DCT and High boost

I decided to make this post to keep DCT owners informed on what I have learned about running high boost on a DCT car. I currently own a 335is with Stage 2 +20T turbos, port injection, inlets, and supporting mods.

Here is what I have found out so far: MHD currently has issues once you raise the boost ceiling on an INAOS map. This puts a cap on your boost level at 21 PSI. Below are data logs of my car with the stock boost ceiling increased. You can see my trans struggles to shift due to the issue with MHD. It even causes the car to lose boost on some shifts. This is not a mechanical slip and is directly being caused by MHD.
http://datazap.me/u/artsoasis/bqe70-...og=0&data=4-23
http://datazap.me/u/artsoasis/bqe70-...og=0&data=4-21
http://datazap.me/u/artsoasis/inaos-...og=0&data=4-24

Martial is working on a fix, but no word on a release date. My trans has yet to slip at 535 whp level when I was using cobb. I'll keep pushing until I notice any slipping and dyno to get an estimate of what power level causes the stock trans to slip. I will wait a few more weeks, but I will go the JB4 route around mid February. Hopefully Terry can square me away.


The only car I have seen running high boost with DCT is a euro 335i that has upgraded clutches, turbos and uses JB4+BEF. His car uses a custom tuned Trebila BEF and JB4. I think he is able to get away without any issues because it's using the stock boost ceiling and having JB4 control boost.

Please post your experiences using DCT and high boost. I get the feeling the high HP cars with DCT will soon hold all of the 1/4 records.

you mean this:

http://www.60-130.com/images/importe...nShot250-1.png


http://www.60-130.com/images/importe...nShot252-1.png

pure stage 2 turbos / TFT inlets, Dodson clutch pack.

calculated torque (green curve) around 700 ft.lbs
still room for more boost (pwm around 60% at 24 psi), fueling is not an issue (PI integrated with JB4), bank 1 and bank 2 trims are matching.

Quote:

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Originally Posted by trebila

you mean this:

http://www.benzboost.com/images/impo...nShot250-1.png


http://www.benzboost.com/images/impo...nShot252-1.png

pure stage 2 turbos / TFT inlets, Dodson clutch pack.

calculated torque (green curve) around 700 ft.lbs
still room for more boost (pwm around 60% at 24 psi), fueling is not an issue (PI integrated with JB4), bank 1 and bank 2 trims are matching.

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If this is me, I'm actually RB turbos :)

Sorry, my mistake ;)

Quote:

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Originally Posted by trebila

Sorry, my mistake ;)

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no worries! It is indeed a beautiful graph!

http://www.60-130.com/images/importe...b2ee95_b-1.jpg

OP, are you still running the Stock TMAP? Also, two of those logs look to me that you're overshooting boost target which is causing some massive throttle closures, that last log seems to be the worst of the 3 so the closures may be why its losing boost, because one happened near a shift it looked like.

there some timing pulls on cylinder 4 and 5 of 5-6 degrees as well on the 1st and second logs. could probably cause torque drops as well.

Those logs have more issues than INA0S

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Originally Posted by V8Bait

Those logs have more issues than INA0S

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Lol #dead

Sorry OP I presume you're self tuning? You need to dial in your WGDC and PID a lot here as boost and wgdc have major fluctuations, something is very poorly matched. I suggest dropping things down until you are under target but stable, and then raising things back up. For more than 20psi on the dct you'll need a N20 sensor and to scale it, or use a JB4, either is fine but if you go flash only you'll need some TLC on the torque calculations and make sure you don't target (or exceed) 200 load for now. Didn't even bother looking at the rest of the log.

Haha and i guess I should clarify I like INA0S its only problem is people who make poor choices in autotragic transmissions :nutkick:

This was tuned by Buraq. I have an N20 TMAP. These logs where to show the post shift issue using INAOS. All of the tuning issues listed have been fixed, but I had to use stock boost control to avoid issues.

Can you show a graph with some shifts?

I ran into the increased ceiling issue on DCT with MHD long ago trying IJE0S_IS, which already has a higher ceiling. Same issue on INA0S_IS when the increased ceiling was released.

Maxboost or the scaling in MHD allow up to 27psi on INA0S with flash only or JB4+BEF, as mentioned. There are options other than just changing a couple bytes for ceiling in the DME. Either seek them out or be patient until it gets sorted. I thought OP was using the scaling already?

I have a JB4 and an unused Maxboost module I'd be happy to sell :)

Quote:

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Originally Posted by Artsoasis

This was tuned by Buraq. I have an N20 TMAP. These logs where to show the post shift issue using INAOS. All of the tuning issues listed have been fixed, but I had to use stock boost control to avoid issues.

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This is not true. To avoid the DCT issue, all you have to do is keep Boost Ceiling set to 1.28bar. You are then free to use the N20 TMAP, and the MHD 3-cell sensor voltage scaling. This will give you a max achievable boost of 27psi.

The race code bug w/ DCT (boost ceiling > 1.28bar) is being looked into, then DCT roms will support 36psi as well.

Quote:

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Originally Posted by RSL

I ran into the increased ceiling issue on DCT with MHD long ago trying IJE0S_IS, which already has a higher ceiling. Same issue on INA0S_IS when the increased ceiling was released.

Maxboost or the scaling in MHD allow up to 27psi on INA0S with flash only or JB4+BEF, as mentioned. There are options other than just changing a couple bytes for ceiling in the DME. Either seek them out or be patient until it gets sorted. I thought OP was using the scaling already?

I have a JB4 and an unused Maxboost module I'd be happy to sell :)

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So if you where in my shoes what would you do? Wait for MHD to find a fix or switch to JB4+BEF?

Also, I have no idea how I missed this thread, but this explains everything very well.
http://www.bimmerboost.com/showthrea...-(335is)/page2

Whether you use a JB4 to help with the tuning or not that isn't going to have any effect on your DCT operation, unless you make some big mistake in setting up the flash maps. You can set the calculated torque (to the DCT) to whatever you want in either situation. The JB4 will greatly simplify the boost control tuning though.

We've tuned plenty of single turbo DCT N54 DCT cars, hybrids, //Ms, etc. It's a good trans for dyno glory and roll racing! You need the Dodson clutch pack upgrade at anywhere from 600whp to 700whp depending on how you drive it. At 550whp it should not even be a concern.

Quote:

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Originally Posted by Artsoasis

So if you where in my shoes what would you do? Wait for MHD to find a fix or switch to JB4+BEF?

Also, I have no idea how I missed this thread, but this explains everything very well.
http://www.bimmerboost.com/showthrea...-(335is)/page2

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Since you already have it, I'd try the 3 column scaling in MHD first. You'll need to keep your loads under 200 and boost ceiling at 1.28 as mentioned. Other than that, JB4+BEF should work no problem.

Quote:

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Originally Posted by trebila

you mean this:

http://www.benzboost.com/images/impo...nShot250-1.png


http://www.benzboost.com/images/impo...nShot252-1.png

pure stage 2 turbos / TFT inlets, Dodson clutch pack.

calculated torque (green curve) around 700 ft.lbs
still room for more boost (pwm around 60% at 24 psi), fueling is not an issue (PI integrated with JB4), bank 1 and bank 2 trims are matching.

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wow. I bet that car is fast as hell!!! I just grabbed a 335is DCT. I''VE already grabbed inlets. Plan on FBO + meth and inlets+outlets to see if I can get near 500 on stock turbos.

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Originally Posted by bigdnno98

wow. I bet that car is fast as hell!!! I just grabbed a 335is DCT. I''VE already grabbed inlets. Plan on FBO + meth and inlets+outlets to see if I can get near 500 on stock turbos.

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That shouldn't be a problem. I'm at 460whp with no outlets, inlets, or meth.

Quote:

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Originally Posted by RSL

Since you already have it, I'd try the 3 column scaling in MHD first. You'll need to keep your loads under 200 and boost ceiling at 1.28 as mentioned. Other than that, JB4+BEF should work no problem.

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Is your JB4 G5? Want to sell me it? I can't find anyone who will tune my car with MHD and scaling

There are 2 methods to target >18 psi flash only with a n20 sensor
- increased boost ceiling (up to 22 psi)
- scaled TMAP voltage method (any target, even above 27)

The increased boost ceiling has been available since day 1 with MHD on i8a0s / ije0s. Support for IKM0S and INA0S has been added recently. INA0S MT cars can make use of increased boost ceiling without issue. It turns out the DCT trans request torque to be dropped while shifting when using increased boost ceiling. On IJE0S and INA0S.

The last 10 days I have explored a workaround for that but testing proved it was not the right solution. Dimitri and Ken have been waiting for the outcome of this testing. So further work is needed to undersand why, with the same map, the presence of the increased boost ciling firmware mod causes poor shifts on DCT.

In the meantime, the scaled tmap voltage method is working well and can be used on DCT cars to target more than 22 psi, while retaining the advantages of a flash only tune (among others, boost and load per gear / rpm).

Quote:

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Originally Posted by martial@mhd

The increased boost ceiling has been available since day 1 with MHD on i8a0s / ije0s. Support for IKM0S and INA0S has been added recently. INA0S MT cars can make use of increased boost ceiling without issue. It turns out the DCT trans request torque to be dropped while shifting when using increased boost ceiling. On IJE0S and INA0S.

The last 10 days I have explored a workaround for that but testing proved it was not the right solution. Dimitri and Ken have been waiting for the outcome of this testing. So further work is needed to undersand why, with the same map, the presence of the increased boost ciling firmware mod causes poor shifts on DCT.

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Is this only applicable to flash only on DCT's or also an issue for JB4/MHD?

To my knowledge the INA0S IS backends still use the stock boost ceiling so this not not apply.

Quote:

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Originally Posted by martial@mhd

There are 2 methods to target >18 psi flash only with a n20 sensor
- increased boost ceiling (up to 22 psi)
- scaled TMAP voltage method (any target, even above 27)

The increased boost ceiling has been available since day 1 with MHD on i8a0s / ije0s. Support for IKM0S and INA0S has been added recently. INA0S MT cars can make use of increased boost ceiling without issue. It turns out the DCT trans request torque to be dropped while shifting when using increased boost ceiling. On IJE0S and INA0S.

The last 10 days I have explored a workaround for that but testing proved it was not the right solution. Dimitri and Ken have been waiting for the outcome of this testing. So further work is needed to undersand why, with the same map, the presence of the increased boost ciling firmware mod causes poor shifts on DCT.

In the meantime, the scaled tmap voltage method is working well and can be used on DCT cars to target more than 22 psi, while retaining the advantages of a flash only tune (among others, boost and load per gear / rpm).

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I've played around with this myself and I'm not convinced it's the increased boost ceiling unless we're talking about two different issues.

http://datazap.me/u/mastawyrm/log-14...0-2-4-20-25-26

Ignore the first half of this log and look at the two different 4-5 shifts. If you look at the first one there is a torque lim 4 that lasts for almost half a second while on the second try it does torque lim 8 for more like a tenth. From my other experience, the number 8 mode is what normal high speed shifts feel like and the number 4 mode feels like a granny shift. This is INA0S and I do have the limit at 1.5 but this is me playing with the throttle trying to find the edge between a fast shift and slow one and the highest boost was 17psi. I had assumed this was due to the "max torque at clutch" table you have under "WIP - testing" but the logged numbers don't seem to line up with that table unless the conversion number of x/32 needs to be different. DME calculated torque in the 580s is the highest I've seen to still allow the fast no.8 shift and that table's highest number is 402. If this IS the table causing things then that would put the conversion somewhere roughly at x/19 to x/22 but there's probably something else going on here.

Well I have no intention of ditching the JB4. Is it possible to raise the boost ceiling, AKA TMAP sensor rescaling with a backend flash regardless of who tunes it?

Quote:

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Originally Posted by bigdnno98

Well I have no intention of ditching the JB4. Is it possible to raise the boost ceiling, AKA TMAP sensor rescaling with a backend flash regardless of who tunes it?

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Raising the boost ceiling in the dme and map sensor scaling are separate issues. Anybody can scale the tmap with MHD and the current XDF. But if you're running a JB4 there's no real point, and you shouldn't, since you already "scale" the boost with the piggyback however Terry wants to.