We REALLY learned something 9-16-10x - Schiefer Media

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29 Νοε 2013 (πριν από 3 χρόνια και 10 μήνες)

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We REALLY learned something…

We hear all the time about how technical schools are just delivering “canned” curriculum and the
students aren’t getting real world experience. Well, that may be true in some cases, but recently at
Wyotech’s Blairsville, PA
campus; students and instructors collaborated on a project that was all about
real world engineering.

The Blairsville High Performance Power Train (HPPT for short) department specializes in teaching
students the theory and procedures for modifying all asp
ects of vehicle performance. One of the most
popular types of modification the students learn about is turbocharging.

Recently,
HPPT
instructors

Ray
Kaufman and Nate Silveri

got together and came up with the idea of
having students build

a turbo setup
t
o use as a demonstration and tuning aid.
The goal was to see what would happen if a readily available
turbo was added to an everyday engine.
Rather than just buying some expensive kit, they decided to
use some “hot rod” engineering and see what could be
built up using what was
lying

around the shop.

Ray
oversaw

most of the fabrication, while Nate handled the engi
ne management and tuning chores.


Several students participated in the construction and tuning of the setup, learning valuable fabrication
and m
echanical skills in the process.

The build started with a 5 year old

Edelbrock
Performer E
-
Tec
Chevy 350 crate engine

that had
already seen some serious chassis dyno flogging in
various vehicles.
With the supplied Edelbrock
injection and long tube headers, the engine base
-
lined
on the
school’s
DTS dyno
at a respectable 375hp and
360lb/ft of torque.
Keep in mind this engine was
well
worn and
never designed
for a turbo application;

with
9.5:1 compression and
a
completely

wrong cam
profile… T
he very fact that it survived what was
coming
says good things about the

work that GM and
Edelbrock do in prepar
ing these engines in the first
place.

The choice of turbocharger came down to what was
lying in the corner, a Holset
HX35 that had been
removed fr
om a 2004 Dodge Cummins diesel pickup.

Mat
ing the
turbo to
the engine consisted of using a set of
cheap
“block hugger”
headers and building a custom “Y” pipe out of 2 ½” mandrel
exhaust
bends.
Earls “Pressure Seal” gaskets were used at
all
the flanges as extra insurance against

leaks
.
As the
pro
ject was planned from the outset to be an engine dyno
mule, the turbo was mounted out front on a bracket made
from rectangular tubing.

Most miscellaneous components
were purchased from Summit Racing, although it’s possible
that
further
shopping around co
uld yield even better deals
.

Stock
Dodge
Holset turbo installed on 350 Chevy crate
engine.

The Edelbrock Performer E
-
Tec 350 with Pro
-
Flo injecti
on was
the engine of choice for this turbo project.

(Edelbrock catalog
photo)

The intake pipe was a portion of the stock plumbing from the Dodge

truck
, and a
Turbonetics carb hat
go
t the
compressed
air turned the right direction. A
38mm Tial wastegate was
added
,

as the stock
Holset
gate actuator could not be modified to open at sufficiently low boost pressures. The injectors
were swapped for a set of 43lb/hr units, and a FAST
XFI computer and harness were used in place of the
Edelbrock

Pro
-
Flo controller (which was not
readily
compatible with a boos
ted setup). …And that’s it.
NO

mods to the turbo or engine, just bolt it all
on and go.

Initial
dyno runs showed that the 38mm
wastegate was not bypassing enough exhaust
energy and would no
t control boost level
adequately. The stock flapper wastegate in the
turbo was equipped with an adjustable control
rod which allowed the wastegate to be opened
slightly to keep maximum boost within
what
was thought to be
a safe level.

“Safe level”
sort
of went out the window, as we shall see…

Several dyno pulls were made in the mid 300hp
range as the fuel and spark parameters were
dialed in to what the engine liked. Once the fuel
and timing were established,
boost was increased slowly on each pull. T
he

engine came alive to the
“tune” of 4
60
hp and 478lbft of torque at 5200rpm, with 12lb of boost and an A/F ratio in the mid 11s at
max torque.

Surprisingly, turbo lag was non
-
existent, with the engine crossing into boost at 2000rpm!
At this point an exper
iment was performed with some NOS Octane Booster. Dumping a bottle into the 5
gallon dyno fuel tank resulted in a gain of 10 hp and 15 lb/ft of torque…with no other changes. GOOD
STUFF!

Closing off the flapper v
alve brought boost up to 15 psi.
The engine was equipped with a “2

bar” MAP
sensor, so 15 psi was the practical limit for tuning

-

and engine life
.
Don’t forget,

we are talking about a
9.
5:1

static compression ratio here…
!
M
ax torque
rose

to
520
lb/ft, but horsepower fell off, and it was
determined that the higher boost was resulting in much higher inlet air temperatures, causing power
loss.

More impressive was the fact that the engine
wa
s showing

no ill effects from several pulls at 15psi
boost levels

As a final “what if” test, a stock Dodge
truck
intercooler
was plumbed in to the intake, and with a fan blowing
through the core, a last pull was made. It was
immediately apparent that

some
thing

was different, as
the rpm shot up and a distinct rumble could be felt in the
concrete floor! The pull had to be aborted

as the A/F
ratio was going dangerously lean, thanks to the much
lower inlet temps. A quick session at the laptop added
some fuel
, and the next pull showed an astonishing 527hp
and 605lb/ft of torque at 15lb of boost.


The turbo acted
more like a supercharger, providing over 600lb/ft of
torque from 2800 rpm and peak torque at 3800. Torque was above 500lb/ft until 5400 rpm, and peak
horsepower came at 5000 rpm. If ever there was an advertisement for the benefits of in
tercooling, this
was it!

Instructors Steve Hower (L) and Nate Silveri assist
students i
n making adjustments on the engine dyno.

Turbo Chevy set up on the engine dynamometer

This project was never about finding maximum power out of a 350 Chevy. Obviously, much higher
numbers are possible. The point was to take some readily available parts, bolt them on to an existing
engine as simply as possible, and

see what happened.
Future plans for the engine involve installation in
a shop vehicle for some chassis dyno time and possibly a few trips to the strip. A purpose built long
block may be in the works, but for now the students and instructors are happy wi
th how well the little
“crate” engine is working out. So, what if you wanted to duplicate this type of setup? Assuming you
already have an injected small block Chevy available…and are not against doing a little shopping on
eBay…the investment breaks down

like this:

(Low estimates are approximate price for actual items found on eBay, high prices are the highest found
from various suppliers).

Holset HX35 (or similar) turbo:


Low
-

$200 High
-

$750

43 lb/hr Injectors for Edelbrock EFI:


Low
-

$250 High

-

$500

Carburetor Hat




Low
-

$60 High
-

$350

Headers




Low
-

$90 High
-

$300

Misc. exhaust and plumbing


Low
-

$200 High
-

$6
00

Intercooler




Low
-

$110 High
-

$1500

Total





Low
-

$910 High
-

$4000


The FAST XFI system runs approximately $
1600
-
2000, but this cost was not included, as most any factory
or aftermarket speed/density EFI control system could be configured to work in this application

with a
little work and

a boost compatible MAP sensor.

So,
a
very
useable
150hp and 250lb/ft of t
orque for
under a grand? Without having to refill a bottle? Yes, with a little planning a
nd elbow grease, it is
possible…and if you happen to have the stuff lying around, you could do it for the price of a night at the
ball game.

Possibly most the most i
mportant knowledge was gained by the students

in the class. Whether they
were directly involved or not, they got to see how these types of pr
ojects are planned and executed;

as
well as what it takes to bring together various technologies and make them wo
rk together…definitely
skills any employer would appreciate.


Ray Kaufman