How fast do you want a car to go?

What is the best way to deal with an engine that needs a new lease on life?

Drivability engines engine repair engine tuning repair shop training technician training A/C training automotive aftermarket TAMPA — Hiding in the depths of the Hendricks Motorsports complex is a room where few are allowed. Even if you are lucky and tour the grounds, no photos are allowed. It is the engine lab, where technicians assemble racing engines that propel Jeff Gordon, Jimmy Johnson and other NASCAR teams around the big ovals at nearly 200 mph.

Here, every engine is carefully assembled and tested. Three separate dyno rooms are located to the right of the lab, and in them every race on the NASCAR circuit can be simulated, right down to altering the weather conditions at the track. After each race, the engines are disassembled, inspected and then reassembled for the next race. Through careful attention to detail and lots of engineering research, these engines can produce between 750 and 800 hp from a conventional, carbureted engine.

Going Fast in the Old Days

I remember growing up in the early 1970s, the era of the muscle car. Then, power was king, and the streets were alive with Chevy 327s and 396s, Mopar Hemis and Ford 429s. Instead of paying attention to the English teacher, many of us had our heads buried in the current issue of Hot Rod magazine, daydreaming of making our rides even faster.

It wasn't all that hard to do either. Manufacturing tolerances were relatively loose, and significant improvements could be made with the addition of better breathing intakes and exhausts, mated with a little bigger carburetion to get more air into the chambers. The next step up was adding a little more valve lift and duration via a new camshaft, and mating the intake and exhaust manifold ports to the openings in the cylinder heads, a technique called porting. After the ports were matched, the rough casting marks were carefully removed and the ports polished to a mirror-like finish. All of these added more air, and of course more fuel, into the existing displacement with a resulting increase in power.

Still want more? Pull the engine down and install oversize pistons. While it's apart, make sure that every specified tolerance in the engine was met and equal across its counterparts. This was a process called blueprinting. All the while, we followed a popular saying: "Speed costs money. How fast do you want to go?" Many of my friends of the era wanted to go pretty fast.

Going Fast Today

According to David Deegan, owner of the Engine Lab of Tampa Bay, in Tampa, Fla., cars made since 1996 already are highly tuned, making blueprinting a step that might only result in small gains. Deegan's shop specializes in engine remanufacture and also does a lot of high performance work. Deegan estimates that roughly half of his current business is high performance, with some of his projects featured on shows like Truck Universe and Two Guys Garage.

Customers come to Deegan's shop looking for help with everything from classic car restoration to squeezing a little more power out of their stocker. One of the first performance modifications Deegan recommends to the street driver is to have the engine's rotating assembly balanced.

"Balancing the rotating assembly can result in an easy 12 to 15 percent increase in torque and horsepower," he says. "Think of it like this: a bicycle. Think of pedaling a bike with just one pedal. That's essentially what a standard (existing) balance is ... pedaling with one pedal. Performance balancing is like pedaling with two pedals. You're equalizing the force (required to rotate the mass) and that's a big deal."

Deegan's shop balances the crankshaft assembly, and prefers to include every part that attaches to it, like the flex plate and harmonic balancer. Pistons, wrist pins and connecting rods all are weighed and matched, and then a special machine measures the balance of the entire assembly. Weight is then added or removed to the crankshaft's counter weights to bring the assembly as close to zero as possible.

"We may start out with an imbalance of 60 pounds at 2,000 rpm and get that down to 4 pounds," Deegan adds. "Keep in mind that the imbalance gets progressively worse with increases in rpm. That imbalance robs power that would otherwise make it to the wheels, so this one modification that results in power the customer can feel in the seat of his pants."

Some Things Never Change

An engine is nothing more than an air pump. The more air we can get in, the more power it can make. The next step Deegan recommends to customers looking to gain horsepower is to increase the air getting into the engine. Depending on the engine, they might recommend larger throttle bodies mated to the appropriate injection system or some change to the cam lift and duration.

But Deegan says they are seeing more interest in some type of forced air induction system, either turbocharging or supercharging, as an alternative to getting the air packed into the cylinders. Can a stock engine handle the loads such a system would add? According to Deegan, most can.

"It's not the bottom end that typically has a problem with the addition of a turbo, it's the pistons," he says. "Generally, compression ratios need to be lower in a turbocharged engine and proper tuning is a must."

In fact, Deegan encourages his customers to take their hot rods to one of four area shops he uses to have the final package properly tuned on a chassis dynamometer. Most failures of modified engines, he says, are a result of detonation caused by improper (or complete lack of) tuning after the performance modifications are made. It is a mistake to think that the ignition and fuel maps of the stock control module will handle the performance differences resulting from the modifications.

Building a high performance engine can be one of the more enjoyable aspects of what we do. No matter who you are, there is just something about the feeling you get when you step on the pedal of a car that has some ponies under the hood. Just keep in mind two things: One, the car still has to meet all local, state and federal regulations, and two, if you have any money left, you aren't going fast enough yet!

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