2008 subaru legacy 2.5 i cold air intake


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Meticulous engineering meets elegant design.

For years you've been asking us for intakes, and for years we've silently worked to create a solution that sets itself apart from the rest. We examined and tested current offerings, and identified their shortcomings. We formed theories, and over months of testing designs we proved them. Combined with our advanced research and development program, we fully utilized our engineering resources to design and manufacture what we believe is the most comprehensive intake solution available for the 2005-2009 Subaru Legacy GT.

Quick Specs

  • Hybrid Cold Air/Short Ram Design - Combining the advantages and eliminating the negatives of both traditional intake designs
  • Air straightener - Dimensionally mimics the factory configuration for accurate MAF sensor readings
  • MAF sensor location - Inside heat shield, isolated from engine bay heat
  • Custom reusable high flow air filter - Integrated velocity stack entrance smooths incoming air
  • Made in the USA - Right here in Minnesota, in fact
  • 30min Installation - Extremely simple with our written and video guides

Design

Based on our testing and research, design requirements for this intake became simple. The MAF sensor must be protected from the heat of the engine bay for more accurate readings. The filter must not be close enough to the ground such that water/hydrolocking are a concern. The MAF sensor must be placed relative to the filter and air straightener, similar to the OEM airbox, so that airflow readings are consistent and reliable. The intake tube must be no longer than necessary with minimum bend angle, to reduce restriction. The heatshield must provide sealing between the induction area and the hot engine bay to keep air intake temperatures low. The GrimmSpeed intake shown here achieves each of these requirements and more. What is accomplished is a true hybrid of traditional Cold Air Intakes and Short Ram Intakes, with all the advantages and none of the compromises.

2008 subaru legacy 2.5 i cold air intake
        
2008 subaru legacy 2.5 i cold air intake

The two engineering studies above illustrate the importance of understanding how air moves within the entire intake system. The figure on the left shows how the GrimmSpeed intake design compares to other intake designs with respect to MAF placement and how that affects airflow readings. Since the MAF sensor samples the velocity of incoming air to measure flow in the center of the tube, having an accurate velocity profile at the sensor is the only way to accurately measure airflow. The figure on the right shows the importance of considering how air moves within the heat shield or box, prior to entering the filter. The GrimmSpeed heat shield geometry keeps air from collecting in sharp corners and 'feeds' the air filter uniformly. This uniform air distribution contributes to more accurate MAF readings, but also reduces filter restriction and increases time between filter cleanings due to even "filter loading." And while the airbox is doing it's job of increasing performance, it's also cleaning up the engine bay and looking good.

Materials

In true GrimmSpeed fashion, no corners were cut in the fabrication of each and every one of these intakes. The aluminum heat shield is laser cut, CNC bent and riveted together before receiving a heavy duty black texture powdercoat. MAF flanges are CNC machined from 6061 aluminum and the intake tube is fabricated from custom bent tubing, made specifically for our application, to provide the perfect MAF diameter. The air straightener is laser cut from the same 6061 material and tumbled before the entire assembly is TIG welded by our expert welders. After welding, each tube receives the same heavy duty powdercoat and is inspected and cleaned to ensure maximum performance and reliability.

Performance and Tuning

This intake was designed with tuners in mind! The consistency of the airflow through the MAF sensor makes this intake very predictable and is as easy to tune as the stock airbox. Intial dyno testing and design theory validation was completed on our 2012 WRX, equipped with a GrimmSpeed 3-Port EBCS, Catted Downpipe, Catless Uppipe and TMIC. We then worked with a local product tester and his 2005 Legacy GT wagon to verify performance on the intended model.

2008 subaru legacy 2.5 i cold air intake
 
2008 subaru legacy 2.5 i cold air intake
 
2008 subaru legacy 2.5 i cold air intake

The chart on the left shows a comparison of the same car with a stock intake and stock tune, followed by the stock intake with the applicable COBB Stg2 OTS Map. Then, the GrimmSpeed intake was installed and the MAF scaled properly for use with the same map. Lastly, wastegate duty cycle was also scaled to increase boost pressure from 15.5psi to 18psi.

The chart in the middle shows the GrimmSpeed Intake vs. Another Popular Intake running on the same recommended COBB OTS Stg2 93OCT +SF Map. Using this tune, the GrimmSpeed intake provides an additional 21whp at the peak and up to 30whp earlier in the powerband. It should be noted that both of these runs were very rich and left quite a bit of power on the table. This is the reason that we recommend a professional tune.

Finally, the chart on the right is similar to the chart above, but the GrimmSpeed intake has been custom dyno tuned by DB Performance in Rogers, MN. The additional 5lbs of boost safely nets 40whp and nearly 50ftlb of torque. This image has been resized. Click this bar to view the full image.

For the most complete summary of the 2005 Legacy GT verification dyno results, follow this link.

Includes everything

  • 1x Intake Tube
  • 1x High-flow Dry Filter
  • 1x Hump Hose Connector
  • 1x Heat Shield Assembly
  • 3x Hose Clamps
  • 2x MAF Flange Screws
  • 3x Precut Rubber Sealing Strip
  • 1x MAF Wire Grommet

Fitment

  • 2005-2009 Subaru Legacy GT
  • 2005-2009 Subaru Outback XT

  • Additional Info
  • Reviews

Additional Info

Reviews

6 Reviews

2005 subaru legacy gt cold air intake

Bolted right on no issues love the color and the sounds will definitely buy from grimspeed again

Amazing product

Install is fairly straight forward, and you can feel/ see the quality. Adds tons of turbo sound too, to the point where I’ve been asked if I have a BOV (but it’s not obnoxiously loud, it’s just right in my opinion) according to my AP, intake temps stay lower, longer, and performance seems to have mildly increased. Overall a great purchase.

Sounds Amazing!

Install was easy, fit is great, sounds amazing, looks good under the hood too!

Great look

The fit is great. It would be an improvement if it had some kind of rubber gasket where it contacts the body of the car. It's metal on car paint. The look is great. The airbox makes it a lot quieter. I can hear it but i can hear the manifold better. Since this is on i can hear my blowoff valve for the first time. Throttle response is definitely better. I have a stage 2 tune that has not been adjusted yet. With 104 in the tank I get a hard pull all the way to the uper end of 5th gear. I don't see a deficit on the top end. The air straightener does look just like the factory airbox. The install was a cinch, 30min with no problems.

LOOOUUUUD NOISES! ! !

This is a FANTASTIC intake and box setup, made right here in the US and A, and made especially for the 05-09 LGT! No custom cutting, modifications or fitment issues! Be sure you measure 1" (or less, maybe 3/4"?) from the end of the intake tube, and mark with a Sharpie, per the instructions. READ READ READ THE INSTRUCTIONS! Now, on to the performance - This is a true Cold Air Intake! I kept an eye on intake temps before and after installation, and saw a 7 - 10deg reduction, overall. Coupled with an aftermarket turbo inlet, such as the Perrin, (If you're shopping for intakes, you should be running one already.) you will experience LOUD INTAKE SOUNDS! Even with a stock turbo setup, you will hear intake, spool, BOV/Recirc with a much greater presence. There will be less of a whistle, and more of a growl, that, from the cabin, might lead you to think there's something wrong with your turbo. I don't recommend this box to those who aren't confident that their surrounding parts are in good working order. You'll drive yourself crazy, otherwise. While this particular intake aims to have the best of both worlds - Short and long ram - there are some sacrifices made, which, I think are pretty decent, all things considered. For those who don't know, "short-runner "ram" intakes --usually for ACTUAL racecars-- sacrifice low-end power and throttle response for the benefit of top-end; long-runner intakes (most other CAIs that extend into the fenderwell) take advantage of colder temps, and low-end power and response, at the expense of top-end performance. This Grimmspeed unit is mid-length, and aimed to give you the best of both low-end response, and top-end performance, and seems to do both quite well. If anything, the sweet, sweet noises at street-level will be enough to distract you from the almost-imperceptible low-end reduction in throttle response. Getting on the freeway/into higher speeds, you will experience a much greater appreciation for the engineering and R&D that went into all this. Finally, YOU ABSOLUTELY WILL NEED A PROTUNE TO TAKE FULL ADVANTAGE OF THIS INTAKE! Yes, you CAN run the appropriate Cobb OTS map for their SF Intake w/Box, however, don't let that be your long-term solution. Find a protuner in your area and book some dyno time - You will happiest with this option, trust me. The MAF scaling of 12% is pretty close, according to my tuner (Mike @ PIA). YMMV. For reference: 2005 LGT 5EAT, (Stage 2 with Custom VF40 and Perrin TMIC) dyno results: 275hp/380tq on a Mustang Dyno. (See dyno sheets posted in the PNW section of LegacyGT dot com) All in all, you won't be disappointed in this intake setup - This item is now MrTris Approved™. Buy Today!

Solid upgrade

I purchased this item as a suggestion from my local subaru performance shop. Great mix of form and function. The install is very straight forward and the instruction from Grimmspeed are easy to follow. The fit is near perfect and feels like it belongs in the car. The looks are sleek and clean and don't have the flashy (ricer) look of most open cone filters. (sorry to all you ricer fans out there). The benefit of that is they have sealed out nearly all of the engine compartment heat from the intake. And the sound! It has really woken up the sound of the engine with a definitive whooshing noise that will have your wife asking whats wrong with the car :) ( again sorry to all the female auto enthusiasts out there)

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