GASOLINE ENGINE PERFORMANCE
by Jim Allen

photography courtesy of the manufacturers

When new stuff comes in, we want you to know about it. Here are a few of the gas engine performance goodies that have come out for ’04, accompanied by the Gearhead’s earthy commentary.

Breathing Deep
In the Army, when a drill sergeant made me run a quarter mile with a pack rifle and helmet, in a gas mask, for facing left when I should have faced right, I learned the true meaning of restricted breathing. The OEMs sometime saddle their rigs with something akin to a gas mask. There is power to be had with improvements to the intake system of just about every rig. How much or little you gain is proportional to how well or badly the OEMs did their jobs.
There are many benefits to a free breathing engine. In some cases, the “generic” calibrations the OEMs use make engines run a little rich, so freeing up their breathing tends to lean them out a bit for a beneficial effect. Pumping losses are also reduced. It costs horsepower to pull air in and pump exhaust out. The less restriction at either end, the less horsepower is lost.

Edelbrock Performer RPM Heads, AMC V8
The cylinder head controls much of an engine’s breathing process. A good cylinder head has the same effect on breathing as a more radical camshaft grind might, but without many of the bad side effects, such as a rough idle. Edelbrock Performer heads for the AMC V8 are made of aluminum and can be purchased bare or completely assembled. They are designed for the standard AMC “big valve” (2.02-inch intake and 1.60-inch exhaust valve) configuration. With stock type pistons in a 401ci engine, this head will offer a 9.5:1 compression ratio from it’s 54cc combustion chamber. The intake and exhaust ports and runners are CNC machined and profiled for optimum flow. These heads will bolt directly onto all ’70 and later AMC/Jeep V8s, and onto pre- ’70 AMC engines with some available adaptation products. For more tech info contact contact Edelbrock at 800-416-8628 or check out www.edelbrock.com.

Airaid Modular Intake Tube (MIT)
The original equipment ducts that connect the air filter housing to the front of a truck or its air filter housing to its throttle body are often restrictive, even for a stock engine. They grow even more inadequate when you’ve increased the engine’s airflow needs with other mods. There are a few cheap and easy upper-end ponies to be had by replacing these stock restrictive ducts with Airaid’s large diameter MIT. Shown is the ’04 Ford F-150 tube, which increases airflow from about 545 stock to 590 cfm (Cubic Feet per Minute airflow). You can pick up another 20 cfm by using Airaid’s Premium filter. For more tech info contact contact Airaid at 800-498-6951 or check out www.airaid.com.

Airaid Premium Filter
There are a few extra ponies to be found by replacing your OE air filter element with a free-breathing Airaid Premium element, but this filter’s benefits also extend into other areas, such as a lifetime of service. It gets dirty, you clean it with soap and water, air dry and re-oil it with Airaid’s special oil, and you’re ready to go again. Shown is Airaid’s new ’04 F-150 5.4L Triton application, but many more replacement and universal filters are offered. For more tech info contact Airaid at 800-498-6951or check out www.airaid.com.

Granatelli Mass Airflow Sensor, 2004 GM Trucks
Not all fuel-injected rigs use a mass air sensor (MAS), but many GM vehicles do. A MAS device reads the amount of air entering the engine so that the computer can adjust the air/fuel ratio and timing advance to match. The problem is that a stock mass airflow sensor may limit, or restrict, the amount of air an engine can inhale. A stock MAS may be fine in stock use, but when airflow needs are increased by other modifications, the OE unit may become a chokepoint. In the case of this Granatelli unit, it will flow up to 47 percent more air than the stock unit and that alone is enough to give an 18 hp boost on larger GM V8s. This gain shows up above 2500 rpm. More importantly, it provides the breathing flexibility required if other modifications are planned. For more tech info contact contact Granatelli Motor Sports at 805-486-6644 or check out www.granatellimotorsports.com.

Airaid Intake System,
’04 Ford F-150 5.4L
If you combine an oversized intake tube with a free-breathing filter into an open housing and duct it to cool air, you’re bound to see some improvement. Airaid’s dyno chart for the new F-150 shows a 20hp and 46 lbs-ft increase, and that’s at a modest 2500 rpm. For more tech info contact contact Airaid at 800-498-6951 or check outwww.airaid.com.

K&N Fuel Injection Performance Kit (FIPK), ’91-95 Jeep Wrangler YJ
Was there ever a time when K&N wasn’t offering performance air filtration? The granddaddy of the high performance air filter industry adds a new FIPK to their already impressive list of applications in the form of a unit for the ’91-95 Jeep Wrangler. You may recognize this kit as being the old AirCharger kit renamed, but the difference is that this one is CARB certified, making it 100 percent, 50-states emissions legal. Between an oversized air tube, the elimination of the restrictive Jeep filter housing, and the addition of K&N’s famous free-flow pleated filter, power increases of up to 10 percent are possible. The FIPK application guide is huge, as is K&N’s replacement air filter line. For more tech info contact contact K&N at 800-858-3333 or check out www.knfilters.com.

Exhaustive Research
Breathing out is just as important as breathing in. Freeing up exhaust flow is almost always worth a few horsepower, if not a double handful. The mods start up front with headers. They come various ways, including shorty headers, long-tube four-into-one headers and tri-Y headers. Each has advantages.

Shorty headers are good when space is a problem and when easy installation is a requirement. Most shorty headers are also emissions legal. Shortys provide an increase in power by smoothing the exhaust flow via mandrill bent tubing and by providing a better match of the header outlets to the exhaust ports.

Long-tube, four-into one headers offer an even larger performance gain, but usually require greatly increased installation effort, especially on the newest rigs. Not all are emissions legal on all rigs. Some may be incompatible with EFI systems in stock form and require some custom tuning.

Tri-Y headers offer improvements in low end and midrange power over four-into-one headers, but can be even more difficult to fit. Cat back exhaust systems offer power increases that run from moderate to stupendous, according to how bad or good the OE system happens to be. The improvements with aftermarket systems usually come from mandrill bent tubes, which do not reduce the diameter of the pipe when being bent, and from free flow mufflers that are selected according to application.

Pipe size is important. Sometimes larger is better, but many times it isn’t. Much depends on the power output and rpm range of the engine. Basically, if larger pipes than needed are installed, they may cost low-end power due to reduced scavenging at lower rpms. If smaller pipes than needed are installed, they will cause excessive backpressure and limit upper end power. Choose a larger system if you are building a big displacement, or high-revving fire breather, but stick to smaller systems if your rig is only mildly built. Remember that mandrill bent systems offer the best performance. Even given the same original pipe diameter, a mandrill bent system will far outflow a standard system and offer an increase in performance. Usually, even the smaller diameter performance systems feature larger diameter pipes than the stock system.

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Gibson Extreme Dual Cat Back Exhaust,
’04 Dodge 1500 Hemi
Add as much as 20 hp to your ‘04 Hemi with Gibson’s dual outlet cat back exhaust system. The twin pipes use gnarly 3.5-inch outlets and the system comes in an aluminized coating or stainless steel. It’s 50 states emissions legal and does not require relocation of the spare tire. For more tech info contact Gibson at 800-528-3044 or check out www.gibsonperformance.com.

Gibson Split Rear Cat Back Exhaust,
’04 Nissan Titan
There’s just something about dual exhaust tips exiting out the back of a truck that spells out S-P-E-E-D. It doesn’t hurt if the truck also can put some of that characteristic into action. No worries here! Dyno tests show a 14hp and 20 lbs-ft increase with Gibson’s new Nissan Titan system. Dual 2-1/2 inch pipes exit from a large capacity muffler and run to the rear of the truck, ending with 3.5-inch polished tips. The system can be ordered in an aluminized, stainless steel or a ceramic coating. For more tech info contact Gibson at 800-528-3044 or check out www.gibsonperformance.com.

Banks Torque Tube, Jeep 4.0L
The Jeep 4.0L exhaust manifolds are notorious for cracking. On top of that, they are well known for not aligning well with the exhaust ports and that costs power. Gale Banks Engineering has the cure for both problems in the form of the Torque Tube; a mandrill bent shorty system made of 409 heavy-duty stainless steel that features seamless Y-junctions for optimal flow. You can attach the Torque Tube to your original downpipe, or go for Bank’s optional 2.5 inch, mandrill bent downpipe to further enhance performance. For more tech info contact contact Gale Banks Engineering at 800-601-8072 or check out www.bankspower.com.

Edelbrock Shorty Headers, Jeep/AMC V8s While it’s been possible to find headers to fit a few applications involving the AMC 304, 360 and 401ci V8 engines, these shorty headers from Edelbrock will fit them all, from ’72-81 Jeep CJs, ’72-91 Wagoneers, and fullsized pickups and even ‘70-79 AMC cars. These headers are designed to fit the ’70 and up heads with the dogleg ports. They come in black painted, nickel plated or a ceramic coated finish. These units are 50 states emissions legal. For more tech info contact Edelbrock at 800-416-8628 or check out www.edelbrock.com.

Gibson Ceramic Headers
Gibson’s ceramic headers will offer power increases that will last a lifetime. Dyno tests show an injected 5.7L Chevy delivering an extra 25 hp at 2500 rpm and 42 lbs-ft of torque with Gibson headers installed. This shows what mandrill bent tubing will do! Other engines deliver similar results. One of the traditional downsides of headers has been keeping them nice looking over the long term. Not any more. Gibson’s new ceramic coating shrugs off heat like a duck shrugs off water. It should look the same after 20 years of use as it does when new. Ceramic coated headers also tend to radiate a little less heat which provides for a cooler engine compartment. For more tech info contact Gibson at 800-528-3044 or check out www.gibsonperformance.com.

Fuel Injection Full Monty
To get the “Full Monty” from your fuel injection, changes in programming are needed. Altering the injector opening times (pulse width),ignition timing and getting other parameters to match all become vital elements in the fuel injection performance equation. In speaking with chip industry professionals, I learned that the OE manufacturers give them lots of room for improvement, so the gains available from a chip change or reprogramming can be incredible, whether your engine is stock or modified.

In some cases, you must replace the chip. In other cases, you can use a programmer. In a few cases, you can do either/or. The programmers feature the most flexibility, because they offer program choices not available with a chip. These programs range from mild to wild. The programmers usually allow you to store the OE program and reinstall it later if needed. They may also allow you to change transmission shift points and firmness, raise rev limits or vehicle top speed limits. They will often allow you to compensate for changes in gear ratio and/or tire size and thus correct your speedometer.

Most chips or performance reprogrammers are compatible with basic, commonly seen modifications. Exhaust system or intake improvements are usually compatible with a chip change or reprogramming, but other mods may not be. Cam changes, head work and some radical exhaust improvements can cause compatibility problems. If you plan mods beyond simple air filter housing changes, headers and a cat back exhaust, check with the chip or reprogrammer manufacturer first to make sure the changes you desire are within the limits of their product. Some manufacturers offer custom tuning options when you step outside normal parameters.

JBA Cat4ward headers,
GM 4.8, 5.3 and 6.0L V8
JBA’s Cat4ward shorty headers are not short on value. JBA claims a 10hp and 20 lbs-ft boost with these 14 gauge mandrill bent tubes. They fit the most common trio of engines found in late model GM trucks and they are 50 states emissions legal. They come standard in a nickel plate finish, but a ceramic coating is optional. For more tech info contact JBA at 800-830-3377 or check out www.jbaheaders.com.

Edelbrock Headers,
’03 Dodge Hemi Truck
Even a Hemi can use some help. Edelbrock comes to the rescue with a header and downpipe kit to fit the 5.7L Dodge Hemi. They come in a black painted, nickel plated or ceramic coated finish. 50 states emissions legal. For more tech info contact Edelbrock at 800-416-8628 or check out www.edelbrock.com.

Jet GM Performance Programmer
Depending on the type of EFI system used, your performance upgrade may be via a chip change or with a programmer. In the case of many late model GM rigs, a programmer is used. With the help of easy to follow instructions, you can improve air/fuel ratios, spark advance, transmission shift points and shift firmness — all towards the goal of increasing power and torque. You can also accommodate changes in tire size and gear ratios to get your speedo reading correctly again. The Jet GM Performance programmer allows you to dial in your performance according to fuel grade, with the most impressive results coming from tuning for, and using, the highest grade premium fuel available. Factory preset rev limits and top speed can be raised, plus you can clear trouble codes. You can also store the vehicle’s original program in case you have to reload it. This unit will interface with most ’98-04 GM trucks. Work is ongoing for programmers designed for other makes. For more tech info contact Jet Performance at 714-848-5515 or check out www.jetchip.com.

JBA Cat4ward Headers,
’97-03 F-150 4.2L V6
There’s no need for owners of fullsized trucks with V6 engines to feel like second class performance citizens. JBA’s 4.2L shorty headers will give your six-banger a boost you’ll feel in the seat of your pants. These 50 states emissions legal headers are built from 14-gauge mandrill bent tubing and bolt up in place of the restrictive OE manifolds. For more tech info ontact JBA at 800-830-3377 or check out www.jbaheaders.com.

Banks Monster Exhaust, Nissan Titan and Armada
No doubt about it, the ’04 Nissan Titan is hotter than chilis packed south of the border, as the rapidly growing list of aftermarket products for it proves. Gale Banks Engineering jumps aboard with a cat-back, 3-inch exhaust system that ensures the Nissan’s 5.6L V8 avoids constipation. The stainless system reduces backpressure by 92 percent and offers a throaty but civilized tone. For more tech info contact contact Gale Banks Engineering at 800-601-8072 or check out www.bankspower.com.

Edelbrock Performer RPM Pro-Flo EFI Systems, Jeep/AMC V8
Many a Jeep/AMC V8 owner has grimaced in frustration by the lack of aftermarket performance products for these engines. Dry your tears boys and girls, here’s a major entry in that market. The Pro Flow EFI system is a port injection conversion designed to fit the big-valve AMC engines (343, 360, 390 and 401ci). The Pro-Flow system is a simple speed/density system, meaning its computer reads engine speed and manifold pressure to make the basic fuel calibration calculations. It also controls spark advance. The system features a high flow, four throat throttle body (1000 cfm capacity) and the kit contains everything needed to install it... including a new distributor and a Calibration Module. The Calibration Module allows you to fine-tune the system to perfection. Edelbrock supplies a chip that is tuned to the particular camshaft you are using and you do the rest with the Calibration Module. No dyno tests are offered for the AMC engines, but a low compression 350ci Chevy gained 126 hp and 120 lbs-ft on 87 octane gas. More importantly, it had a broad, flat torque curve that offered the same torque at 5000 rpms as it did at 2000. For off-road use only. For more tech info contact Edelbrock at 800-416-8628 or check out www.edelbrock.com.

Superchips Max Microchip Tuner for ’98-03 Dodge Ram Trucks
Superchips Tri-Tune Max Microtuner offers three options for 3.9L V6, 5.2L and 5.9L V8s. Two of these options require the use of 91-93 octane premium fuel. The “87 Octane” mode provides a minimal performance increase, but allows for tuning transmission shifts and the option of recalibrating for tire diameter or gear ratio changes. For non-towing, high performance, the fuel rate and timing curves are altered to gain a very usable 18hp at 4100rpm and 29.5 lbs ft of torque at 3500 rpms on a 5.9L engine. More impressively, the torque curve shows a big jump at 2200rpm, gaining 59.4 lbs-ft. from stock at that level and a very nice plateau from 2300 to 3500. The Towing Performance mode doesn’t offer as much of an increase because it reduces the timing a bit to avoid pinging under load. For more tech info contact Superchips at 407-260-0838 or check out www.superchips.com.

Jet Performance Powr-Flo Thermostat
What does a thermostat have to do with performance fuel injection improvements? Stock t-stats run the engine at a pretty high temp, generally around 195 degrees or more. Aside from just running hotter and leaving less cooling reserve, the hotter the engine, the more lean the engine management system will run the engine. By installing a lower temp thermostat, the engine runs cooler overall, but a little richer too because the EFI system, fooled by the lower temp, richens the mixture. . More importantly, it may also allow a bit more timing advance. Both of these situations are worth a tiny bit of power on some engines. This mod is most useful as a sideline tuning element alongside a chip change or with reprogramming. Shown is a Jet Performance Powr-Flo 180 degree unit for ’99-03 GM trucks, which is designed to be used with Jet’s programmer or chip. For more tech info contact Jet Performance at 714-848-5515 or check out www.jetchip.com.

Jet Performance Module, ’03-04 Dodge Hemi Trucks & SUVs
If 330 hp isn’t enough, add 10 percent to your 5.7L Hemi V8 by simply plugging Jet’s Performance Module into the system. This module piggybacks onto the original system, optimizing the air/fuel ratio and timing for a very noticeable performance boost. Installation is simple and fast. For more tech info contact Jet Performanceat 714-848-5515 or check out www.jetchip.com.

Superchargers Blow!
When you buy a supercharger kit, it’s kinda like buying horsepower in bulk at Sam’s Club. You may have to buy a bunch and the ticket price is high, but when you measure the hp/dollar ratio, it’s pretty cheap horsepower.

One of the best characteristics about a well designed supercharged engine is that in day to day use, it will seem much like a stock engine in terms of startup, smoothness, noise and fuel economy. The differences will come when that right pedal gets pushed down. In general terms, a system with 6-7 psi boost will offer a 40-50 percent boost in power and a 30-40 percent boost in torque. A hefty portion of that extra punch is down low and a mid range improvement is especially noticeable.

What does a supercharger do? A naturally aspirated engine uses only natural air pressure (14.7 psi) to fill its cylinders and will average about 85 percent volumetric efficiency at sea level. At high altitude that number drops. That means the cylinders only get about 85 percent of the air and fuel mix they can actually hold. Intake and exhaust restrictions contribute most to these losses. A supercharger puts at least 100, and up to 150 percent, of the air/fuel mix into the cylinder by forcing it in under pressure; hence the term “Forced Induction.” More air and fuel in the right mix makes a bigger “explosion”, and the result is more power- lots more power.

Paxton ’01-02 4.7L Dodge Durango and Ram Supercharger
Equipped with Paxton’s Novi 1000 centrifugal supercharger, this kit pumps out 6-7 pounds of boost. That’s enough to give the Mopar 4.7L V8 a boost in power from 235 to 322 hp and a torque gain from 296 lbs-ft to 363 lbs-ft. Fuel system upgrades come with the kit, including a high flow fuel pump, auxiliary fuel injectors and an electronic fuel and timing control unit. For more tech info contact Paxton at 805-604-1336.

Vortech ’99-01 6.8L V-10 Ford Super Duty Supercharger
Vortech offers two versions of this kit, one with an aftercooler and one without. What’s an aftercooler? Also known as an “intercooler”, it’s an air cooling device. When air is compressed, it heats up. The more it’s compressed, the more heat is produced, and, because hot air contains less oxygen, you loose some of the gain you got from increasing the air volume in the first place. Vortech’s dual pass, air-to-water aftercooler drops the air temp and gets back that extra power. The aftercooled version is the better choice for working trucks because it keeps air temps. lower on a hard pull. It’s also good for quite a bit more power. Both systems give 8-9 psi boost, but the aftercooled system makes 464hp vs 425hp for the standard system. That works out to 50 and 37 percent increases over stock, respectively. Stock torque is a respectable 425. The Vortech non-aftercooled kit boosts it to 515 lbs-ft and the aftercooled set-up bumps it up to a whopping 542 lbs-ft. For more tech info contact Vortech at 805-247-0226 or check out www.vortecsuperchargers.com.

Hypertech Pumps Up 2004 GM Trucks, SUVS and Hummers
Hypertech has two new Power Programmers™ for 2004 GM trucks, SUVs and Hummer H2 models. These 2 part #’s cover GM vehicles with 6.6-liter Duramax diesel engines, and all 2004 GM vehicles powered by 4.8/5.3/6.0 and 8.1-liter V8 gasoline engines. Road-tested calibrations in the Power Programmer produce gains of up to 92 horsepower and 151 ft./lbs. of torque over stock tuning (based on application). The Power Programmer also gives off-road adventurers the power to reprogram onboard computers to match their equipment and driving styles. They can adjust engine rpm limiter, top speed limiter, automatic transmission shift points and firmness, part-throttle shifting, and speedometer/odometer readings with up to 38” tall tires.

The Power Programmer for 2004 GM trucks and SUVs with gasoline engines features Hypertech’s “Dual Fuel” calibrations for both regular and premium gas. Power Tuning for regular gas is more powerful than stock tuning with either regular or premium fuel, providing increased power without the high cost of premium gas. Duramax diesel owners can choose from three different power levels. The Power Programmer also respects the environment; it’s legal for use in all 50 states under CARB Executive Orders D-260-11 and D-260-12. Stock tuning can be restored at any time. For more tech info contact 901-382-8888 or check out www.hypertech.com.

Paxton ’03 Dodge Hemi Truck Supercharger
If saying “Hemi” just isn’t enough for you, Paxton offers you the chance to grunt “Hemmmiiiiiiiii” as you are pressed back breathlessly into the seat from catapult-like acceleration. This kit comes with a Novi 1200 centrifugal supercharger and an aftercooler. Tests are still underway at this writing, but Paxton estimates this kit will give a 45 percent boost to the Hemi’s already impressive 330hp output. Yeeha! For more tech info contact Paxton at 805-604-1336.

Vortech 4.8, 5.3 and 6.0L GM Supercharger
If you drive a ’99-02 GM truck with a 4.8L, 5.3L or 6.0L V8, Vortech’s new supercharger kit offers an easy 40 percent increase in power and 30 percent increase in torque on the 5.3L. The other engines get a similar increase. The V-2 supercharger pumps out 6.5-7.5 psi maximum boost and is belt driven from the engine’s crankshaft. Everything you need comes in this complete system, including fuel system upgrades. It installs in 8-12 hours. It’s also 50 states smog legal! For more tech info contact Vortech at 805-247-0226 or check out www.vortecsuperchargers.com.