If you're budget-minded, hunt...
If you're budget-minded, hunt the swap meets for a used Doug Nash or Richmond five-speed. Although this trans (shown) uses a 1:1 Fifth gear, its low 3.27 First gear will provide great launch gearing and allow you to retain your stock 2.73 or 3.08 rearend ratio for better fuel economy, while maintaining good acceleration.
A typical 12-inch stock converter...
A typical 12-inch stock converter (shown right) loses about 250 rpm at cruise speed, and a high-stall 10-inch converter (shown left) loses much more rpm. If you won't be running a transmission that uses a lockup converter, you may want to choose a converter with less stall speed to maintain fuel economy. Just remember to match the engine's camshaft to the converter. Typically, torque converters with less stall speed should be paired with engine camshafts with shorter amounts of duration. Check with the cam company for a recommendation.
This is the inside of a typical...
This is the inside of a typical high-stall converter (non-lockup design). If you want to combine a high stall speed with a lockup function, look to the aftermarket. Companies such as TCI offer performance lockup converters that also provide higher stall speeds for many late-model overdrive GM automatic transmissions.
Fourth-Gen Camaros offer tremendous...
Fourth-Gen Camaros offer tremendous perfor-mance and excellent fuel economy. The optional six-speed transmission, good aerodynamics, and electronic fuel injection enable this performance car 24-28 mpg on the road.
The lighter the car is, the...
The lighter the car is, the quicker it will be and the better its mileage will be. Here we've added a fiberglass hood to this '87 Camaro to remove some weight from the vehicle. Noticeable changes generally occur when 100 or several hundred pounds are removed from the car.
If the exhaust system is clogged...
If the exhaust system is clogged or too small, you can gain performance and sometimes fuel mileage by adding a larger, freer-flowing system.
Newer computer-controlled...
Newer computer-controlled cars should have the O2 sensors replaced, typically at 100,000 miles, to provide good performance and optimal fuel economy. Most auto parts stores offer new O2 sensors as well as the special socket to replace them.
Oils such as Pennzoil's Platinum...
Oils such as Pennzoil's Platinum Full Synthetic 5W-30 offer excellent anti-wear protection and improved fuel efficiency. This is partially because the lighter-viscosity lubricant does not cause as much mechanical loss through the pump, compared to thicker oils.
Remember to check the easy...
Remember to check the easy things too, such as initial timing, plug wire condition, and routing. Sometimes the simplest items can be overlooked and cost performance and mileage.
Gear Accordingly
Here's the math to show how Overdrive transmissions provide great acceleration and economy. A good all-around performance combination that will generally not kill mileage is a combined First gear ratio of 10.0:1 (First gear multiplied by the axle ratio) and the capability to drive at freeway speeds at low rpm with overdrive. In other words, if your current rear axle ratio is 3.31:1 and the overdrive transmission you'll be adding has a 3.06 First gear, your total combined gear ratio in First gear will be 10.13 (3.31 axle ratio x 3.06 First gear = 10.128:1). This combined First gear ratio is equal to having 4.56 axle gears and an M21 or M22 Muncie in First gear (2.20 low). We can illustrate this by dividing the final combined ratio of 10.128 by the Muncie M21 First gear ratio of 2.20:1 (10.128/2.20 = 4.60:1). Additionally, your effective High gear ratio with the 0.70:1 overdrive and 3.31:1 axle ratio will equal 2.32:1 (3.31 x 0.70 = 2.317:1). At 75 mph, this combination will put your freeway engine speed at 2,250 rpm.