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Inside A Precision 6262 Turbocharger

The intention of these articles are to inform you, the public, about what you are purchasing to enable you to make an educated decision about where and what you are spending your money on. As you are aware there are many, many alternative products on the market and sometimes simply choosing the right product from the massive volume of options can be the most confusing part of your performance car build.

The reason for these articles are simple –

  • To educate you, the consumer, about what it is exactly that you are buying.
  • To protect you, the consumer, from the sometimes uninformed retailers who themselves may be unaware that they are selling you an inferior product for a premium price.
  • To provide a general knowledge about products and their alternatives on the market today, as well as their pros and cons.

We hope to educate both retailers as well as the public about what should be looked for in a quality product, which is not going to have a negative impact on the car builders pocket or the cars performance.

We will be addressing many different automotive components from the turbocharger, to pistons, to engine management systems, clutches and the list goes on. For this first article we strip down a Precision6262 Ball Bearing turbocharger, and provide you with an inside view into what makes this turbo tick. Please note that this is in no way an attack on the Precision product, the product is not terrible and certainly holds a place in the performance market. This Turbocharger is simply being used as an example of what can be noted from a number of branded, reputable products on the market. Let’s begin.

Some background information into this specific test turbocharger, this was a brand new turbocharger which failed due to a lubrication failure, which is no weakness of the product in any way, the cause of the failure was a result of installation error, we simply chose this to strip down as it had already failed and we were requested to do an assessment on the failure, as a result you will see the failed components as we progress through the strip down procedure.

Let’s take a look at the compressor housing, this housing uses a design based on the Garrett A/R 70 compressor housing from a GT3582R turbocharger. This design has proved to be very efficient for Garrett and for this reason it has been copied and rebranded by many turbocharger manufacturers of which Precision is but one. As Garrett did not issue any patents on this housing the copying of the design is 100% legal and should in no way effect ones decision to purchase these products. If anything it merely proves that the Garrett design is one to be proud of.

Now let’s look at the compressor wheel – this unit is a billet machined wheel and is a downscaled version of the original Garrett GT billet compressor wheel which was manufactured by Garrett for large turbo sizes for the worlds drag racing applications. There is little difference in design or technology when compared to the similar Garrett GT35R unit apart from the Precision unit being billet, in fact the two wheels show one very specific difference in the root or hub of the compressor wheel. This difference is there a specific reason, to allow for a larger blade area. This type of compressor wheel design, with narrowed hub and larger blade area offers both pros and cons, as a pro it should theoretically offer greater air flow while still maintaining the “same size inducer and exducer diameters”, as a con however, which is the most important point to make note of when using compressor wheels with this design is that  it weakens the strength of the compressor wheel at its highest stress point.

Facts show that the highest stress area on a compressor wheel is in the root itself. Here’s a picture to illustrate:-

 

Here is the Original Garrett GT35R comp wheel next to the Precision 6262 compressor wheel – notice the massive size difference in the root/hub of the two compressor wheels


 

Below is a picture of what happens to a compressor wheel in a burst situation during high speed operation. Now when you purchase a ball bearing race-intended turbocharger, you are certainly looking to run very high boost pressures in order to make the desired HP for your application – the higher the boost pressure, the faster the rotating speeds of the turbocharger - Keep in mind that Ball Bearing turbochargers are used mainly in race engines and high performance street car applications, these turbochargers rotate at very high speeds, higher than the journal bearing counterparts, the potential for similar failure is a concern with turbochargers with narrow compressor wheel hubs. This indicates merely an area where there may be potential for failure, it is advisable to assess the root diameter sizes of any turbocharger which uses variations of researched designs.

Next let’s look at the bearing housing, this specific unit uses an air cooled unit, we would however advise the use of water cooled housings wherever possible, especially for ball bearing units due to their higher operating loads and temperatures. The cooler housing helps guard against carbonisation of the lubricant and will insure the maximum life out of your turbocharger bearings.

The flange face of the bearing housing along with many other aspects of this housing resemble that of the original Garrett T04 bearing housing – here they are next to one-another for you to clearly see the similarities.

 

  1. 1.The Precision unit, as with most precision turbos, uses the exact same o-ring position and size as the original Garrett unit, allowing the unit to be serviced with Garrett components.
  2. 2.The PCD of the mounting holes in the Precision bearing housing that hold the backplate also match the dimensions of the Garrett unit.
  3. 3.The overall physical size of the Precision bearing housing is almost identical to an equivalent Garrett unit, with small cosmetic changes, this allows these units to be interchangeable with very little modification.

Next let’s look at the flange face of the two housings below – this is the oil drain of the turbocharger – note the Precision unit uses the same size and pattern as a Garrett unit.

 

Now we move further into the rotating assembly of the units, and we take a closer look at the internals of the Precision turbocharger.

Below

 

From left to right—the original Garrett thrust collar from an old design Garrett T04B/E series journal bearing turbocharger and the Precision thrust collar (Precision claim to use a different word to describe this part, whatever its word is, does not change the fact that the part is almost identical to the Garrett unit with very little differences for example the hole diameter and base plate)

We remain sceptical about Precision’s methods of using somewhat out dated Garrett journal bearing designed thrust collar with ‘modern’ ball bearing technology, ball bearing turbochargers were introduced, in part, to cope with the high thrust loads generated by high performance applications, with the ball bearing itself carrying the thrust load as well as the rotational load. Our best educated guess would be that it was a suitable solution to an otherwise expensive engineering exercise.

Let’s look at the ball bearing design that Precision have adopted for their rotating assembly, the bearing design in the Precision is very similar to the Garrett design except that it is made slightly larger and uses ‘ceramic’ balls. In fact this bearing design is almost identical to the Garrett GT45 Ball bearing cartridge used in the Nissan Truck UD440 – Garrett uses a bronze cage in their larger GT45 design, and is almost identical in dimensions to the Precision shown below.

 

The Garret Design has been flawless in operation for many years and there is little doubt as to why it has been copied by so many turbocharger manufacturers worldwide. It would be difficult to dismiss the similarities as coincidental; the assumption would be that the size differences were merely a method of overcoming copyrights and critics comments. Hey the Garrett design is generally the yardstick everyone measures against, so why wouldn’t it be copied? It’s like blaming Bridgestone for copying the tyre! Should we be concerned about the design changes made by Precision? Let’s check?

 

The above picture is the perfect illustration of the differences between the use of steel balls and ceramic balls in turbocharger applications. Where the benefits are realized are during extreme operation, or on the brink of failure – the above picture shows the Steel ball versus the failed Ceramic ball – during high thermal and thrust loading which exceed operational conditions.

Ceramics are intolerable to unstable conditions, like impact, vibration, contaminated oil and lack of lubrication conditions – the fact that Precision utilize an air cooled bearing housing as opposed to Garrett’s water cooled unit, questions its reliability.

Let’s move onto the most concerning part of this strip down, the turbine wheel. This again seems to be a direct copy of a Garrett turbine wheel. However there is an obvious difference in the thickness of the blades. A Garrett wheel has a blade thickness of 0.6mm and is made from a super-alloy known as Inconel 713LC and has a Chrome-Moly shaft electron beam welded to it.

This specific Precision shaftwheel’s blades measure 1.4mm thick and this specific component is made in China by a company called Worldturbocharger, this company is well known for manufacturing “copy” products of OEM original Garrett, KKK, IHI, Holset etc – this company uses a material called K18 for the turbine head, which is a steel derivative with a high thermal ceiling, but by no means anywhere near the same quality as the Inconel 713LC material used by Garrett, KKK or Holset, hence the thicker blades on the Precision turbine, thicker blades simply mean more weight, and for any component which relies on its ability to accelerate, weight is not great. The shaft also appears to have been friction welded onto the turbine head.

What is also interesting is that Precision and TurboneticsINC both use this component in their turbochargers, in fact the shaft in this Precision turbo still has the Turbonetics logo cast into the back of the shaftwheel which can be seen in the pictures below.

 

This picture was taken in the Chinese factory of the Turbonetics shaftwheel used in our Precision turbocharger.

As a matter of interest we measured the running face of the Garrett T04E Journal Bearing shaft wheel known as a T4 Stage2 – Garrett Part# 446905-0501 next to the Precision 6262 ball bearing shaft(Pictures below) and this is what we found.

1. The Garrett shaft face where the journal bearings run measured 10.16mm and

2. The Precision shaft measured at the same point on the shaft measured 10.18mm

 

These two shafts are within 2 hundredths of a millimeter from one another. Put simply you will be able to use this Precision shaft inside a Garrett Journal Bearing turbocharger using the Garrett journal bearings with a 360 degree thrust collar – in fact its commonly used practise to convert failed Precision turbochargers into Garrett Journal bearing units using Genuins Garrett parts so that they can be repaired, customized and upgraded.

Lastly let’s look at the oil supply to the bearing cartridge. Aside from the basic shape and the fact that it screws into the bearing housing, the functional design of this unit is again duplicated from the Garrett turbocharger unit.

Precision locator and oil restrictor on the left and the Garrett unit on the right – both perform the same function in almost identical bearing housings.

Now let’s put the design comparisons behind us and concentrate on performance. As it’s been made fairly obvious by our investigation, the Precision turbocharger is for all intents and purposes manufactured with components copied from the designs used by Garrett turbochargers. So it seems only fair that we draw performance comparisons with a competitive Garrett unit.

It has been said that the ceramic ball bearing turbocharger are better and spool up faster aswell as handle higher heat than the steel ball bearing units, this is not entirely true, since the boost response does not rely only on the ball bearing cartridge alone, it is a combination of many things – for example. The Precision turbocharger has the same physical dimensions in terms of the turbine wheel and compressor wheel outside diameters(bar the Precision turbine wheel inducer is 72mm as opposed to the Garretts 68mm)  but the turbo has tested to be laggier than the comparative Garrett unit. The reason for this is threefold –

  • The bearing cartridge from Garrett is smaller and has less rotational drag, and less weight – therefore better transient response (less lag)
  • The Garrett turbine wheel blades are lighter and thinner than the Precision, allowing it to accelerate faster and therefore once again allow for less lag
  • Lastly the turbine housing designs differ in A/R – the Garrett unit has an A/R of 0.63, and the Precision unit has an Air Ratio of 0.64, although this is very slight in terms of the number itself, the facts remain that the Garrett housing combined with the rotating assembly out-spools the Precision unit by approximately 500rpm according to tests we have conducted on numerous occasions.

When we set out to investigate comparative product for this “know what you’re buying” series we were not expecting to discover the somewhat controversial evidence that we did. We were led to believe that Precision Turbochargers manufactured their turbochargers in house, and there can be no doubt that Precision have made a mark on the performance markets. They certainly enjoy a loyal following and deserve credit for what they have achieved and will, no doubt, continue to achieve. That being said we did discover, at least for this particular turbo, that it consisted of components from many unrecognised manufacturers, and copied technologies long being used by Garrett. Yes we do have concerns about materials used and subsequent longevity, and some hesitations when it comes to performance efficiencies but in the most part the turbocharger works and those that have purchased them seem happy with their purchase. Personally I don’t believe the price is justified when compared to a genuine Garrett turbocharger, but it would certainly be an option if the alternative is a very poor quality ‘FongKong’ fake. The first rule when buying a turbocharger should always be: Buy only recognised brands from legitimate authorised dealers. If you have any doubt about a dealer’s credentials visit the websites of the turbo Manufacturers for a list of authorised distributors. We would also like to extend an invitation to submit products for evaluation and comparison should it be for personal interest or possible marketing reasons

A SHORT DOCUMENT RE-ITERATING THE FACT THAT ITS COMMON KNOWLEDGE THAT PRECISION TURBOCHARGERS USE/USED TURBONETICS TURBINE WHEELS – THIS IS PUBLICALLY AVAILABLE ONLINE AT THE FOLLOWING URL – PLEASE NOTE THE BELOW INFORMATION IS AN EXCERPT FROM THIS URL, AND NOT THE COMPLETE DOCUMENT.

http://www.enginebasics.com/Advanced%20Engine%20Tuning/Precision%20vs%20Garrett%20vs%20Borg%20Warner.html

Precision Turbo

Precision is a company that up until recently was really just a distributor of Garrett turbo’s. They would take Garrett turbo’s and resell them, mainly focusing on the aftermarket scene. Then they started to modify Garrett turbo’s and openly advertise how their turbo’s were out performing standard Garrett turbo’s. As you can guess Garrett wasn’t happy about that. You would have to assume Precision as a company knew what they were doing. We have all heard the saying: “you shouldn’t crap where you sleep”. Garrett then cut off precision as a supplier.

Precision then moves on to make there own CHRA center housings and continues to supply their own wheels and housings. Enter the DARK YEARS of precision. As one could assume with a new company there product was not very reliable. Failures were all over the place, and there is no shortage of stories on the internet about it. Once Garrett cut them off, they had to bring products to the market faster than they really should have. Also it was there first time making the inner guts of a turbocharger. I am talking about the CHRA center with its shaft, bearings, cooling channels, and seals. Because of this Precision turbo’s got a bad reputation. Also they had never designed there own turbine wheels before, just comressor wheels, so they stole/borrowed the turbonetics designed turbine wheels for the first production runs on some of there more popular turbo's.