HPS Silicone Intake Hose Kit – Fact Check

Background:

HPS sells an intake hose for the Mk7 GTI that is purported to have a number of performance benefits.

This post reviews the claims made for the product and assesses how well the claims are substantiated.

Search for facts
Search for facts

Post theme:

The product description for the HPS Silicone Turbo Inlet Hose illustrates a flaw that appears in a large number of aftermarket product descriptions. The problem is with describing specific characteristics of the products, i.e., size, weight, materials, texture, and then claiming that these characteristics produce a measurable change in a process the part supports.

HPS Claim:

HPS makes some notable claims for this product that I have highlighted in yellow and summarized below the screenshot.

Summary of highlighted claims:

  • “replaces 2015-2020 Volkswagen GTI 2.0T Turbo stock OEM rubber restrictive air intake hose”
  • “HPS silicone intake kit also reduces heat soak while keeping the stock well designed air box perform at high efficient level.”
  • “Besides performance gains…”
  • Improves air flow and throttle response. Delivers power gains and better driveability.”
  • “Integrates with factory fresh air scoop and air box to direct cool air to the engine for the best cooling effect.”
  • “Prevent or fix the bad idling and air vacuum leak issue commonly caused by cracked, damaged or collapsed OEM rubber air injection hose.”
  • “Optimizes the airflow”
  • “Excellent heat dissipation”

Claims Inquiry:

To give HPS the opportunity to address the claims made for this product I contacted them to learn how they measured the performance changes caused by the product and how much change resulted from their part.

HPS Silicone Hose Questions
HPS Silicone Hose Questions

The reply from HPA is below.

Hi Jeff,

We appreciate you reaching out regarding this product. Hopefully we can bring some light and answer them for you. 

I believe some of these questions can be answered together so I’ll do my best to address them.

On our intake tube, the interior tract of the tube is smoothened out and in doing so allows air to travel unobstructed. The factory piece has accordions built into it which at higher velocities creates a high pressure area. Air bounces on the high spots of the accordions, like skipping rocks. By allowing air to have a more direct path between the air filter and the turbocharger, spool time is improved thus throttle response and driveability are also improved. (1) (2) (3) (4)

The most obvious is that it is a direct bolt-on replacement. As we know, the factory AEM(ETHYLENE ACRYLIC ELASTOMERS) intake tube is prone to hardening and cracking over time, heat and exposure to chemicals. The factory piece has a wall thickness of maybe 1mm to 1.5mm at best whereas our silicone piece is reinforced with 3 layers of polyester webbing bringing the overall wall thickness to around 4.5mm. (6)

As for temperature, AEM plastic is only capable of withstanding 300 deg F whereas silicone is able to withstand temperatures up to 350 deg F. The construction of the tube is also a big part in regulating air temps. With 3 layers of polyester webbing between each of the 4 layers of silicone, it takes more time for heat to transfer through to the interior lining of the intake tube. (5) (7)

“The best cooling effect” is just a poorly written sentence to describe the intake tube’s ability to dissipate heat and minimize heat soak. (9)

We have done thorough power testing on our Dynapack dynamometer however we were not able to improve the overall power output of the vehicle. Thus, “delivers power gains” should not have been in the description of the product at all. When there is a power increase, we will disclose a dyno sheet to back up the claim. We will remove this claim of power increase shortly. (8)

With all this said, we did get a chance to look at your website a bit. Very impressive stuff. Love what you’re doing. If you’re interested in doing any of the testing on our intake tube, we’d be more than happy to send you one to get started.

We greatly appreciate your questions and the insight you’ve provided. Feel free to reach out if you have any other questions.

Thank you,

HPS Research and Development

Response Analysis:

For each product claim, the applicable excerpt from the HPS response will be shown followed by my assessment of how well the reply answers my questions and addresses the claims.

  1. Replaces restrictive Volkswagen part and optimizes airflow.
  2. Improves airflow
  3. Better throttle response
  4. Better driveability

On our intake tube, the interior tract of the tube is smoothened out and in doing so allows air to travel unobstructed. The factory piece has accordions built into it which at higher velocities creates a high pressure area. Air bounces on the high spots of the accordions, like skipping rocks. By allowing air to have a more direct path between the air filter and the turbocharger, spool time is improved thus throttle response and driveability are also improved. (1) (2) (3) (4)

HPS Research and Development

How was each of the attributes measured? – Not answered.

What was the amount of change measured for the attribute? – Not answered.

No evidence is provided to show that the stock accordion hose is restrictive. No evidence is provided to show that the HPS product improves airflow, throttle response, or driveability.

Dodge

This reply from HPS is an example of the point made at the start of the post. A characteristic of the product, a smooth interior wall, is hypothesized to change a measurable process. No evidence is given to demonstrate that the hypothesis was proven by the vendor to be correct.

6. Prevent or fix bad idling commonly caused by damaged Volkswagen part.

The most obvious is that it is a direct bolt-on replacement. As we know, the factory AEM(ETHYLENE ACRYLIC ELASTOMERS) intake tube is prone to hardening and cracking over time, heat and exposure to chemicals. The factory piece has a wall thickness of maybe 1mm to 1.5mm at best whereas our silicone piece is reinforced with 3 layers of polyester webbing bringing the overall wall thickness to around 4.5mm. (6)

HPS Research and Development

How was each of the attributes measured? – Not answered.

What was the amount of change measured for the attribute? – Not answered.

Dodge

This claim relates to reliability. Previously I’ve made a post on the topic of reliability to detail how difficult it is to quantify reliability.

The claim also does not make sense because a leak before the turbocharger on a vehicle that operates based on speed density, and not a Mass Airflow Sensor, will not suffer from “bad idling” from a vacuum leak before the turbocharger.

HPS again refers to characteristics of the product and hypothesizes that these characteristics will produce a process change and provides no evidence to prove the hypothesis is correct.

  • 5. Reduces heat soak
  • 7. Excellent heat dissipation

As for temperature, AEM plastic is only capable of withstanding 300 deg F whereas silicone is able to withstand temperatures up to 350 deg F. The construction of the tube is also a big part in regulating air temps. With 3 layers of polyester webbing between each of the 4 layers of silicone, it takes more time for heat to transfer through to the interior lining of the intake tube. (5) (7)

HPS Research and Development

How was each of the attributes measured? – Not answered.

What was the amount of change measured for the attribute? – Not answered.

Dodge

You probably now realize why I said the post theme is stating the characteristics of a product as the reason for a process change. HPS theorizes that because their part is silicone and thicker it takes longer for heat to transfer to the interior. Notably, this doesn’t mean it would reduce heat soak or improve heat dissipation.

9. The best cooling effect.

“The best cooling effect” is just a poorly written sentence to describe the intake tube’s ability to dissipate heat and minimize heat soak. (9)

HPS Research and Development

How was each of the attributes measured? – Not answered.

What was the amount of change measured for the attribute? – Not answered.

This is another way to state the other unsubstantiated claims.

8. Delivers power gains

We have done thorough power testing on our Dynapack dynamometer however we were not able to improve the overall power output of the vehicle. Thus, “delivers power gains” should not have been in the description of the product at all. When there is a power increase, we will disclose a dyno sheet to back up the claim. We will remove this claim of power increase shortly. (8)

HPS Research and Development

This exchange with HPS took place in May 2022. At the time of publishing this post, the claim of power gains from the intake hose is still on the HPS product description page.

Conclusions:

HPS makes multiple performance claims for the silicone intake kit for the Mk7. None of the claims are substantiated on the product description page. Communication with HPS for substantiation of the product claims was unsuccessful in generating the missing evidence.

HPS claims for the intake tube illustrate a common problem with performance products. Characteristics of the part are hypothesized to produce measurable performance changes without going through the process of verifying whether the hypothesis is true or not.

References:

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