers?

-- Mike Testa

My Gtech is handy for seeing if a mod improved things but not all that accurate for absolute HP readings IMO.

. -- Jim '96 TR SHO

"Butterflies" refers to the eight butterfly valves which prevent airflow through the secondary intake valves below 3400rpm. In the attached pic of the lower intake manifold you'll see eight pairs of intake ports. Look closely and you'll see that the larger of each pair is blocked by a butterfly valve. These valves are held closed by a watchspring and open automatically when the attached spindles are rotated by the Intake Manifold Runner Control (IMRC).

I removed my broken IMRC and used a zip tie to hold the butterfly spindles in the open position.

On Thu, 6 Jan 2005 21:28:36 -0800 (PST), Jon Michael <stangerjon@yahoo.com> wrote: > excuse my ignorance, but what are the butterflies? And > how does one go about opening/closing the?

 -- Mike Testa 97 VW, 138k Welded





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