Test-driving the souped-up Dodge Omni GLH - whooosh!

It was onlym a four-door Dodge Omni, introduced by Chrysler Corporation in 1978 as a high-mileage automobile that was strictly in tune with the times. Fuel economy was king, and this was Chrysler's answer to the demand.

But thism new Omni GLH, I soon found out, was a whole lot different.

Here at Chrysler's Shelby Performance Center, one-time auto-racing champion Carroll Shelby of Cobra fame can beef up the engines of rather standard-looking cars to his heart's content. Shelby, in fact, is right in his element.

After passing the time of day in his office, the Texas-born racer asks: ''Want to go for a ride in an Omni?''

''A great idea,'' I muse, knowing full well that Shelby had something up his sleeve.

First, with Shelby at the wheel, we spin around the skid pad in an ever-tightening circle, the tires screeching and sticking to the road as if the wheels were in grooves. Then the one-time Texan - well, not really, because he still has a ranch in east Texas - says: ''Let's take the car down the straightaway.''

Again, Shelby has another surprise up his sleeve. The Omni GLH is superfast and, with the wall approaching with agonizing speed, Shelby stomps on the brakes , the car coming to a stop with the smell of burned rubber filling the air.

It is an impressive drive, all agree.

The turbocharged, 4-cylinder Omni GLH, I am told, is built to get 160 hp., spurt from 0 to 50 m.p.h. in less than 5.5 seconds, and reach 65 to 70 m.p.h. at the end of the one-eighth-mile drag strip.

''It's built to outperform the Volkswagen GTI Rabbit by about 10 percent,'' Shelby says.

Then, looking at me, he asks: ''Want to take the wheel?''

''Why not!'' I reply.

I drive the souped-up Omni as hard as I dare, ending up with another blazing stop at the end of the drag strip.

Impressed, I hand over the keys to Shelby, who replies: ''Not bad.'' The high-power Omni isn't bad, either, and, if the price is right, should find a ready market for the performance buff who can't afford a Porsche.

This is what the Shelby Performance Center is all about. ''It wasn't established as a racing center,'' Shelby says, ''but rather as a product-development facility.'' The ex-racer also is fooling around with 16 -valve engines, supercharging, and a lot more.

Supercharging vs. turbocharging is going to become a controversial issue, and Shelby says there are advantages and disadvantages to both systems. ''If you're driving a Chrysler T-wagon in very hot weather and you have a half-ton load in the back of it, you don't want a turbocharger,'' he says. ''The wagon will operate far more efficiently with a supercharger under those conditions.

''In other applications, you'd be better off with a turbocharger.'' Both systems cost about the same.

The quick-like-a-bunny Dodge Omni GLH is due on the highway next spring, according to Chrysler.

Like all automakers, Chrysler is on a performance kick these days. Simply, carmakers are responding to those motorists who are tired of poky cars. With the price and supply of fuel remaining stable, they're demanding more zip and better handling in the cars they buy.

The upcoming Dodge Omni GLH, the turbocharged 2.2-liter Dodge Daytona and Chrysler Laser, and the zippy Dodge Colt by Chrysler's Japanese affiliate, Mitsubishi, are right on track.

The Dodge Colt GTS Turbo, for example, spurts from 0 to 60 m.p.h. in a shade over 8 seconds, the fastest-pickup Colt of them all. Like the VW Rabbit GTI and the swift-pace Dodge Omni, the Colt GTS sticks to the road with determination, going where the driver points the nose.

Equipped with a 1.6-liter, overhead-cam, 4-cylinder engine beneath the hood, including twin electronic fuel injectors, the Colt GTS comes with a choice of twin-stick manual transaxle or optional 3-speed automatic. Horsepower is rated at 102 at 5,500 r.p.m.

Yet if the Colt GTS is fast, the upcoming turbo-boost Omni is even faster, unofficially moving from 0 to 60 m.p.h. in about 7.3 seconds, ex-race driver Shelby figures. That's reallym fast!

Harold K. Sperlich, head of Chrysler's North American Automotive Operations, says, ''The world is beginning to take fuel economy for granted.'' Now, he adds, more people want their cars to perform.