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Unabomber's Manifesto - Turbo Inlet FAQ

Time:2018-02-13 08:12Turbochargers information Click:

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The primary purpose of an aftermarket turbo inlet is to replace the OEM turbo inlet with a better flowing unit. It also increases the diameter for better flow and increases reliability.

HP gain is 5 to 10 HP. This figure is highly debated as different manufacturers use different dynos with different cars with different levels of mods. This figure is pretty subjective as well as not many people have performed before and after comparisons and this figure is based on correspondance with a few manufacturers.

When first introduced, these were one of the first mods for Subarus. Hence they were very popular, but little was known about power gains as they were a plug and play mod with no drawbacks. While they didn't gain much in terms of power, since few power adders were available, they became popular as a power adder even though there wasn't much bang for buck with them. After several years, they are even more popular not due to power but reliability. The OEM turbo inlet tube is made of some really bad plastic and due to age or constant removal for turbo swaps, tears very easily. Now this is seen as a fix or reliability mod more than anything.

Which manufacturer is best? This topic is highly debated and there is no real winner.

But what about collapsing inlets? There have been turbo inlets that have been reported as collapsing. This is due to weak body structure and under runs on the dyno, the silicone body has collapsed. Once power is off, the body springs back into shape. Perrin, though not the lone manufacturer with this issue, stated that they have had rare reports of collapses. Their new design incoporates a wire skeleton imbedded in the silicone to prevent this. Perrin has stated that "As long as the inlet hose was purchased from an authorized dealer or directly from us and is within the warranty period we are more then happy to inspect the product and offer a replacement part or credit if necessary." Most of the other manufacturers have seen this problem though except for Samco. This does NOT mean only consider the newer Perrin or Samco as the collapsing issue is a rare one and generally only occurs with 20G and larger turbo set-ups.

So how do I fix a collapsing inlet now or later? The solution is quite simple really. Add 3 or 4 large diameter hose clamps to your inlet spaced equally along it's main thickest length. This creates an external skeleton and will prevent any collapse. While it's not the prettiest solution, you really can't see the turbo inlet that well, so it's not as bad as it sounds. Or another alternative other than buying the two brands mentioned is to get a hard pipe model such as the APS unit or one of it's clones.

So I should put hose clamps on my inlet regardless? No, not unless you really feel like it. As stated, collapsing inlets is a very rare issue.

Who manufactures turbo inlets? Perrin, APS, Vivid Racing, Samco, Gimmick Motorsports, GP Moto, eBay, AVO, BPM, and STI.

STI makes one??? JDM OEM FTW!!!! Cool your jets buddy. The STI unit is a JDM model and will run you around $800. If you spend $800 on a turbo inlet, you don't need this FAQ, you need a therapist.

What types of turbo inlets are there? There are two types: Normal and Long. Additionally, there are normal outlet sizes ones and ones with 3" outlets for larger turbos.

Normal length ones are a direct replacement for the OEM unit. They are the same length as the OEM unit though have a larger plenum section between the MAF tube and the inlet to the turbo.

Long length ones are L shaped and replace both the turbo inlet and the MAF tube with a one piece unit. In the case of the APS unit, it is a two piece L shaped unit.

What turbo inlet material is best? Turbo inlets are made from silicone and metal tubing. There is no irrefutable evidence that one material is better than the other.

Which turbo inlet has the best gains? There is no irrefutable evidence that any turbo inlet has better gains than another.

Are there any downsides to turbo inlets? None really. Other than price and sometimes install complications, it's a plug and play mod that requires no engine management and causes no CELs or other ills. If you are using a larger turbo that requires a 3" outlet version, TGV deletes become a requirement due to fitment issues with the stock TGV motors.

Where do I buy a turbo inlet? Every Subaru/Import performance store sells turbo inlets. For purchasing, support your local economy or the NASIOC Vendors.

How hard is it to install a turbo inlet? This is a hard question as there are many variables to this. This is one install where there is no standard install. You can read one story about a 2003 WRX owner did a Samco inlet and it was a cake 1 hour install and 2 weeks later someone else with the same car and inlet posts a horror story. This is due to variances in manufacturing of the inlet, if the car has TGV deletes or not (deletes generally make for an easier install), PCV locations (04 Subarus have an extra fitting on the OEM turbo inlet), car manufacturing tolerances, turbo location and type tolerances, and many other factors. Your best bet is either professional installation or have someone with you that has done this before unless you trust yourself and allow a full, calm day for this install.

In addition to the instructions below, ensure that 100% of your turbo inlet fittings and T splices have a small hose clamp or quality zip tie on the fitting connection. This will ensure there are no slips and/or vacuum leaks now or later. The main install ills with turbo inlets are vacuum leaks due to poor or forgotten connections and forgetting sensor replacement for those models that require removing the intake manifold.

How do I install a turbo inlet? Refer to the turbo inlet manufacturer's instructions. For turbo inlets without instructions, below are links to some of the better known installation instructions:
APS's Instructions
Perrin's install video
AVO instructions
Scoobymods.com instructions

Do I need engine management with a turbo inlet? No tuning or engine management is needed for this mod, just bolt it up and go. Mind you the full benefits of this or any other mod won't be seen until tuned.

Should I reset my ECU after this mod? It is never a bad idea to perform an ECU reset after a mod. The traditional route is to disconnect the negative battery terminal, press the brake pedal for a few seconds to bleed the system of charge, and reattach. Some use the more advanced Vishnu Reset.

Editors Note

This post was created because I wasn't able to find a good turbo inlet FAQ. I came up with the text based on LOTS of searching here. It was also created to be intentionally brand neutral so that it serves as a stepping stone for further research. Upon reading this you should have an idea of what type of turbo inlet best suits your needs. The manufacturer is up to you.

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