GM Hydra-Matic 4T65 Transmission
Essential Component Of Marty Ladwig's
ENGLISHTOWN, N.J., Sept. 23, 2004 - Okay, so the production-based, turbocharged 2.0L GM Ecotec engine you use in your 2004 Pontiac Sunfire is making close to 1,200 horsepower. Now how do you get all of that raw energy applied to the racetrack? If you're 2004 HOT ROD champion Marty Ladwig, realizing the full potential of your Ecotec powerplant is made possible by the performance and durability of another GM Powertrain production-based component - the Hydra-Matic 4T65 transmission.
"The Ecotec has always been very reliable, and from the very beginning it has given us plenty of horsepower to get the job done," said Ladwig. "But the performance numbers we obtained this year, and ultimately the championship, were made possible with the boundless improvements made to our 4T65 racing transmission. That enabled the car to get that power to the ground and made our 2004 Pontiac Sunfire a much better racecar. The result is that GM Racing engineers and GM Powertrain have done a terrific job getting the production-based Hydra-Matic to where it is now the state-of the-art drivetrain in the series.
"We were able to beat teams that were using expensive aftermarket pieces, while at the same time, we demonstrated that you can be successful and run the big numbers using a production-based transmission. That's absolutely unheard of in a sport as demanding and competitive as drag racing. That shows that the entire package, the Ecotec engine, the Hydra-Matic automatic transmission and the Pontiac Sunfire, have all come together to create a championship combination."
While many teams racing today in Sport Compact competition have been proficient in figuring out the best ways to produce horsepower, the transfer of that power to the racing surface has proven over time to be an expensive weak link, an Achilles heel so to speak, that the GM Racing program has had great success in rectifying with the Hydra-Matic 4T65.
"Our goal at GM Powertrain is to support the GM Racing Sport Compact program and bridge this activity with some of our production transmission applications," explained Steve Coleman, racing engineer at GM Powertrain. "We're stretching the envelope all the time with the amount of engine power we have, so whatever we learn at the racetrack we're going to apply that to the production side of the business. In return, the production side helps us because we can see what type of testing they're doing, where they're having problems and what areas we need to focus on when we get to the racetrack. It also demonstrates the tremendous amount of confidence we have in our production quality because we're racing with production components without having to run any additional quality checks."
Using Marty Ladwig's Ecotec-powered Pontiac Sunfire as a rapid, at-track research laboratory on wheels (albeit at 185 mph), the GM Racing team (working in conjunction with GM Powertrain) has spent the '04 season continuously improving the strength and durability of the 4T65 drivetrain. Their inexhaustible work toward a reliable, economical solution to expensive drivetrain parts breakage will benefit all racers in the series and have long-term implications for the continued development of the sport.
"The automatic Hydra-Matic 4T65 in Marty's Pontiac Sunfire is basically the same transmission used in the Pontiac Bonneville and Grand Prix," explained Coleman. "The base transmission that we start with is the Heavy Duty version. One of the things we're most proud of is the ability of the Hydra-Matic to handle over 1,200 horsepower, fluidly shift at 10,000 rpm and perform where it's cost effective. There are teams running transmissions that cost anywhere from $15,000 to $35,000, but with the Hydra-Matic 4T65, we're running a transmission, that even with the parts we modify it with, probably costs around $4,000.
"There is a substantial research-and-development investment made initially by GM Racing, but the benefit to all of the racers by supplying them with an essential part that they can afford is something we're very proud of. When you look at the All Motor cars where these guys don't have huge budgets, that's pretty important. If they break something, they can acquire the necessary parts at a GM Service Center or a dealership, go and pay a few bucks for a gear set or a clutch and they're back on the track."
Like the Ecotec engine that powered Ladwig's Pontiac to a second straight NHRA HOT ROD championship this year, one of the things GM Racing engineers are quick to emphasize are the number of production components in the racing version of the Hydra-Matic 4T65, an inherent reason for the relevant low cost to the grassroots competitor.
"Approximately 80 percent of the racing transmission is built with production parts," explained Coleman. "If we had to, we could truly go out to the parking lot, find a Grand Prix or a Bonneville, scavenge their parts and use them. Now that's pretty remarkable when you stop to consider what that could mean for the average guy or sportsman racer who doesn't have a lot of money to spend, but still wants to compete as a hobby.
"With the racing transmission, we didn't have to modify any of the bearings, drivegear sets or input reaction gear setups. Our clutches are all production, with the exception of a third clutch where we added a clutch plate. That makes it less expensive to work on the car and allows us to accelerate our testing of parts, if for instance we see a particular problem. We can go out for a race weekend, and then come back and fix the problem, so we're using the racetrack as an extension of our GM Powertrain research-and-development center. The great thing about it is that we are able to test the benefits of base pieces on the racetrack and transfer the information we learn back to production."
The result for Marty Ladwig is a consistent, powerfully smooth-running Pontiac Sunfire that from a powertrain standpoint, is completely under control and charges in a straight line all the way to the finish stripe. So far in 2004, Ladwig's Sunfire has captured six national events, competed in seven finals rounds, earned low qualifying honors at six meets and was the first car in the HOT ROD category to run in the "sevens" posting a national-record elapsed time of 7.973 seconds. Ladwig's Pontiac has also run the fastest speed in the class at 184.32 mph and holds the category national speed record at 182.38 mph.
"The key is being able to control the shifts and that's actually the biggest benefit of using an automatic transmission in drag racing," said Coleman. "You don't have to take any power away from the wheels when you shift. With most transmissions, you have to take power away when you shift and then put it back in. Using the Hydra-Matic transmission, we don't have to take any engine power out and that enables the Sunfire to make a nice, fluid run all the way down the racetrack. Marty basically commands the shift, and less than a tenth of a second later the ratio change is done and he's never off the gas - the engine power never comes down. He's basically accelerating all the way down the racetrack."
As with the Ecotec engine, the GM Racing pit area continues to be an open book with engineers ready to answer questions and share information on the turbocharged, four-cylinder powerplant, the Hydra-Matic 4T65 transmission, and other areas including safety and aerodynamics, that will help contribute to the growth of Sport Compact drag racing.
"From an information standpoint, we're pretty open with what we have done with the Hydra-Matic," said Coleman. "For anybody that comes and asks, we'll tell them basically how it works, why it works and why it's an advantage. When you look out there today, a lot of people tend to have transmission problems in these cars. If the transmission isn't breaking, they're having a hard time figuring out how to pull the power out and put the power back in, making those shifts without losing a lot of time. However, there hasn't been a 4T65 yet that has been put in the car and hasn't run its first time down the track. Again, from a 'doing it right' standpoint, there's a big benefit to having that.
"The Hydra-Matic transmission is not something that's exotic or rare. You just go to your Pontiac or Chevrolet dealership down the street and get what you need, it's as simple as that. It's a durable, reliable, economical powertrain, and because of its universal availability, the 4T65 is a tremendous boon for the grassroots sport-compact racer."
General Motors Corp. (NYSE: GM), the world's largest vehicle manufacturer, employs 325,000 people globally in its core automotive business and subsidiaries. Founded in 1908, GM has been the global automotive sales leader since 1931. GM today has manufacturing operations in 32 countries and its vehicles are sold in more than 190 countries. In 2003, GM sold more than 8.6 million cars and trucks, nearly 15 percent of the global vehicle market. GM's global headquarters is at the GM Renaissance Center in Detroit. More information on GM and its products can be found on the company's consumer website at www.gm.com.
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