GrimmSpeed Post MAF Hose Kit (15-21 WRX)

GrimmSpeed Post MAF Hose Kit

First is the smooth inner surface, removing the pockets from the OE structural corrugated folds. The GrimmSpeed Post MAF Hoses are comprised of 4-ply silicone and unlike our competitor's offerings, are reinforced with an internal stainless steel wire running the length of each piece. This makes our hoses sufficiently flexible and also allows them to retain strong structural properties for a design that maximizes flow, is very easy to install, and won't collapse under vacuum.  

The second feature is tapered end portions, making sure the inner diameter matches the OEM air box and turbo inlet. A mismatched diameter creates steps, which will interrupt the airflow trajectories and create small vortexes in the post-MAF hoses. Our variants are designed specifically to prevent these issues.

Applications:

• 15-21 WRX

Quick Specs:

• 4-Ply Stainless Steel-Reinforced Silicone - Extremely durable, yet flexible; available in red or black 
• OEM Fitment - Easy install, no modification required 
• Seamless Flow - CAD optimized design  
• High-Quality Breeze Hose Clamps - Included in every kit
• No Tuning Required - Even when coupled with GrimmSpeed DRY-CON Panel Air Filter for maximum performance
• GrimmSpeed Logo to Represent your Favorite Brand!

Methodology:

The first step in improving on an existing part is to find its shortcomings. The OEM rubber hoses require sharper angels and corrugated structural folds as part of their design. This contributes to uneven airflow through the hose with high and low-pressure spots. The GrimmSpeed Hose design supports a minimal curve transition and is perfectly smooth inside, resulting in more consistent airflow to the turbo:

Install Guide:

• Written - GrimmSpeed Post MAF Hose Kits - 15-21 WRX Install

The tapered portion is also an important design choice for contributing to even flow through the hose. A plot comparison showing vorticity (a calculation used for flow disruption) between a non-tapered version and GrimmSpeed’s Tapered Hose shows an additional reduction in turbulence: