diy fi flowbench(assembly)

11
Warning The project described hereiD uses flam- mable liquids and may present a fire hazard.. Reasonable care has been exer- cised in designing the flow bench. None"' when you USe ga$olil)e as the ouklooTsor With high ventilation. A fire extinguisher be kept on hand. We highly recommend you employ a fan set up to blow away vapors as they are emitted. If you choose to build this device, you accept all risks involved. Neither Perfor- mance Engineerin§ Magazine nor its staff accepts any liability if you hurt yourself or others while using this de- vice. Photo 1 - The fu el inj ecti on fl ow bench, front & back vi ews. 4 By John De Armond Introduction This article is the first of a series on building and using a fuel injector testing and cleaning machine. The machine is easily built, is based on an IBM-PC and can cost as little as $200 to build. This first article will show you how to build the machine and will present some basics of testing. Subsequent articles will go into consid erable detail about using the machine in a high perfor- mance environment. The purpose of this machine is fairl y simple c To a llow you to measure and record a ll impo rt ant parameters of an electronic fu el inj ecto r. The design and construction of thi s machine is also fa irly simpl e. Some of the unde rl ying concepts may not be. Of course, th at is why thi s magazin e exists, to de-myst ify thi s stuff. Some Basics What is the purpose of 'any fuel metering system? Keep it simple now. That's ri ght, to create the optimum fu e l/a ir mi xture

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Page 1: DIY FI FlowBench(Assembly)

Warning The project described hereiD uses flam­

mable liquids and may present a fire hazard .. Reasonable care has been exer­cised in designing the flow bench. None"'

when you USe ga$olil)e as the

ouklooTsor With high ventilation. A fire extinguisher alw~ys be kept on hand. We highly recommend you employ a fan set up to blow away vapors as they are emitted.

If you choose to build this device, you accept all risks involved. Neither Perfor­mance Engineerin§ Magazine nor its staff accepts any liability if you hurt yourself or others while using this de­vice.

Photo 1 - The fuel injection flow bench, front & back views.

4

By John De Armond

Introduction

This article is the first of a series on building and using a fuel injector testing and cleaning machine. The machine is easily built, is based on an IBM-PC and can cost as little as $200 to build. This first article will show you how to build the machine and will present some basics of testing. Subsequent articles will go into considerable detail about using the machine in a high perfor­mance environment.

The purpose of this machine is fairly simple c To allow you to measure and record all important parameters of an electronic fuel injector. The design and construction of this machine is also fairly simple. Some of the underlying concepts may not be . Of course, that is why this magazine exists, to de-mystify this stuff.

Some Basics

What is the purpose of 'any fuel metering system? Keep it simple now. That's right, to create the optimum fuel/air mixture

Page 2: DIY FI FlowBench(Assembly)

under all conditions. See, that was easy. This holds true whether the device metering the fuel is fuel injection, carburetion or someone pouring gas down the intake. As with many things in life, while the theory is simple, implementa lion is quite complex .

Let's presume for a moment that the best mixture under a ll conditions is the chemically correct one, 14.7: 1 for gasoline . That is, for everyone part by weight of gasoline, there must 14.7 parts by weight of air to completely burn the fuel. This is known as the stoichiometric mixture. I tend to abbreviate this as "stach" , pronounced just like it looks.

Achieving this, particularly with fuel injection, should be easy. Just measure the air flow, calculate a proportional amount of fuel and shoot it in. Problem is, physics rears its ugly head. Both air and fuel have the inconvenient tendency to change properties with temperature and pressure . Air is even worse because it changes density with pressure. If we didn 't have all these considerations, a simple, all mechanical system such as the Hilborn would work perfectly under all conditions. Reality dictates all the fancy electronics we have today.

In order to configure any kind of fuel injection control system, one must know the characteristics of the final actuator, the fuel injector. That is, the tuner must know how much fuel per unit time the injector will deliver, how much delay after he commands the injector open before the actual delive ry starts and how long after he commands it shut it actually stops flow. See the sidebar for more deta ils on injector parameters.

Pressure Regulator

Pressure Gauge

FuOl Injector :f Undel Test

Catch Bowl

Figure 1 - Piping Diagram

Injector, Parameters

You might be asking yourself. "SO I've built the tester. Now what do I testT Fortunately the important parameters of the fuel injector are well defined. The first thing you need to acquire is a copy of the SAE sfandard on fuel injectors. This is SAEJ1832, "Gasoline Fuel Injector Highway Vehicle Recommended Practice." This docu­ment can be ordered directly from the SAE and can even be paid for on your credit card. See the Resources Box for details. This standard is al­most 50 pages long and covers injection mea­surements in vastly greater detail than could any magazine article so you should order this stan­dard and have it available when reading this section.

Flow

The most basic parameter is the fuel deUvery. That is, how many units of fuel per time interval the injector delivers. If the fuel pressure is held constant, the amount of fuel injected is directly proportional to the amount of time the injector is open. The actual parameter is the mass per second, typically grams per second. The reason mass is needed is mixture is specified in terms of the ratio of the masses of the air and fuel. The rate of delivery is dependent on the fuel pressure, the viscosity of the fluid and the dimensions of the internal orifice. We'll standardize the test pressure and the fluid so all injectors can be compared against each other. You can either measure the volume of the fuel delivered and, using the density of the fuel, compute the mass, or you can actuaUy measure the mass directly with a lab balance. We'll be looking at both methods.

As with many things, this simple concept gets complicated in practice. What we referred to above is the static flow rate or Qs (all variables will be the ones used in J1832.) That is, if we apply fuel and yank the injector open. how much will it flow? Easy to measure. That is only peripher­ally relatecl to actual operating conditions. In the engine, the fuel flow is started and stopped once or twice each power cycle . When the injector opens, the fuel, having inertia like any other matter, tal,es a bit of time to start moving. Because of this delay. if the injector is open 50% of the time, the flow will not quite be 50%. The actuaL flow is known as the dynamic flow rdte or

(continued)

Pe rformance Engineering Magazine 5

Page 3: DIY FI FlowBench(Assembly)

Overview

What must an injector tester do? Not that much really. It must supply the injector with a stable supply of fuel (or other working fluid) at a known pressure. It must supply the proper voltage for the injector. It must provide the means to precisely and repeatedly actuate the injector. Finally it must provide the facilities to measure the injector's operating parameters. Thanks to the ubiqui­tous IBM-style PC and a touch of hardware we will fabricate or inexpensively buy, these requirements are simply achieved.

In addition to a PC and the hardware we are going to fabricate , you will need a couple of other pieces of equipment. The most expensive is an oscilloscope. Since we are dealing with relatively slow events, most any old scope will work. The cadillac of scopes for automotive work is the digital storage scope. This instrument is really a special purpose computer that digitizes the signal in question and displays it on a screen. Because the signal is stored in the scope's memory, it is visible until either replaced with a new trace or erased. That means very slow events such ignition or fuel injection cycles can be viewed at will. It also means that with the right equip­ment, hardcopy of the trace can be generated.

In the automotive context, the cadillac of digital storage scopes (DSO) is the Fluke 97 Scope Meter. This hand­held unit combines the functionality of a dual trace, 50 MHz oscilloscope and a digital voltmeter. See Photo 2. All the scope traces and data presented in this series of articles are generated from PE's Fluke 97. At $1795 retail, this scope is within the reach of the professional Performance Engineer and even for many hobbyists. Note that this scope is not necessary in order to build and use the fuel injection tester. Nice but not necessary.

One of the tests you will perform on a fuel injector is to measure the opening and closing time. This is done by mounting an accelerometer on the injector and record­ing the vibrations generated by the injector opening. See Photo 3. An accelerometer is a device that converts acceleration to an electrical signal. Typically the output is specified in terms of signal magnitude per G of acceleration. The accelerometer we use here at PE is a fairly expensive commercial piezoelectric accelerometer made by Endevco. These units typically cost $200 or more. However, a very satisfactory accelerometer can be constructed from an ordinary knock sensor.

Tester Description

The tester is pretty simple. A miniature fuel supply loop, almost identical to that found on the car, is set up under controlled conditions. The loop consists of a standard FI fuel pump, filter, bypass regulator and pres­sure gauge. See Fig. 1. The regulator pictured is a fixed pressure unit from a Datsun 280Z. For a more general purpose tester, use an adjustable regulator available from

Injector Parameters (continued)

Q. Since the inertial delay is fixed, the shorter JUld faster the opening pulse, the larger proportion of the total flow interval is con­sumed by the intertial interval.

The only way to determine the slope of this dynamic flow curve is to actually pulse the Injector under the same conditions and deter­mine the flow rate vs pulse width.

Spray Pattern

The spray pattern is important because it dictates where in the intake the injector is placed and how well itwiU work. The ideal configuration is for the injected fuel to spray directly onto the head of the intake valve. This gets the fuel as closlf as possible to the combustion chamber and none is sprayed on the intake walls. The .tester allows you to observe and even measure the spray pattern. J1832 details pattern testing in great detail.

(continued)

Photo 2 - The Fluke 97 Scopemeter

6 Performance Engineering Magazine

Page 4: DIY FI FlowBench(Assembly)

Photo 3 - Accelerometer and in­jector clamping detail.

a variety of sources. See the Re­source list.

The pump is supplied with 12 volts through a switch and a rheo­stat. The rheostat is provided to adjust the speed of the fuel pump until the bypass regulator just starts to bypass. The purpose is to intro­duce as little heat to the fuel as possible. Fuel is supplied to the injector through a flex hose and is secured via a homemade quick action clamp. The injector is held in the fixture by a common wood­working toggle-clamp. The accel-

erometer is attached to this clamp. Photo 4 illustrates this assembly. You will observe that there is a small flowmeter in the line to the injector. This meter is optional and is not necessary to conduct any test in this series. The meter is convenient but very expensive so the design was developed with­out it.

Below the injector mount is a spray catch-cup used to catch the spray from the injector when observing the spray pattern. It is fabricated from a 4" CPVC pipe endcap. It is designed so it can be quickly moved out of the way for tests so requiring. See photo 1. In

Performance Engineering Magazine

this photo the cup is white so it will show up better. It should be paint­ed flat black with appli­ance epoxy paint so the spray pattern can be more easily observed. The cup hanger is fabri­cated from a piece of gas line flattened in a vice and drilled for at­tachment to the panel. The bends are accom­plished with an ordinary tubing bender available at the car parts store. The loops that hold the cup to the hanger are

ordinary nylon wire clamps avail­able from Radio Shack or other electronic supply houses.

A quick peek at the schematic in Fig. 2 reveals the simplicity of the electrical circuit. The reason this circuit is so simple is that the PC does all the work. The printer port adapter is nicely buffered. The soft­ware does all the actual testing. Ain 't PCs grand!?! The circuit pro­vides the ability to test both saturat­ed mode and peak-hold mode injectors. Which mode is in effect is strictly the function of the software. The potentiometers are adjusted to provide the proper peak and hold current in peak-hold mode or VR-

Photo 4 - Regulator, flowmeter , pressure gauge and piping detail. Note the homemade T-handle clamp at bottom-center.

7

Page 5: DIY FI FlowBench(Assembly)

8

1 alone is used to set the saturated current for saturated-mode opera­tion. We'll cover this aspect in great detail in the next issue.

Construction

The chassis of the tester is con­structed from plywood. All joints are glued, braced and screwed with sheetrock screws. This makes a very sturdy but easily "machined" base. A heavy coat of aerosol ep­oxy appliance paint provides a non­stain finish . Control legends were created by laying out the pattern in CorelDraw and laser printing them on overhead transparency film. The legend is glued to the panel using ultraviolet curable epoxy. If you don 't have such esoteric glue (Mine waS stolen from Doreen 's stained glass studio), superglue will do fine.

The piping is three-eighths inch brake line: [ used metal piping be­cause it is sturdy and fireproof, a consideration that should not be underestimated. The return piping should extend to below the surface

of the liquid in the reservoir in order to minimize foaming and evapora­tion. Be sure to plug the opening to the reservoir with some fiberglass cloth as shown. This a vapor barri­er and a fire stop .

The electrical construction is sim­plicity personified. See photo 6 for details. Basically, everything is sim­ply screwed to the wooden chassis. The heatsinks on the transistors are not necessary and were includ­ed in an early stage of develop­ment. They remain completely cool to the touch. None of the wiring or layout is critical. [ recommend us­ing shielded wire for the lead to the Pc.

Power for my tester is supplied by a regulated power supply. This is convenient and may be neces­sary for some of the SAE sp~cified testing but is not required. A car battery will work just fine. If you do use a regulated power supply, be sure to include an outboard filter capacitor as illustrated on the sche­matic and in Photo 60. This capac­itor filters the switching transients

Performance Engineering Magazine

Opening and Closing De­lay, Turndown Ratio

When the ECU applies a pulse to the injector, itd~ not oJ)?n immediately. The tor coU inductance Iy resists the flow of clll'i'ei1tiatl.d the valve parts have inertia. Both these faqj:ors Iimit.~ opening SJ)?ed of the inje¢tbr. It is important to mirlim12'£ this delay. The reason is a parame­tercaUed the "ilJmdown ratto". That is, the ratio betweeti;t'he maximum and minimWn open time. Themaximumopent'lme is .. set by how much tim~. a pOwer cycletakes at maxirrrum RPM. See F'Jgure 8. Forexam­pie, if the engine's m ~d is lO,QOO RP

These injectors will be mafched as to fuel delivery and opening t~But what ifene goes Orgetsdlrty?Howdoyou the .replacement to the s~ Un­less you buUd this macl:ilne or you~ve about ~lO,OOO a cbmmerciaUy buUt fuel ' tester, you don't.

The last benefit might not be so obvious. This.tester lets you get "down to thll! bare meti:ll. ,­You'll be able to measure and get the feel for almost Wery oJ)?rating parameter of a fuel injec::ror and you can quickl!l corn-­pare one injector design to an­other. This level of experience and understanding makes it much easier to grasp the rest of the injection system design process.

Page 6: DIY FI FlowBench(Assembly)

+ 12 Vol ts (OvlIooXI!tvVolIOble)

j ' +12 Volts

Fuel InJectOf

VRI lOOQ· 20watt Wirewound Potentiometer Clarostot or equiv.

VR3 200-20woM Wirewound Potentiometer Clarosta! or equiv.

FuefPump

Fig. 2 - Schematic Diagram

created by firing the fuel injector. I learned from experience that these transients will burn out the power supply unless trapped. Most any value capacitor larger than about 30,000 uF will work fine.

The Software The software is amazingly simple

considering what it allows us to do. Its basic function is to turn the fuel injector on and 6ff for precisely timed intervals and to' total the amount of time the injector is open. The software uses the hardware timer built into each Pc. The timer is used in a high resolution mode that gives us the ability to measure time in microseconds. The actual timer routines were taken from some public domain code written by David Kirschbaum. This soft­ware is written to be as portable as possible and has run on every type of PC tested to date.

The operation is simple. Four values must be specified. These are:

• The time the peak current flows. T(peak)

• The total on time. T(on)

i u.J T(hold) l')

~ 0 >

t >--z u.J

'" '" :::J U Coil Current

--------j""-- ---

i z u.J "-0 "'--If-_ ..... I--+--------+---'~'_P::..:intle Motion

TIME ---~

Fig. 3 - Idealized voltage and current waveforms and pintle motion for Peak/ Hold (solid lines) and saturated driver (shaded lines .)

Performance Engineering Magazine 9

Page 7: DIY FI FlowBench(Assembly)

A

B

• The total cycle time. T(cycle} • The lotal number o f cycles.

See Fig. 3 for del ails . Once these parameters are spf'cified . the go command can be issued to fire the injector. During each cycle, both transistors (bits 0 and J) are fired for T(peak). Then the peak transistor is turned off (bit 0) and the injector is held on for the time interval equal to T(on) - T(peak}. The hold transistor (bit 1) is turned off for T(cycle) - T(on} and then the cycle repeats until the total number of cycles are run or a key is pressed. A keypress ter minates Ihe test. The lota l on time is accll1111 ilated during test-

10

ing and is displayed at the end of each cycle . This time is vital for computing the fuel delivery of the injector. This time accLm1ulator can be reset at any time.

A second mode is the current! purge mode . This mode simply fires the injector continuously so that the peak and hold current can be set. Some caution must be used because excessive current can quick­ly burn out injectors. Because the peak current is often many times the rating of the injector, the peak on-time is limited to one second at a time . A second use of this mode is to turn the injector on continu­ously so air may be purged after an injector change and to release pres­sure prior to changing the injector.

Perfonnance Engineering MagaziJl e

c

D Photo 6 - Wiring Details

A !l1ird mode is the software calibration mode. Because every computer requires a finite amount o f time to execute a sequence of instructions and because the time intervals we are dealing with are very short, a compensation factor must be developed for each ma · chine. The software ships with a compensation value appropriate for my 25 MHz 386sx laptop. The calibration mode allows you to al lernately generate a 0.5 ms and a 5 111S pulse from bit 0 while chang·· ing the compensation factor. You would place the program in this mode and then observe the pulse output on an osci lloscope while dithering the compensation factor until the pulse widths are exac!.

Page 8: DIY FI FlowBench(Assembly)

A 5V DC B 5V OFF 500ms/DIV SINGI E Trig A 1

r;ll ~ Off Time l~ !~ •

I Start Cyc le Storts of

End of New

~ Cyc le Cycle

" Fnd Peak. ) Begin Hold

I-

r.-..

-Fig. 4 - Lamp test waveform

Injector Parameters (continued)

maximum amount of time avail­able to inject is that taken by two revolutions.

10,000 /60 =, 166.66 revs per second.

1 / 166.66 RPS = 0.006 seconds per rev.

Two revolutions is 12 millisec­onds

So we have 12 miUiseconds maximum to supply the needed fuel at full RPM. It is desirable to size the Injector f10wrate such that the injector is open almost all the time. That maximlzesth~ turndown ratio. It is very~POr­tant to note that the opening delay must be accommodated In thiS 12 ms interval. More accu­rately, the opening delay minus the closing delay must be ac­commodated. The closing de­lay. which is almost always

10..-

Performance Engineering Magazin e

Th is compensa tion fac tor only matters when crea ting interva ls shorter t han about 2 ms. The value vou develop may be polaced in an ~ nviro nme nt- va ri abl e ca ll ed FITCOMP_ Sec the documenta­tion thClt accompnnies the code for details_ Please refer to the Resollrce I .ist for sohwi'lre Clvailahility .

Testing

I suggest you test the mechanicCl I components first. Insli'lll i'ln injec­tor. fill the tank with gasol ine and fire off the pump at full speed. Q'lickly look for leaks and verify the pressure wgulator is function­ing. VClry I-he speed knob and veri fy the pump chi'lnges speerL Tllm off the pump and bleed the pressure by loosening the pipe , lamp on the injector nnd allowing the gas to leak into the cnlch bowl.

Electrica l tests are conducted with

]1

Page 9: DIY FI FlowBench(Assembly)

a small 12 volt, approxi­mately 2 amp (taillight)

BNC Connector

)

on the front panel of the flow bench r------.,

I I

, "/1 Accelerometer

Iightbulb installed in place of the injector. Connect the PC and start the pro­gram. This is important because the first thing the program does is reset the parallel port. In my expe­rience, about half the time a parallel port will power up with the output bits set; i.e . .. the transistors

I ' Chan A I Chan B

I _: ~In~o<~<o~,.~ .. ~;,~ I - - - - -- - - I "{T

fired. This could, of course, burn out the in-jector. Apply power and verify there is 12-14 volts

- available at the injector power switch. If that is in order, turn on the injec­tor power switch. The lamp should be off. If nO,t, check your wiring. Enter the cur­rent/purge mode . Fire the peak transistor. The lamp should light. Turn thepeakpot. Thelightinten­sity should vary. Turn the peak transistor off and fire the hold tran­sistor. The lamp should again light. Turn the hold pot. The lamp in­tensity should vary. In each case, with the lamp at full brilliance (min­imum resistance), verify that the collector of the applicable transis­tor is switched within about a half volt of ground. If it is not, either the transistor has low gain or your parallel port has insufficient drive. If insufficient drive is the problem,

'1 'J

Idddobi D ==C'J DDDDGJ

Od8m 00000 o ~D

see the Resource List for a known good parallel port card. Turn the hold transistor off. Return to oper­ate mode. Set the following pa­rameters:

• Total cycle interval 3000 ms • Peak interval 1000 ms • On interval 2000 ms • Repetitions 100 • Peak potentiometer fully

counter-clockwise, maximum re­sistance

• Hold potentiometer fully clock­wise, minimum resistance.

Run the test. You should see the

Fig. 5 Standard connection diagram

lamp come on dimly for a second, go full intensity for a second and turn off for a second. If you have a scope connected to the monitoring point, you should see a waveform similar to Fig. 4. Testing is com­plete. Press any key to terminate the test.

Operation

This is going to be brief because the majority of the next issue 's article will cover operation. This is just enough to get you going.

Install an injector. Connect the scope as illustrated in Fig. 5. Set the

A 5V DC B 500mV DC Fig. 6 A 5V DC B 200mV DC l msjDIV SINGLE Trig' A l 1 msjDIV SINGLE Tri g' A l

IT "\ '\ ,

, l'-

fI IT ... tv "'-V' rvv A 1 ~L. It. ~ ....., ~,,~ '\I"'U v

Fig. 7

12 Performance Engineering Magazine

Page 10: DIY FI FlowBench(Assembly)

scope as follows:

• Chan A - monitoring point, 2 volts per division

• Chan B - accelerometer, full sensitivity, usually 5 mv/division

• Trigger - Chan A, DC cou­pled , negative slope

• Sweep - 1 ms/division, Normal trigger.

Set the peakand hold pots fully counter-clockwise {maximum resis­tance}.

Start the software and apply pow­er to the injector. Leave the fuel pump off at this stage. Set the following parameters for peaklhold injectors:

• Peak time 5 ms • Tota l cycle time 15 ms • On time 10 ms • Repetitions 10,000

Start the test. You should see some activity on the scope. Adjust the trigge r level for a stable display similar to Fig. 6. The injector may be making some noise but probably is not opening. Start turning the peak pot clockwise. You should hear the sound of the injector change. At some point the change will become marked : This will oc­cur when the injector gets enough )eak current to actually start open­ing. You should see some activity on channel B, the accelerometer. You should see a vibration spike shortly after the current is applied and perhaps a second spike as the injector closes when the peak cur­rent turns o ff. If the injector closes when the peak current turns off, gradually tum the hold current pot until the injector stays on for the duration of the on time.

You have now determined the approximate peak and hold cur­rent requirements of that injector. You can back the peak time off until the injector fails to open. This will determine the approximate peak time required. This is normal­Iyabout 1-2 ms Fig. 6 illustrates a

typical peak/hold waveform. You may now go to current mode and evaluate the currents you have set.

For Saturated Driver Injectors, use the follOWing parameters:

• Peak time 0 ms • Total cycle time 15 ms • On time 10 ms • Repetitions 10,000

Start the test and observe the scope. You should see a display similar to Fig. 7. Start turning the Hold pot clockwise. Atsome point the injector should start opening. The accelerometer should show some activity and the sound should change. Continue increasing the current by further turning the hold pot and observe the opening de­lay. The delay should decrease rapidly at first and then remain fairly constant. Just a bit more than what is necessary to tum the delay "knee" is usually about right. If the injector is a high impedance {no ballast resistor} unit, the hold pot should end up near zero ohms. If a ballast resistor is used in an existing installation with low im­pedance injectors, the pot should end up near that value.

Since we don 't have any fuel flowing at this point , don 't run these tests for too long lest you overheat the injector. Once you get the approximate electrical pa­rameters set, you may start the fuel pump and actually inject some fuel!

Working Fluids

For most testing, you will want to use the actual fue l you will be burning in the engine. If you plan on testing a lot of injectors , you might want to consider using N­Heptan e as outlined in SAE J1832. It has a lower vapor pres­sure than gasoline and is much more stable over time. If you use gasoline , you should use new gas­oline each day. Pump the old gas out and use it in your hotrod lawnmower or something.

Performance Engineering Magazine

This tester is very effective in cleaning dirty injectors. The work­ing f1wid I've found very effective is a half-and-half mix of gasoline and Chevron Techron® fuel injector cleaner. Simply clean the injector on the outside and then connect it to the tester. Run the injector at about a 50')-(' duty cycle for 15 minutes. The vibration of firing the injector appears to assist in the cleaning operation. More on this next issue.

In Closing

This just about wraps up the first installment in this series. Use the time to build your tester , acquire the software, acquire a copy of SAE J1832 and get everything working.

Ordering Files by Emall

If you are on the Internet or any of connected.networks, you can request the Software that accompanies this article via -electronic mail. There is no charge. lfyouare ona network other than the Internet, consult your~­master tor instructio~ for malIingfo an Internet address. The.. ipstructions 3SS\ltM you lritemet. .

Address the mail to dlxie.com. This is an aut.:mJ.<mc. server. There need not be.any ·Sub­ject". In the. body of the message. irlclude the following:

address <your mail get help

The file will be returned to your address in uuencoded format. You wiD need a uudecoder in order to process the fUe. These are widely available from Bulletin Board sys­lems, including Courts of Chaos list­ed opposite.

13

Page 11: DIY FI FlowBench(Assembly)

---------- - - ------- ---- - _._--- - - - -

14

Resource Guide Software

The software may be obtained from the following sources: • Courts of Chaos BBS • By e-Mail • By mail from PE Magazine_

Fuel Pressure Regulator

5 01 '3155-0059 Send request 10 [email protected]

Send a LargeSASE and $S.OO

A stock regulator from your car of choice may be used or an adjustable regulator lTIay be ordered from: Kenne Bell, 10743 Bell Courl. Rancho Cucarnonga. CA l) j 730. 7 14 94 1-6646, 714941-0985 (tech sUPPOli)

Electronic Parts Q1.Q2 TIP-120 Transistors 01 Diode, 6A, 50PIV VR-1.2 Rheostat, lOOn ,12.5 IR l tt

VR-3 Rheostat, 20n ,25 walt S1.S2 Toggle Switch, SPST. :3 amp BNC- 1 BNC panelmount connector TP-1 Dual Bananna Jack

Compatable Printer Pori Card

Toggle Clamp

Radio Shack P/N 276-2068 Radio Shack PIN 276-166 1

Newdrk PIN 871'3611-50 III Newark PI N 87f6:390-20 12]

Radio Shack PI N 275-322 Radio Shack Radio Shack

Magillonics PIN A-B10913]

This is a standard 1" woodworking toggle clamp available from most hardware stores. An alternative supplier is Stone Mountain Power Tools in Stone Mowltain. GA_ 404446-8390.

Accelerometer The knock sensor mentioned is a standard automotive knock sensor. Mine is from

a Dodge Turbo Lazer. True accelerometers can be had horn:

SAE

Endevco 30700 Rancho Viejo Rd. San Juan Capistrano, CA 92675 714661-7231

PCB Piezotronics Inc 716 684-0001

J1832 may be ordered from the SAE, 400 CornmorlweLIlth Dr.. Warre l!cia le , I-'A 15096. 412 776-4970 , 412776-0790 (FAX)

Hard-to-Find Parts The above marked items are available from Rapid Deployment Systems Inc. PO Box

670386, Marietta, GA30066 . 404 578 9547. Add $4 to each order forS/H. Allow 6 weeks for delivery.

[lJ [2J [3J

VR-1,2 -VR-3 -Card -

$10.00 each. $15.00 each . $19.95 each.

Peljormance Engineering Magm:ille