[marconi118]

Another question Tony,
why did you switched from Evolve to DMS?

Are the prices of DMS competitive?

[marconi118]

and last but not least Tony,

If you can ask DMS to remove the boost compensation with temperature so that boost is always at maximum possible of the turbos...
Stock DME reduces boost at low temperature to mantain boost constant, if you remove it you will get some extra torque in cold weather or in the future if you use methanol that gives extremely low IAT

I tink this could be possible, it should be a table in the code somewhere...

[E92Fan]

Originally Posted by marconi118

Another question Tony,
why did you switched from Evolve to DMS?

Are the prices of DMS competitive?

I never had an Evolve map - always was with DMS

[E92Fan]

Originally Posted by marconi118

and last but not least Tony,

If you can ask DMS to remove the boost compensation with temperature so that boost is always at maximum possible of the turbos...
Stock DME reduces boost at low temperature to mantain boost constant, if you remove it you will get some extra torque in cold weather or in the future if you use methanol that gives extremely low IAT

I tink this could be possible, it should be a table in the code somewhere...

It might be possible to reprogram the boost table in relation to temperature, but I am unlikely to do this to my own car. I will ask DMS if it is possible so that you meth guys can run max boost. I personally am not going down the meth route as goal is not actually going for all out power.

[SiKkBaSs]

Originally Posted by E92Fan

I personally am not going down the meth route as goal is not actually going for all out power.

Why that would be ludicrous, it would save you those couple of milliseconds down at the pod

[Rob@RBTurbo]

From my observations the Wastegate Arm Shaft (Rod, Axle) is wearing abnormally too. That may not have been the case with yours, but its something I've seen. The shaft definitely is a much harder material, but that's not helping it entirely. Tightening up the bushing tolerance is definitely a good start though. As for the Wastegate Flapper (Valve, Seat), there is some wear there as well. This is from a misaligned Wastegate Arm that causes the Flapper to not evenly seal against the Turbine housing, and in turn places alot of stress and wear on a given area. Over time, that can cause abnormal wear on that area which damages the turbine housing. Again, you may have caught yours early enough and the wear could've been unnoteworthy... but that will not be the case all of the time.

Just wanted to toss in my $.02.

Thanks,
Rob

Originally Posted by E92Fan

The problem with the wastegate wear is not the rod itself, it's the bush that the rod goes through. With the heat cycling and soaking that is in the turbo, that bush starts to deform and wear quickly, allowing the wastegate rod to travel sideways and thus getting worn and stuck. If the bush is redesigned and the wastegate crank modified to suit, then the longevity will be much much greater. There is no problem with the wastegate seat diaphragm itself - all it is is the wear of the bush as the pictures of my turbo show.

Turbo Dynamics have addressed this issue by remanufacturing the crank bush with a completely new insert.

[E92Fan]

Originally Posted by RobBeck

From my observations the Wastegate Arm Shaft (Rod, Axle) is wearing abnormally too. That may not have been the case with yours, but its something I've seen. The shaft definitely is a much harder material, but that's not helping it entirely. Tightening up the bushing tolerance is definitely a good start though. As for the Wastegate Flapper (Valve, Seat), there is some wear there as well. This is from a misaligned Wastegate Arm that causes the Flapper to not evenly seal against the Turbine housing, and in turn places alot of stress and wear on a given area. Over time, that can cause abnormal wear on that area which damages the turbine housing. Again, you may have caught yours early enough and the wear could've been unnoteworthy... but that will not be the case all of the time.

Just wanted to toss in my $.02.

Thanks,
Rob

Hi Rob

Thanks for your input. From what I gather, the wear on the wastegate arm shaft is due to the slop in the bush, and this slop has a knock-on effect to abnormal wear on the wastegate seat and valve. Making the bush tolerance that much tighter, and modifying the crank arm so that the arm travels on a plane through the bush should minimise the wear rate. Looking at the wastegate arm that came off the turbo, scoring was very much evident and this was aligned to the play in the bush.

I took a belt&braces approach and sent down a complete new set of wastegates (8mm variant, from BMW) so that they had new components from which to work. Given the cost of these wastegates (insignificant in the overall scheme of things) it would have been a false economy not to have installed new components and I would suggest that anyone contemplating doing a turbo upgrade in the same fashion (ie. modifying their own turbos as opposed to buying new versions from the likes of ASR et al) should do likewise.

Rob - what's your take on the rest of the turbo workover?

[marconi118]

Tony
How did you get a set of new 8mm wastegates? normally it is all part of a new turbo by BMW?!

Again on the boost correction with IAT, BMW does this to maintain torque constant at different IATs, to make the driver feel the car consistent all over winter and summer. ECU dims boost at low IAT and raise it at higher IATs.
I think the best would be to disable this feature and let the turbos spool at the maximum boost they can safely perform independent of IAT.

This would allow people living in cold countries like us to have the same high boost in winter as in summer. Not only useful for methanol, but for bigger FMIC in winter minus temperature...

I am NOT talking to disable the ecu boost IAT decacy security that decreases boost at extremely high temperatures, this is another mechanism that should stay in place to protect engine and turbos.

Tony, even if you don't want to use this on your car, yes please ask DMS if they can do it, and ask if they can disable SES catalysator control for cat less DPs

I am really planning to go to DMS flash if they can do all this

[Rob@RBTurbo]

Regarding this whole 6mm vs. 8mm discussion. Im not sure its clear on which component is being discussed. From what I have seen, 6mm applies to the Wastegate ACTUATOR Rod... and I do not believe there has ever been a revision as even the latest Part Number has a 6mm Rod. As for the 8mm, this is the dimension of the Wastegate ARM Shaft (Rod/Axle)... and I do not believe there has ever been a revision here either. So I'm not real clear on what you all are talking about here.

I have already dissected and compared the new Wastegate actuator vs. the old Wastegate actuator on N54 Tech months ago. The only difference between them is a slightly longer/stiffer spring. It appears to be a bandaid approach to fixing a rattling Wastegate Arm in the bushing. This likely will not work most of the time but it was probably worth the try to save costs

As for your turbo upgrade, it appears to be very high quality work. As for how it works and longetivity, I am not sure... let time sort that out.

But if you want my $.02, I'd just have to say that I'm not a big fan of the stock Turbine wheel. The shaft, journal bearings, and Center Section are also very small and I'm not convinced they will fair well with a bigger compressor wheel over time.

On top of that the turbine wheel is just very small/restrictive and is a bottleneck in the N54s ability to move air. You can stuff a big compressor wheel in and ideally make more boost but all it is doing is pushing more air into the same restrictive turbine.

Think about it like this. Take a funnel with a very small end and try to fill a 1 gallon container with water. Its going to take some time as the volume of fluid flow is limited by the small end. Now take the exact same funnel but with a bigger end and fill the same 1 gallon container. This is going to move much more water because the bottleneck is much less. THIS is the exact same principle that Turbochargers work in, but with air.. and we all know that the ability to move more air equals more power. So in the case of your turbochargers, what has been done is you've taken the exact funnel with the very small end and opened up the ENTRY (which wasn't really the problem). There is abit more to it than that as this is a very condensed explanation of theory, but this is the principle in a nutshell. I'd be surprised if a compressor only upgrade makes significantly more power than with the OE Compressors... as I think the 10T Compressor is sized appropriately for the Tiny TD03L Turbine.

Also keep in mind pushing more and more boost into a restrictive turbine just ends up with some exponential higher and higher preturbine exhaust pressures, which creates a big imbalance in Engine Intake pressures vs. Engine exhaust pressures. The much higher pressure on the exhaust can cause reversion, or the backwards flow of gasses. This ultimately leads to poor evacuation of exhaust from the cylinder, which contaminates the Air charge and combustion process. This contaminated cylinder charge in turn needs more and more fuel (or upgraded fuel/meth) to quel knock/detonation, something else we don't want as we have fuel system limitations already and knock can easily bust piston ring lands. You want to therefore keep preturbine exhaust pressures as low as possible to prevent this from happening... and the only way to do that is to open of the funnel end.

Yes swapping out the Turbine wheel/shaft is big hassle and increases R&D and costs dramatically, but IMHO it's going to be the only way to make significantly more power. ASR/RD have the only upgrade that is proven thus far to function and have a modified turbine, so I'd stand by their product for now.

Hope this helps.

Thanks,
Rob

[marconi118]

Rob, do you still have your conversion underway? is it ASR/RD lyke?

As for the 6mm/8mm my understanding was that the wastegate axle was upgraded from 6mm to 8mm in last turbo revision. Did BMW modified something else?

For the actuators is it 4mm or 6mm? of course not 8mm it is too big for an actuator rod.

[Alpina_B3_Lux]

@RobBeck: Thanks for your input, this contributes a lot to this discussion. Very interesting - keep the info coming!

@marconi118: As far as I know the deactivation of the SES control should be no problem for DMS, Tony should already have that on board anyway.

Originally Posted by marconi118

Tony
Tony, even if you don't want to use this on your car, yes please ask DMS if they can do it, and ask if they can disable SES catalysator control for cat less DPs

[E92Fan]

Originally Posted by RobBeck

Regarding this whole 6mm vs. 8mm discussion. Im not sure its clear on which component is being discussed. From what I have seen, 6mm applies to the Wastegate ACTUATOR Rod... and I do not believe there has ever been a revision as even the latest Part Number has a 6mm Rod. As for the 8mm, this is the dimension of the Wastegate ARM Shaft (Rod/Axle)... and I do not believe there has ever been a revision here either. So I'm not real clear on what you all are talking about here.

I have already dissected and compared the new Wastegate actuator vs. the old Wastegate actuator on N54 Tech months ago. The only difference between them is a slightly longer/stiffer spring. It appears to be a bandaid approach to fixing a rattling Wastegate Arm in the bushing. This likely will not work most of the time but it was probably worth the try to save costs

As for your turbo upgrade, it appears to be very high quality work. As for how it works and longetivity, I am not sure... let time sort that out.

But if you want my $.02, I'd just have to say that I'm not a big fan of the stock Turbine wheel. The shaft, journal bearings, and Center Section are also very small and I'm not convinced they will fair well with a bigger compressor wheel over time.

On top of that the turbine wheel is just very small/restrictive and is a bottleneck in the N54s ability to move air. You can stuff a big compressor wheel in and ideally make more boost but all it is doing is pushing more air into the same restrictive turbine.

Think about it like this. Take a funnel with a very small end and try to fill a 1 gallon container with water. Its going to take some time as the volume of fluid flow is limited by the small end. Now take the exact same funnel but with a bigger end and fill the same 1 gallon container. This is going to move much more water because the bottleneck is much less. THIS is the exact same principle that Turbochargers work in, but with air.. and we all know that the ability to move more air equals more power. So in the case of your turbochargers, what has been done is you've taken the exact funnel with the very small end and opened up the ENTRY (which wasn't really the problem). There is abit more to it than that as this is a very condensed explanation of theory, but this is the principle in a nutshell. I'd be surprised if a compressor only upgrade makes significantly more power than with the OE Compressors... as I think the 10T Compressor is sized appropriately for the Tiny TD03L Turbine.

Also keep in mind pushing more and more boost into a restrictive turbine just ends up with some exponential higher and higher preturbine exhaust pressures, which creates a big imbalance in Engine Intake pressures vs. Engine exhaust pressures. The much higher pressure on the exhaust can cause reversion, or the backwards flow of gasses. This ultimately leads to poor evacuation of exhaust from the cylinder, which contaminates the Air charge and combustion process. This contaminated cylinder charge in turn needs more and more fuel (or upgraded fuel/meth) to quel knock/detonation, something else we don't want as we have fuel system limitations already and knock can easily bust piston ring lands. You want to therefore keep preturbine exhaust pressures as low as possible to prevent this from happening... and the only way to do that is to open of the funnel end.

Yes swapping out the Turbine wheel/shaft is big hassle and increases R&D and costs dramatically, but IMHO it's going to be the only way to make significantly more power. ASR/RD have the only upgrade that is proven thus far to function and have a modified turbine, so I'd stand by their product for now.

Hope this helps.

Thanks,
Rob

Thanks for your input. I can see the point you're making about volume of air going through the turbo and the restriction of the exit side. However I believe that Turbo Dynamics have modified the exhaust turbine wheel to increase the speed of expellation, or flow rate, and this should mitigate the apparent restriction of the exhaust turbine size.

Also, do you not have a concern that the ASR/RD turbos will suffer from heat soak issues given the CHRAs aren't water-cooled? ASR state that the new Garrett cores are so robust that they don't require water-cooling, yet when you look at the Garrett website which lists all the available CHRAs, the vast majority are all water-cooled (especially in the GT28 and GT35 ranges)

[Rob@RBTurbo]

Clipping will help out somewhat, but the overall bore and diffuser area will still remain untouched and the wheel will still be a significant restriction. The biggest reason I can see to clip the Turbine wheel in this application is not so much for the marginal airflow increase, but more for protection against compressor surge. Every compressor wheel has a flow map (or flow chart) where you can see a line on the far left side, called the surge line. The map is a measurement of wheel performance documenting its ability to produce Pressure vs. Airflow, and bigger wheels generally react very poorly to High pressures vs. low engine airflow. The clipping of the TD03L Turbine wheel on your turbos is thus doing two things to aid with this:

1) Slightly increasing airflow per a given pressure level, mostly at higher airflow levels.
2) Slowing down the turbines response to exhaust heat and pressure so that it will not as easily make the compressor produce intake pressure (ie. laggier response) and thus keeping the compressor to the right of the surge line (ideally). Some wheels have a more friendly surge line than others, and this is where wheel choice becomes of importance.

The TD03L Turbine also appears to have been designed with a form of clipping as part of its original design from MHI, and I believe there was likely alot of research into the blade design to make it perform optimally (alot more physics than I am qualified to speak about). Overall when you start modifying a wheels construction, it really comes down to some trial and error. In some instances, you just find that you can only mismatch a compressor vs. turbine SOO much and there comes a point where you need to keep them sized appropriately for one another. My gut tells me that the OE compressor is sized very well for the OE turbine, and going bigger is only pushing the envelope. However my gut instinct only means so much whereas real world testing means so much more, so I will stay tuned to see what you come up with out of these.

As for the ASR/RD Turbos not being water cooled, I dont know what to say as to why they both chose that path when all Water Cooling functionality is in place on this platform and Garrett readily offers Water Cooled CHRA's that would appear to work (aside for simplicity of adaptation/cost reduction).

I do know that ball bearing turbos use only a little oil for lubrication, so don't count on much cooling from the Oil either. This leaves you solely with the air cooling, but considering the environement our turbos are in I think the coolant flow would be very advantageous (or at minimum ALOT of Oil flow). These turbochargers are really crammed in a tight location with the direct presence of both Turbine housings, exhaust manifolds, very close engine block, and Both downpipes' Radiant heat 24/7... which surely doesnt help those casting "fins" to do much to expel the heat. If I went the ASR/RD Turbo route (just my personal thoughts) I would at least wrap the Downpipes as much as possible to help with radiant heat.

Please note I am far from a Garrett Turbo Engineer, but I'd think the only way to know precisely how well they would perform long term is to know the facts on the CHRA's ability to fight off heat vs. Ambient Temps. Surely Garrett has some documentation on ideal ambient and operating temp ranges that these CHRAs could be subjected to and still perform as intended, but I am not privy to it nor have I measured the temps in that region of the compartment to compare.

Rob

Originally Posted by E92Fan

Thanks for your input. I can see the point you're making about volume of air going through the turbo and the restriction of the exit side. However I believe that Turbo Dynamics have modified the exhaust turbine wheel to increase the speed of expellation, or flow rate, and this should mitigate the apparent restriction of the exhaust turbine size.

Also, do you not have a concern that the ASR/RD turbos will suffer from heat soak issues given the CHRAs aren't water-cooled? ASR state that the new Garrett cores are so robust that they don't require water-cooling, yet when you look at the Garrett website which lists all the available CHRAs, the vast majority are all water-cooled (especially in the GT28 and GT35 ranges)

[MarkE92]

Good luck at DMS today, can't wait to read the results.

Best regards,

Mark

[E90Yaz]

no updates today then

[MarkE92]

No updates ....... hope everything stayed in one piece !!!!

[Alpina_B3_Lux]

Originally Posted by MarkE92

No updates ....... hope everything stayed in one piece !!!!

Good things come to those who wait - I'm sure Tone will give us all the info we need when he's put it all together as he usually does.

If you're bored in the meantime, read this - that should occupy some of your time... http://www.e90post.com/forums/showthread.php?t=322185

Alpina_B3_Lux

[E92Fan]

No proper updates yet unfortunately. Have had some setup issues with the pre-load on the actuators - I think our pressure gauge was a little bit 'out' () so we've got another one coming to get it right.

I have been driving the car a little bit and first impressions is that it is a beast, even in pre-tuned form. The midrange pull is astonishing, and far far far far better than the standard turbos. No discernible increase in lag either at the moment. That's all I'm saying for now, until everything else gets sorted...

As Marcel says, good things come to those who wait... so patience people, patience...!!!

[MarkE92]

Thanks for the link in the mean time Marcel..... good guideline when I decide to keep the 335 and start on the engine

[marconi118]

Really hope that no news = good news

[MarkE92]

Let's hope all goes well he doesn't want to embares us all with his results....

[E92Fan]

Originally Posted by MarkE92

Let's hope all goes well he doesn't want to embares us all with his results....

Why would I worry about embarrassing you ?!

I'm not posting anything about the upgrade until I've done a few hundred miles of solid testing to iron out any possible issues (so far there are none)... won't take me long don't worry.