[a1reader]

Originally Posted by E92Fan

On what basis do you make those thoughts? Have you taken the turbos apart to inspect the assemblies and measured the tolerances of the rods and bushes?

I can tell you categorically that your assumptions are incorrect. The wastegate assembly is actually perfectly fine, even under heavy load and high temperatures. The problem lies with the actuator rod. In high temperatures there is distortion of the actuator rod, and this leads to the wastegate being left partially open and therefore not sealing properly. If the rod were perfectly true, the wastegate would be fine. When the rod distorts, it starts prematurely wearing the bushing away so that the aperture no longer remains circular, but in fact becomes slightly elliptical. This increase in bushing tolerance leads to excess movement of the arm, and coupled with the distortion this leads to the wastegate diaphragm going out of alignment.

The 8mm is much less prone to head-induced distortion, and so the alignment of the wastegate diaphragm remains true. FACT.

So how do I know if I have 6mm actuator rods or 8mm rods??

[E92Fan]

Originally Posted by a1reader

So how do I know if I have 6mm actuator rods or 8mm rods??

There isn't an easy way of telling. It depends on the build date of the car, although the exact changeover point isn't exactly clear! When was your car built?

[a1reader]

Originally Posted by E92Fan

There isn't an easy way of telling. It depends on the build date of the car, although the exact changeover point isn't exactly clear! When was your car built?

Week 36 2009 (beginning of September)

[Rob@RBTurbo]

E92Fan,

When you speak of the actuator rod, what specific component do you speak of?

[NFS]

Originally Posted by E92Fan

There isn't an easy way of telling. It depends on the build date of the car, although the exact changeover point isn't exactly clear! When was your car built?

I assume a Dec 09 build will have the newer ones?

[E92Fan]

Originally Posted by NFS

I assume a Dec 09 build will have the newer ones?

Yes, a December 2009 has the newer actuators already, and is much less prone to suffering from all these early turbo issues.

[E92Fan]

Originally Posted by RobBeck

E92Fan,

When you speak of the actuator rod, what specific component do you speak of?

I'm talking about the actual 6mm or 8mm shaft, or crank arm, that connects directly to the wastegate diaphragm and moves in a lateral plane through a bush to open or close the diaphragm.

See the highlighted area in the picture below (the only picture I can find at the moment that shows the arm)

[Rob@RBTurbo]

I thought that is what you were thinking. But unfortunately you are not correct. That components dimension has not changed, at least not that I have witnessed (and I have seen and measured quite a few of these). In another words if this spec was ever 6mm, I have not witnessed one.

Originally Posted by E92Fan

I'm talking about the actual 6mm or 8mm shaft that connects directly to the wastegate diaphragm and moves in a lateral plane through a bush to open or close the diaphragm.

[Rob@RBTurbo]

Wow, I was even confused after reading your description. The pictoral helped more. Even yet, still incorrect. From the beginning of time, til present, that rod has always been 6mm.

[E92Fan]

Originally Posted by RobBeck

Wow, I was even confused after reading your description. The pictoral helped more. Even yet, still incorrect. From the beginning of time, til present, that rod has always been 6mm.

Rob, I don't doubt your knowledge and expertise in turbo designs, but I can tell you categorically that the rod is now 8mm in diameter, fact. I bought the replacements myself and compared the two directly. That's also why Turbo Dynamics machined an entirely new bush to replace the previous one, the aperture of which was too small, and also worn to an elliptical shape, to accommodate the new crank arm. The change to from a 6mm to 8mm arm has been an in-production running change made by BMW, without change to the turbo part number itself. The new actuators have their own part number, which isn't listed on the graphical ETK but is available on request direct from BMW AG

[Rob@RBTurbo]

Interesting. I did too. That actuator rod (long rod that extends from the actuator body) was still 6mm.

Originally Posted by E92Fan

Rob, I don't doubt your knowledge and expertise in turbo designs, but I can tell you categorically that the rod is now 8mm in diameter, fact. I bought the replacements myself and compared the two directly. That's also why Turbo Dynamics machined an entirely new bush to replace the previous one, the aperture of which was too small, and also worn to an elliptical shape, to accommodate the new crank arm. The change to from a 6mm to 8mm arm has been an in-production running change made by BMW, without change to the turbo part number itself. The new actuators have their own part number, which isn't listed on the graphical ETK but is available on request direct from BMW AG

[E92Fan]

Originally Posted by RobBeck

Interesting. I did too. That actuator rod (long rod that extends from the actuator body) was still 6mm.

Are the rods you measured brand new off a latest-spec turbo, or did they come off an existing car? You and I are measuring the same component - same long rod that extends from the actuator body and whose movement is controlled by a crank arm.

[Rob@RBTurbo]

Ordered the latest avail maybe 3 months ago, only difference was a slightly longer unsprung spring with more tension.

Originally Posted by E92Fan

Are the rods you measured brand new off a latest-spec turbo, or did they come off an existing car? You and I are measuring the same component - same long rod that extends from the actuator body and whose movement is controlled by a crank arm.

[E92Fan]

Originally Posted by RobBeck

Ordered the latest avail maybe 3 months ago, only difference was a slightly longer unsprung spring with more tension.

Three months? That's about the time the changes were happening as retrofit kits - late October / early November. I wonder if you have the previous version... I'll get the part numbers on Monday for the latest actuators and you can compare that to what you ordered...

[Rob@RBTurbo]

Please do as I will need to order another set. I just looked at the ones I ordered again, and they certainly are not the latest. The long rod aside, an indicator to me that they are not the latest is that the end piece has a 6mm hole. I know for a fact that has been changed to 8mm (the reason for the bushing on the TD upgrade). Cool that the rod diameter increased to 8mm as well, one more thing to hopefully help these things out.

Rob

Originally Posted by E92Fan

Three months? That's about the time the changes were happening as retrofit kits - late October / early November. I wonder if you have the previous version... I'll get the part numbers on Monday for the latest actuators and you can compare that to what you ordered...

[marconi118]

How is turbo lag compared to stock?
Can the turbos achieve full boost below 2Krpm?

[hun77777]

do you by anychance know the part numbers for the 8mm rods or any other necessary part numbers? i inquired this to part dept in my local dealer and they are like "huh?"

[dxb335d]

If someone was in the market for a used 335i. What mileage car would be ''OK'' as it weree.

I know thats a vague question.

Would you steer clear of High mileage cars Tony or not?

[DrunkenMonkey]

Originally Posted by E92Fan

On what basis do you make those thoughts? Have you taken the turbos apart to inspect the assemblies and measured the tolerances of the rods and bushes?

I can tell you categorically that your assumptions are incorrect. The wastegate assembly is actually perfectly fine, even under heavy load and high temperatures. The problem lies with the actuator rod. In high temperatures there is distortion of the actuator rod, and this leads to the wastegate being left partially open and therefore not sealing properly. If the rod were perfectly true, the wastegate would be fine. When the rod distorts, it starts prematurely wearing the bushing away so that the aperture no longer remains circular, but in fact becomes slightly elliptical. This increase in bushing tolerance leads to excess movement of the arm, and coupled with the distortion this leads to the wastegate diaphragm going out of alignment.

The 8mm is much less prone to head-induced distortion, and so the alignment of the wastegate diaphragm remains true. FACT.

WOW, nice thread man.

I had the above problem with my car ( 2007 build ), High temps, you plant your foot down ... and get blimp mode. BMW replaced the rods with the 8mm ones and it has seemed to have solved it.

[dxb335d]

what is standard size?

[DrunkenMonkey]

Originally Posted by dxb335d

what is standard size?

6mm

I suspect alot of drivers dont push their cars hard enough to get the problems, so alot of the older cars may not have the newer 8mm ones retro fitted

I only got the problems when driving hard for 2 hours +

Mate from your posts Ive read, I'm betting you would fookin love the 335i, + plenty of modding for you to do

[dxb335d]

Oh yes, its either than or an M3 for my next car.