11/2000
Subject: Classic looks, and trouble-free, high-tech
performance. With Imagine Fuel Injection's electronically-driven,
"IR" throttle body setup, you get...
By Bob McClurg
The Italian-manufactured Weber 48IDA downdraft
carburetor and a Ford V-8 racing engine seem to
go together as natural as ice cream and apple
pie. When bolted in 2x4 configuration onto an
individual runner (IR) intake manifold, (whether
it be 427 FE, 351 Cleveland, or Hi Po 289,) the
quick-revving, 48IDA Weber downdraft carburetor
provides peak torque and "instant" horsepower,
as opposed to a conventional plenum-type 4v carburetor
and intake manifold which progressively "builds"
torque and horsepower, while maintaining those
performance characteristics over a much broader
power band. Simply put, a 48IDA downdraft Weber
carburetor induction system performs much like
mechanical fuel injection, yet gives you the street
drivability of conventional 4v carburetors.
While lightning quick throttle response and performance
are the Weber 48IDA's strong suits, looks are
another reason for this carburetors overwhelming
popularity with high performance buffs. Anybody
can bolt on a Holley, but when you slap a set
of these sexy little Italian downdrafts onto that
small block-powered Deuce highboy, vintage race
car, that long-awaited Cobra replica project,
a genuine, 289, or 427 Shelby Cobra restoration,
or its pony car siblings the Shelby GT350, and
GT500 Mustangs, you make a high performance "statement"
that cannot be ignored.
But here's the dilemma. These carburetors went
out of production sometime in the 1980's, and
are in extremely short supply. Of course, their
relative scarcity dictates a lofty selling price
whether they be new/old stock 48IDA's, (good luck
finding a set of those!) or used sets, being sold
used, as rebuildable "cores."
Enter Bob Ream and partner Wes Henderson from
Phoenix, Arizona's Imagine Fuel Injection. Last
summer, the guys from Imagine Fuel Injection debuted
their new Weber-inspired, individual runner, electronic
throttle body fuel injection system to an enthusiastic
audience (which included Carroll Shelby himself,)
at SAAC-25, held at Lakeville, CT's Lime Rock
Park Raceway.
"We started this project in November, 1999,"
said Bob Ream. "The Weber 48IDA carburetor
was quickly disappearing from the performance
aftermarket, and there were people out there who
still wanted the performance, economy, and the
looks offered by the Weber 48IDA without having
to scour the country, and pay the lofty prices
being commanded for these carburetors."
Ream and Henderson reasoned that if they could
offer an IR-based, electronically-managed "Weber-type"
throttle body fuel injection setup at an attractive
price, they could effectively re-capture, as well
as revive a waning market segment of the performance
induction systems industry.
"Today everybody drives an electronically-managed,
fuel injected car, or truck. They drive them to
work. They drive them to the race track. One thing
which the EFI cars of the 90's have taught motorists
is that a car can perform at its best at all operational
levels with this type of system. So, why not install
a setup similar to this on the car you drive for
pleasure?"
Using readily-available cast aluminum Weber
IR intake manifolds as the foundation, the guys
from Imagine Fuel
Injection designed a billet aluminum down draft
throttle body which essentially utilizes all the
outer dimensions of the Weber 48IDA. "By
doing it this way, we can use the Weber intake
manifolds, their gaskets, their induction stacks,
and even their air cleaners," said Bob Ream.
The throttle body itself is manufactured from
CNC-machined T-6, 6061 heat-treated billet-aluminum,
and features a 2-inch (50.8mm) standard throttle
bore size with stamped-aluminum throttle plates.
On "turn-key" induction systems, these
throttle bodies are port-matched to the IR intake
to achieve maximum air/fuel flow, and performance.
Imagine Fuel Injection's bi1lett-bodies are finished
in either a clear bright anodizing, or an optional
polished aluminum show finish.
"When it came to the throttle linkage,
we found that (due to the proximity of the electronic
fuel injectors,) we had to re-locate the system's
throttle linkage, l-inch higher on the throttle
body for clearance." This modification was
also necessary to maintain fuel injector-to-intake
valve alignment which is so critical with throttle
body-type, multi-point fuel injection systems."
What type of fuel injectors does Imagine use
with these systems? "A lot it has to do with
the compression ratio of the engine, the rpm power
band which you intend to operate the engine at,
and the cam profile which you're using,"
says Bob Ream. "Traditionally you would use
either a Lucas, or Bosch electronic fuel injector
with these applications. For example, we would
use let's say a 43 lb./hr fuel injector for a
427 FE engine application, while we would choose
perhaps a 30 lb./hr electronic fuel injector for
a smallblock application like a Hi Po 289."
Imagine Fuel Injection also manufactures their
own CNC-machined, billett-aluminum fuel rails
from raw bar stock. These fuel rails work in conjunction
with a standard Bosch 200 lb. electronic fuel
pump along with an Aer-O-Motive billett-aluminum
high pressure fuel regulator and filter.
So much for the mechanical aspects. Now for
the "star wars" technology. "We
like using either the HalTech F9A, or Electro-Motive
distributorless engine management systems,"
said Ream. "The F9A is a well known unit
with a 15-year track record for precision, and
reliability. This system is primarily used on
applications which for technical authenticity,
like a Shelby or Mustang application, require
the use of a conventional distributor. It's very
trouble-free, and in any type of motorsports,
that is the name of the game."
On the other hand, Imagine recommends the Electro
Motive distributorless engine management system
for more high tech applications like the Vortech
supercharged, 351-W late-model Mustang which they
are currently working on in conjunction with Phoenix,
Arizona's B&R Automotive.
Another integral component in the Imagine IR
throttle body system is the use of an RS-232 cable
which can be setup to interface with either Ford
or GM-type electronic engine management sensors.
Ream went on to relate that rather than employing
the more commonly used Microsoft; windows engine
management systems computer software program,
* the company has elected to use the older DOS
version.
"The reason we did this is because the
DOS computers are in-expensive, and plentiful.
As such, they become practical to take to the
race track where adjusting fuel distribution and
airflow is critical. You can beat them around.
You can get dirt on them, and should one of them
ever fail, you can go back to the local swap shop
and pick up another one for around $150.00."
Imagine Fuel Injection also builds a number
of "use specific" wiring looms which
interface with their electronic throttle body
fuel injection systems. "We offer wire looms
for both small, and big block Cobra's. We manufacture
a wiring loom for the DeTomaso Pantera. We manufacture
wiring looms for both small block, and big block
Shelby GT350's, and GT500's. These looms will
also work just fine on early-model Mustangs. We
even manufacture wiring looms for Chevrolet and
Volkswagen throttle body applications!"
Of course, you can talk all day about how great
a product is, but how well does it hold up in
"real world" situations? "Our dyno
man, (Terry Kell, Las Vegas, NV.) says this system
is the best thing he's ever layed hands on,"
said Wes Henderson.
Testing at Kell's Las Vegas dyno shop was done
using one of the Shelby aluminum alloy 427 FE's,
built by Shelby American's resident engine man
Mike LeFevers. "We pitted our intake manifold
against a Holley 850 Edlebrock victor dual plane
intake. We recorded torque, horsepower, and exhaust
gas temperatures. At 4500 rpm, the Holley/Edelbrock
setup produced its most significant amount of
torque, 406.24 lb./ft., while the Imagine Fuel
Injection throttle body setup produced 427.19
Ib./ft. Optimum horsepower figures for the Holley
setup came in at 5,500 rpm, registering 399.98
hp. On the other hand, the Imagine IR system recorded
its best horsepower figures at 5,000 rpm, registering
a solid 418.96 hp.
Naturally with any IR type intake setup, the
exhaust gas temperatures (EGT's) also straightened
out between cylinders. The Imagine Injection IR
system showed as much as a 400-degree temperature
drop between engine cylinders temperatures. That's
a lot!
"This is really THE intake system to have
for a street Cobra," says Finish Line Motorsports
(Las Vegas, NV.) president Roy Hunt. "It
runs as smooth as a Mercedes, yet exhibits absolutely
crisp throttle response while exhibiting a slight
"lope" which give you an indication
of the performance potential which lies beneath
the hood."
Getting back to Carroll Shelby, Ream and company
installed one of their big block IR setups on
Californian Mike McAllister's Finish Line Motorsports-prepared
CSX4124, and handed Carroll Shelby the keys SAAC-25.
"Mr. Shelby was extremely impressed with
the power, throttle response, and clean operation
of the IR throttle body system. In fact, he ordered
one of these systems for his own personal Cobra
(427SC "Completion Series," #CSX3056.)"
How do you lay your hands on one of these killer
IR setups? Should you already own a Weber setup,
or already have the intake manifold, any, or all
of these components can be purchased separately.
Or, you can purchase "the whole nine yards"
for about the same money as you would spend a
fully decked-out 48IDA setup. For dealer information,
just contact Imagine Fuel Injection at the telephone
number listed below. The sky is the limit! MI.
* For those wishing to use a windows engine management
software program, Imagine offers an optional program
in Beta form.
SOURCE
Imagine Fuel Injection
2538 W. McDowell Avenue
Phoenix, AZ. 85017
(602) 272-6474
1. Shown is Imagine Fuel Injection's complete
IR/EFI system for the Ford big block FE. You can
purchase these units all, or in part through participating
Imagine Fuel Injection dealers for about the same
price as you would pay for a set of Webers!
2-3. Imagine Fuel Injection's "Weber-type"
throttle bodies feature 2-inch (50.8mm) throttle
bores, and are CNC-machined from 6061, T-6 bollett-aluminum.
These bodies can be had either clear anodized,
or with a "show polish" finish.
4. Shown is the smallblock (289) Ford unit which
Imagine exhibited at last summer's SAAC-25 national
convention. These throttle bodies utilize all
existing Weber hardware which are readily-available
throughout the performance aftermarket, intake
manifolds, gaskets, velocity stacks, and air cleaners.
5. In order to maintain correct fuel-injector-to-intake
valve alignment, it became necessary to re-locate
the throttle body linkage up 1-inch on the throttle
body from the traditional Weber mounting position.
This overhead view also shows the proximity of
the 30 lb/hr. Lucas fuel injectors and fuel injector
bosses in relation to the throttle linkage.
6. This "down the throat" angle shows
the systems 2-inch bore (50.8mm) stamped-aluminum
throttle plates. These units were designed to
utilize Weber factory velocity stacks, (either
tall or short,) and mount to the Imagine Fuel
Injection throttle bodies in the same manner as
a Weber 48IDA, using a Weber gasket, and a pair
of 3/16-inch machine screws.
7-8. Imagine Fuel Injection also manufactures
its own fuel rails from CNC-machined-aluminum
bar stock. These rails utilize a standard Aer-O-Motive
billett-aluminum high pressure fuel regulator
and fuel filter.
9. This shot shows the Ford Parts and services
fuel sensor and harness used on the 289 system.
10. These sensors "plug in" to either
a Hal Tech F9A computer (shown) which is used
for traditional applications, or the high tech
Electro-Motive engine management system used in
more sophisticated applications. Also shown is
Imagine Fuel Injection's wiring harness for a
427 Cobra.
11. And speaking of Big Block Cobra's, this overhead
view of Californian Mike McAllister's 427 Cobra
(CSX4124,) clearly shows the quality and appearance
of the Imagine Fuel Injection electronic throttle
body IR setup. Note the slick mounting of the
fuel rails, fuel regulator and gauge. Those oval
air cleaners are Imagine items.
