“Driver’s Classes” across the world of motorsports seek to pit the skill sets of enthusiasts against each other over a level playing field of seemingly equal equipment. These sorts of classes have brought about the concept of the sealed engine package — in the name of budgetary concerns and defusing inevitable arms races of parts and technology, competitors are limited to a powerplant in trim as delivered from the OEM. But racing a sealed motor package is chock-full of it’s own complications, as Chris Muzio of Danzio Performance showed us.
The engine in question for this case study is the GM EcoTec, a stout 4-cylinder workhorse that has powered passenger vehicles across GM marques for ages. These engines have grown to prolific usage among racers — specifically the desert racing and road-racing crowds. The idea is that everyone has an equal engine, but it is widely known that some are more equal than others. Danzio Performance has perfected the techniques to maximize output and stay within the rules.
The EcoTec engine has progressed through a few different itterations over the years, varying in displacement and other features. The most common aftermarket application of the EcoTec is an open-wheel desert racing class known as Class 10, which similarly equates a to Formula 3 road race car.
“When the class first came out there was a 2.4-liter, port-injected engine — they make around 180 horsepower. We came out with this engine in 2011, which is a direct-injected version of the 2.4, but we were able to do it because we had the ECU. We developed this package and the first year Casey Folks of Best In The Desert wouldn’t allow it,” recalled Muzio. “The good thing with DI engines is we are able to make 220 horsepower, and the fuel efficiency — most of the cars are getting 6-7 miles per gallon. They rev a little higher than the port-injected engine, and it’s just a stronger engine in general from GM.”
Optimizing Sealed Engines
Knowing that the nature of a sealed engine class prohibits touching anything in between the valve cover and oil pan, we asked Muzio what can be done in the quest for more power?
“You can’t do anything, the only thing you can do when you get them is select parts that GM makes for that engine — so injectors, intake manifolds, things like that. We are allowed to change the oil pans, we can put a deeper sump oil pan with baffles. To be honest with you they did a pretty damn good job of engineering that stuff at the factory so if you’re trying to make more power with them you really need to start changing rods and pistons or you’re going to start breaking stuff,” Muzio explained.
Herein lies the the reason a garage engine-builder like you or me can’t build a tagged and sealed engine to compete with professional builders. The builders have stock piles of homologated OEM parts from which they can cherry-pick the very best. The best flowing manifolds, the lightest and closest matched connecting rods, the best injectors and so on. The ability to pseudo blue-print without actually modifying parts is an incredible and legal advantage when it comes to sealed engines.
Where the rule set opens up is the electronics side of things, the ability to completely scrap the OEM ECU and start from scratch means the builder can re-teach the engine how to behave. “The ECU we use in there is fully mapped by us, all the tables for the cams and everything is done by us. Since 2011 we’ve probably done about 250 of these engines, so the tune we have for these engines now has a lot of R&D in it. We use brand new engines, we order them and hand pick them from GM, we buy them as a longblock and then we put all the parts that we want on there. We tag for SCORE, for BITD the only people that are licensed to do that is Turnkey Engine Supply.”
Changing fuel and ignition maps, alongside variable-valve-timing (VVT) means the safe and sedate GM parameters are nowhere in sight. One of the most controversial features builders and racers must decided to retain or discard is limp-mode functions. In the case of this particular engine, the limp-mode system has been disabled because at a previous race the car was disabled by a failed sensor. However, Muzio highlighted a scenario where limp mode saved a customer’s race.
“We had a car in the Baja 1000 last year that got all the way to within 50 miles of the finish and it went into limp mode. They pulled over and found that a rock had gotten between the oil pan and the skid plate, it rubbed a hole in it and they lost all the oil, but because of limp mode they didn’t destroy the engine. They actually patched it with gas tank repair and all kinds of stuff, filled it up with oil and drove it across the finish line.”
Tuning And Features
After the package is built, comes the tuning. Danzio prides themselves on their dyno cell tuning-procedures before an engine makes it into a car and on the chassis dyno. “One of the biggest things that we do, and a lot of people don’t, is the R&D we do on sealed motors in there (the engine dyno cell). Five to ten horsepower is a lot in a sealed engine, it can give you an advantage over another guy. With temperatures from outside, the cooling system, tire pressures, it’s very hard on a sealed engine to get the edge on the chassis dyno,” explained Muzio.
The tuning session today was just a check-up and update in preparations for an impending endurance race — The Baja 500. “I adjusted the no-lift shift, because anytime they have the gearbox out it changes that, changed the tune a little bit since the 500 is a bit more of an endurance race to optimize mid-range and fuel efficiency,” Muzio summarized. This particular engine and car were wired in-house at Danzio to ensure everything works together as best as possible.
“We wired the whole chassis, pretty much a full electronics package, we used a Life Racing PDU, keypad, and dash, and then we did all the programming. Most of the cars we do these days have a GPS box that goes on the roof that goes into the ECU, and then we can do up to 12 different pit limits,” Muzio explained. The ability to program-in features to racing engines is becoming a more mainstream trend as the technology and applications become more accessible.
Subverting the seemingly restrictive rules, which limit aftermarket parts to OEM-only, Danzio has re-purposed the Flex-Fuel technology used in other GM models for the option to alternate or blend ethanol and gasoline-based fuels. “We actually have a flex-fuel option, we run the sensor that they put in Tahoes and you can run E85, 91, and you can run a mixture of the two. The E85 definitely has an advantage for power, it’s good for the short races — fuel economy it does affect, it takes a couple miles per gallon off the fuel-economy on these cars,” Muzio concluded. “The average power to the wheels is 162, but 220 on the engine dyno, they make about 175 on E85.”
There are a number of options for sealed engines, different OEM suppliers both foreign and domestic, and builders who market them. If the EcoTec is your choice of power it’s important to know what kind of work it takes to be on top.
For you off-road fans check out our gallery of the new, first of it’s kind, mid-engined Jimco Class 10 this engine will power.