Before we handed back the keys of our Matrix back to Toyota, we paid a visit to the tuning facilities at DRT (Drag Racing Technologies) in Queens, NY during the winter off-season to see if the TRD exhaust lived up to its power improving claims on the lie detector of the tuning world ? a dyno. Operating DRT?s Dynojet Chassis Dynamometer would be DRT owner and tuner extraordinaire, Rafael Estevez.

 
 

If you know the name, its because a) you follow sport compact drag racing and you know Estevez is the crew chief for Manny Cruz?s 199mph Duttweiler powered Cougar and that Estevez has campaigned a nine-second twin turbo Civic in the Hot Rod class b) you own the Fast and the Furious DVD and read the acknowledgement that the Movie was based on an article about Racer X, who is ? you guessed it, Rafael Estevez.

After strapping the Matrix down securely, Estevez propped up the hood and installed the Ignition Wire Inductive Tach Pickup Lead that will serve as the umbilical cord of information to the processing PC.

  

Before running the dyno tests, Estevez recommends we run a simple air/fuel ratio (AFR) check to see if tuning the AFR would produce any significant horsepower gains. We accomplish the test by installing a MoTeC AFR exhaust probe into the exhaust tip of the TRD exhaust can. Connected to this probe is a digital readout that we place on the dash ? within view of Estevez while he puts the car through its paces on the dyno.

A couple of quickies on AFR. Air/Fuel Ratio measures the amount of air molecules per fuel molecules that are leaving the car uncombusted (combustion is never complete in an engine because of the short combustion cycle). Over the years, scientists and engineers that much smarter than the staff here at UrbanRacer.Com (not a hard feat for the most part) have determined that 14.7:1 is the ideal AFR, scientifically known as Stochiometric. In other words, if your engine is spewing 14.7 air molecules for each fuel molecule out the exhaust, it is running at an ideal efficiency ? you?ll get the best gas mileage.

AFR?s lower than 14.7:1 means your engine is running more fuel than the Stochiometric condition ? commonly known as ?running rich?.

AFR?s higher in number than 14.7:1 means the engine is running less fuel than the ideal efficiency ? commonly known as ?running lean?.

Engines normally make the most power at a slightly richer condition that produces an AFR of 12.5:1 (12.5 molecules of air for each fuel molecule). Most factory-tuned engines tend to be tuned to a leaner condition for fuel economy and durability issues. Most modern cars control the AFR automatically through an O2 sensor that tells the ECU what the AFR is at a specific time. The ECU will then adjust the amount of fuel introduced into the combustion chambers based on programmed fuel maps to achieve the desired factory set AFR.

  

Starting with an AFR in the 19 range at idle, Estevez slowly brought up the revs and the AFR quickly and expectedly was remapped to a near stoichiometric 14.83:1. However, when Estevez floored the gas pedal and the revs quickly swept past the 4,200 rpm range ? activating the VVT to an more aggressive valve timing overlap, an impressive 12.60:1 flashed on the LCD readout. Pretty aggressive considering the usually conservative tuning of factory number crunchers.

Happy with the factory fuel maps, we went back to the business at hand. How much horsepower was this 1ZZ-FE producing with a rear section TRD exhaust as the only engine performance modicifation?

Estevez ran through several pulls on the dyno before he was satisfied with the data. With the final dyno graphs in hand, we were really shocked at the results. The first run was a baseline run of sorts for us. Peaks of 124.9 hp and 120.7 lb.-ft. torque were charted on the first graph. Not bad. Remember, this is wheel horsepower and the factory ratings of 130 hp and 126 lb.-ft. torque are at the crank.

  

Next up, to simulate real world driving conditions, a 40,000 cfm fan at the head of the Matrix was flipped onto simulate the air conditions found at highway driving speeds. The ram air-like effect of highway driving air was instantly reflected on the next dyno pull ? 129.0 hp and 123.7 lb.-ft. torque. Now, we?re talking. We nearly equaled the factory crank horsepower and are just shy of the torque, could this TRD exhaust really be responsible for all this power?

  

No time to think. Still hungry for more power, we decided to remove the filter element from the factory box to simulate a high flow intake. Estevez runs the Matrix through the revs one more time. Looking at the last dyno graph, we found out that the Matrix was pushing out 130.0 hp at the wheels! Factoring in the normally accepted 15% driveline losses to the factory rated 130 crank hp gives us a theoretical 110.5 baseline wheel hp ? which translates to a whopping 19.5 hp gain! Even using a more conservative driveline loss percentage of 12% still yields a 15 hp gain ? still phenomenal! Remember, this is only a rear section exhaust system that we are talking about. A quick check of average retail pricing around the Internet has the exhaust costing anywhere from $550 – $650. That kind of money is still cheap considering the 15% percent increase in power that we saw (using the 15% driveline loss percentage).

  

Even when we applied the SAE correction factor for our results, we were still impressed. SAE correction is applied to standardize all hp and torque ratings by removing the effects of ambient weather and barometric weather conditions ? which control the density of air and affects the performance of your engine. Using SAE corrected data allows people dynoing a Supra, say at 90-degree temps and 100 feet below sea level compare their data with a Supra dyno?ed at 60-degree temps at sea level. The max SAE corrected ratings for our Matrix XR equipped with the TRD Sport Exhaust were 125.6 hp and 118.6 lb-ft of torque. Now we had proof to support our seat of the pants evaluations of the TRD exhaust.