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What Makes the X-Ram Different Everything is different about the X-Ram except for the placement of the throttle bodies and the design configuration of the top plates that emulate the design of the Crossfire. The X-Ram had three requirements in the design stage, they were: 1)Performance – maximum air flow and fuel delivery while incorporating a ram effect to produce boost pressures exiting through the head and valves. 2) Make it fit under the hood of the 84, all others will fall in place. 3) It must look like a Crossfire after it is installed.
The challenge wasn’t easy but the end results were better then we had planned. The base manifold is a race proven 360-degree low profile street ram. Originally designed by WEIAND and now built by Holley. The base unit is better then ever with smoother runners and more even pressure delivery of the fuel and air mixture.
The Crossfire could have been designed with full size runners by allowing the cast of the bottom at the correct depth and then adding the water transfer under that. But that wasn't the reason for the way it was designed. The real reason was that the Tuned Port was to be the new performance design, and without the port restriction, the Crossfire would be capable of producing much better horsepower figures. So the Crossfire received the axe, and that axe fell hard. The restrictions became even greater and airflow was cut by over 40%. And if that wasn’t enough, the cast was designed so that the runners could not be enlarged without braking through the cast walls.
The Crossfire was un-modifiable!
The new manifold received extensive modifications to lower its overall height, and open the intake port to allow unrestricted flow from the Crossfire configured top plenum. The base manifold can flow an unrestricted charge of well over 1000 CFM per engine revolution. The top plenum and main intake opening on the base can flow more then 1400 cfm. This leaves the world of performance modifications wide open. |
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When comparing the X-Ram exit ports (top) to the Crossfire exit ports (bottom) it is clear to see the major difference between the two manifolds.
But taking a even closer look at the exit port and it can be seen that the X-Ram is very smooth and each port is 40% larger, and the same exact size.
Looking at the ports on the Crossfire (previous page) the ports are not only uneven, but their also different in size (the right port is smaller then the left.
A question was asked: How can the X-Ram be only .140 taller then the Crossfire and still have full size ports? The answer is simple: The Crossfire had its ports on the inside of a main chamber, with the bottom depth of manifold raised.
The X-ram feeds its runner from a center chamber, with the bottom depth
of the manifold in an even line with the head's intakes. The results, a full size port, without raising the overall height. The X-Ram Performance Margin
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Until the X-Ram, there was no single part replacement that could produce a real noticeable increase in horsepower and performance on a Crossfire.
An Underdrive performance crankshaft pulley set were rated for 10 to 15 hp increases; but on the Crossfire, the increase was only around 3 hp. Free flow exhaust system would make 25 to 30 on any other Corvette but again on the Crossfire, the gains were only 5 to7. Any add on only produced around 20 % or less of the normal hp increase. |
The addition of the X-Ram alone will produce a minimum 50+ rear wheel hp increase that would prove to provide a hard acceleration that has never before been felt from a stock crossfire engine-right up to the red line. With the help of 1.6:1 Full Roller Rockers the engine started to come really alive by overcoming the low-end vacuum loss produced by the wide-open ports of the X-Ram and generated faster accelerations and even higher torque curves.
Now an Underdrive pulley system was showing an increase of 8 to 12 rear wheel hp increases, and free flow exhaust was testing out at 22 to 28 hp increases.
But if total performance is your quest, the X-Ram is just the starting point. The X-Ram will flow in excess of 250 CFM per runner without any runner port polishing. This makes it possible to deliver over 1000 CFM per revolution. This means there are now a wide range of modifications that can be done to increase performance. The X-Ram is also capable of flowing over 1440 CFM to the base manifold for a wider margin of even more extreme performance modifications. |
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There are only 2 slight modifications that need to be made. A small hole will be required to be drilled in the throttle linkage and the kick down linkage (for automatics) or over drive linkage plate (for 4+3 transmissions) brackets, to connect the bracket plates to the top of the manifold. And the re-routing of the heater and vacuum hoses.
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