I spent a lot of time researching options to control fuel delivery in my l28et for the Sinister s30 project.  Xenon’s website is a great resource overall, and answered the majority of my questions, but I had trouble finding a concise explanation as to what common fuel management choices were available.

Fuel Storage

First off, if you’re putting an l28et into your own s30, you’ll need to decide if you’re going to keep the stock fuel tank or not.  The stock tank is un-baffled, so fuel sloshes around when cornering, accelerating, or braking.  If the tank isn’t full, the fuel pickup will sometimes run dry and won’t deliver fuel to the engine.

If you don’t mind replacing the stock tank, make sure you get a baffled tank.  These essentially have doors that keep a small amount of fuel at the pickup so the fuel pump never runs dry.  Many s30 owners install baffled fuel cells, which are the ideal solution but are time-consuming and require a welder to install.

If you’re keeping the stock tank without modifying it, you’ll need two fuel pumps and a surge tank.  The surge tank is a small container (less than a gallon) that holds fuel.  The first fuel pump feeds the surge tank, and the second pump pulls fuel from the bottom of the fuel tank into the engine.  This is a simple, economical option if your stock tank is in serviceable condition.  I’ll be using an old  1.5liter fire extinguisher as my surge tank, and I’ll post up a diagram of exactly how it works later.  For now, you just get a picture of the extinguisher.

The third, more uncommon option is to fill your stock tank with a sponge-like foam.  The foam holds fuel and keeps it from sloshing.  It reduces lateral weight transfer and is relatively inexpensive, but render conventional fuel gauges useless.

The final option is to keep the stock tank but add baffles.  I can’t come up with a compelling reason to do it unless you’re really into keeping the car looking completely stock.  You’ve gotta be pretty OCD to care what the fuel tank looks like, though.

ECU

280zx-t ecu is pretty much a paperweight that uses electricity.  For most cars, it’s better to unplug the o2 sensor, which feeds information that would be absolutely critical to any other car.  The z31 ECU is pretty much plug-and-play and will improve mileage somewhat.  There are aftermarket ECUs available, such as the Wolf, which come highly recommended, but are expensive ($1000+ USD).

I came to the conclusion that the ideal solution is to install MegaSquirt, but it’s a time-consuming ordeal.  First, you’d have to decide which version of MegaSquirt to purchase.  There’s MS1, MS2, and MS3, and there are various versions of software that can be run on each.  Without getting into too many details, my recommendation is a pre-assembled MS2v3.  It’s worthwhile to purchase a relay board, a cable to connect the two, and another cable to run to the engine itself.  You’ll still have to connect all the wires to the correct sensors and inputs, but it’s a straightforward affair.  You can get away with building the whole thing for around $400 if you don’t value your time very highly and have a moderate amount of experience with soldering, but I highly recommend the pre-assembled kits.

Sensors

The most crucial sensor on for fuel delivery is the air measurement sensor.  The stock AFM (air flow meter, uses a flapper to measure air being sucked/pushed into the engine) is inferior to a MAF (Mass Air Flow sensor, measures air density/velocity), which isn’t quite as good as a MAP (Manifold Absolute Pressure, measures how much pressure is in the intake manifold).  MS2v3 comes with a MAP sensor built-in, and can accurately read up to 15psi of boost.

The second sensor that’s important to note is the o2 sensor.  It measures the amount of unburned oxygen that leaves the engine, and the ECU adjusts the fuel map based on what information the o2 sensor offers.  I’ve heard from several people that the stock 280zx-t ecu goes a little crazy with an o2 sensor plugged in and they recommend removing it for better performance and mileage.  It’s strange and contrary to normal logic, but it’s become common knowledge at this point.  That’s just one more reason for me to dislike the stock ECU even more.

If you’re installing megasquirt or making a major change to your engine configuration, you’ll want to borrow or buy a wideband o2 sensor.  A wideband displays just how rich or lean your fuel/air mixture is.  It’s much more useful than a traditional o2 sensor that essentially only tells you if you’re rich or lean.

The more accurate the information you’re feeding into the ECU, and the more information you’re feeding it, the more accurate it can be.  The faster and smarter the ECU, the more precise the end result will be.  There’s a big difference between accuracy and precision, but you want both, not one or the other.

Conclusion

Fuel management is where you’ll gain almost all the mileage gains on an older efi car.  There can be significant performance increases as well if you end up fine-tuning your setup and spending a respectable amount of time getting it right.

A good modification adds to one aspect of a car enough to offset any downside it carries with it.  There are a few upgrades that can be made with virtually no downside to them, and offer a huge performance or mileage boost without too much work.

1. Tires

camber wear

Tires are the best upgrade you can possibly make.  Tires have seen the most technological progress out of any automotive part in the past decade, and the right tires will last longer, grip better, and perform in all the weather conditions you’ll be driving in.  I’ve ordered tired from tirerack several times, and highly recommend them.

Remember, your contact patch is essentially just the width of your tires, so wider is better.  Try to keep the same outer circumference, no matter what tires you use.  Your vehicle’s suspension is set up for the stock circumference, and your speedometer is calibrated to tell you the speed based on how far you travel per rotation of the tires.  Check the tire size calculator if you’re curious as to how new tire sizes will affect your gearing and speedometer reading.

Stainless steel braided brake lines

2. Braided brake lines

Most vehicles use rubber hoses to deliver brake fluid to the brakes when you press the pedal.  Because your wheels need to move with the suspension and steering components, the lines that connect the brakes to the brake lines need to be flexible.  Unfortunately rubber hoses are flexible and stretchy so they absorb some of the pressure sent through them.  That decreases brake response and how well you can ‘feel’ the brakes working.

Braided stainless steel brake lines address this problem, providing flexible but non-stretchy lines that transfer the maximum amount of pressure you press down on the brake pedal directly to the caliper.  They are an inexpensive way to dramatically improve brake feel and response.

949 Racing's 6ul 15x9 wheels

3. Wheels

Wheels allow for bigger brakes and wider tires, which increases your traction contact patch, giving more grip in all situations.  Lighter wheels will also improve handling, acceleration, and braking.  My last CRX project was centered entirely around mounting 9″ wide 6ul wheels on it.

4. Coilovers (Springs and Struts)

Car suspension is designed to keep the car’s weight distributed as equally as possible between the 4 wheels.  Lowering your car will improve aerodynamic efficiency, decrease drag, and improve mileage.

Be cautious lowering your car because driving on public roads still requires ground clearance to avoid bottoming out and damaging any number of components.  Tires can also rub against the inside of the fender when going over bumps or turning very hard, and camber changes can cause improper tire wear.  Coilovers generally suggest a “kit” of springs and struts (hydraulic shock absorbers) and often allow ride height to be adjusted by moving the perch that holds the spring on the car up or down.

5. Seats

Performance bucket seats grip you more firmly and keep you from having to brace yourself while cornering hard.  They hold you right where you belong: behind the wheel.  I consider them to be a safety improvement, as well as a psychological performance improvement.  You’ll certainly feel more in control with race seats than with an old bench seat that doesn’t hold you in place at all.

6. Camshaft

An aggressive camshaft can dramatically increase your engine’s performance.  It causes the valves to open wider and and stay open longer, providing the engine with more fuel and air to burn off.

The downside is that camshafts almost always decrease mileage, and in some cases change the power curve.  New camshafts may only increase power output in certain RPM ranges (v8 camshafts commonly increase 3,000rpm-6,000rpm power, while l4 camshafts focus on 6,000rpm to 10,000 rpm output).

7. LSD

Differentials connect your transmission to the axle(s) of the vehicle, and some will limit the the speed of one wheel if it does not match the corresponding wheel on the other side.  This helps prevent a loss of traction on one wheel when accelerating (and in some cases, an LSD will assist with braking as well) and lets you maximize the traction you have available (see tires, above).

8. Gutting

Personally, I love hearing the road, my tires, my exhaust, and all the little wiggles and wobbles created when driving.  Carpets and sound-deadening have no place on my vehicles, and are actually fairly heavy.  Removing or replacing anything extraneous (such as a can of fix-a-flat instead of a 50-lb spare tire) will improve mileage, acceleration, braking, and handling.

9. Body Panels

Most cars have more weight in the front, which throws off its balance and changes handling characteristics.  Ideally, a car should be as close to 50/50 weight from front to rear as possible.  A fiberglass or carbon fiber hood may drop 50lbs from the front of the vehicle, and fenders will help as well.

10. Lighting

Adjusting headlights and foglights to point exactly where they belong will increase your visibility and keep you from blinding oncoming drivers with your headlights.  Brighter headlights will further increase visibility, and lighter composite buckets are lighter than steel headlight buckets, making the car less front-heavy.

His quads ache each time he leans into the pedals.  He’s focused on keeping his line as straight as possible until he turns in for the apex of the next turn.  He’s tucked low to minimize drag, and is starting to feel his shoulders cramp up from the long ride.  This is his ride every day, and he’s a more efficient driver than you are.

On a bicycle, your muscles push along every foot you travel.  Your body is the primary source of drag.  You feel every grade change, bump, and crevice in the road.  No longer are you simply the brain, giving instructions second-hand to your wheels as to how fast they should go and controlling your steering through a complex rack of gears.  You are a part of the vehicle.

OHNO!

Why it’s different

Along with this increased awareness of the vehicle that carries you, the danger to yourself is higher.  You’re smaller and less stable than cars.  A strong gust of wind or a patch of sand have the potential to throw you violently to the ground.  Minor traffic accidents can quickly turn serious or deadly.  Although the vehicle you’re controlling is much less dangerous to others, it has much more potential to get you hurt than a car would.  Our basic survival instinct dictates that our awareness level increases, and we pay more keen attention to our environment.

Results

A bicycle will actively train you to seek the path with the greatest economy of motion.  Because you’re powering this bicycle, you’ll be more aware of how economically you’re driving it.  You’ll see improvements in your acceleration, braking, steering, and even coasting techniques.  All these same principles can be applied to driving a car, and s an added bonus, it’ll help you get/stay in shape!

Start today!

I happen to be a relatively active bicyclist (to/from work, and most of my shopping is done by bike), but mostly just because parking is expensive and the bike is a faster way to get to work than by car.  If it makes sense in your situation, start commuting!  I promise after a week you’ll start to see changes you could make to your driving habits that will save you wear, tear, gas, and frustration.  I read quite a few sites daily about bicycling, and recommend:

http://urbanvelo.org/

http://www.ibiketo.ca/blog

http://www.bikecommuters.com/

http://therecord.blogs.com/take_the_lane/ (warning, this one gets a little preachy sometimes)

They’re all great resources for anyone interested in bicycles.  Sometime soon I’ll write a bit about my bike and problems I’ve run into (like my fractured patella I won when my bike spit me out a couple weeks ago).

Let’s face it, most cars make terrible daily drivers if their factory specs are left alone.  Mushy suspension, bargain-quality tires, overcomplicated interiors, and extra weight all tend to ruin the daily driving experience.  Here’s a short list of the top 5 ways to completely ruin an otherwise serviceable Daily Driver.

1.  Donk it.

You’ve all seen them.  $10,000 24″ wheels on a $500 Cavalier that had to be raised to give enough wheelwell clearance to fit them.  Most modifications to cars emulate a performance enhancement (if only in appearance), and I don’t care enough to look into the history of the scraper, so I don’t know where this strange modification originated.  I’m not sure why scrapers are seen as a good thing in some cultures, but then again… some people juggle geese!

2.  Stretch it

Stretched tires have become something of a fad.  From what I can tell, they can be traced back to other countries who only allow certain tire widths so drivers install the widest tires they can on the widest wheels they can to flatten the contact patch as much as possible.  In that context, it makes sense to stretch your tires a small amount but it’s still a dangerous practice to get into.  There are a lot of reasons tire manufacturers have recommended wheel widths, and if anybody knows tires it’s the companies that spend millions on R&D to make the best products they can.  Have a little faith in their recommendations, they know what they’re talking about.  For more information on what size tires you should run, tire rack has excellent advice:

Tire Rack Tech

3.  Slam it

Cars are meant to have ground clearance.  I’m a strong supporter of slightly lower, more precisely tuned suspension but there is such a thing as taking it too far.  Unless you’re riding on an adjustable suspension, your car’s chassis should never be able to touch the ground (including bumps and potholes that it regularly sees on public roads).  Sure, it may look cool when it’s parked in the lot, but a daily driver is built to be driven not to be parked.

4.  Slap it

I’m more of an audiophile than most, but I always end up with a confused expression  when I hear car alarms start going off four blocks away and feel the bass.  I can only imagine what those 8 15″ subwoofers feel like inside the tinny little Scion xB, and it’s almost like imagining what Chinese Water Torture is like.  The more power your sound system is drawing, the more powerful your alternator needs to be to drive it, and the more power it draws from your engine.  That’s performance, mpg, and your hearing that you’re sending out, not thuggin’ beats.  Everyone outside the car just thinks you’re an idiot, and everyone inside the car wonders how long they’ll be able to go before they go deaf.

5. Gadgetize it

Your car is a mode of transportation.  It carries you from A to B, and sometimes carries cargo an (if you’re not American) even carries other people sometimes.  You don’t need a blender, a coffee maker, a wireless card, or any of the other gadgets that seem to be commonplace these days.  I even consider speakers and a stereo to be optional.  Keep it minimal and clean, you really only need a GPS and a sound system of some sort.

At the gas station last night I met an inquisitive new driver named Jill who was trying to decide why she should buy Premium gas.  I decided to help her out with her decision, since she was driving a fairly normal econobox car: an early 90′s Toyota Camry.

First, let me explain why we need different grades of gasoline.  Modern engines do 4 things to produce one explosion of power:

1. suck air and fuel into the chamber
2. compress the air and fuel inside the chamber
3. detonate the compressed air and fuel, using a spark from the spark plug
4. release exhaust gases

This happens thousands of times each minute while you’re driving, and is a fairly refined process.  The amount of fuel is automatically decided by the engine computer or carburettor and the driver directly controls how much air is let in.o  The compression ratio is a static amount of pressure a piston puts on the air and fuel, which allows it to burn more effectively.  More compression creates more power and less compression puts less strain on the engine.  Turbochargers can complicate this process by compressing the air before it enters the engine, allowing the static compression ratio of the engine to be lower while still producing reasonable amounts of power.

Why buy high octane?

Compressing air and fuel creates heat, and in some cases can cause the air and fuel to explode without the use of a spark.  That causes the delicate balance of the engine to go awry and for an instant the engine is fighting against itself for all its worth.  This is called ‘pinging‘ or ’knocking‘.

To control this, gasoline is given an octane rating, which indicates the combustion point of the particular mix of gasoline.  Regular gas is generally rated between 87–92 Octane, with Plus and Premium ranging up as high as 98 Octane.  Grassroots racers refer to this range as ’Pump Gas’, and many racers are proud of their ability to push the limits of common gasoline.  Ratings higher than 98 are considered race fuel and are usually illegal for the street.

Higher octane ratings only indicate a higher detonation point and resistance to pinging at high compression ratios (or high-powered turbochargers and superchargers).  While your owners manual can certainly give an indication of what grade fuel you should fill your tank with, it’s a safe bet that if you can hear pinging while driving (normally when you press down the throttle pedal hard while at low RPM’s) you should step up a grade.

Conclusion

For almost every car owner (excluding very high-end sports cars), higher octane fuel is a waste of money and offers NO benefit.

The d16z6 and d16y8 amount to the same gains.  Both are economical single-cam true-vtec engines.  Both are common in salvage yards, available in 1992–2000 Civic EX and Si’s, and some models of Del Sol.  Power output is roughly 130hp for each model, but a frankenstein of the two is reputed to work best.  The d16z6 has a better-flowing head and the d16y8 has a better-flowing intake manifold, so putting the two together on top of any d16 block will yield some power gains.

The most notable difference between the two is the onboard diagnostics.  The d16z6 is an obd1 engine, while the d16y8 is an obd2 engine.  Both can be converted to obd0 easily enough, or your wiring harness can be converted to obd1 (obd2 is not recommended for engine tuning other than specific applications). During the wiring harness conversion, the vtec solenoid should be wired into the ECU (automatic ECUs are particularly useful for this modification).

Availability of parts and relative ease of engine installation make both these engines excellent candidates for any CRX.

From time to time, I receive emails asking for help and I generally send an email back to the original sender and consider the matter closed.  Sometimes, these answers to these questions are general enough that others could benefit from seeing the answers, so I’m starting a Reader Mailbag section of the site.  Send in your questions and I’ll publish any questions that could help others.

My name is Eric, I’m Bam’s friend he told you about with the CRX? Anyway, here is the trouble I’m having.  I have a 91 CRX HF shell, that bam had previously swapped the guts into off of his old 91 Si.  When I got the car it had a pretty much dead motor, the car still ran, but it had no compression, so I swapped the motor.  The motor I ended up with is a D15b6 out of a 91 HF.  So the motors in there, and has the correct motor harness, PM8 ECU, connected to the Si’s dash wiring.  Here’s the catch, everything works, except I’m not getting spark?  I have fuel, I have compression, but not spark.  Plugs are new, I’ve tried swapping dizzy’s, ECU’s and checked connections, and can’t seem to find a problem? and am at a loss as to where to look next?  Any help or insight you could give me would be awesome.

Well Eric, there are a few causes that you can check for.  I would go about this by process of elimination.  Systematically eliminate problems in the chain, one component at a time.  Start from the end result and work back until you find the source of the problem.

1. Spark plugs — Inline spark testers are inexpensive and work well, but you can also test them the old-fashioned way.  Unscrew the plug from the engine and put the diode (the end that would go inside the engine) close to bare metal and crank the engine.  If a spark jumps from the diode to the bare metal, the plug is functioning correctly.
2. Spark plug wires — Test spark plug wires with a multimeter or a test light.  Plug one end into a power source and the other end into a test light.  If the light doesn’t turn on you can be relatively sure that the cable is bad and should be replaced.
3. Distributor — The most common malfunction with distributors is a worn cap and rotor, which will prevent spark plugs from receiving electricity that would allow it to create a spark.  It’s also a good idea to make sure your distributor timing is correct (check with your manual) using a timing light (available at most local automotive stores).
4. Ignition Coil — An ignition coil is essentially a capacitor which stores electricity and powers the spark plugs (the distributor just controls when the coil and a spark plug are connected, the coil is the power source).  Most Hondas (including your CRX) use an internal coil, meaning the coil and distributor are one unit.  Since you’ve replaced the distributor (and I’m assuming you tested it to make sure it worked in another car, or bought a remanufactured one that had been tested), you should be in the clear on both the coil and distributor.
5. Fuses — Check the fuse box under the dash, on the driver’s side.  There should be a fuse labeled ‘ignition’.  Is it blown?
6. Relays — Relays are a great idea to put in cars, until you have to start troubleshooting.  The main relay on obd0 cars are notorious for dying on all Hondas, and are generally in terrible locations (close to the fuse box under the driver’s side dash).  There’s a good writeup on tegger.com that discusses them.
7. ECU — Since you’ve already swapped the ECU for another pm8, this is probably not the problem.  Double-check to see if the ECU is throwing any codes (a blinking light on the ECU itself is a good indication).
8. Wiring — If you check everything above, the wiring harness or connectors are most likely at fault.  Since so many CRX owners upgrade to obd1 (or even obd2 in some cases) wiring harnesses are inexpensive online and you should be able to get a replacement without breaking the bank.

I definitely want to know how this turns out, so be sure to update me directly or on the forum (link below).  I hope to hear that this is sorted out and your HF is purring like a kitten soon!

Late last night I finished rewiring the injectors I bought from odistiger, replacing the cracked old connectors with fresh new ones, soldering them in, and heat-shrinking the connections.  I also took a closer look at the wiring harness, and have to wonder what the hell Nissan was thinking.  There are butt-connected wires for the + side of all the injectors, and it’s just a messy hack-job that’s a sorry excuse for wiring under the factory heatshrink.  I’m going to have to clean it up a bit, but there’s really only so much that I can actually fix in there.  The wiring harness is simple and straightforward though, so I may just rewire it from scratch using the stock end connectors.

I excitedly started attaching my injectors to the intake manifold, hopeful that I’d get to hear the engine turn on its own power.  Each injector has a mounting adapter and two screws that hold it onto the intake manifold, and ensure a tight connection.  You can clearly see properly mounted fuel injectors on my intake manifold in the picture to the right.  On my intake manifold, one of the screws had been torn out of the intake manifold at some point, ripping the threads out with it.  I filled the hole with jbweld and will re-tap it as soon as I get my hands on a tap kit.  Until then, I only have 5 injectors and can’t hear the engine fire.

I’ll be sure to get some more pictures of the final setup once the jbweld hardens.

Hybrids get a lot of press.

They’re touted as being incredibly fuel-efficient, getting between 30–45mpg in some cases. Wow. What most of these green fanatics don’t realize is that they’re hurting the environment more than the creepy hippie in his VW bug.

It takes roughly 50,000 miles of fuel savings to recover the cost of manufacturing for the average hybrid car, and that number comes closer to 80,000 for hybrid SUVs (they require more materials to manufacture and weigh more, decreasing fuel economy). That’s a huge carbon debt to pay off, especially if the car ends up in an accident or has mechanical failure resulting in its salvage. Older cars have already paid their carbon debts, so we should do everything we can to maximize their life after the debt is paid off. Every time a new car is purchased, an old (often working) car is crushed.

Consider the financial impact, as well. When buying a new car, everything on it is brand new. Once those new components begin to break, they are going to be the most expensive components on the market, because they aren’t yet in common circulation. Parts (and mechanic fees) for older cars are lower, and because they’re generally simpler designs, they are less likely to fail when given regular maintenance.

On top of that, the initial cost is lower. The KBB value of a 1991 Honda CRX Hf with 100,000 miles on it in EXCELLENT condition is USD$2300. Assuming you want a freshly rebuilt motor ($1,000) professionally installed ($750), along with new tires ($400) and suspension ($1500, installed), and you wanted to freshen it up with a professional paint job ($2,500), your total would still be $8,450, compared to the Toyota Camry Hybrid’s $23,474. You’re saving the environment and money in the bank! If the 2-seater CRX just isn’t big enough, you could look into a 1996 Honda Accord 4-door, which changes the starting price to  $4,585 and the ending price to $10,735. That’s still half off, and far less to pay in maintenance!

Finally, you’ll save more fuel by going with many older cars. The Honda CRX Hf, for example, averages 43mpg, according to fueleconomy.gov. The new Toyota Camry hybrid averages 34, according to the same site. Overall, unless you’ve already fallen in love with the idea of a new car and a payment plan, a used vehicle is a better way to go for your wallet, the environment, and your peace of mind (you have a recipt and warranty on all work performed by a local shop).

For more information, feel free to visit:

Wired Blog

CRX Photo courtesy of Wiros, VW Bus Photo courtesy of zaphodsotherhead.

After the jump:

I’ve noticed that a certain Spanish enthusiast site has taken notice of this post!

Apparently, this particular CRX has gone internationally cool!

People often talk about what will happen to the Earth when we use up all the fossil fuels, and where we’ll all be in 10 years. I’m more concerned with my project cars. Project cars aren’t about to switch over to electric power or hydrogen, all our engineering has gone into one particular gasoline engine or another. What then, is your plan for increased regulations or unavailability of gasoline?

Courtesy of Freefoto

Personally, I seek other projects. A bicycle is just as much fun to work on, and normally less expensive (there are exceptions to this rule), but not as fast. It also doesn’t allow me to be quite as lazy. What are your thoughts on future transportation? Will you continue the hobby after you can’t afford fuel?

Lately I’ve been reading a lot about EGR systems, how they work, and how they’ve changed over the years.  Generally speaking, it’s a controvertial subject and has generated quite a bit of debate over the years.

What is EGR?

EGR stands for Exhaust Gas Recirculation, and is a system designed to reduce combustion temperatures under moderate load (anything but idle and full throttle).  In a nutshell, an EGR system takes exhaust gas and recirculates it through the engine in an effort to reduce NOx gases.

A little history on EGR systems:

In the 1970′s, emissions laws began to pass and a new age dubbed the “Malaise Era” began.  Emissions control was an imprecise science, akin to a religion.  At first, performance suffered (considerably) due to the crude systems implemented and some misunderstandings about what the chemical results would be.  As vacuum sensors gave way to electronic control modules, emissions controls became more strict and engine performance blossomed.  Since the early 1990′s, EGR systems often contribute power gains, mpg gains, engine longevity, and decreased harmful exhaust gases.  Great strides are being made even now with engine management systems, and I whole-heartedly applaud the efforts of modern car manufacturers toward these goals.

Why remove it?

The only real reason to remove an EGR system is to clean up an engine bay, or to replace it when it doesn’t work.  They’re a good idea.*

Why keep it?

Although you may be inclined to lump this into the “Emissions equipment is bad for performance so I don’t want it” category, resist the urge.  There are a gaggle of reasons to keep your EGR system maintained and installed on almost any engine.

1. It lowers combustion temperatures, increasing the longevity of your block, rings, and pistons.
2. It reduces harmful NOx gases.
3. It helps warm up your engine more quickly (in some situations).
4. It reduces the chance of pinging (preignition, where combustion happens too soon) by lowering combustion temperatures.
5. It allows for more aggressive spark advance.
6. Most ECU modules require it.
7. It’s legally required for smog tests.

What else can I read?

Excellent article by Henry Guzman (a little dated, but holds true):  http://www.asashop.org/autoinc/nov97/gas.htm

Mandatory wikipedia article:  http://en.wikipedia.org/wiki/Exhaust_gas_recirculation

Howstuffworks article:  http://auto.howstuffworks.com/fuel-efficiency/hybrid-technology/exhaust-heat-recovery-recirculation2.htm

Last but not least, a hard-to-find article often referenced by Ford gurus to their young apprentices:  http://www.fordscorpio.co.uk/egr.htm

1. The valve was sticky and I couldn’t free it.
2. I live in one of the most consistent climates in the United States.
3. The air pump was frozen.
4. I don’t have (or want) the belt to the air pump.
5. The stock EGR system on the l24 is an inefficient, inconsistent vacuum system with an air pump.
6. The engine is easier to tune without EGR in the mix.