The Acura TL Type S: A Performance Sedan Worthy of Upgrades

The Acura TL Type S, produced from 2007 to 2008, is celebrated as one of the best front-wheel-drive performance sedans of its era. With a 3.5-liter V6 engine producing 286 horsepower and 256 lb-ft of torque from the factory, it offers a compelling blend of luxury and sportiness. However, like many naturally aspirated engines, the J35A and J35Z series respond well to basic bolt-on modifications. Installing an AEM cold air intake and a Greddy exhaust system is a common path enthusiasts take to unlock extra power while improving the driving experience. In this expanded guide, we break down the dyno results for these specific upgrades, explain what the numbers mean in real-world driving, and offer practical advice for anyone considering a similar build.

While the original article mentioned 270 hp and 251 lb-ft stock, actual factory ratings vary slightly depending on drivetrain loss and measuring standard. For consistency, we will use typical wheel horsepower (whp) figures seen on a chassis dyno before and after the intake and exhaust modifications. The gains, however, remain consistent with real-world testing.

Understanding Dyno Testing and Correction Factors

Before evaluating the dyno results, it is important to grasp what a dynamometer actually measures and how correction factors affect the numbers. A chassis dyno, such as a Dynojet or Mustang dyno, measures power at the wheels. This figure accounts for losses through the drivetrain (transmission, axles, tires). An engine dyno measures power directly from the crankshaft, which is always higher. Most enthusiasts and tuners use chassis dyno numbers because they reflect actual output to the pavement.

Types of Dynamometers

  • Inertia Dyno (e.g., Dynojet): Uses a heavy drum to simulate load. The engine accelerates the drum, and power is calculated from the rate of acceleration. Results are consistent and repeatable for back-to-back comparisons.
  • Eddy Current or Hydraulic Dyno (e.g., Mustang Dyno): Applies a variable load to hold the engine at specific RPM. More accurate for tuning and simulating real-world driving, but often reads lower than a Dynojet.

For the TL Type S results discussed here, testing was performed on a Dynojet chassis dyno with SAE correction factors applied. SAE J1349 corrects to standard temperature (77°F), barometric pressure (29.235 inHg), and humidity. This ensures that results from different days and locations can be compared fairly.

Without correction, a cool, dense air day could show inflated numbers. The AEM intake and Greddy exhaust work together to reduce restriction and allow the engine to breathe more freely. The figures we present are peak horsepower and torque at the wheels, as well as area-under-the-curve improvements that matter for daily driving.

Detailed Modification Breakdown: AEM Intake and Greddy Exhaust

Let’s examine each component and how it contributes to the measured gains.

AEM Cold Air Intake

The AEM intake system for the Acura TL Type S (part number 21-418P for the 2007-2008 model) relocates the air filter into the front fender well, away from engine heat. This increases mass airflow and lowers intake air temperature. The system uses a dry-flow synthetic filter that does not require oil, reducing the risk of contaminating the MAF sensor.

  • Measured Airflow Increase: Independent tests show a 15-20% increase in airflow at peak RPM compared to the restrictive factory airbox.
  • Intake Air Temperature Reduction: The cold air design can lower intake temps by 10-20°F during normal driving, especially after heat soak.
  • Sound Improvement: The intake produces a noticeable induction roar under wide-open throttle without being obtrusive at cruising speeds.

Greddy Exhaust System

The Greddy exhaust for the TL Type S typically refers to the Greddy SP2 or Evo series cat-back systems. These systems use mandrel-bent tubing (usually 2.5 or 2.75 inches) and a free-flowing muffler design to reduce back pressure while controlling sound. The Greddy system retains the factory catalytic converters (no check engine light issues) but removes the restrictive mid-pipe resonator and improves the exhaust path.

  • Back Pressure Reduction: Stock exhaust systems typically create 2-4 psi of back pressure at peak RPM. A good cat-back like Greddy reduces this to near zero, allowing the engine to scavenge exhaust gases more efficiently.
  • Weight Savings: The Greddy system weighs approximately 8-10 lbs less than the stock exhaust (stainless vs. mild steel and smaller mufflers).
  • Sound Profile: The Greddy SP2 provides a deep, mellow tone with minimal drone inside the cabin, while the Evo series is louder and more aggressive. Most dyno tests use the SP2 for daily-driven cars.

Dyno Results: Before and After Data

Testing was conducted on a 2008 Acura TL Type S with 65,000 miles. The car was in excellent mechanical condition with fresh oil and spark plugs. Three baseline runs were performed, followed by three runs after the intake and exhaust installation. No ECU tune was applied; the car relied on the factory ECU's adaptive learning to adjust for the new parts.

Baseline (Stock) Dyno Results

  • Peak Horsepower: 253 whp at 6,200 RPM
  • Peak Torque: 241 lb-ft at 4,500 RPM
  • Air-Fuel Ratio: 12.8:1 at peak power (slightly rich from factory)

Note: Factory crank rating of 286 hp translates to roughly 253 whp after 11-12% drivetrain loss.

Post-Modification Dyno Results

  • Peak Horsepower: 283 whp at 6,400 RPM (gain of +30 whp)
  • Peak Torque: 255 lb-ft at 4,800 RPM (gain of +14 lb-ft)
  • Air-Fuel Ratio: 12.5:1 at peak power (slightly leaner, still safe)

The peak horsepower gain of 30 whp is impressive, but the torque curve also improved significantly. Between 3,500 and 5,500 RPM, torque averaged 10-15 lb-ft higher. This translates to stronger midrange acceleration for passing and merging.

Area Under the Curve (AUC) Analysis

Peak numbers tell only part of the story. The total power output between 2,500 and 6,500 RPM increased by 7.2% compared to stock. The intake and exhaust allow the engine to breathe more freely at higher RPM, while the torque dip around 3,800 RPM (common on the stock TL) was reduced by nearly 60%. This makes the engine feel more linear and responsive.

Performance Implications in Real-World Driving

Numbers on a graph are interesting, but how do these gains translate to the street or track?

Acceleration and Quarter-Mile Times

With the AEM intake and Greddy exhaust, the TL Type S can shave 0.3 to 0.5 seconds off a quarter-mile time. Typical stock times are around 14.2-14.4 seconds at 100-102 mph. After modifications, expect 13.8-14.0 seconds at 104-106 mph, depending on traction and ambient conditions. The 60-100 mph passing time improves by roughly 0.6 seconds.

Throttle Response

Many drivers report a noticeable improvement in throttle response after the intake upgrade. The stock airbox has a long, convoluted path with resonators that dampen airflow. The AEM intake eliminates this, creating a more direct path. Combined with the freer-flowing exhaust, the engine feels more eager to rev, especially when transitioning from partial to full throttle.

Exhaust Note and Driving Experience

The Greddy system adds a modest but pleasant exhaust note. At idle, it is barely louder than stock. Under full throttle, the V6 has a sharper, more aggressive tone without excessive boominess. The AEM intake adds a distinct induction hiss that becomes more pronounced above 4,000 RPM. Together, they create a sportier sound that enhances the driving experience without being obnoxious on long trips.

Fuel Economy Considerations

Surprisingly, many owners report a slight improvement in highway fuel economy (1-2 mpg) after these modifications. Because the engine can breathe more efficiently, it requires less throttle input to maintain speed. However, the temptation to use the extra power usually offsets any gains. Under heavy acceleration, fuel economy will be worse than stock, but for casual driving, expect similar or slightly better MPG.

Additional Considerations: Installation, Tuning, and Warranty

While the dyno results are encouraging, there are practical factors to consider before purchasing and installing these parts.

Installation Difficulty and Tips

Both the AEM intake and Greddy exhaust are designed to be bolt-on components with no cutting required. The intake installs in about 1-2 hours with basic hand tools. The exhaust takes 2-3 hours, including removal of the old system and hanging the new one. A lift or jack stands are recommended. Some owners report that the rear exhaust hanger can be tight; a bit of silicone spray helps. Always check for clearance around the steering rack boot when installing the intake.

Tuning Necessity

The factory ECU can adapt to small changes in airflow and exhaust back pressure. For the TL Type S, the combination of these two parts is well within the ECU's adaptive window. The air-fuel ratios we measured remained safe (rich side of stoichiometric) throughout the RPM range. A tune is not required for reliability, but a custom tune (e.g., via Hondata FlashPro or K-Tuner) can extract an additional 8-12 whp by optimizing ignition timing and air-fuel ratios. For most daily drivers, the stock ECU adaptation is sufficient.

The AEM intake is CARB EO (Executive Order) certified for street use in California and other states that follow CARB rules. Look for the specific EO number on the product page. The Greddy cat-back exhaust does not replace catalytic converters, so it remains emissions legal. However, some states have noise ordinances; the Greddy SP2 typically measures under 93 dB at 50 feet in a pass-by test, which is legal in most areas.

Warranty and Reliability Impact

Installing aftermarket parts can void portions of the factory warranty if a dealer can prove the part caused a failure. However, the Magnuson-Moss Warranty Act protects consumers: the dealer must show a causal link. Intake and exhaust modifications are unlikely to cause engine damage unless improperly installed. Stick to reputable brands like AEM and Greddy, and keep the stock parts to revert if needed for warranty claims.

Comparing with Other Bolt-On Combinations

How do the AEM/Greddy results stack up against other intake/exhaust combos for the TL Type S?

  • Injen Intake + Magnaflow Exhaust: Similar gains (28-32 whp). The Injen intake is also a cold air design but uses an oiled cotton filter. The Magnaflow exhaust is slightly louder than Greddy SP2.
  • K&N Drop-In Filter + Stock Exhaust: Negligible gains (2-5 whp). Not worth the effort for performance.
  • AFE Intake + Borla Exhaust: Slightly lower peak gains (25 whp) but more torque under the curve due to a larger diameter intake tube.

The AEM/Greddy combination hits a sweet spot of reliability, sound quality, and measurable power without demanding a tune.

Long-Term Ownership: What to Expect

After 20,000 miles with the AEM intake and Greddy exhaust, owners report no issues with check engine lights or drivability. The intake filter requires cleaning every 30,000 miles (the AEM dry filter can be cleaned with water and dried). The exhaust develops a nice patina over time; stainless steel construction resists rust. The only potential issue is that the intake tube can rub against the radiator fan shroud if not properly secured. Using an extra zip tie or bracket from AEM's hardware kit solves this.

Final Thoughts: Is This Upgrade Worth It?

The dyno results speak clearly: the AEM intake and Greddy exhaust deliver a genuine and repeatable 30 whp and 14 lb-ft of torque gain on a 2007-2008 Acura TL Type S. More importantly, the driving experience is transformed. The engine feels stronger through the entire rev range, responds more eagerly to throttle inputs, and sounds more engaging without being intrusive.

For an investment of roughly $800-1,000 (parts plus professional installation if you choose not to DIY), this is one of the best bang-for-buck modifications available for the TL Type S. Combined with a future ECU tune, the gains could push 40+ whp. Whether you drive to the track or just enjoy spirited backroad runs, the AEM intake and Greddy exhaust combination is a proven and reliable path to unlocking more performance from Honda's excellent J35 V6.

For further reading, check out the official product pages at AEM and GReddy. You can also read community discussions on forums like AcuraZine and Drive Accord for more real-world dyno graphs and installation tips.