Cheap Knock Off Turbos

Cheap is expensive,” the old adage goes. Paying less in the short run ends up costing you when the cheap product underperforms or breaks. This applies more to turbos than just about any other automotive part.

In our decades of experience in the turbocharger industry we have seen quite a bit of knock-off product and learned one lesson above all others: NEVER BUY A CHEAP CHINESE-ASSEMBLED KNOCKOFF AFTERMARKET TURBOCHARGER.

Overseas factories can be useful in the procurement of component parts, but we have found this is only true when tight controls are placed on the foundry casting the part and the machinist who finishes them. An experienced sourcing company can usually control these factors but when a turbo arrives assembled from overseas, especially China, it’s a Pandora’s box of potential problems and often a time-bomb waiting for one of it’s many production short-comings to detonate.

Unfortunately many online distributors of turbochargers, even US companies, and of course on Ebay, are selling these sub-par products with reckless abandon, offering “12 month replacement warranties” and “NO CORE CHARGE” which they can afford because the turbos often cost them less than $200 a piece. And they don’t need your cores because they don’t and/or can’t rebuild it, they just sell pre-assembled turbos they import often times without even looking in the box before they ship.

Below we will illustrate why these products cannot be trusted, from our personal experience

Backing plates

Our first exhibit is our most recent. A shop we know thought they could trust such an innocuous part as a backing plate from China purchased a small batch from a more reputable Chinese manufacturer than most and installed them on a handful of units. Within short order five quickly failed. Reason? Poor quality aluminum casting, too many air pockets in the casting, the part lacked the strength of the OE part of the same specification and broke. One of these units broke in transit and arrived to the customer in two pieces! Even though the samples looked good and the spec was right, the devil was in the details only an xray could have discovered the flaw. This Chinese vendor, who is a vendor of many American companies with their own “in-house line of turbos,” is never going to supply Turbo Concepts.

Turbine Housings

This is what it looks like when brand new turbine housings are melted down. Why? Because we caught the factory trying to get away with using a cheap iron alloy when we ordered the part in a good one. An insufficient alloy will cause the housing to crack and/or warp within a short period of operation. Even if the turbo doesn’t fail it will perform steadily worse as the iron deforms. EVERY SINGLE TURBO assembled in China uses a dirt cheap variation of grey iron, low silicon ductile iron that’s barely qualifies as “ductile.” If it’s driven like a grandma and the car never overheats there’s a chance it’ll do fine.

But it’s not just housing alloy that’ll determine life or death of the turbine housing, equally important is the actuator flapper mechanism. See pictures of a flapper that didn’t survive our test runs. Most flappers parts coming out of aftermarket turbo factories overseas use a form of ductile iron and the best use a basic stainless alloy, when a higher grade stainless alloy is used by the OE manufacturers and recommended for this application. If your flapper breaks your car will lose power as the turbo can’t pressure properly, and then you get to fish out the broken flapper bits from your catalytic convertor. Just another inconvenience you can expect by using a cheap knock-off turbo.

Most cheap knock-off compressors will look like the right on the back side (the side you can’t see unless you take the turbo apart). This wheel will cause a wobble during high spool and slowly erode the bearings and bearing bore. Another common cheap compressor problem is what we call “chipping,” where a section of the wheel between the balancing divot and the edge breaks off during operation and ends up somewhere in the intercooler. This is due to poor quality casting with impurities or air pockets which creates a small section of weakness that gives way over time.

Both of these problems might not result in turbo failure right away. They usually happen down the road, weeks or months after you’ve left your positive feedback on Ebay.

Compressor Covers

When cheap aftermarket covers are used instead of re-conditioned OE housings, the buyer of the turbo is suspect to a couple insidious flaws.

First, without cutting the cover you don’t know whether internal air passage volutes match original spec and will move air as they should. See pic to left, we tried buying some large cover castings from a more reputable Chinese manufacturer and look at the difference between its volute and that of the OE.

Second issue common to knock-off covers are excessive air pocket in the casting. If a big enough pocket occurs in the area where the cover seals to the bearing housing, a pressure leak will occur causing the turbo to underperform.

Neither of these problems will destroy the turbo, but something that will erode the soul of your engine as the turbo underpressurizes the combustion chamber and saps the engine’s power.

Actuators

Here’s another area where one might think Chinese knock-off product would be fine. Uh uh. Here are a few things we’ve seen go wrong with seemingly-fine discount actuators.

First, on the right. After evaluating this sample we discovered that though the pressure was correct on opening the rod throw was shorter than it should have been. So we took apart to can to inspect the spring and found THIS. Rather than using the correct spring, then threw whatever spring in there and tightened the pressure using washers!!!! Not only adding weight in an place not designed for it but this would impede the proper operation of the wastegate potentially causing the turbo to overboost and in the long term destroy the turbo and possibly the engine.

Below we see the nipple broken off due to inadequate affixing. These were samples we evaluated. Of course the factory said they would fix it but then they would just try to cut some other corner when they think we’re not looking. Vender not approved! We use re-conditioned OE actuators or make our own from scratch with verified OE suppliers. 

Turbine Shafts

This was “handed to us” literally. This turbine came out of a knock-off ebay turbo that was sent to our shop to rebuild. The shaft had a pit in the surface large enough for a fine tip pen to detect. This was caused by an impurity in the steel and shouldn’t have passed QC, but the knockoff factory workers didn’t see it or didn’t care so it ended up and a turbo sold in the US. This divot destroyed the bearing causing failure shortly after operation.

There is a dozen ways a sub-par turbine could end a turbo’s life. From rough shaft surface galling the bearings, to incorrect spec on the piston ring groove causing oscillation, to bad turbine head alloy that will stretch during operation and bang on the housing, to incorrect shaft OD not leaving enough space for oil. You name it, in our years of experience we’ve seen it. We protect our customers this kind of trash by either using reconditioned good-as-new OE product or that from a bona fide genuine OE manufacturer.

Rebuild kits

Every knock-off turbo uses a knock-off build kit, these are the critical parts that hold the turbo together and perform essential functions like heat containment, oil dispersal, and hold the rotating assembly in position during operation. Some of these parts have tolerances down to two 10,000th of an inch, that’s .0002”!

In the following section we will list some of the problems we’ve seen with each part from knock-off kits and how it could deep six a brand new turbo, a standard Mitsubishi kit will be used to illustrate (left).

A) Thrust bearing:
Poor ID surface where the shaft rides, can gall the shaft, disturb oil flow and destroy turbo.
Poor quality material, erodes over time in operation and ruins balance of turbo and residue infects oil flow areas, destroys turbo.
Incorrect location of oil ports, if too close to edge will break over time, destroy turbo.
Improper oil dispersion divots next to shaft hole, won’t properly lubricate the collars and destroy turbo.
One time we got a sample without the check ball in the outlet hole!!!

B) Journal bearings:
Incorrect OD, not enough space for oil to flow, failure due to lack of lubrication.
Incorrect ID, too tight or lose for shaft, cause wobble will which destroy internals, cause failure.
Poor ID finish, gall shaft, cause failure.
We’ve even seen journal bearings with “hanging chads” from the holes where someone forgot to clean them after drilling!!!

C) Piston rings:
Very hard to get right, ultra critical that width perfectly mates with bearing housing so shaft is held in place during operation. Can cause wobble and destroy internals causing failure.
We have even seen piston ring samples not made of spring steel!!! So when compressed they stay compressed instead of extract to hold in place.

D) O-rings: Often time the thicknesses are incorrect causing the turbo not to seal properly, impairing its performance.

E) Seal plate:
This part usually is not machined to OE spec but is fairly uncritical so long as the oil deflect mates up properly, which it often doesn’t.

F) Oil deflector:
Usually doesn’t mate up perfect with it’s seal plate, causing damaging vibrations in the center housing.
Knock-offs are rarely coated like the OE so the oil will not flow as good around it.
Most worrisome is that the defector is rarely bent correctly, which will cause the oil not to flow as it was designed.

G) Thrust collars/spacers:
These highly critical parts are rarely made with the correct right steel with the heat treatment.
We have seen collars with insufficient finish gall the thrust bearing and cause failure numerous times.

H) Turbine clamp:
Rarely made of OE spec stainless steel, instead using basic grey iron steel, have been known to break over time.

I) Snap rings:
Very hard to get tapering correct, won’t hold turbo together as well as OE. Mostly an issue with performance models.
And again, have seen samples from China not in spring steel!!!

J) Heat shield:
We have seen many knock-off samples made of basic steel instead of stainless with vastly inferior performance properties. Plain steel will allow more heat to soak through and damage the back side of turbine wheel causing premature failure.

Bearing housing

We saved the best for last. This is the hardest part to make correctly and is the most common cause of knock-off failure. See blurred image of a bearing housing we developed with an OE manufacturer below. While you cannot see the specs, because that’s our property, you can see the immense volume of critical specs, many as tight as .0002”. If any one of these are out of tolerance failure, either short-, medium-, or long-term is inevitable. Even local suppliers are not 100% reliable, so we mic out and “feel test” every part of the housing. At the end of the day only a highly-experienced assembler can protect you from an inferior bearing housing, and our assembly team’s combined 50 years of experience is your best safeguard against such problems.

Below is an example of a common problem we see with samples we’ve received, often unsolicited, from knock-off manufacturers. See the difference in the decking where the thrust bearing sits? This flaw will prevent the thrust collar from sitting flat and will interfere with the lubrication of the thrust bearing, causing eventual failure.

In summary

See sign on the wall in a knock-off factory we visited in China below, translated:

Basically says our quality goal is 90% non-failure rate.

Would you trust your car to a factory who aspires to someday achieving the goal of only 1/10 of their turbos failing on startup? It’s inevitable that turbos will fail due to improper installation, but the turbo itself should be above reproach. Years ago we purchased a lot of turbos from a factory far better than the one pictured below and experienced 33% failure rate, from that day forward we vowed to never buy turbos assembled by knock-off factories and thoroughly vet any component part manufacturer and closely examine every part going into our rebuilds.

That is why reputable auto parts stores and dealerships trust our turbos, and why you should too.