SMG II Pentosine Replacement

[poss]

I recall someone describing the SMG as like having a truculent teenager operating the clutch for you. I can understand why when I first bought the car, but things improved markedly after CSL firmware, new salmon relay, and, of course, learning to feather the accelerator during changes.

I recently did an SMG pump relocation and decided to also do the Burkhardt 'pentosine replacement'.

I must admit, my first impressions are very favourable. Gear changes are now silky smooth - except for 1 to 2 - which is not perfect but still excellent - better than I could manage with a manually operated clutch.

Anyone else tried the pentosine replacement?

[8000RPM]

Sorry no feed back but are you using Burkhardt because CHF11S isn’t readily available near you? My local Autozone carried the real stuff.

[Johnvu]

I recall someone describing the SMG as like having a truculent teenager operating the clutch for you. I can understand why when I first bought the car, but things improved markedly after CSL firmware, new salmon relay, and, of course, learning to feather the accelerator during changes.

I recently did an SMG pump relocation and decided to also do the Burkhardt 'pentosine replacement'.

I must admit, my first impressions are very favourable. Gear changes are now silky smooth - except for 1 to 2 - which is not perfect but still excellent - better than I could manage with a manually operated clutch.

Anyone else tried the pentosine replacement?

I have the burkhart fluid and it definitely reduces the pump running time. I will definitely be using this fluid from now on!

[Icecream]

I recall someone describing the SMG as like having a truculent teenager operating the clutch for you. I can understand why when I first bought the car, but things improved markedly after CSL firmware, new salmon relay, and, of course, learning to feather the accelerator during changes.

I recently did an SMG pump relocation and decided to also do the Burkhardt 'pentosine replacement'.

I must admit, my first impressions are very favourable. Gear changes are now silky smooth - except for 1 to 2 - which is not perfect but still excellent - better than I could manage with a manually operated clutch.

Anyone else tried the pentosine replacement?

I used it, seemed to need to prime less with it but that result is anecdotal, much like your silkier shifts. Being that you had to re-bleed the system, used fresh fluid and probably ran an adaptation, I would say that had more to do with it. My car shifts better than ever (minus the increased primes) and I am back on OEM fluid.
Also the salmon relay won't affect the quality of your shifts either, not sure why everyone thinks it would. It either works or doesn't. On/off, its a relay. It either lets the pump prime or it does not. It has no control over anything else.

[poss]

I used it, seemed to need to prime less with it but that result is anecdotal, much like your silkier shifts. Being that you had to re-bleed the system, used fresh fluid and probably ran an adaptation, I would say that had more to do with it. My car shifts better than ever (minus the increased primes) and I am back on OEM fluid.
Also the salmon relay won't affect the quality of your shifts either, not sure why everyone thinks it would. It either works or doesn't. On/off, its a relay. It either lets the pump prime or it does not. It has no control over anything else.

I refreshed the fluid (with pentosine) and bled the system only a few months prior, and that made no real discernible difference (unlike this time with the Burkhart fluid). Did run an adaption as well this time - so that may be the sole reason for smoother shifts. Shifting was pretty smooth anyway except for random clunkiness between 1 and 2, and to a lesser extent 2 and 3 (which increased after several hours of driving). These issues have all but vanished. The previous intermittent nature of rough shifts makes me think it is not simply the adaption at play, but I have no real evidence either way.

In any case, the overall combined results are gear changes that no reasonable person can complain about.

BTW: A relay is not a perfect binary device, as the contact points can (and do) degrade with use, which can result in increased resistance or intermittent current. I noticed a small but definite improvement in swapping my old (but still functioning) relay for a new one (fewer random hard shifts).

[Icecream]

I refreshed the fluid (with pentosine) and bled the system only a few months prior, and that made no real discernible difference (unlike this time with the Burkhart fluid). Did run an adaption as well this time - so that may be the sole reason for smoother shifts. Shifting was pretty smooth anyway except for random clunkiness between 1 and 2, and to a lesser extent 2 and 3 (which increased after several hours of driving). These issues have all but vanished. The previous intermittent nature of rough shifts makes me think it is not simply the adaption at play, but I have no real evidence either way.

In any case, the overall combined results are gear changes that no reasonable person can complain about.

BTW: A relay is not a perfect binary device, as the contact points can (and do) degrade with use, which can result in increased resistance or intermittent current. I noticed a small but definite improvement in swapping my old (but still functioning) relay for a new one (fewer random hard shifts).

Doesn't matter if the relay is degraded or not (it's still on or off). The pump will either prime to a pressure that allows a shift to occur or it won't. A shift will not be initiated unless there is sufficient pressure in the system to complete the shift as designed (also binary, it either has enough pressure for a shift or it doesn't). Only thing a bad relay will do is prevent the pump from building pressure (which means it won't even attempt a shift). In other words, if I primed the pump externally to spec, a perfect shift could be completed and the relay would have nothing to to with it. The relay does one thing and doesn't talk to any of the computers that do the actual shifting (at least none that I am aware of). The SMG computer is dumb, I'm pretty sure it runs at 1/2 mHz and .25 bytes of memory and is prone to f*cking up a shift once in a while lol. Glad your's is shifting well though!

[Rkymtnrider]

I believe, and correct me if I’m wrong, the Burkhart oil has a higher boiling point. Meaning stays thicker when it’s hotter. Right?

[oceansize]

I believe, and correct me if I’m wrong, the Burkhart oil has a higher boiling point. Meaning stays thicker when it’s hotter. Right?

I use Burkhart's SMG oil.

Burkhart's Description:

The high hydraulic Performance oil has a higher viscosity than the Pentosin CHF 11s and allows the pump to reach maximum pressure up to 25% faster. This helps with the heat problem of the SMG (e.g. error 56 - duty cycle hydraulic unit).

The new oil is miscible with pentosine. When exchanging, max. 5% residual oil should remain in the hydraulic system.

The range of application of the oil is from -20 to +130 degrees, so it can be used all year round without any problems.

[Rkymtnrider]

I use Burkhart's SMG oil.

Burkhart's Description:

The high hydraulic Performance oil has a higher viscosity than the Pentosin CHF 11s and allows the pump to reach maximum pressure up to 25% faster. This helps with the heat problem of the SMG (e.g. error 56 - duty cycle hydraulic unit).

The new oil is miscible with pentosine. When exchanging, max. 5% residual oil should remain in the hydraulic system.

The range of application of the oil is from -20 to +130 degrees, so it can be used all year round without any problems.

is there a place to get it in the states or do you have to order it from burkhart in Europe?

[oceansize]

https://www.blunttech.com/shop/replacement-parts/clutch-flywheel/1466btkt

[dredpyrt]

Blunttech Industries in Minnesota is a Burkhart dealer and they carry it.

[Rkymtnrider]

Thanks!!

[Arith2]

CHF202 was the replacement for CHF 11 if anyone has any issue finding it. The expiration date on mine was like 3 or 4 years after the manufacture date which was a bit worrying. Maybe so many SMGs fails as a result of not changing the fluid. BMW didn't suggest it should be changed but they also said transmission fluid last a lifetime. Their definition of lifetime is 5 years and 1 day because the warranty doesn't exceed 5 years

[eacmen]

CHF202 was the replacement for CHF 11 if anyone has any issue finding it. The expiration date on mine was like 3 or 4 years after the manufacture date which was a bit worrying. Maybe so many SMGs fails as a result of not changing the fluid. BMW didn't suggest it should be changed but they also said transmission fluid last a lifetime. Their definition of lifetime is 5 years and 1 day because the warranty doesn't exceed 5 years

Would you suggest extracting fluid from the reservoir and topping it off? To avoid having to bleed the system.

Or is a full flush/bleed the only way to change it?

[oceansize]

I've fully flushed mine twice without issue. If your pump and system is in good working order at present I wouldn't hesitate.

See this thread I created that describes some potential issues and resolutions on bleeding and relocation in general.