Questions and Answers

Dyno Tuning

more info

Common Problems with Crossfire 0nly Injection Systems

Will the X-Ram work on an 82 Crossfire Corvette?
Will the X-Ram work on a 305-Z28/TA?

The Crossfire intake was used on 3 vehicles, the Corvette, Camaro Z-28, Firebird T/A and a few select trucks, all between the years of 1982 and 1984. There was no difference between any Crossfire's intake base manifold, whether it being a 305-Z-28 or T/A, or the 82 to 84-350 Corvette, or for that matter, even the truck version Crossfire. They were all the same Crossfire's and throttle bodies. The difference came in the truck versions top plate that didn't require throttle body synchronization. Other then that, they all flowed the same 475 CFM.

How much more horsepower can be expected?

This is really a tough question. We have tested over 40 stock Crossfire's, including 82’s and 84’s. All Corvette's tested had multiple previous owners and were in various levels of condition.

Chevrolet quoted 200 net hp for the 82 Corvette and 205 net for the 84 Crossfire Corvette's. The only real deference between the two was the exhaust system and a slight weight difference. The computer chips were even the same.

Note: Net Horsepower is that figured by the engineers being created and produced at the output of the engine with all accessories on the engine running. This is not the true Horsepower being delivered to the ground by the rear wheels. Torque Converters, Transmissions, Drive shafts, Axles, Jack Shafts (independent axels), third members (rear ends), Universal joints, Tires and even the weight of the vehicle all require hp to move, and what is left over is the True Horsepower that reaches the ground.

Figuring a 20% drive train loss in horse power, all 350 Crossfire's tested should have produced 160 to 165 hp at the rear wheels. None did, and only a few came close.

All the Crossfire Corvettes tested with horsepower ranging between 118 to 146, were totally stock. A few needed a good tune-up with 118. Most averaged between 122 to 128. A few with free flow exhaust, under drive pulleys, 160 degree thermostat & fan switch, K&N air filter, new or rebuilt distributor with 9 mm wires and AC platinum plugs, a stage 2 performance chip and Mobil 1, 5W30 oil produced a range of 133 to 146.

One Crossfire which had been extrusion honed was also tested. It produced 166 hp with the same modifications as the above 146 hp Corvette’s. It basically showed a 20 hp increase over a well tuned engine. The X-Ram with the addition of a 85 Tuned Port Fuel Pump was also tested on each one of these cars and produced and average of 171 to 217 horsepower. That was an increase of 53 to 71 horsepower at the rear wheels.

A few of the tested Corvette’s received a set of 1.6:1 full roller rockers. Below is a Dynojet performance test of a stock 350 with all of the pre mentioned modifications installed.

How big of a cam can be installed?

Cams are a special science within themselves. When choosing a cam some careful thought must be taken. Only a cam that has been ground to work with a computers requirements can be used. Most of the leading manufacturers of cams make computer cams, both hydraulic flat tappet and roller lifter designs.

Cams that have a medium to rough idle will cause the manifold vacuum to bounce and thus causes the MAP sensor to transmit erratic readings to the computer. This causes the computer to flag engine problems.

Solid Lifter Cams (roller or flat tappet) make the best hp, but the rocker arm gap that has to adjusted in to them makes a metal to metal pinging or ringing sound that is picked by the knock sensor and registered as a fuel problem in the computer. This also causes the computer to flag engine problems.

For these reasons, we suggest that the rockers only be changed with a set of 1.6:1 Full Roller Rockers. These rockers will produce a little more lift and duration in the valves, increase the fuel and air charge to the cylinders. They will also greatly increase the low end torque and produce 23 to 28 hp gains.

What is the difference between the low cost and high cost roller rockers?

Roller rockers are designed to handle a large range of cam shafts and spring designs. High cost rockers are designed to handle very high spring pressures and high RPM ranges. High spring pressures are required with high lift cams to get the valves closed when the high rpm range (6500 and up) are reached.

Because the Crossfire is a computer-controlled engine, it uses only a moderate lift cam and spring pressure. Also because of the computers rev limiter of 5800 and a red line of 5500 rpm’s, the low cost rockers work very well.

Will I loose any low-end torque?

Yes low-end torque is slightly less then that of the Crossfire. This is because of the full flow characteristics of the base manifold. It is like placing a 180 degree hi-riser against a 360 Degree hi-riser. The 180 has better response out of the hole but the 360 has better mid range.

But there is an answer to the question of “How do we get the best of both?” The answer was revealed by GM in 86 when they introduced the first of the roller cam engines. Roller Cams have an extreme loss of low-end manifold pressure, but by installing a set of Roller Rockers the pressure was regained and then some.

The same holds true with the X-Ram, a set roller tipped rockers of stock ratios 1.5:1 regained all the torque loss and added an additional 6 hp to the rear wheels. Full Roller Rockers with 1.6:1 ratio, on the other hand, developed a whopping 26 pounds of extra torque and 29.3 HP over the stock rockers.

What kind of a difference will it make?

Every engine is different and in various levels of condition, but the average show 1 to 1.5 seconds quicker in the quarter mile and 8 to 12 mph faster.

How much CFM will it handle?

The total flow of the X-Ram is 250 cfm per runner with a total of 1440 cfm on a flow bench at sea level.

Is it California emission legal?

We do have an EGR Adaptor kit for the X-Ram now to make it legal for California Smog testing. We do not carry a Calif. exempt number however.

Are there any guarantees?

The X-Ram carries a 30-day Satisfaction Guarantee that we extended to 45 days to offset the shipping time. If you are unsatisfied for any reason, simply ship the X-Ram and any options back to us in the 45 day period, and we will refund all money including shipping charges. Try and get any other performance part manufacturer to do that.

How much dose it cost?

The cost of the X-Ram is $385 and has not gone up in 4 years. But unfortunately things change. Holley has increased their cost alone 3 times over the last 2 years. Manufacturing cost has increased from $45.00 per hour to $75.00 per hour from when we started, Even packing material has increased, not to mention advertising cost.

As of January 2, 2004, the cost of the X-Ram will increase to $425.00 per unit.